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A multi-component study of the administration and preservation of nitrate negatives Reid, William S. 1993

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A MULTI-COMPONENT STUDY OF THE ADMINISTRATION ANDPRESERVATION OF NITRATE NEGATIVESbyWilliam Scott ReidB.Sc. The University of ManitobaB.A. The University of ManitobaA THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THEREQUIREMENT FORTHE DEGREE OF MASTERS OF ARCHIVAL STUDIESinTHE FACULTY OF ARTSFACULTY OF GRADUATE STUDIES(School of Library, Archival and Information Studies)We accept this thesis as conforming to the required standardTHE UNIVERSITY OF BRITISH COLUMBIAJUNE 1991© William Scott ReidIn presenting this thesis in partial fulfilment of the requirements for an advanceddegree at the University of British Columbia, I agree that the Library shall make itfreely available for reference and study. I further agree that permission for extensivecopying of this thesis for scholarly purposes may be granted by the head of mydepartment or by his or her representatives. It is understood that copying orpublication of this thesis for financial gain shall not be allowed without my writtenpermission.(SignatureDepartment of Gx-The University of British Columbia^ S‘cv.ck:(Vancouver, CanadaDate ^DE-6 (2/88)11AbstractCellulose nitrate negatives pose serious problems of preservation andaccessibility to archival institutions, and create pressure on an archivesphysical and administrative resources. Archivists must take precautionaryactions designed to prolong the life of the images in their care until theycan be copied, and to safeguard against damage to other archival materialthat shares space with them.This thesis presents and discusses the issues surrounding themanagement of nitrate negatives in archival institutions of all sizes. Thephysical and chemical characteristics of cellulose nitrate, and its role in thehistorical development of photography introduces the specific archivalconcerns of preservation and access. A diplomatic analysis of thephotographic negative, which shows that it does not need to be retainedfor evidentiary purposes, prompts the recommendation that cellulosenitrate negatives can be copied onto stable base film and then destroyed.The need for proper long term storage facilities is however recognised, andtypes of facilities are presented.Finally, this thesis provides guidelines for the preservation ofcellulose nitrate negatives, and discusses the types of procedures presentlyin Canadian archival repositories.This thesis proposes that archivists concentrate their efforts towardsthe preservation of the information contained in the images themselves,rather than in their physical form, and thereby minimise the danger posed111by the nitrate negatives by investing in a systematic copying program andin the construction of separate storage vaults.Table of Contents^ IVUnit^ Page NumberAbstract iiList of Tables^ vList of Figures viAcknowledgement^ viiIntroduction 1Chapter I: The Nature of Cellulose^ 10NitrateChapter II: Cellulose Nitrate and the ^ 30Photographic ProcessChapter III: The Preservation and 55Administration ofNitrate Negatives withinArchival InstitutionsChapter IV: Conclusion^ 87Appendix I: The Survey 102Appendix II: CD ROM Technology^ 110and its Application tothe Storage of VisualImagesAppendix III: Brand Names of^ 119Cellulose NitrateProductsAppendix IV: Some Trade Names for^120Cellulose NitrateBibliography^ 122VList of TablesTitlePage NumberTable I: Nitrogen Content of VariousCN Materials^ 21Table II: Types of Nitrogen GasesReleased During CN^ 25DeteriorationTable III: Dates of Discontinuationfor CN Film Formats^ 44List of FiguresTitleFigure 1: Cellulose ChainFigure 2: Hydrogen BondingBetween Cellulose ChainsPage Number1617Figure 3: Cellulose Sheets in LayeredStructure^ 18Figure 4: Crystallisation of CelluloseBundles 19Figure 5: The Nitration of Cellulose20Figure 6: Cross Sections of CN andCellulose Diacetate Film^ 43Figure 7: Direct Duplicate NegativeMethod-Variation A^ 73Figure 8: Direct Duplicate NegativeMethod-Variation B^ 74Figure 9: Direct Duplicate NegativeMethod-Variation C^ 75viviiAcknowledgementFirst and foremost I would like to thank my thesis advisor, ProfessorLuciana Duranti for her patience, hard work and advice which made thisthesis a reality. I would also like to thank Betty Blight at the ProvincialArchives of Manitoba for suggesting the topic, Mike Moosberger for hissupport and Rosaleen Hill and the conservation department at PAM fortheir advice and help. Finally, my wife Karen and the rest of my familydeserve much credit for lending their support and encouragement in thisendeavour.1Introduction Prior to World War II, the amount of photographs and photographicmaterials which found its way into archival institutions was very small;consequently there was little regard for the acquisition and specialpreservation needs of images. After the War, many institutions which hadpreviously survived with scant resources were able to expand their staffand the scope of their acquisition policies, and to establish new and farreaching programs. This fervour of archival activities affected all levels inthe established local, state and federal repositories in the United States,and a large number of new programs was brought into being in local andregional historical societies, local public libraries, business firms,professional associations, social service agencies, churches, and educationalorganisations. This increase in the activity of archival repositoriescoincided with an increase in the numbers and types of materialsacquired, and among them there was a growing amount of photographs.In the United States, the Library of Congress and the NationalArchives and Records Service established separate still image collections.Yet, even as late as the 1950's photographic material was still consideredby most repositories to be of a secondary importance.' Because theprofession was relatively new to the acquisition of historical images,archivists tended to handle the disposition of photographs in a tentativemanner; furthermore, the nature of the medium was such that itsusefulness as a historical source was not easily recognised, therefore2photographs tended to accumulate passively in archival repositories asaccessional components of textual fonds. In the 1970's this situationchanged rather dramatically as the interest in photography as a source forthe documentation of society grew considerably. Archivists were nowcompelled to deal with a new demand for historical images from thehistorical as well as other research communities. This meant that therepositories could no longer allow for the passive accumulation of images;and the existing collections would now have to be properly managed andpreserved.Today, most archives acquire photographs, just like other culturalinstitutions, such as historical societies, libraries, museums, researchcentres, and private companies. Thus, archivists now find themselvesinvolved in the management of what is now known as one of the mostpowerful and self-sustaining popular media in modern society. Along withthe images of the past which have come down through the generations aspart of the historical record, archivists now have to deal with thetremendous production of images which has come about through theincrease of such popular activities as amateur photography, due to thedevelopment of technology. Over the years, the camera has becomeincreasingly simplified and easy for the non-professional to use, with theresult that the number of photographs being produced annually in NorthAmerica alone is estimated at an amazing 10 billion.'Given that archivists are now dealing with historical photographs in a3more comprehensive manner, it appears that a great deal of work stillneeds to be done. This realisation is enunciated by Leary when he writesthat,Despite the growing intellectual respectability of photographsas historical documentation, an enormous task of education andproselytising lies ahead. Very few archival institutionshave devoted more than a token of their resources to theacquisition and preservation of photographs and other visualrecords. In far too many archives, photographs are treated asan afterthought.'However, even if all still images of research value made their way into theproper repositories serious problems would have to be solved. Thepreservation component of photograph administration can at times be veryproblematic as the modern day archivist and conservator must cope with atechnological revolution which has been ongoing for over a century.Although its roots are in the late 19th century, and even though the paceof the initial developments do not come close to the speed of today'sadvances, this continuing progress still has repercussions on the way wehave to deal with the photographic medium in the modern context. Thisproblem is compounded by the labour intensive nature of the medium, andcosts which are part and parcel of the administration of photographiccollections; with these factors in mind it becomes obvious that archivistsare faced with a daunting situation indeed. They now find themselves inneed of resources and supplies which are outside the realm of themanagement of textual records: photographs, as other types of modern4media records, require very specific types of environmental conditions andconservation activities. The situation becomes more complex if oneintroduces into the equation the factor of spontaneous degradation of thevisual image with which archivists are faced when they are involved in thepreservation and administration of large numbers of cellulose nitratenegatives.Cellulose nitrate film is proving to be a serious challenge forarchivists and their resources. While there is little disagreement amongstprofessionals that the presence of such self-destructive materials inarchival vaults has become a problem, there still seems to be a good dealof variance in opinion on how to administer the functions of preservation,appraisal, and access in light of their physically sensitive and ephemeralnature. The actual amount of these items in archival repositories varies toa great degree, but even small quantities can be a problem for those whomust deal with them. The unstable nature of nitrate, and the risks it posesto other archival material with which it shares storage space requires thearchivist to take special precautionary actions. These actions must bedesigned to prolong the life of the image and to safeguard other archivalmaterial, not to mention the health of the people who have to work withnitrate negatives in advanced stages of disintegration.Cellulose nitrate film was first introduced in 1887 by GeorgeEastman. The composite from which this film gained its name was the firstplastic backing with sufficient clarity and strength to be used as a5photographic emulsion support. It proved to be something of abreakthrough for the time, as it was stronger than gelatin film, resistedbreakage, and laid flatter in a roll holder for a sharper picture. Its usecontinued for about sixty years: dates of discontinuation vary by format,manufacturer, and country, but the dates for the United States range from1933 for x-ray film to 1951 for motion picture film. Furthermore, itbecame common practice for photographers to respool cinema film onto35mm still camera holders after the discontinuation date: the result wasthat nitrate negatives became far more ubiquitous than one might think.Cellulose nitrate is a generic name for several plastics that can bedifferentiated by their degree of nitration. Plastics with approximately10.5% nitration are considered to be of low concentration and are commonbases for lacquers, adhesives and collodion; and this concentration isconsidered to be relatively stable. At greater nitration than 12.5% theplastic is called gun cotton and is both flammable and explosive.The sensitive nature of nitrate negatives and the threat they pose toother archival material raise specific issues that must be directly dealtwith. These issues include: (1) The length of their retention period. Ifnitrate negatives are to be retained indefinitely, the archivist must be fullyaware of the requirements for preserving this material and cognizant ofthe potential hazards of keeping nitrate negatives in less than idealconditions. (2) Their destruction after duplication. (3) The reliability andauthority of copies as evidence of their context and content.6The overall aim of this thesis is to synthesise and address the issueswhich surround the preservation and administration of nitrate negativephotographs. A survey of the existing literature on this topic revealsextensive but diffuse resources, especially in terms of archivalconsiderations. There is a perceived need to fill in the gaps in the archivalliterature dealing with the conservation aspects of nitrate negatives andthe related appraisal, diplomatic and legal issues. It would seem that theproblems presented by nitrate negatives have been recognised in thoserepositories that have significant accumulations of this material, and yetthere is a distinct lack of commonality in the way nitrate is handled at thebasic level. Furthermore, the conservation and archival considerationswhich are associated with nitrate negatives can often work against eachother, and some form of harmony between solutions must be reached.Sources for this thesis span a range of disciplines, from writings onchemistry and the nature of cellulose polymers and synthetic chemicalderivatives, to work done on the conservation aspects of nitrate materialsas well as writings on the history of photography, the archivaladministration of ephemeral material, and diplomatics.The thesis includes a description of the nitrate negative as a physicalentity, including an analysis of its production, its chemical composition andthe specific nature of its breakdown over time; a history of nitratenegatives in the context of the development of photographic processes,including their use and proliferation; a presentation of the conservation7aspects of nitrate negatives, including their identification, handling andlong term storage characteristics; a discussion of the archival concerns ofaccess, including an analysis of the types of decisions which have to bemade in order to preserve this material, and of how these decisionsimpinge on archival functions, and a brief review of the types ofprocedures which are being implemented in other repositories; an analysisof practical approaches in dealing with nitrate negative collections withinthe realistic parameters of institutional resources; and a consideration ofthe practical implications of maintaining nitrate collections indefinitely.In the final analysis, this thesis recommends that nitrate negativesbe copied with the best and most reliable methods possible and thendisposed of. Although this is a radical solution, the physical and intellectualcharacteristics of the material renders it expendable after it has beenproperly reproduced. In fact, the negative has little artifactual orevidential value, while the first perfect document, the first print, is theitem of historical, juridical and artistic consequence.Because of the increasing recognition of the photograph as anart medium and an historic document, it has become important for thearchivist to acquire, reproduce and make available photographs for the useof the people. Unfortunately, little attention was given at first to thetechnical aspects of photographs because the basic criteria for acquiringimages was simply the importance of the artist and of the subject matter.Much of this has changed now, and archivists are much more aware of the8unstable and unpredictable nature photographic images. As Pamela Haashas noted, a photograph is "chemistry, chemistry and more chemistry. Itexists thanks to a chemical reaction, and its inherent complex and unstablechemistry makes it more susceptible to environmental variation thanpaper alone or than even a piece of ink-imprinted paper." Because of this,the preservation of the historical image in the public institution requiresthe combined skills of many experts, that is, paper conservators, chemists,archivists, librarians, scientific photographers, and art photographers.However, where the archivist cannot have the benefit of the expertise ofdifferent professionals, it is of the utmost importance that he or she be asknowledgeable as possible about photographic materials. There is indeedmuch to learn about the medium, the various processes available, and thevarious possible courses of action as well as the ramifications which arisefrom choosing a particular strategy. What archivists are attempting to dowhen dealing with the historical image is to straddle the worlds of history,technology and art in order to keep for posterity those materials which arebound irrevocably to the technology of the day. In order to do this jobproperly we have to be fully prepared to do what is possible within theconstraints of the archival institution and its resource and budgetconsiderations. It is the ultimate objective of this study to provide arational and practical guide for the archival preservation andadministration of nitrate negative materials.9' Mary Lynn Ritzenhaler, Gerald J. Munoff and Margery S. Long,Administration of Photographic Collections, (Chicago: Society of AmericanArchivists, 1984), 55.2 Ann Elizabeth Carroll, "Acquisition of Photographs DeterminingArchival Quality" (MAS diss., University of British Columbia, 1989), 4.3 William H. Leary, The Archival Appraisal of Photographs: A RampStudy With Guidelines, prepared for the General Information Programmeand UNISIST, (Paris: UNESCO, 1985), 4.Pamela Haas, "The Conservation of Photographic Collections." Curator.Vol. 26 No. 2 (1983) 90.1 0Chapter One The Nature of Cellulose NitrateThe history of cellulose nitrate (CN) is long and varied. There issome dispute as to when the first form of CN was developed and bywhom, but there is little doubt that this polymer was first developed in themid 1830's or 1840's. Maynor and Van der Reyden believe that CN wasthe first major plastic in commercial use, having been formulated in 1832by Braconnot. They trace the origin of its production back to 1845 inEngland, where it seems to have been initially used by the military as anexplosive commonly known as gun cotton, and later plasticised withcamphor to produce the first successful synthetic plastic.' An alternatehistory of the CN polymer is that Charles. F. Schonbein first patented it inSwitzerland in 1845, followed in 1861 by Alexander Parkes who patentedparkesine CN in Britain. However, it is known that, by the mid-1860s, JohnW. Hyatt and others were producing CN in the United States and, in 1870,Hyatt patented a more stable variation of the material which made greateruse of camphor.' Early trade names for CN include parkesine, celluloid,pasbosene, xylonite, and zylonite. 3CN was one of the first major plastics in commercial use and has beenutilised in a variety of ways throughout its one hundred fifty years ofexistence. Because of its early viability as a polymer and its developmentduring the industrial revolution, CN became a very popular material forthe production of a great many articles. For these reasons CN can be11classified as truly ubiquitous. Although its use has declined over the years,its initial popularity amongst the early, technically oriented industries hasensured that it will remain a problem for archivists, museum curators andconservators for many years to come. In fact, this plastic was popularduring the great expansion of the photographic industry in the late 1800sand early 1900s, because it provided a flexible and transparent supportfor light sensitive emulsions. Therefore, cellulose nitrate was used as thebasic film support for many years.Because of the problems associated with its preservation, an archivistwho is responsible for the care of film on this support must be armed witha certain degree of knowledge as to the chemistry involved in theproduction of CN. One might argue that this sort of understanding shouldnot be part of the professional knowledge of the archivist because it ismore closely associated with the competence of the conservationprofession. Yet it has to be considered that CN appears in a variety offorms and is found among the holdings of many different archivalinstitutions which have correspondingly diverse budgetary and resourceconstraints. It is therefore imperative that archivists be adequately armedwith a knowledge of why CN behaves the way it does: by learning somebasic chemistry, they would be better equipped to deal with the practicalproblems of dealing with this material.Cellulose nitrate was produced by dissolving cellulose in the form ofcotton linters or wood pulp in a mixture of sulphuric and nitric acids; by12varying the strength of the acids, the temperature, time of reaction, andthe ratio of acid to cellulose, a wide range of products with varyingcharacteristics could be produced. CN, in its most basic form, had theconsistency of dough, and this characteristic allowed it to be pressed intoblocks and then sliced into thin sheets. The sheets could subsequently beheat pressed together to form a striated texture known as French Ivory; orthey could be blow moulded. CN could not be injection moulded orcompression moulded using early technologies, because of its sensitivity toheat. However, it was easily worked by cutting and abrading, and theedges could be tapered with solvents.' CN was water white transparent,and could be finished with a high surface gloss; it could also have a faintyellow tint from a possible trace contamination of iron. It could be dyedand mixed with fillers to simulate other more expensive and decorativematerials, and these imitations usually took the form of ivory or tortoiseshell!CN was at one time a very popular material among artisans, and itwas used in the production of all kinds of articles besides film, such assafety glass, celluloid collars and cuffs, early spectacle frames, combs,buttons, dressing table sets, blow moulded toys in the form of dolls andrattles, and false teeth. It is still used today for adhesives and lacquers,although on a much restricted basis. Ping pong balls are still fabricatedfrom CN as no other plastic has the requisite speed and bounce.'The basic component of this polymer is cellulose. Cellulose molecules13are built up from glucose molecules bonded together into long chains. Theatoms of carbon, hydrogen and oxygen which make up glucose are heldtogether by essentially two types of chemical bonds, or atomic interactions,called covalent and hydrogen bonds. Covalent bonds are the primaryforces which hold together glucose molecules making up the cellulosechain; hydrogen bonds play an intermediate role in linking adjacentcellulose chains into sheets. Covalent bonds are formed when atoms shareone or more pairs of electrons between their outer energy "orbits". Theseelectrons are not lost to a particular atom, but are shared, and each pair ofnegatively charged electrons spends a greater or lesser amount of time ineach of the outer orbits of the various atoms comprising the molecule,depending on their relative attraction to the nuclear charge of the atoms.This atomic configuration results in a stable situation within the molecule,because atoms enter into such chemical reactions in order to achieve astable outer orbit energy level of eight electrons.' Different atoms vary intheir ability to attract electrons. Thus, when atoms are covalently bondedto molecules, the negatively charged electron spend a disproportionateamount of time orbiting the nucleus of the atom which most stronglyattracts them.Hydrogen bonds are formed as a result of the relative ability ofdifferent atoms to attract electrons. The imbalance in the time spent byelectrons within the different outer orbits of bonded atoms results in anelectrostatic polarity within the molecule: the molecule essentially behaves1 4like a bar magnet, where one end has a slightly more positive or negativecharge than the other end. In the case of molecules of hydrogen andoxygen bonded together within the cellulose molecule, the electrons spenda longer period of time orbiting the nucleus of the oxygen molecule, due tothe greater attraction that it exercises on these electrons.' This gives theoxygen atom a more negative charge in relation to the hydrogen atomwhich is in turn positively charged. When separate molecules containingan oxygen atom bonded to a hydrogen atom (as in cellulose) approach eachother, the electrostatic polarity inherent in this covalent bond will holdthese two molecules together; the hydrogen atom with its positive chargeon the one molecule will be attracted to the oxygen atom with its negativecharge on the other: this is what is referred to as a hydrogen bond.Cellulose is built up from glucose molecules bonded covalentlytogether to form long chains. Each alternating glucose ring is flipped overand a water molecule is split off, leaving an oxygen molecule between eachring. The aspect of such chains is shown in Figure 1 below:LFigure 1: Cellulose Chain.'15These chains continue for as many as 3000 to 5000 units and,through side by side hydrogen bonding, are built up into sheets. Figure 2shows how these chains are built up into sheets by side-by-side hydrogenbonding. The black arrows represent hydrogen bonds.Figure 2: Hydrogen Bonding Between Cellulose Chains!'These sheets will in turn be held together in staggered layers, one ontop of the other, by forces known as Van der Waals forces. A Van derWaals force is a combination of three different types of forces: 1) a dipoleattraction, such as it is found between the positive and negative poles in amagnet; 2) an induction force, corresponding to the way a magnet canaffect a non-magnetized piece of iron; and 3) a form of weak attractionwhich all molecules have for each other." Figure 3 shows the way inwhich cellulose sheets crystallise from chains of cellulose. The arrows16indicate Van der Waals forces which join these sheets in staggered layers.5 5 5 5 5 \ 5 '5 5 5 \ 5 '5/ o' / / / / / / / / / / /5 5 5 5 \ \ \ \ \ 5 \ \ 5 5/ / I /.// / / / / / / //5. 5. 5 5 5 5 5 '5 5 5 5 5 5 5 5/ / / / /// / / / / / ///5 5 5 5 5 5 5. \ 5. 5 5 \ .5 5 S./ //// /// // / / / /1 /\ 5 5 5 5 5 \ 5 5 5. 5 \ \ 5 5 5 5/ // / /// / / / / / /// /5 \ 5 \ 5 5 5 \ 5 5 5 5 \ 5 \ 5 5/ / / /If/ 1/ 11/ / // //.5 5 5 5 5 5. 5 \ '5 5 .■ % 5 '5 \ ... 5 5/ / / / / / / / / / / / / / / /5 5 5 5 5 5 5^k..5 \ 5, \ 5. .5 5 5 \ 5Figure 3: Cellulose Sheets in Layered Structure: 2The result of these interactions are small units of cellulose known asmicrofibrils. Microfibrils are then crystallised by means of the same side-by-side hydrogen bonding and layered Van der Waals forces into cellulosebundles. Bundles are further crystallised into fibres by the sameinteraction of forces. It is important to note that, in the early stages ofmicrofibril formation, the bonding is nearly perfect at both side-by-sideand inter-layering levels, but each successive stage of formation has aprogressively less perfect bonding, due to the fact that any imperfectionpresent in the early stages is magnified throughout the crystal structure:the final fibre formation and its resiliencies are therefore very muchdependent on the quality of the early interactions between the chains ofglucose. Figure 4 shows how microfibrils are arranged into bundles, andhow bundles are then crystallised into fibres. It is essential not to losesight of the fact that the basic building block of the cellulose fibre is theIalla ••■■ I^I ."—om •-.....^...J. II .--• --a, --z--:- --.1^— ■M=Ir-lburRIMI.■•1=(7.7_ =- ge -I=chain of glucose molecules covalently bonded. - 17 L- I I 7• -7 T -n- -1 -- ---- «II17II . .=. ■••=7 I 1 -;-%. -._ =`=)1 I--' .-m== II -- _ — __. 1Microfibrils^ Bundles^ FibresFigure 4: Crystallisation of Cellulose Bundles. 13As mentioned earlier, CN is produced by dissolving cotton fibres inmixtures of nitric and sulphuric acids, and plasticising the resulting slurrywith camphor or some other agent. By manipulating a number ofprocessing parameters, a variety of material characteristics can beproduced. The nitrate process serves to replace one to three hydroxylgroups within the glucose ring. A hydroxyl group consists of an oxygenatom bonded to a hydrogen atom, and each may be replaced by amolecule of NO 3, or nitrate. Figure 5 illustrates the nitration process; asshown, three molecules of nitrate supplied by the sulphuric and nitricacids can replace the three hydroxyl groups on the glucose ring structure.As a result of this chemical reaction, three molecules of water are split off.18Figure 5: The Nitration of Cellulose."Theoretically, all three hydroxyl groups can be replaced by nitrategroups, thus producing a calculated nitrogen content of 14.14%. However,this is not practically feasible, because the resulting material could beunstable, being the upper limit of nitration at approximately 13.8%nitrogen content. The product of this process is referred to as gun cotton,which is highly explosive. Most commercial CN's have a nitrogen contentwhich ranges between 10.9% and 12.2%. Types of CN where the degree ofnitration is relatively low are used as lacquer bases because of their rapiddrying characteristics. Collodion and pyroxilin are other forms of lownitrate plastics which vary in actual nitrogen content.' The cellulosenitrate used for film tends to be in the region of approximately 11.8% to12.3%, while CN adhesives tend to be highly nitrated. Table I shows therange of nitrogen content as it corresponds to different types of CNapplications:19Percentage ofNitrogen Names Uses10.9-11.2 Pyroxilin Plastic,Soluble CNPaper coatings, plastics, lowodor lacquers, printing inks11.3-11.7 Pyroxilin plastic,Soluble CNCellophane and paper coatings,alcohol-soluble lacquers,textile coatings11.8-12.2 Pyroxilin Plastic,Soluble CN,Collodion,PhotocottonDopes, adhesives, coatings,artificial leather, collodion,fast drying lacquers12.6-12.8 PurocellulosePyrocol l odi onPropellants13.0-13.8 Guncotton,Smokeless PowderPropellants, explosives,Smokeless powderTable I: Nitrogen Content of Various CN Materials."It is clear that the stability of cellulose nitrate is strongly influencedby the amount of nitrogen present within the glucose ring structure: thegreater the nitrogen content, the more inherently unstable the resultingmaterial will be. Some products with high nitrogen content, for examplethose with a percentage of 13.5, will explode if subjected to heat, frictionor shock. Objects with less nitrogen component are not explosive but can,under certain conditions, be extremely flammable.CN degrades to produce acidic (and oxidising) nitrogen gases,including nitrous oxide, nitric oxide, and nitrogen dioxide." In closedareas with restricted ventilation, high concentrations of these gases buildup and can corrode metals, embrittle and discolour organic materials, and20accelerate the degradation of the CN itself. ^In fact, the process ofdenitration is autocatalytic; this means that, the greater the rate ofdegradation, the greater will be the concentration of gases within theplastic, and this causes the material to degrade at an even faster rate.Cellulose nitrate essentially "stews in its own juices" and a critical point canbe reached if this degraded material is heated.The progressive deterioration of CN is accompanied by a steadydecrease in the auto-ignition temperature. The auto-ignition temperatureof a particular substance is defined as the lowest temperature at which itwill self ignite without a direct source of heat" . Fresh undegraded CNauto-ignites at 150 C, a relatively low temperature when one considersthat the auto-ignition temperature of paper is 315 C to 375 C. In the laststages of decomposition, CN can self-ignite at temperatures as low as 50 C,a condition which can easily be present near light bulbs, radiators andheating equipment, or in unventilated buildings and attics during hotsummers. The heat from these indirect sources is sufficient to set theprocess of deterioration into motion; once started, the deterioration is selfsustaining and constantly grows and produces heat. The heat continues tobuild until the ignition temperature is reached and a fire is started. Thepresence of camphor in CN is very important in this respect as it tends toretard its decomposition; aging stock, however, can lose camphor throughnormal evaporation and the remaining plastic is very vulnerable." Reportsof spontaneous ignition of cellulose nitrate films have regarded only21collections of photographic motion pictures and x-ray films which havebeen stored in dense masses in poorly ventilated, bulk storage deposits.The extreme flammability of CN is related to the amount of freeoxygen present in the nitrated cellulose molecule. A highly nitratedmolecular structure contains a great degree of oxygen in the form of NO 3 .The greater the oxygen component, the greater will be the combustion.Once CN is ignited the burning process is very thorough, and CN cannotsmoulder, for there are no places in the molecular lattice structure whichcan be reached by outside 02 . Because of this built-in supply of oxygen,methods of extinguishing the fire based on the exclusion of air are totallyineffective, and it has been shown that CN can actually burn under water.'A given quantity of CN does not produce as much heat as the burning of anequal amount of wood or paper but the comparison becomes irrelevantwhen one considers the speed of CN combustion, which is a dozen timesfaster than that of wood and paper, and a ton of CN can be completelyconsumed in little more than one and a half minutes.' The liberated heatis truly remarkable, the flames can extend like blow torches in alldirections, and the fire can spread very rapidly; this speed of combustionqualifies CN as a hazardous material.There are several outward manifestations of deterioration which arepresent in all types of cellulose nitrate artifacts. These include theformation of oily brown liquid droplets, consisting of nitric acid or oozing22plasticisers on the surface of the material; this process is often referred toas "weeping" and its probable cause is storage in conditions of highrelative humidity.' "Crazed" cellulose is another sign of CN decay: the termrefers to the fine surface cracking which gives the material a crystallineappearance with or without opacification, softening, yellowing ordarkening." This severely damaged condition is probably caused byinternal stresses which have been created within the molecular structureduring the manufacturing process, and released as soon as CN is weakenedby the loss of plasticiser. Ultraviolet light and the presence of fumigantsalso seem to be responsible for this type of damage. If the concentrationof the gaseous byproducts of this breakdown remains unventilated, thematerial may eventually be reduced first into a soft sticky mass and theninto a formless brown powder. Other manifestations of deterioration in CNare: discolouration of translucent CN in sunlight, with a concomitantalteration of pigment additives; distortion and discolouration from heat(for example from exhibition lighting); and damage from microorganisms.'The problematic nature of CN, and the special requirementsassociated with its proper storage and preservation have been recognisedand debated for some time in the literature of the photographic arts,museology and archives. However, a facet of the nitrate problem whichseems to have been given little attention is the potential for cellulosenitrate to cause health problems to those who work with it for extendedperiods of time, or to those whose work space includes storage areas where23cellulose nitrate is kept under less than optimum conditions. Decaying CNcan indeed represent a problem of some importance when one considersthe possible human consequences of working with a material which isextremely volatile and can degas a variety of irritants over potentially longperiods of time.In their report, Deteriorating Negatives: A Health Hazard In CollectionManagement, Hollinshead et. al. have noted incidents of eye irritation,rashes, sores on the skin, and breathing problems amongst personnelinvolved in the cataloguing of film collections. A photography technicianalso experienced episodes of vertigo, nausea, headaches and swollenglands.25 It is reasonable to expect that an individual's symptoms in suchcases may be directly related to his or her degree of sensitivity to suchsubstances and yet it is to be noted that many of the byproducts ofcellulose nitrate decay are recognised as being potential irritants and quitehazardous to the body if prolonged exposure is maintained. DeterioratingCN produces a range of nitrogen oxide gases as well as a powdery basewhich can be irritating to the skin, eyes and respiratory system. Thesenitrogen gases can further deteriorate into nitric acid, another dangerouschemical agent. Table II shows the range of nitrogen gases which can bereleased by decaying cellulose nitrate:24Name^Chemical FormulaNitric Oxide NONi trogen Dioxide^NO 2Nitrous Oxide N 2 0Nitric Acid^HNO 3Table II: Types of Nitrogen Gases Released During CN Deterioration.'Nitrogen oxide gases are primarily deep lung irritants, althoughirritation of the lung and other mucous membranes may occur. Ifrepeatedly inhaled, these gases may cause chronic headaches, blurredvision, and loss of appetite. A distinction has to be made in the degrees ofexposure one might face in dealing with these types of gaseous byproducts:acute exposure refers to a brief exposure to relatively large quantities ofgas, whereas chronic exposure describes a condition where the individualhas been exposed to a moderate quantity of gas over a long period of time.The latter condition would be representative of a situation where a personis performing a specific operation with cellulose nitrate objects, forexample arrangement and description of a collection of photographs, orwhere nitrate collections stored in substandard conditions occupy the sameareas as the employee's work space. Acute exposure to these gases canresult in fever, nausea, dyspnea and vomiting, while chronic exposure mayresult in chronic headaches, blurred vision, loss of appetite, and othersymptoms of systemic damage. 27 The following is a brief summary of thetypes of symptoms to be expected from exposure to these types of gases:25Nitric oxide: There are presently insufficient data from animal orhuman studies showing that NO is a health hazard; it is, however,potentially toxic, because it can oxidise to NO2, producing nitrogen dioxide.Nitrogen dioxide: Nitric oxide oxidises in air to form nitrogendioxide in a light catalysed reaction. Nitrogen dioxide is highly toxic ifinhaled, and has the ability to penetrate to the deep lung; this cansometimes result in a build up fluid in the lung, a condition which isknown as pulmonary edema. This is accompanied by a decrease in lungarea suggestive of emphysema, and a potential for the increase in lunginfection. Evidence seems to suggest that the development of these formsof respiratory dysfunction is equally a result of the length of exposure asof the level of exposure to these gases.'Nitrous oxide: This gas may or may not be present in thedecomposition of aging CN materials, and takes the very same form as thecommon anaesthetic; chronic exposure to it over prolonged periods of timehas been linked with various nervous system disorders, but this will occurat only very high levels.Nitric acid: Gaseous nitrogen dioxide may combine with water toform nitric acid. This is a very corrosive agent and a primary irritant forthe mucous membranes of the eye, nose, and throat. The fumes are highlytoxic by inhalation, and may cause chronic bronchitis and emphysema.Other gases which may be emitted during the deterioration ofcellulose nitrate include acetone, mesityl oxide, and acetic acid. Acetone26has a relatively low acute and chronic toxicity, and there have been noconfirmed reports that prolonged inhalation of low vapour concentrationsmay result in the incidence of serious chronic effects in humans. 29 Mesityloxide is a derivative of acetone used as a glue base in the making ofplastics, acetates, and films; it can effect the skin, eyes, respiratory system,and the central nervous system. Acetic acid is irritating and corrosive tothe epithelial layer of the cornea, and other mucous membranes, and it canirritate the upper respiratory tract, and result in bronchial constriction.The foregoing physical ailments associated with decaying cellulosenitrate need not be considered a problem if the necessary safeguards arein place; the potential for problems exist, but it should not be consideredcause for undue alarm. Nonetheless, it is important to exercise caution,especially when one is dealing with obviously decayed material.The greatest problem associated with the collection andpreservation of CN film lies not in the health hazard which this materialpresents to the archivist or conservator who works with it, but rather in itsself destructive properties. CN poses a threat not only to itself but also toother archival materials with which it may share storage space. Therefore,it is advisable to possess a knowledge of the role CN has played in thedevelopment of the photographic process. The detection and properappraisal of nitrate negatives is greatly facilitated by an understanding ofthe history of cellulose nitrate as a flexible film support in the period1890-1950. In the next chapter the history of the development of the27photographic industry in relation to the development of CN will beexamined, as will the problems that this particular polymer has caused tothose who are involved in the preservation of historic images.28' Catherine J. Maynor and Diane Van der Reyden, Paper ConservationCatalogue (Washington: American Institute of Conservation of Historic andArtistic Works,1989), 38.2 Julia Fenn, Ethnographic Conservator for the Royal Ontario Museum, apreliminary draft of a monograph on plastics and polymers (untitled),(May 1989), p. 1.3 Ibid.4 Ibid.5 Ibid.6 Ibid., p. 2.7 Ibid.8 Ibid. This ability to attract electrons is determined by the number ofprotons, or positively charged particles, within the nucleus of the atom. Inan atom the number of protons is equivalent to the number of electrons.9 Ibid., p. 4.10 Ibid., p. 6." Ibid., p. 3.12 Ibid., p. 6.13 Ibid., p. 6.14 M. Lazar, T. Bleha, and J. Rychly, Chemical Reactions of Natural andSynthetic Polymers, (New York: John Wiley and Sons, 1989), 75-76.15 Maynor, op. cit., 39.16 James H. Meidl, "Plastics: Cellulose Nitrate. (Cellulose Nitrate FireHazards; Shipping and Storage)."^Flammable Hazardous Materials. (Beverly Hills: Glencoe Press, 1970), ^219.17 R. Scott Williams, Display and storage of Museum Objects containingCellulose Nitrate, (Ottawa: Canadian Conservation Institute, 1988), 1.18 Ibid., p. 2.19 Meidl, op. cit., 220.20 Ibid., p. 219.21 Ibid.22 Fenn, p. 2.23 Ibid., p. 3.24 Ibid.25 Patricia W. Hollinshead et. al., Deteriorating Nitrate Negatives: AHealth Hazard in Collection Management:  (Tucson: Arizona State Museum,1987), 1.26 Ibid., p. 3.27 Ibid." Ibid., p. 4.29 Ibid, p. 5.2930Chapter TwoCellulose Nitrate and the Photographic ProcessCellulose nitrate has been associated with the photographic processfor nearly one hundred sixty years. CN product names which may befamiliar to those who have studied the development of photographyinclude collodion, celluloid, nitrate and nitrocellulose. Collodion was firstmentioned in the scientific literature in 1847, when Louis Menard andFlores Domont communicated their discovery in the French Academy ofScience.' In 1848, the Englishman Frederich Scott Archer discovered a wayto light sensitise a glass plate which had been coated with collodion. Thiswas known as the "wet plate" method, and by 1860 had become thedominant process in the photographic industry and had supplanted thedaguerreotype and the calotype. 2 Collodion's popularity as a sensitisingbase was due to its ability to stick tenaciously to the glass plate even afterrepeated submersions in the various chemical sensitising and developingbaths. The process was indeed quite cumbersome but remained thetechnique of choice until the 1880s, when the gelatin dry plate processbecame viable. It is in the development of the wet and dry plate methodsof photography prior to the advent of flexible film that cellulose nitratewas first used, but it was to play an even greater role in the quest for aclear plastic support on which to place a sensitised emulsion.The idea of having a lightweight and flexible support for thesensitised emulsion came early in the history of photography; but the31relatively primitive technology of the time proved to be the majorstumbling block for developing such a support. The calotype process ofWilliam Henry Fox Talbot was essentially the first process to utilise aflexible support: the calotype technique involved treating paper withsolutions of silver nitrate and potassium iodide to produce a light sensitivesilver iodide in the paper. The paper was made more sensitive by washingit with a mixture of gallic acid and silver nitrate, and exposing it for a fewminutes. The invisible latent image was developed with a solution of gallicacid and silver nitrate and heated to produce a clearer print; it was thenfixed with a solution of potassium bromide, which was later abandoned infavour of hyposulphite. 3 Generally, the calotype could not compete with itscontemporary daguerreotype for portraiture, but it was better suited forthe broad effects of landscape panoramas and architectural photography;in fact the paper grain tended to obscure fine details in the negative, andthe prints tended to fade appreciably unless carefully processed.'Nevertheless, historians point to the calotype as the precursor to themodern photographic process.The next step in the evolution of photography was a furtherdevelopment of the glass plate. Despite its popularity amongstphotographers, it soon became evident to amateurs and professionals alikethat some sort of replacement for the glass plate was needed; in fact it washeavy, bulky and inefficient for those photographers who wished to travelany sort of distance to capture images. It proved exceedingly difficult,32however, to find a material which was as transparent and smooth as glass,yet free from impurities and grain. The ideal material for flexible films,celluloid or Parkesine, as mentioned earlier was developed in 1861 by theEnglishman Alexander Parkes, but it did not find use as a flexible supportuntil the technology was available to slice it thinly and evenly. Until thistime, photography on film took two forms: stripping film and flexible film,with a brief revival of the paper negative process.'Stripping film was a paper negative with a difference; the paper wasmerely used as support for the emulsion and was later peeled off beforeprinting to avoid the effects of the paper grain. Frederich Scott Archerfirst developed a stripping film in 1855, by coating a finished andvarnished plate negative with a layer of gutta-percha; on immersion inwater, the sensitised collodion could be peeled from the plate leaving afilm from which positive photographs could be made. This process helpedto reduce the weight which had to be carried during long trips as, oncestripped, the film could be kept in a portfolio and the plates used overagain. This process did not find favour with the day-to-day photographer,however, nor did the variations on plate stripping produced by suchnotable individuals as Rev. J. B. Beade a few months later, AlexanderParkes in May of 1856, and J. A. Ferrier in September of 1857. 6 Thetechnique of film stripping was taken up again in 1875 by Leon Warneke,whose complicated process involved coating glazed paper with coatings ofcollodion and india rubber solution, thereby producing a transparent33support for the sensitised collodion emulsion. After exposure, theemulsion could be stripped from the paper and placed on a moistenedglass plate, and could then be treated like a normal glass plate negative.This process proved to be very expensive and failed to generate sustainedinterest in the photographic community.'Several other types of stripping film were on the market up until thelate 1880's, but the one that generated the greatest interest was the filmproduced by George Eastman in 1886. This particular stripping film wasmanufactured for the Eastman/Walker Rollerslide camera in 1886 and forKodak in 1888. Its life was very short, for it was superseded only a yearlater by cellulose nitrate roll film and its production was ceased in 1891.Because developing was so complex, it necessitated the Eastman Kodak Co.to process the film itself in the Company laboratories.'Another process which was developed for the production of flexiblefilms was the paper negative; it was not so much a revival of the oldcalotype as it was an improvement and refinement of this process. Thespeed of the sensitive coating had been greatly increased and the grade ofpaper had by this time been improved. Moreover, whereas the calotypehad produced an image in the paper, the paper negative produced animage in the emulsion itself, with the paper acting only as the support.Eastman/Walker lent a certain impetus to the production of papernegatives with the production of the rollerslide; the camera was loadedwith enough paper negative to produce twenty-four exposures and it was34introduced in the US and England in the summer of 1885. The negativematerial was fine grained paper coated with a gelatin emulsion.' A fewmonths later Warnecke produced a paper negative which was superior toeven the Eastman/Walker negative and involved the coating of the paperwith emulsion on both sides. Warnecke reasoned that any imperfections inthe original negative would be cancelled out by the reverse image on theopposite side of the paper, and the grain would be removed by the doubleexposure. Warnecke believed that this process would usher in the paperera in photography, and it may well have been so had it not been for thearrival of cellulose nitrate film merely three years later."The flexible film which dispensed with a glass or paper support hadits beginnings with Alexander Parkes, who formulated the aforementionedParkesine, or celluloid-cellulose nitrate, in 1861. The one problem withusing celluloid as a base for flexible films at the time was that it was still athick and streaky material; manufacturers could not be persuaded toprepare the material thin enough to render it applicable to photography,arguing that the process was too expensive to make it cost-effective. Thisdid not stop certain individuals, such as Ferrier and Pumphrey, fromexperimenting with such materials as collodion and gelatin to produceflexible film without the need for a support." On the whole, theseattempts fell short of becoming successful, and it was not until 1888 that aviable alternative, in the form of thin cellulose nitrate sheets, wasintroduced.35Celluloid was registered as a trademark in the United States andGreat Britain in 1873 by John Wesley Hyatt of the Celluloid ManufacturingCompany of Newark, New Jersey. He had been persuaded by John Carbutt,an English photographer living in America, to produce celluloid in thinsheets of 1/100 inch thickness.' 2 John Carbutt had previously laid claim tothe distinction of having been the first to produce the gelatin dry plate inthe Unites States, and in 1888 was the first to produce emulsion coatedcelluloid films called "Carbutt's flexible negative films"." These sheetswere produced by slicing thin sheets off a condensed block of cellulosenitrate, which were then coated with a sensitised gelatin emulsion. Theresults of Carbutt's four years of experimentation were published in theJournal of the Franklin Institute in Philadelphia: 4The next logical step in the production of flexible films was to find amethod by which this union of cellulose nitrate and gelatin emulsion couldbe produced in the form of roll film. As previously mentioned, roll holderswere already in existence and had been used extensively with the papernegative roll film, but the technical problems in producing a cellulosenitrate roll film were indeed quite formidable: the CN solution had to befluid enough to flow onto the film forming support (usually a glass drum),then to be mechanically spread into a uniform layer, but also had to beviscous enough to stay in position. Furthermore, the solvents used todissolve the cellulose nitrate had to be of a specific volatility; if theyevaporated too quickly, air bubbles would be left in the film. If, on the36other hand, the solvents evaporated too slowly the process was not costeffective: 5 These problems were solved by three Americans: the Rev.Hannibal Goodwin and, together, George Eastman and Henry Reichenbach, achemist with the Eastman Dry Plate Company of Rochester New York.Goodwin had in fact applied for a patent for his flexible roll filmmade of cellulose nitrate and camphor eighteen months before Carbutt hadintroduced his perfected cut film to the market. Goodwin's patent wasdelayed for some time as he was acutely short of money and his claim wasnot considered specific enough by the patent examiners." While Goodwin'sclaim was under examination, Eastman was able to corner the market forroll films. His chemist, Henry Reichenbach, had been experimenting withthe process of producing thin, flexible sheets of cellulose nitrate and hadfound the answer to the roll film question. Reichenbach discovered thatthin sheets of celluloid could be produced by pouring a solution of cellulosenitrate in alcohol on to glass plates; the resulting sheet was thin andtransparent, but rather brittle. He added camphor and found that the filmwas more flexible, but crystallisation of the finish rendered it uneven andspotty. Finally, Reichenbach added two more solvents to the mixture, amylacetate and fusel oil, and found that a thin, strong and perfectlytransparent film could be produced. A patent for the new process wasapplied for in April of 1889, and was issued in December." UnlikeHannibal Goodwin, Reichenbach was able to supply the patent examinerswith an exact formula for his process. Goodwin, for his part, was still37hamstrung by money difficulties and was unable to raise enough money tobegin production of his film until 1900. Shortly before this, he died in anaccident."Eastman's production of the new material began in August of 1889,using an apparatus devised by Eastman himself. Transparent film wasmade by pouring the liquid mixture of cellulose nitrate and solvents on toplate glass tables two hundred feet long and three and a half feet wide.When the mixture had set, the cellulose was coated with the emulsion.When this was dry, the film was stripped from the tables, slit into rolls,and cut to sizes which fit the Kodak camera and the roll holders. The newfilm was called Eastman's Transparent Film, and was the first commerciallyavailable transparent roll film." Within one year, the demand for thenew film had become so great that Eastman Kodak had to build new plantsjust to keep the production up to the demand.2° The Eastman'sTransparent Film was produced from 1889 to 1903; it was very thin andcurled rather easily. A slightly thicker, non-curl film was produced in1903 with a coating of gelatin on the back to prevent curling; this gelatinbacking also tended to reduce flammability and improve stability.After Hannibal Goodwin's death, the firm of Anthony of New Yorkacquired controlling interest in the Goodwin Film & Camera Co., and beganto produce the CN roll film in December 1902. At the same time it suedEastman Kodak for infringement, on the grounds that Eastman'smanufacture of the film had departed from the formula devised by38Reichenbach, and was in fact the same formula as Goodwin's. The lawsuitwhich ensued was long and complicated; it occupied the courts for twelveyears and was documented in 5,500 printed pages by the time it wassettled in March 1914. The Appeal Court, at that time, held that Goodwin'sapplication, filed in 1887, had indeed revealed the essential features of thenew process, and that the Eastman Company was guilty of infringement.Eastman Kodak was ordered to award a settlement to the Ansco Company,by now the owner of Goodwin's patent, based on its profits from the sale ofthe film in question. The settlement was for five million dollars."With the advent of the flexible film, the modern era of photographyhad begun. The increased convenience of this type of film allowed theprofessional photographer to shoot more pictures under varyingconditions, but it was the amazing increase in the number of casualphotographers which proved to be the real blessing to the industry.Eastman Kodak's cameras were immensely popular with the amateur andcasual photographer, and the company catered to the demand by providingexcellent service. The swiftly developing amateur market soon became theeconomic foundation of the photo industry. The types of cameras whichwere developed for this market removed photography from the realm ofthe "serious" or "art " photographer, and made the novice the prime targetfor the sale and distribution of photographic equipment. The camera wasno longer a complicated apparatus whose manipulation was best left toexperts, but rather a toy for the amusement of all. The upshot of this was39that all the photographic components had to be mass produced, and thistechnical base served to establish a large industry and a consumer packagewhich in turn served to fuel the demand around the world. At the heart ofthis new era in the industry were the flexible film and the standardisedcamera.It soon became apparent to those who produced and worked with CNfilm however, that it had some rather severe drawbacks; the material wasinherently unstable over even short periods of time, and was dangerouslyinflammable if stored improperly. Photographers were swift to notice thatthe film tended to decompose over time and a series of fires atwarehouses, cinemas and businesses provided clear evidence of the dangerof nitrate film. The Ferguson Building fire in Pittsburgh in 1909 was anearly example of the dangers of CN; thirty people were injured in the fireand subsequent explosion. The building itself was improperly designedand held several film groups. Nitrate film was the cause of at least twomajor fires a year in such companies as Metro, Famous Players,Thanhouser, Universal, Pathe, Edison, and Lubin during the early 1900s. Afire at the Lubin location in 1914 caused particular interest as it appearedto have started in a poorly designed nitrate vault. 22The disaster at the Cleveland Clinic Hospital on May 15, 1929 caughtthe attention of the world and facilitated the growing general awareness ofthe potential problems of CN film: a huge explosion and fire caused thedeath of one hundred and twenty five people, and injuries to many more.40The greatest cause of death was the gas produced by the fire andexplosion; people were seen to drop where they stood from inhalation ofthe fumes, and the situation was further exacerbated by the explosionwhich blasted the gas through the building ventilation shafts." I Insubsequent inquiries into the disaster, CN x-ray film was determined to bethe culprit. The National Chemical Warfare Board which investigated thedisaster determined that a number of potentially lethal gases wereproduced during combustion of the film. The Board found that the primarygases produced during the combustion of CN film are carbon monoxides(47%-59%), carbon dioxide (21%-24%), and nitrous compounds (7%-9%). Itwas also determined that, on the average, twenty five cubic feet of carbonmonoxide were released by five pounds of nitrate film, equivalent to onereel of motion picture film or one hundred and twenty five 8 x 10negatives.Although its ready combustibility had been understood for sometime prior to the Cleveland disaster, little had been done to draft andenforce regulations on the handling and storage of the film. The early,initial attempts to codify fire regulations by various underwritingassociations were given added impetus by this disaster.' At the time ofthe disaster, Eastman Kodak admitted that cellulose nitrate film wasindeed inflammable but only if it was kept in inadequate storageconditions. The dangers of CN were fully recognised by 1930, and it beganto be replaced by cellulose acetate, or safety film, which had much reduced41burning properties!' In 1937, cellulose diacetate, as well as other filmbases composed of mixed cellulose esters, were produced. In 1947,cellulose triacetate film was introduced, but CN roll film continued to beproduced up until 1950. 26 Eastman Kodak discontinued production in1951.   Figure 6 serves to compare the structure of cellulose nitrate anddiacetate films; cellulose nitrate still plays a part in the production ofdiacetate films but primarily in the subbing layer as an adhesive. Cellulosediacetate is much more stable than nitrate and is certainly not as prone tocombustion; advances which have been made since the introduction ofdiacetate have ensured stabilities which are several times greater than theearlier safety films.Subbing Layer(CN & Gelatin)Cell ulose NitrateSubbing LayerAnti Curl/GelatinCellulose Diacetate Film Gelatin SupercoatTop Gelatin EmulsionLover Gelatin EmulsionSubbing Layer(CN & Diacetate)Cellulose NitrateSubbing LayerAnti -Curl/Anti - Halation42Cellulose Nitrate Film^Gelatin SupercoatGelatin EmulsionFigure 6: Cross Sections of CN and Cellulose Diacetate Film.'Institutions which acquire photographs from the period 1890-1950are very likely to have CN films in their possession; it is therefore of theutmost importance that those films be identified in order that they mightbe adequately dealt with in the context of the institution's mandate andresources. There are several ways in which CN films can be identified;some are complicated and require certain expenses, while others are muchsimpler but concomitantly less reliable. It certainly helps to know the ageof the film; there are certain general date guidelines which might be used43to determine the likelihood that the film in question is cellulose nitrate.The following table serves to show the general dates of discontinuation forvarious formats of cellulose nitrate film:Last Year of NitrateType of Film^ ManufactureX-ray films 1933Roll films in size 135^ 1938 (A)Portrait and commercial filmssheet films (8)^ 1939Aerial films 1942Film Packs (C) 1949Roll films in sizes 616,620, etc. (D)^ 1950Professional 35mmmotion picture films 1951Table III: Dates of Discontinuation for CN Film Formats.'It is important to bear in mind the following notes when consideringthe above dates as they will help in the physical identification of the filmbeyond simply dating them. Taking the date and the following intoconsideration will aid in the identification of the film.(A) It has been common practice for photographers to buy bulk rollsof 35mm film and respool it onto cassettes for still camera use. Because ofthis, it is not uncommon to find still camera negatives on nitrate film forsome time after this date or until any amounts of CN held in reserve wereused up after the 1951 discontinuation date for motion picture reel film.(B) Nitrate sheet film tends to have a very thick and rigid base,44while professional sheet film will also have coded notches on one corner toallow the photographer to determine the emulsion side in the dark.(C) Film pack negatives were produced in the same sizes asprofessional sheet film but have a much thinner and more flexible base,and will feel like roll film. They lack a notch code, but may have anegative number, generally 1 through 12.(D) These sizes were called amateur roll film formats and were verypopular with the casual photographer; they are quite common in personaland private collections.A problem inherent in identifying photographs by date is thatEastman Kodak is the only manufacturer to supply any dates on thediscontinuation of cellulose nitrate films, and these dates cannot be appliedto other manufacturer's films. Another complication is that in almost allcases there was a carry over period during which both nitrate and safetyfilms were in use. Because there is no specific date as to when safety filmswere actually introduced, it is not possible to tell with certainty whether afilm is a safety format based solely on its date.'Border markings are also a relatively simple, yet not entirely reliableway of determining whether a film is nitrate. Many manufacturersstamped professional sheet films along one edge with identifying markingsand the words generally identified the manufacturer and the type of film:nitrate or safety. This is the easiest way of determining the type of film ifthe markings are there, but unfortunately border stamping was not done45by some manufacturers; and the practice was not present for early nitratefilms nor for some roll formats. Amateur roll films were not marked, butthey can be identified by their tendency to curl into very tight scrolls; rollfilms were eventually coated on both sides to reduce this tendency."One established method for film type identification is the float test.A small portion of the film can be clipped with a hole punch from anunexposed section of the film and placed in a test tube of trichlorethylene.This test is a measure of the film's specific gravity; nitrate film is heavierthan both acetate and polyester safety films, and trichlorethylene is asolvent with a specific gravity between that of nitrate and acetate. Aclipping of a nitrate film will therefore sink in the test tube while safetyfilms will float or remain suspended in the liquid. Caution should beexercised when using this particular test as the solvent trichlorethylene isextremely toxic, and the test should only be performed under a fumehood.'Burn tests are also fairly accurate in determining the nature of thefilm material. A sliver of film trimmed from a non-image margin can beheld upright in a pair of tweezers and ignited. CN film will burn rapidlyand constantly, whereas safety films will burn much more slowly or not atall and may often simply self-extinguish after a short period of time. It isa good idea to experiment with several edge stamped films so that thespecific burning characteristics can be noted and recorded for futurereference."46The diphenylamine spot test is a fairly reliable means forestablishing whether a film is nitrate or safety. This test consists of takinga small chip from the unexposed portion of the film and placing a smalldrop of diphenylamine solution (6% in concentrated sulphuric acid) on it.In the presence of nitrate the spot will change to a distinctly blue colour."A fresh batch of diphenylamine solution must be kept on hand as thereaction becomes less distinct with aging of the solution, and the testshould also be done under a fume hood. A final means of determining thenature of the film is by observing its infrared spectrum. This test requiresthe use of an infrared spectrometer, a technical piece of equipment whosecost is prohibitive for small institutions; the test, however, is very accuratebecause, on an infrared spectrum, CN shows prominent and distinctivebands at 6.1 and 11.9 micrometers.'The progressive deterioration of nitrate negatives can be brokendown into five stages:Stage One: Amber discolouration of the film base, and beginning ofimage fading.Stage Two: The emulsion becomes adhesive, negatives tend to sticktogether or to their enclosures, and may have an acidic smell.Stage Three: The film shows gas bubbles and emits a strongnoxious odour.Stage Four: The film becomes soft, welded to adjacent film and isfrequently covered with a viscous froth.47Stage Five: The film mass degenerates partially or entirely into abrownish acrid powder."While it is important to note that there is no clear demarcationbetween these different stages, and that a particular negative may exhibitcharacteristics associated with one or more of them, this means ofidentifying the deterioration of nitrate is nevertheless a very importantpractical tool. Most negatives will retain legible photographic detail intothe third stage of decomposition. They may indeed be brittle, but, ifcarefully handled they can be duplicated. Generally, negatives in stagesfour and five have little or no image detail, and should be disposed ofimmediately.The rate of deterioration is erratic and unpredictable; some nitratefilms degrade slowly and steadily over a period of years, whereas othernitrate films show little or no signs of deterioration for fifty years or moreand then reach stages four or five in a matter of months. Furthermore,several different stages of deterioration may be seen on the same reel offilm, and there is absolutely no predictability in the way individualnegatives shot on the same stock will behave over a given period of time.Films from the same manufacturer, processed by the same photographer,and stored side by side often exhibit distinctly different rates ofdeterioration; this phenomenon has yet to be explained."There are several factors which contribute to the degradation ofnitrate film, and no single cause, but rather combinations of factors tend to48be the cause of CN breakdown. To begin with, there is the matter of theoriginal quality and purity of the film base itself; much of the filmmanufactured in the years during and immediately after the Second WorldWar was of inferior quality due to the scarcity of raw materials.'Furthermore, the standards of production may well have variedconsiderably within a particular company, and certainly betweencompanies. The early industrial era in which CN was initially producedwas not known for its high standards of production overall, let alone forthe film industry by itself.Temperature also plays an important role in the decay of cellulosenitrate film stock; it has been estimated that the deterioration of CN isaccelerated by a factor of four for each 10 C rise in temperature(approximately a factor of two for every 10 C rise in temperature)."Humidity plays a major role in deterioration because water is necessary tothe formation of acids and other deteriorants within the film itself. Highrelative humidity accelerates the process of deterioration dramatically; themaximum humidity level within a storage area should not exceed 40%."Also the gases which are produced during the decay of cellulose nitrateshould be allowed to escape the film storage area because of theautocatalytic nature of the reaction.The temperature in the storage area should not exceed 21 C (70 F)and a lower temperature is desirable, if it can be maintained withoutincreasing the relative humidity above 45%. A relative humidity below4940% is desirable, but there is a risk that the film will become very brittle ifconditions are too dry. With nitrate negatives, the relative humidity iscritical because a compromise must be reached between making the basetoo brittle and making the gelatin so tacky that it will adhere to sleeves orother negatives."The format also has an effect on the rate and nature of thedeterioration of nitrate film; it is the format of the film which has thegreatest direct effect on the mobility of those gases which are producedduring the break down of nitrate. Professional sheet film is the thickestplastic with a nitrate base of 8mm, and consequently it has the leastinherent stability. On the other hand, professional motion picture film,with a base of 5mm is the thinnest nitrate-based film, and thus shouldlogically have the greatest inherent stability. But because motion picturefilm is tightly rolled onto itself, its relative mass is greatly increased andits actual stability is therefore much lower than sheet film. Similarly,sheet films which are stored together without individual sleeves are muchmore prone to deterioration than sleeved or interleaved sheet films. Thesevarying stabilities are not the result of varying chemical compositions, butrather they are a reflection of the ability of the deteriorant gases to escapethe film.'It would be remiss at this point not to consider an alternativeanalysis of the progressive deterioration of CN negatives. In his article,"Fire Risk by Storing Nitrocellulose and its Behaviour During Combustion."50Rudolf W. Gobel takes a somewhat different approach in analysing thenitrate problem. Through extensive tests conducted on a very largeamount of nitrate reel film, Gobel comes to the conclusion that the ignitiontemperature of cellulose nitrate is independent of the degree ofdisintegration. Evidence shows that the ignition temperature is linkeddirectly to the degree of dessication of the film base, and is thereforeclosely associated with the relative humidity of the storage area." Gobelnotes that the ignition temperature was particularly low for films whosesilver image and emulsion were still completely intact but which showedsigns of dessication. CN films reach a very dangerous stage when they are,irrespective of age, dry and brittle; in this regard the quality of the originalfilm base can be considered a strong influencing factor on the rate ofdessication of the film base. Furthermore, dessication phenomena wereparticularly noticeable in films which were stored in rooms heated withsteam or water central heating; another influencing factor may be amethod applied for some years in which the films were rinsed with alcoholafter fixing in order to obtain fast drying. The alcohol withdraws humidityand plasticisers to such an extent that the base loses its ability to reabsorbthem."Gobel also notes that throughout his extensive investigations ofnitrate deterioration, little evidence was produced showing that selfignition of nitrate was indeed possible." This assertion would seem tocontradict the findings of the National Bureau of Standards, which in 194951showed that deteriorated nitrate could undergo spontaneous combustion attemperatures as low as 106 F, and possibly much lower.' It would seemirrefutable that auto-ignition of cellulose nitrate is indeed a pressingconcern in regards to the storage of motion picture films, but is onlysecondary for nitrate sheet negatives. Overall, it is the generaldeterioration of cellulose nitrate film which is the most pressing issue forarchivists and conservators who have only limited resources.Ideally, in order to minimise the decomposition of nitrate, it shouldbe separated from other archival materials, placed in airtight enclosures,and stored in a freezer. At freezing temperatures the naturaldecomposition and the production of deteriorant gases is completelystopped. Small quantities of film can be frozen relatively easily, but thecost and inconvenience involved in freezing large quantities of cellulosenitrate can be very high and may prove to be hard to manage logistically.A less costly option is to provide a controlled environment with thetemperature maintained between 50 and 70 F and a relative humidity of30-50%. Cycling of the climatic conditions must be avoided at all costs asfluctuations in the relative humidity and temperature will hasten thedeterioration of the nitrate negatives. The area around the negativesshould also be well ventilated to allow the gases to dissipate." It will benecessary to return to these procedures in a later chapter and examinethem in terms of the effects they can have on administrative andpreservation policies.52In the next chapter, the nature of cellulose nitrate films which arebeing kept in archival institutions will be examined. The relationshipbetween the hazardous qualities of CN and the administration ofinstitutional policies of preservation, access, copying and disposition ofarchival CN will be considered. The archival administration of nitrate canbe very difficult indeed, and the decisions which are made in regards to itsdisposition may have lasting, and not always good consequences. Theproblems involved in maintaining cellulose nitrate in an archives must beconsidered in a holistic manner. With this in mind, the different methodsof preservation and administration of nitrate film material will beconsidered. Emphasis will be placed on the administration of nitratenegatives in their various formats, although much of what will be said willalso be applicable to motion picture film.53' Michael Hager, "Saving the Image: The Deterioration of NitrateNegatives," Image 26, 4 (1983): 2.2 Ibid.3 Helmut Gernsheim and Alison Gernsheim, The History of Photography 16 9 5 -1914  (New York: McGraw-Hi11,1969), 62.4 Brian Coe, George Eastman and the Early Photographers, (London:Priory Press, 1973), 33.5 Gernsheim., p. 405.9 Ibid.7 Ibid., p. 406.8 Ibid.9 Ibid., p. 407.°Ibid." Ibid.12 Hager., p. 3.13 Gernsheim., p. 408.14 Hager., p. 3.15 Ibid.16 Gernsheim., p. 408.17 Coe., p. 71.18 Gernsheim., p. 408.19 Ibid.20 Steven Puglia "A Short Guide to Nitrate Negatives: History, Care, andDuplication" ( Andover, Mass: Northeast Document Conservation Centre,1987), 1.21 Gernsheim., p. 409.22 Karr., p. 2.23 "Poison Gas Kills 100 in Cleveland Clinic; Explosions Spread Fumes,Fire Following; Patients, Nurses, Doctors Die in Flight," New York Times, 16May 1929.24 "Strict rules Guard Hospital film Here," New York Times, 16 May 1929.25 Gernsheim., p. 409.26 Cellulose Nitrate and Safety-base Photographic Films, p. 1.27 Ibid.28 Puglia., p. 3.29 Ibid.30 Ibid.31 Cellulose Nitrate and Safety-Base Photographic Film, p. 3.5432 Christine Young, "Nitrate Films in the Public Institution," History NewTechnical Leaflet, 44, (July/August 1989): 3.33 Fenn and Coxon., p. 2.34 Maynor., p. 39.35 Puglia., p. 5.38 Ibid., p. 3.37 Karr., 3.38 Young., p. 3.39 Ibid.40 Coe., p. 34.41 Ibid.42 Rudolf W. Gobel, "Fire Risk by Storing Nitrocellulose and its BehaviouDuring Combustion-A Contribution to Film Preservation by the FIAF,"Institut Fur Filmkunde (nd). , 2.43 Gobel., 2. Gobel also takes a different approach in identifying stagesof film deterioration by noting three stage rather than the more familiarfive. These identifications are typified by extensive physical descriptionsof the film, in conjunction with its behaviour under combustion.44 Ibid., p. 4.43 Young, p. 3.46 Puglia., p. 5.55Chapter ThreeThe Preservation and Administration of Nitrate Negatives within ArchivalInstitutions Today the bulk of extant nitrate film is held in cultural institutionsrather than in photographer's files or in commercial film establishments.The ramifications of this situation can be very far-reaching. The mostobvious is that the primary handlers of nitrate film may tend to be lessknowledgeable about its physical nature, and unaware of the hazards itmay present, and consequently they may handle it without all thenecessary care. This lack of proper knowledge and care is sometimesaggravated by the fact that insurance companies and fire fighting agenciesmay feel that nitrate film ceased to be a problem when its manufacturingwas discontinued, and may be unaware of its continuing presence inarchival institutions.' For example, in the United States, the National FireProtection Agency has not updated the code for professional film since1936, while the code pertaining to motion picture film has been revised asrecently as 1982, but remains focused on the handling of the film withinthe film industry: no code regulates the conditions of storage of film inpublic institutions. 2The risks of such a situation should not be underestimated,particularly in view of the fact that film which was once preserved insmall private repositories is now being concentrated in great quantities inlarge public buildings. Concomitantly, the resources and institutional56infrastructures of the public bodies now responsible for the preservationof nitrate film material vary, and there may be a great discrepancybetween the capability of one institution to cope with this material andthat of another. Furthermore, the nitrate films which are being collectedby cultural institutions are often decades old, and may have already begunto deteriorate.Many archival institutions which have acquired films manufacturedprior to 1951 will have nitrate within their vaults. In acquisition decisions,the unique visual information on this material has been a more importantfactor than its instability and potential for destruction. But archivists needto weight the hazards presented by nitrate film against the importance ofthe information contained in it. In order to do so, they have to considerthat (1) permanent retention of nitrate materials implies that measuresmust be taken to guarantee its preservation and to eliminate or reduce therisk of damage to adjacent material; (2) separation of the film from theother documents of the fonds in which it belongs, for reasons of preventiveconservation, will require the establishment of tracking systems able tomaintain both the physical and intellectual control of items removed fromtheir documentary context; and (3) certain preservation techniques, suchas cold storage, must be applied judiciously and with proper guidelines inplace.In dealing with CN film, archival institutions have to focus onpreventive conservation rather than on restoration.^In fact, attempts to57restore deteriorating nitrate negatives have not proven entirely successful,with the exception of the process developed by Vilia Reed, a colourretoucher at Eastman Kodak. The process involves removing the imagebearing emulsion from the nitrate support, and transferring it to a newsafety type film base.' Reed bases her technique on an emulsion strippingsystem for colour materials, owned in part by Sears, Roebuck and Co. Thesystem consists of removing the nitrate support with a solvent and placingthe image bearing pellicle on a new, stable support previously wetted witha solution of water and Photo-Flo. It is a very delicate operation, and thefilm material is very easily damaged by excessive handling. Althoughproven successful in the hands of a skilled technician, this type of processcannot be used in large scale operations. When the gelatin emulsion iswetted, it expands, distorts and becomes extremely fragile; this problemcan be further compounded by hand manipulation and squeegeeing.'Over-manipulation can result in image-silver migration, which causespermanent tonal variations in the negative. In addition, this method isrelatively slow, and the cost of labour and materials is so high that itrenders it prohibitive for most institutions.Because of the problems involved in restoring nitrate negatives, andof the large quantity of this material which is currently accumulating at anincreasing rate in public institutions, the administrative emphasis has beenplaced on preventive conservation of nitrate negatives, and eventually onpreservation of the images they contain by copying them on another58support. Preventive conservation programs have been adopted in severalarchival institutions, with a great degree of variation in the actualprocedures put in place, and with consequently differing results. This lackof uniformity in the administration of nitrate negatives is due to a numberof factors, ranging from the specific needs of each institution, to limitedbudget and resources.There are several archival issues which are to be addressed whenconsidering the preservation and administration of nitrate negatives, anda few rather broad concerns which may impinge on other areas of decisionmaking. In examining nitrate preservation policies we will move from thearchival issues, which are strictly related to appraisal criteria, to the broadconcerns which are peripheral for archivists.An initial decision has to be taken as to whether or not nitrate filmsare to be kept. A decision in favour of retention would have to be basedon the intrinsic and evidentiary value of the film; the willingness of theinstitution to establish more or less elaborate tracking systems, which byguaranteeing proper intellectual control allowsthe repository to physicallyseparate the film from the fonds in which it belongs and to preserve thesignificance of the fonds as a whole; and the ability of the institution tocover the ongoing costs of using expensive equipment and regularlyinspecting the material.If, on the other hand, it is the intention of the institution to destroythe negatives after duplication, the implementation of this decision would59have to be preceded by the establishment of copying priorities, thedetermination of the means of interim storage and handling of the materialwaiting to be copied, and a choice of the means of destruction of the copiedmaterial. Indeed, before adopting a general policy, its effects on specificsituations have to be considered. For example, it should be investigatedwhat effect would such a policy have on the appraisal of a fonds formonetary or tax credit purposes? Destroying the originals places the focusof the archival institution on the reproduction technique, which must bechosen very carefully. The process must be proven and reliable, because,once an original image is destroyed, there is little or no recourse if thecopy image is seen to deteriorate.In late May 1990, this author conducted, in conjunction with theProvincial Archives of Manitoba (PAM), a poll of various archivalinstitutions across Canada. Its purpose was to help PAM to develop apolicy for the administration of its own rather extensive collection ofnitrate-based negatives. PAM has on-site cold storage facilities in place,and it was felt that guidelines needed to be developed and finalised withregards to the storage of nitrate negatives and other sensitivephotographic materials. PAM, as well as the Hudson's Bay CompanyArchives (HBCA) conducted a survey of their holdings, and determinedthat the number of nitrate negatives held by the Historical Division of PAMnumbered around three thousand, while HBCA had a collection numberingbetween six and ten thousand, with conceivably more yet to be found. It60seemed to be a logical move to start dealing with the problem presentedby such large numbers of photos on nitrate film by conducting a survey ofthe procedures in place at other institutions. The findings of this surveyshed a great deal of light on how the problem is being approached byvarious Canadian archives. The findings, which follow are not reportedhere for evaluative or judgmental purposes, but for showing how variousinstitutions with correspondingly dissimilar budgets and resources arecoping with the disappearing images on nitrate film.The questionnaire used for the survey was very straight-forward,and consisted of the following questions:(i) Do you retain the original nitrate negatives or do you copy andthen destroy them?(ii) If you retain the originals, then what criteria are used forselection, (i.e. intrinsic value, artifactual value, etc.)?(iii) If you destroy the originals, then what process is used?(iv) What are your copying costs? What method do you use toprepare copies?(v) If you isolate sensitive materials in cold storage, what are yourprocedures for doing so? Are these materials still accessible for research?What procedures are used to retrieve them from cold storage?Responses to the questionnaire were swift in arriving, indicatingthe importance of this problem for the archival profession; most responsescame through the mail, although some information was received through61telephone conversations. The most striking preliminary observation wasthat the various guidelines used by archival institutions did not constitutea unified body of accepted and standardised procedures for the handling ofnitrate negatives. The fact that there appeared to be little commonality inthe way in which archival institutions approached the nitrate problem canbe attributed primarily to the differences in fiscal responsibilities andrestrictions in money support for such specialised programs. Theinstitutions themselves realise the necessity of dealing with the problem ofadministering nitrate collections, and yet the variety of what is actuallyaccomplished seems to be primarily dependent on the means andresources at hand, and not on any disagreements of an archival or purelyadministrative nature.All the institutions surveyed agreed that there were problemsinvolved in the storage and preservation of nitrate collections, and that thebasic components of any program for the preservation and administrationof nitrate negatives should include their identification, separation fromother archival material, duplication of those deemed to be of historicalsignificance, and identification of new acquisitions of nitrate material.Also, all institutions agreed that such programs should be continuing andnot ad hoc. However, if we examine the way in which the variousinstitutions attempt to fit their basic understanding of the problem intoexisting fiscal considerations, it is possible to see how differences inpractise develop.62The way most institutions deal with budgetary constraints regardingephemeral visual media is familiar and time-tested: it basically involvestargeting special needs and making priority decisions. An example of thisis provided by the Provincial Archives of Alberta (PAA), where theintention is to copy and dispose of all nitrate still and moving imagenegatives, pending the acquisition of the necessary budget. As it standsnow, a good deal of copying has been done, but those films which have notbeen copied are retained and monitored for any signs of deterioration.However, this remains a policy as yet to be implemented as the Archives isunsure of the stability of direct copying film, and therefore retains for thepresent all copied originals until the relative stability of direct-duplicationfilm is fully determined. Of course, given a large budget, a particularinstitution has the option to carry on larger and more intensive programs,while smaller budgets oblige the targeting of certain needs and the use ofthe available technology. The National Archives of Canada, (NAC) is a goodexample of the first situation, while the Saskatchewan Archives Board(SAB) is a typical example of the latter. The SAB shows an ability toimprovise with its procedures, as it employs a commercial frost-freerefrigeration unit at a temperature of 3 C and 34% relative humidity forstorage, and actually takes care of some of the disposal on its own. This isa good example of a well directed program which is run on a smallerbudget and limited resources.Another approach is used with regard to a special project. ^The63Toronto City Archives has the extensive Globe and Mail collection ofjournalism photographs, many of which are on nitrate base. The Archiveshas in place a special project whereby a certain amount of time and moneyis set aside each fiscal year for the expressed purpose of copying a portionof the negatives onto polyester safety-base film. The project is run forapproximately twelve weeks, and six hundred negatives are copied duringthis time. This type of approach is particularly useful when the targetedcollection is too large to be copied all at once, or when funds are limited.It is on the question of whether the original nitrate negatives shouldbe disposed of or kept in storage after they have been copied that thereare some differences of opinion between institutions. It seems that mostarchives would choose not to keep the originals, if there were no questionsas to the dependability of the various copying systems. The ProvincialArchives of Alberta (PAA), states emphatically that the original would bedestroyed given that the stability of the duplicating film can bemaintained, whereas the Notman Photographic Archives retains theoriginals until they show signs of deterioration. The latter approachparallells that of other archival institutions, for example NAC and the SAB.It must be noted that, as in most situations involving nitrate material, tokeep or not to keep is a question which is distinctly influenced by theavailability of certain resources. Here, as with other facets ofadministration, policy decisions reflect what works for an archives withinan existing fiscal framework.64Conscious decisions have been made on certain copying procedures inorder to get the most out of the available resources, and to ensure thatproper preservation techniques are followed; for example, the negative-interpositive method seems to be quite popular, as it provides more thanone copy of the negative, which can be retained for preservation andsecurity purposes. Although the direct duplication method is generallyregarded as being less expensive and labour intensive in the long run,some institutions are hesitant to implement such a process for fear of itspossible instability. An example of this sort of decision can be seen withthe PAA, which has delayed the destruction of recently copied material forfear of silver migration in negatives copied by direct duplication methods.The survey, the results of which are shown in greater detail inAppendix I, shows that' procedures for the preservation of nitratecollections vary from one institution to another. However, thesedifferences reflect more the fiscal variation among institutions thanspecific contrasts in archival policy and implementatioi. Still, it should bepossible to formulate general guidelines for the preservation, copying,disposition, and handling of nitrate films, which might be followed to agreater or lesser degree depending on various fiscal and policyresponsibilities.Pamela Haas suggests some actions that can be undertaken relativelyeasily, and which may provide good administrative results in manydifferent situations. She writes that, after local fire codes have been65studied, cellulose nitrate-based material must be identified, andperiodically rechecked for decomposition.' One must endeavour to obtaininformation as to the numbers of nitrate films which have been selectedfor permanent preservation within each fonds, their condition, the amountof film presenting extensive decomposition, as opposed to those still intact.Once this process of identification is complete, specific actions must bedirected to the proper preservation of nitrate negatives. Nitrate materialshould be segregated from other material, if possible in a totally differentair space. It is especially important to avoid areas in which books or otherpaper materials are stored.' An attempt should be made to control theclimate in such a way as to prolong the life of nitrate negatives: if it isimpossible for the institution to provide cold storage for nitrate, thenevery avenue should be explored to ensure that the temperature ofstorage is maintained between 50 and 75 F and the relative humiditybetween 30% and 50%. Other options include the use of commercial frost-free refrigerators; in which it is possible to monitor constantly the relativehumidity. Reel film should be dealt with first: as it presents aconcentration of hundreds or thousands of feet of nitrate film, it is moredangerous than sheet film. The whole process of administration andpreservation of nitrate material requires the use of significant resources, interms of time, money and staff. At one time, experts considered itappropriate to duplicate all nitrate film by photographic processes, andthen dispose of the originals. Now this is no longer the prevailing66philosophy. As Haas puts it,Now it is felt that the appraisal of the intrinsic value of the materialmust first come into play. At this time we are advised to copy-atdifferent levels of accuracy with commensurately different pricetags-and then to store the originals in a safe place.'It is generally accepted that nitrate negatives of permanent valuemust be kept intact until the resources to have them copied becomeavailable; whether they are to be destroyed or not after copying is adecision which must be based on archival principles, and on a realisticconsideration of administrative, fiscal and human resources. Whateverthis decision will be, it is incumbent on the archivist or conservator to beaware of the technologies available for the copying of nitrate negatives.The efficacy of any program dealing with CN material hinges on thereproduction techniques which are utilised; poor workmanship oruninformed decisions can have disastrous consequences.When determining a duplication program, the administrator mustfirst consider the quantity of negatives to be reproduced on to safety film,and the amount of resources available. The latter element is often thedetermining factor in the choice of the type of technique which will beadopted. The administrator should first consider the following issues: (1)What are the different methods for duplicating negatives and what wouldthe costs entail? Due attention should be given to the relative merits anddisadvantages of each method.^(2) Which method would be best for aparticular project?^(3) How much lab work, equipment, and supplies67would be needed, and furthermore, how much archival work would benecessary to locate the negatives, prepare them for duplication, cataloguethem, and then prepare them for refiling? The cost of supplies would haveto be taken into account as would the need for additional storage cabinetsfor the new duplicates. (4) How much time will be required to train projectstaff and maintain quality control? (5) How will the archival staffrecognise the deteriorating negatives? (6) Which of the endangerednegatives will be duplicated? (8) What would be the plan of work? (9)What will be done with the originals and, if they are to be kept, willstorage space and equipment be needed?'In any copying program, several decisions are taken simultaneously;the duplication method chosen will determine the design of the cameraand the lab procedures, and these in turn will have a bearing on theidentification and cataloguing procedures. What follows is an evaluation ofthe various copying procedures available.Ways to Produce New Negatives1. CAMERA COPYFrom an original negative, a positive paper print (preferably 8x10) isis made by contact or enlarger. Then, a new negative (preferably 4x5 orlarger) is produced from the positive paper print by camera. Compared toother methods, this technique is relatively simple and inexpensive, but ityields a new negative which is less accurate in scale of tones than theoriginal, and presents a concomitant loss in resolution.'682. INTERMEDIATE POSITIVE METHODAn intermediate positive is made on film from the original negative;from the intermediate positive a duplicate negative is made. This methodcan reproduce the original image accurately tone for tone, if it is properlydone. The film interpositive serves as an insurance against loss or damageof the original duplicate; this process also uses familiar film emulsionswhich have been tried and tested. There are three variations to thismethod.Variation A: Contact positive to contact negative . From the originalnegative, a same-size intermediate positive is made, emulsion to emulsionby contact. From this intermediate positive, a same-size duplicate negativeis made, emulsion to emulsion on film by contact. This is a very good wayof making duplicates of nitrate negatives: because both the intermediatepositive and the duplicate negative are made by contact in a vacuumframe, they are the same size as the original and reproduce fine detail witha resolution which is greater than that of a lens system. Having anintermediate positive image is also an advantage. However, this system isquite expensive, and may be beyond the budget of many institutions.Variation B: Contact positive to reduced-size negative . From theoriginal, a same-size film intermediate positive is made, emulsion toemulsion on film by contact. A reduced-size duplicate negative can thenbe made through a lens system. This process produces an intermediate69positive the same size as the original negative and with very highresolution, ' while the duplicate negatives can be made in reduced sizes.An advantage of this process is that, by using the lens system to producethe duplicate negatives, this final step can be delayed if funds are notavailable, or if relative scarcity of funds dictates that final duplicates beproduced at a slower rate.Variation C: Reduced - size intermediate positive to duplicatenegative, same size. The original negative is placed on the light box of aduplication camera, and a reduced-size intermediate positive is producedon film, (4x5 sheet film, 70mm roll film, or 35mm film), through thecamera's lens system. A duplicate negative is then made from theintermediate positive, usually by contact. Larry and Jane Booth believethat duplicate negatives should not be made any smaller than 4x5, unlessthe nature of the material is such that there is not a great demand for thehighest resolution, for example, the duplication of thousands of progressshots." If small duplicate negatives are feasible, they can be producedwith a good deal of savings in cost.3. DIRECT DUPLICATE NEGATIVE METHODA direct duplicate negative can be made from an original negative inone step, using Kodak Professional Direct Duplicating Film (Estar ThickBase) with conventional processing techniques. Tone is reproducedaccurately, and because only one piece of film is used to produce a directduplicate negative, this method is less expensive size for size than the copy70camera method or the intermediate positive method.Variation A: By contact , exposed through film base with pointsource of light. The original negative is placed emulsion side up over the4168 film, also emulsion side up. The exposure is by contact to produce aright-reading duplicate negative. See Figure 7.POINT SOURCE OF LIGHTORIGINAL NEGATIVE EMULS IONFILM BASE EMULS IONFILM BASEDUPLICATE NEGATIVEFigure 7: Direct Duplicate Negative Method, Variation ABecause it is made by exposure through the original negative's filmbase, this duplicate negative has poor resolution, even though a pointsource of light is used. This method would be suitable only for films wherehigh resolution is not a critical factor.Variation B: By contact, emulsion to emulsion The original negative071and the duplicating film are placed emulsion to emulsion, and exposed bycontact to yield a same-size direct duplicate negative. The negative will,however, be wrong reading. See Figure 8.LIGHTORIGINAL NEGATIVE FILM BASEEMULSIONFILM BASEDUPLICATE NEGATIVEEMULSIONFigure 8: Direct Duplicate Negative Method, Variation BIt has been found that a duplicate negative made by contact,emulsion to emulsion, in a vacuum frame will be of the highest resolution.Besides being rather expensive, this method can prove problematicbecause the resulting negative will be wrong reading, and sharp contactprints cannot be made from such negatives using conventional methods.72This process can be used for negatives which will always be printed byenlarger, because the negative can be placed in the enlarger emulsion sideup to produce right-reading prints.Variation C: By camera, emulsion down. With the original negativeplaced emulsion side down on the light box of a duplication camera, SO-015 film is exposed to make new duplicates of any size. The new duplicatewill be right reading. See Figure 9.Figure 9: Direct Duplicate Negative Method, Variation CThis variation can produce duplicate negatives of any size.^Thequality of the reproduction depends on the duplicate negative size, aproperly aligned camera system, and a good lens designed for the73magnification range corresponding to the particular size of duplicatenegative."The relative merits and faults of all duplication methods have to beweighed before designing the duplication program, in order to ensure thatthe maximum number of images with high resolution are produced withina given budget. Booth maintains that no duplicate smaller than 4x5 wouldbe considered of acceptable quality, because "even the most carefulhandling of a negative less than 4x5 in size results in wear scratchesobjectionable for high-resolution enlarged prints".'In their report on the program for the duplication of the TICORcollection of photographs, Larry and Jane Booth explain why KodakProfessional Direct Duplicating Film, at the time named SO-015, (now called4168 Direct Duplicating film), was used for this particular large-scaleproject. Two reasons are mentioned for choosing this particular film: first,it is capable of yielding high resolution negatives when an 8x10 image isreduced through a camera lens system to 4x5 film, and secondly it makespossible for normal contrast negatives an exact reproduction, tone for tone,of the original negative. The film is also suitable for the reproduction ofsharp, high resolution 4x5 negatives by contact in a vacuum printing. Aproblem inherent in this process is that the resulting duplicate is alwayswrong-reading, which implies that a contact print made from such anegative would also be wrong-reading. This would result in the productionof many historically and diplomatically inaccurate prints if the negatives74are not clearly coded to ensure that the darkroom personnel properlyorient them to produce right-reading prints, that is, with the emulsionside up. The Booth's solution to this problem is to put a new notch on theduplicate print at the other end of the same edge that has the factory'snotch; the factory notch would then be snipped off. This new orientationof the notch automatically leads the darkroom worker to make right-reading prints both by contact and by enlarger."Another potential problem exists with Kodak 4168 film. In the earlyeighties, when the SO-015 version of this film was first being used in thereproduction of sensitive images, it was determined that negativesproduced on this direct duplicating film were more susceptible totarnishing in storage than conventional emulsions, and that the image tonewas sensitive to strong light. At the time, Kodak began testing the imagestability of SO-015 and other types of Kodak films. The results of thesetests, as published, indicated that the image stability of SO-015 was indeedless than that of Kodak Commercial Film and Super-XX, when stored underthe same conditions. Thus, serious questions arose as to theappropriateness of using this type of duplication film. Kodak implementeda full-scale program of testing on it, and published a report with specificrecommendations for processing and post-processing of SO-015 negativesto obtain greater image stability. Since that time, Kodak's extensiveresearch into the matter has proven that the film will retain its stabilitycharacteristics if its-processing and storage guidelines are followed75exactly." These guidelines have been illustrated in a publication titled,"Stability and Restoration of Kodak Professional Direct Duplicating Film SO-015", by F.J. Drago and W.E. Lee."Direct duplication should not be used to reproduce nitrate negativeswhich are to be discarded. In fact, such duplication produces only onecopy, and therefore there would be no back up image in the event that,after the original is destroyed, the new copy is damaged. If the original isretained in proper storage conditions, then direct duplication can be usedfor large quantities of nitrate negatives, as the process is most appropriatefor mass reproduction techniques. Where originals are retained, directduplication can be used effectively to make negatives for consultationpurposes.The interpositive/duplicate negative method of copying has certainadvantages over other methods besides its better reproduction of tone anddetail: in implementing a program based on this method, the process couldessentially be split into two steps. Those films which are in immediatedanger of decay could be saved by producing an interpositive copy on film,while the making of duplicate negatives could wait. This would save theimages, and allow an indefinite time period for the institution to raisefurther funds for making duplicate negatives.Many institutions do not have the budget or the resources to conductin-house duplication programs, and therefore must send their negatives tooutside processors. If this is done, then certain guidelines should be set up76in advance for having a guarantee of good quality. A logical first step is toinvestigate the various laboratories in light of the procedures to be used inthe duplication process and the type of equipment required: it would bewise to consult independent labs or university photography departmentsfor assistance in setting up quality control guidelines. Once an outsidelaboratory is chosen, a contract should be drawn up specifying the amountof residual silver thiosulphate and sodium thiosulphate allowable in thenegatives. Such standards are defined by the American National StandardsInstitute Specifications for Photographic Films for Archival Records, SilverGelatin Type, on Cellulose Ester Base, ANSI PH 1.28-1976, and on CelluloseEster Base, ANSI PH 1.41-1976." Independent tests may be performed onrandom samples of the processed duplicates in order to measure theamount of residual chemicals in the duplicate. This might be done at anindependent testing lab, provided that the institution has the budget or thenecessary contacts for such a procedure. At all times, the new duplicatenegatives should be checked against the originals for accuracy of tonereproduction, dirt, dust, fingerprints, scratches, and stains. If the contractis to include the production of prints with the duplicate negatives, then theother conditions to be specified in the contract should include the type ofprocess to be used, the size of the duplicate, the type of paper for theprints, and whether the print is to be made from the original or from theduplicate negative.' 7From a budgetary point of view, there are several possible ways in77which a copying program can be carried out. Some institutions use "specialevent " situations in which to carry out copying of collections; for example,they mark an important event or person to which a specific set of imagespertains, or bring attention to a particular body of photographs. Anotherapproach, and one which is especially effective in larger institutions withcorrespondingly bigger budgets and collections of photographs, is theestablishment of an ongoing program in which funding is set asideaccording to specific budgetary considerations and fiscal policy. Eitherapproach to copying may indeed be successful depending on the nature ofthe institution and its budget and resources. Whatever the case, thegreatest danger in implementing any type of policy of duplication isprocrastination: nitrate material is not only decaying at an acceleratingrate, but is also being acquired actively in the present. At the very least, aprogram for the location, description, and assessment of nitrate negativescould be instituted while planning a program of copying.There are further risks in delaying the implementation of aduplication program: additional nitrate negatives can be lost throughcontinuing deterioration; funding set aside for nitrate duplication may beredistributed within the institution for other purposes, or even disallowedlater on; finally, the institution's administration or the local fire officialsmay insist on the removal of the negatives from the premises before theycan be properly duplicated.It is wise to consider an ongoing program of duplication as the logical78step in the administration of nitrate negatives. Unfortunately, for someinstitutions, this program is not feasible for a variety of reasons. Whilesometimes it is just not possible to garner the necessary funding for anongoing project, other times the sheer volume of material does not make itpossible to duplicate the negatives with the desired speed. In these cases,it is important for the institution to maintain the nitrate negatives in suchconditions that will ensure their relative safety during the waiting periodfor duplication.It is important that the institution consider in advance whether itwill keep nitrate originals which have been duplicated, or whether it willdestroy them. This should be a policy decision, rather than an ad hocdecision and should be carried out as a routine. In fact, it is no smallmatter to destroy material of this nature, and the decisions made in thisregard should be considered carefully in advance. The archival andhistorical ramifications of such a policy will be dealt with later on. At thispoint it is essential to point out that, if nitrate is to be destroyed, it shouldbe only under carefully controlled conditions, with supervision of theproper fire authorities. Only a small number of nitrate films in goodcondition can be disposed of through normal waste channels. Nitratenegatives should not be incinerated with office paper." Large quantities ofdecayed film should be handled with the same degree of care which isgiven to explosives and other unstable materials; if a large quantity ofmaterial is on hand and awaiting disposal, it should be attended to in79observance of the local fire codes.The safest way to dispose of nitrate negatives is through carefullycontrolled burning by qualified personnel in the open air. In most cases,fire prevention and environmental regulations will require that suchdisposal be supervised by the proper authorities. A suitable locationwould have to be selected which would be removed from any building orfrom other combustible materials, such as gases, brush, or litter. Nitratefilms should never be burned in a furnace or other enclosed spaces,because of the toxicity of the gases and their high pressure. A high qualityincinerator may be used if it is equipped with pollution-control devices,and if the rate of burning can be limited by controlled-rate feeding. Onlysmall quantities of nitrate should be burned at a given time.If, however, nitrate material is to be kept for an indefinite period oftime after duplication, or if the quantity of material is such that long termplans for duplication are necessary, then it is very important that stepsare taken to prevent these films from deteriorating while they are waitingto be copied. If the original film is considered to be of value beyond theimage itself, then long term storage, with or without duplication may beconsidered as the best option. If long term storage is considered to benecessary, for whatever reason, then the institution is bound morally, andin some cases legally, to provide storage conditions which will reduce therate of deterioration and which will guard against the risks of fire and thebuild-up of toxic fumes. Basic guidelines have been already mentioned as80to the steps which can be taken to prevent the further decay of nitratenegatives. The techniques to be employed may vary from institution toinstitution, and are dependent on the mandate and resources of theparticular archives. For organisations with adequate budgets, cold storageshould be considered as the most viable method of long term conservationof nitrate negatives.Ideally, to minimise the decomposition of CN negatives, they shouldbe placed in airtight enclosures and stored in a frost-free freezer. At verylow temperatures, the natural decomposition of cellulose nitrate iseffectively reduced to near zero. The freezing of small quantities ofmaterial can be done with relative ease, but to do it for larger quantities ofnitrate negatives can prove to be quite prohibitive in cost. If a commercialfrost-free refrigerator is used for even short term storage of smallquantities of film, great care should be exercised in monitoring the relativehumidity of the environment, as these units are known to fluctuate andthey are not built to a standard suitable for the long term storage ofnitrate films.Cold storage vault requirements will undoubtedly vary from oneinstitution to another, but there are several basic considerations to bemade when planning and implementing a cold storage program. First ofall, it may be necessary to precondition film prior to refrigeration,especially if the following conditions exist:- The room in which the film is packaged for storage has a relative81humidity greater than 40%-50%;- The refrigerator is not frost-free;- The storage temperature is less than 55 F."When conditioning film for storage one must ensure that thehumidity is dropped below 40% in the preparation area, because coolingthe air will bring a concomitant increase in the relative humidity (RH), ifthe RH becomes high enough then condensation will occur. In the wintertime the humidity is often already low enough due to heating, and thepreconditioning phase can sometimes be omitted, but in the spring andsummer it is almost always necessary to properly condition the film. Smallquantities of film can be dehumidified by placing them in sealed plasticbags with a dessicant such as silica gel.' Once the film has reached thedesired humidity it should be placed in the freezer as quickly as possible.Nitrate negatives should be inserted in acid free buffered paperenclosures, and then placed in air-tight sealable plastic bags; Kodakmanufactures a bag which has been used successfully in these cases. Theuse of these types of bags is somewhat problematic as the hermetic sealwill maintain a certain amount of moisture within the bag, but at the sametime will trap any gases which are emitted by the film; if however, therefrigeration compartment is truly frost-free (the cooling apparatus isexterior to the compartment), then the internal humidity of therefrigeration unit will be low, and sealed bags will serve little positivefunction beyond the occurrence of fluctuations of temperature due to82equipment malfunction. If the refrigeration is only pseudo frost-free (doesnot need defrosting but the cooling coils are internal to the unit), then it isquite possible that the RH will fluctuate greatly and will occasionally bequite high; in this case sealed bags would be desirable. Standardrefrigerators that require defrosting have generally low humidity and canbe used for storage of nitrate without bags so long as alternate storage isavailable when the units have to be defrosted.A cold storage vault will probably have a storage atmosphere ofaround 2 C and a relative humidity of approximately 35%. Maintainingthese conditions requires very specialised and rather expensiveequipment. Therefore guidelines must be set in place in order to maintainthe physical integrity of the collections contained within the vault. Itemsto be placed in the cold storage vault should be preconditioned with theirstorage materials for a period of twenty four hours in the stack area (forexample, at 4 C and 47% RH). After this period of acclimatization iscomplete, the materials could then be moved from the stack area toanother place, where they will be allowed to acclimatize to the vaultconditions for a further twenty four hours. Storage materials which couldbe used are individual mylar sleeves for each negative, and Kodak StorageEnvelopes (Cat. 148 6398), in which these mylar sleeves would be placed.In order to keep the workload at a minimum, a system could be devisedwhereby the nitrate materials and their envelopes are properly identifiedand partially assembled prior to acclimatization in the stacks. This would83mean that the mylar sleeves containing the nitrate negatives would onlyhave to be placed in the envelopes by the worker in the vault.Mylar sleeves have several advantages with respect to paper; theytake up less space in the envelope, do not stick to decaying negatives, areinert, and facilitate checking for deterioration. Identification for theproper tracking of items can be done by using gummed labels on theoutside of the mylar sleeves, or by marking the sleeve itself with a stableinsoluble pen. Some concern has been expressed as to whether nitratenegatives should be placed in alkaline buffered envelopes, but this isinadvisable as the buffering compound may cause deterioration of theimage.'The mylar sleeves containing the negatives should be placed in theenvelopes to a thickness of no more than one-half inch; this is to ensurethat no physical distortion occurs. Air can then be pressed out of theenvelopes, and then they can be heat sealed; the resulting vacuum, and thelow temperatures will reduce or eliminate altogether the possibility ofoxidative reactions. The Kodak envelopes can be opened and resealed inorder for negatives to be removed and inspected for signs of deteriorationor for copying. These types of sleeves can only be resealed a certainnumber of times, however, as each time the envelope is sealed a certainamount of it is used up in the process, and the envelope would have toeventually be discarded.Items which are to be removed from cold storage could be inserted84into a closed polyethylene bag to prevent condensation, and allowed toacclimatize to stack conditions for twenty four hours; the Kodak storageenvelopes should remain sealed. These items could then be moved toroom temperature for twenty four hours prior to being opened. Thepreconditioning procedures outlined above must then be repeated whenthe materials are returned to the vault.These procedures are necessary in order to ensure that the negativesretain their original clarity and tone, free from oxidative deterioration.Needless to say, such storage procedures can only be undertaken in anarchives where there is a program of copying already in place and running;the materials which are to be put into cold storage vaults should not beaccessed on a regular basis as the logistics do not provide for easy andquick retrieval. This is long term storage in the strictest sense; and is to bemaintained in intellectual deference to the original image, and as a propersafety precaution with modern copying methods.At this point attention might be given to a new form of technologywhich may come into play in the long term mass storage of both imagesand textual material in archival institutions. This new technology is knownas CD ROM storage and has come on line in recent years as a practicalalternative to conventional information storage techniques. However, asthe presentation of this type of technology is outside the immediate scopeof this thesis, and is highly technical, it has been included in Appendix II.This chapter has attempted to deal with some of the most important85issues which surround the preservation of nitrate negatives in publicinstitutions.^The matter is not a simple one, and various organisationshave developed guidelines and procedures which are often institutionspecific. It is not the purpose of this thesis to establish a set of rules andregulations which must be adhered to, but to highlight certaincircumstances or ramifications which may arise from various courses ofaction. It has at all times to be remembered that the consequences of thedecisions made today will remain for many years, and that a bad course ofaction taken at the outset will prove very hard to reverse in the course ofsetting future administration policy.86' Young., p. 4.2 Ibid.3 Eugene Ostroff, "Rescuing Nitrate Negatives," Museum News, (Summer/October 1978): 35.4 Ibid., p. 42.5 Pamela Haas, "The Conservation of Photographic Collections," Curator,26, No.2 (1983): 95.6 Ibid.Ibid.8 Larry and Jane Booth, "Duplication of Cellulose Nitrate Negatives,"Picturescope, 30, No.1 (Spring 1982): 12.9 Ibid., p. 13.'° Ibid." Ibid., p. 14.12 Ibid. p. 13.13 Ibid., p. 15.14 Puglia., p. 7.15 Cited in Booth, Larry and Jane, p. 18.16 Ibid., p. 17.'7 Fiber-based prints should be chosen for long term archival copieswhereas resin coated papers are sufficient for work prints. Also, it haslong been recognised that toning of images on paper prints enhances theimage permanence, and this is a standard recommendation for enhancingthe stability of paper prints. The addition of potassium iodide to the fixingsolution has been used in the production of microfilms since 1969, this hasbeen recommended to provide protection from micro dot stains. Toningshould be looked into as a possible way to maintain stability in silver-gelatin images.19 Eastman Kodak Co, The Preservation of Photographs (Rochester:Eastman Kodak Co.,1979), p. 34.'9 Young, p. 6.20 Ibid.21 Interview with Jane Dailey, Head Conservator for the ProvincialArchives of Manitoba.87ConclusionBecause the hazards of nitrate films are not generally known, it isimportant to educate and encourage the archival community to arm itselfwith the facts before attempting to deal with them. Nitrate's reputationmay cause some to take radical actions which are not befitting thecircumstances. As G. William Jones states, it is important to "do the wholejob of talking about the preciousness as well as the danger" of nitrate film.In other words, nitrate film is certainly no demon; it is possible to put inplace programs and operations which allow one to deal with its volatilenature, and at the same time, avoid risks for the material itself or for thepeople who work with it. Despite many commonly-held perceptions of thedangers of nitrate film, it is indeed possible to care for it in such a way asto render it safe as well as long-living. With some education and practicalexperience, the archivist can deal with the material in a rational and logicalmanner, much like s/he would with any other sensitive material withinthe framework of established procedure. It would be rather unfortunate ifarchives were to go so far as to avoid acquiring nitrate film because of itsperceived danger; the fact is that nitrate film is as dangerous as themethods which are used to store it. If the necessary precautions are takenthere should be few problems. The main reason why archives should notshy away from the further acquisition of nitrate film is its historicalfunction in the creation of a mass photographic interest: this film was thebasis of the growing popularity of photography in the late decades of the88nineteenth century, and many of the images which are captured on nitratefilm lend a perspective not only on important events in the past, but onevery-day life as well. It is therefore not uncommon, given the time-frame in which nitrate film was used, as well as its popularity as the firstviable flexible roll film, to find large amounts of nitrate negatives and reelfilm within an archive's fonds.Once nitrate film is within an archival institution, there are severaloptions open for its administration. The first and most important questionto be answered is whether the film is to be kept in storage for the long orthe short term, that is, whether the material will be copied and thendestroyed, or copied and retained. These two courses of action must beconsidered well in advance of implementing the copying policy as theyhave a bearing on the type of duplication processes used as well as on howthis and other types of ephemeral material will be approached over thelong run.The consideration of this particular aspect of nitrate preservationhinges on the concept of the form of the document, which in this case is thenitrate negative. If the physical form of the negative is not necessary toour understanding of the image, then we need do little else than to acquirenitrate film, copy it, and then destroy it. If, on the other hand we are toconsider the form of the negative to be functional to the understanding ofthe image then we must build a case for retaining the nitrate negativespast the copying stage. The simple assertion that the original is unique89and holy and is the only entity which is capable of providing true andadmissible evidence is not a valid argument for preserving it, because acopy would be capable of accomplishing the same evidentiary functions asthe original, if it is properly authenticated. To understand better theproblem of form with regard to nitrate negatives we must turn todiplomatics and the concept of documentary forms.According to diplomatics, every written document has a form, that is,the information it contains is expressed by means of rules ofrepresentation which are themselves part of the message. These rules ofrepresentation, or form, reflect specific political, legal, administrative andeconomic structures, as well as culture, habits, myths, and, "constitute anintegral part of the written document, because they formulate or conditionthe ideas or facts which we take to be the content of the documents": Theform of the document comprises both physical and intellectualcomponents: the external makeup, which is the physical form of thedocument, and the internal articulation which is its intellectual form. Tounderstand the document fully one must comprehend its physical andintellectual forms. However, the strict observance of rules of form cannotalways be expected in a personal context, because the inner freedom ofhuman beings is such that the diplomatic study of forms may reveal littlewith regards to documents which result purely from personal activity.'One can argue in light of diplomatic analysis that a photograph hasall the basic elements of a written document: an emulsion adhered to a90flexible transparent backing (physical form), a message to transmit,constituted of that which the photographer sees and wishes to express(content), and an internal articulation expressed in the photographer'schoice of angles of composition, apertures, speeds and possibly speciallenses (intellectual form). Therefore, a photograph can be analysed to thesame degree in which we approach any written document. This approachmay seem more suited to the photographs taken by an art photographer orby the so-called professional, and less to the simple amateur photograph.This is not true, however, because intellectual form does not necessarilyresult from a conscious choice; rather it is the natural result of the effort tocommunicate.One must wonder, however, whether we can approach thephotograph and the negative from which it results as we would a writtendocument produced according to administrative and legal rules. Theanswer to this question is especially important in the identification of whatis original, and can determine whether a nitrate negative should be keptfor as long as possible, even if it has been reproduced in the best way thattechnology has to offer.In diplomatic terms, the concept of originality hinges on twoimportant precepts: the first, primitiveness, and the second, perfection.Primitiveness means simply that the document is the first in order, whileperfection in a document indicates that it is complete, finished, withoutdefect and enforceable. A document having the status of original is91capable of producing the consequences for which it was created, and istherefore a means to an end as well as an end in itself. Therefore, inestablishing the status of a document, the medium is a consideration, "if itinfluences the enforceability of the document": In the case ofphotographs, the negative is the precursor of the print, and thereforeexhibits primitiveness, but at the same time it lacks perfection, because itis not a complete and finished photograph. Most importantly, it is not anenforceable document because it is not fully capable of producing theconsequences for which it was created. It is, in fact, the first print whichcreates the consequences and achieves the end for which the photographwas taken in the first place, and it is therefore the first perfect document.In instances where we have many first prints, we have many originals ofthe same document; where subsequent prints are made at different timesand distributed, the first one to be transmitted is the original, whilesubsequent images are copies in the form of the original.'If the original is the first perfect document, and with photographs,that original is indeed the first print and not the negative, then can weconsider the negative to be a draft? In diplomatic terms, the draft of adocument is a sketch or outline of the definitive text, it is prepared forpurposes of correction and is considered to be provisional. The final draftof a document generally has most of the elements of the original but notthe physical form. The draft of a document represents the creativemoment in the documentation process and, "because of this, has the92greatest importance not only for a diplomatic understanding of thatprocess, but also for the diplomatic understanding of the fact and willdetermining the creation of the document"! Indeed, the negative of aphotograph will contain all the information of the first perfect print, butthe opposite is not necessarily true and the transmission of the informationfrom negative to print may alter it in such a way that that only the trainedeye can determine the relationship between the negative and the firstprint: for example, apertures can be changed, and resolutions can bemanipulated so that the actual information which is conveyed in theoriginal is much different from the information conveyed in the negative.'Therefore, it may be said that the negative is the essential vehicle in thefinal production of the print and is a draft, yet it is not like a final draft. Itdefines a creative moment, but only one in a series of creative momentswhich culminate in the production of the first perfect document, theoriginal print. Moreover it is not a draft in the traditional sense, because ittends to carry more, rather than less information than the original andmuch of it is included in the negative not by the will of the photographerbut by the mechanics of the technology. This implies that the will of theauthor can only be visible in the first print, which would contain only thatwhich the photographer wishes to convey to the observer. Thus while withtraditional documents the draft constitutes the creative moment and theoriginal the formal moment, with photographs both draft and originalcontain elements of creativity as well as of formality.93In the art community, the emphasis is placed on the first andsubsequent prints of a given negative rather than on the negative itself:the print is of the greatest importance and the negative is of much lessvalue to the art curator. The negative is merely the means to the finalprint, which is the end; it is the instrument for the production of the finaland artistically significant print. Archivists may balk at the thought ofaligning their ideas with those of the art curator, but such an approach,aimed at understanding the relationship between two states oftransmission, would be diplomatically orthodox. Besides, the issue here isthat form, in a draft, is not an essential part of the document, but usually itis precisely that part which is meant to be different in the original. As amatter of fact, a document is made complete and effective by its form, theperfection of its form makes it original. Therefore, we do not need topreserve the initial form of the negative to capture the information in itsentirety, as long as the historical context provided by the material ispreserved in its form of descriptive information. Many of the nitratenegatives which are acquired by archives can be classified as amateur innature and their form does not add to the meaning of the image even inthe print.It is important to note, however, that the policy of copy-and-destroyin no way eliminates the need for facilities which will ensure the safe, longterm storage of nitrate material. Nitrate negatives are truly ubiquitousand can be found in almost all institutions which acquire photographs.94Because nitrate was the first roll film to gain a foothold in the mass marketand is closely tied to the boom in amateur picture taking which occurredin the late eighteenth and early nineteenth centuries, the actual numberof nitrate negatives which exist in the world today is enormous;concurrently, the number of those images which are of lasting historicalimportance is also very large. It would be materially impossible for mostarchives with fixed budgets to copy all the negatives in their holdings atone time; most often, copying programs are carried on in the long term.Long term storage facilities are therefore important to ensure that thoseimages which are to be copied in the future are maintained in goodcondition so that the best copy images are produced, and that both theirsafety and the safety of the archives is guaranteed. Such facilities wouldalso allow for a "cooling off" period for the copied images: the nitratenegatives should be retained on hand for a specific period of time in orderto ensure that the techniques and materials used in the copying processare stable and reliable and that the highest possible quality is maintained.Some may argue that if we can justify the disposal of original nitratenegatives after copying, then we can also rationalise the destruction ofdocuments in other media. It might be contended that when writtendocuments are photo-reproduced, as for example on microfilm, it would belogical to destroy them, just as we would do with nitrate negatives. Thisreasoning, however, can be proven incorrect. The original journals of theHudson's Bay Company posts held in the Hudson's Bay Company Archives95may be taken as an example; they have all been microfilmed, and many ofthem are in such delicate condition that they have been removed fromcirculation. Is it correct to contend that the journals may be destroyed, onthe basis of the same argument used for nitrate negatives? The answer isunequivocally negative. With a photographic negative, we would bedestroying the equivalent of a draft, which lacks enforceability and doesnot carry forth the the intentions of the photographer. With the Hudson'sBay Company journals we would be destroying the originals; the microfilm,if authenticated may be as enforceable as the original, but lacking some ofits formal elements would be bereft of much of the information which onlythe original is capable of conveying. The actions and intent of the writerare expressed and carried out in the act of writing, whereas for the mostpart, the actions of the photographer are fully conceived and carried out inthe act of printing of the first original print.Moreover, the artifactual value of the nitrate negative is minimal; thetechniques are established and fully documented, and the negative isfamiliar to those who have studied it. Therefore, a representative sampleof this material is all that is necessary for the purposes of historical studyof the technology' . To attempt the preservation of all nitrate negativeswould put needless pressure on resources and management time, not tomention the fact that we run the risk of falling into the trap of preservingevidence of the material itself and not of the facts it attests to. Such anapproach would increase the likelihood that the central purpose of96photographic administration, that is, the preservation and dissemination ofthe photographic "record"-and not the whole-hearted yet misdirectedcuratorship of objects-be missed.It is important in the final analysis to consider a set ofrecommendations which pertain to the administration of nitrate negativematerials:(1) It is recommended that a copying program be put in place at thearchives, and that nitrate negatives should be copied and destroyed. 8(2) If a copying program does not exist, then the necessaryprecautions must be taken to ensure that the negatives can be stored untilsuch time as they can be copied. This may involve storing the negatives inan existing stack area separate from other archival materials and withinreasonable ranges of temperature and humidity, or placing them in longterm cold storage in a frost free refrigerator or advanced technology coldstorage unit.(3) If the material is to be copied and then destroyed, the techniquesused should guarantee stable copy negatives. ^It is advisable that morethan one copy be produced and preferably two or three; so that one maybe used as a research/reproduction copy, while the others serve assecurity and archival backups.(4) A "cooling off" period is suggested for the copied negativesbefore disposal. If the negative is at less than stage three of deterioration,and is therefore reproducible, then it should be kept on hand until such97time as it can be determined that the copy image is stable. Such a routineshould be established in cases where there is no recourse to producingmore than one copy image.(5) It must be decided at the outset whether the archives is going tocarry out the copying program on-site or if the negatives are to be sent toa commercial laboratory for copying. If the work is to be "farmed out", itis imperative that the arrangement be a contractual one, which specifiesthat certain standards of reproduction and processing be maintained; thearchives must reserve the right to have the tonal quality of thereproductions tested by an independent lab, and to send back at no chargenegatives not adhering to the agreed upon standards. It can at times be arisky proposition to have such critical procedures done outside theinstitution, and any potential problems must be considered and accountedfor well in advance.(6) At all times archival controls must be exercised to maintain theintegrity of the fonds in which the negatives belong; this is especiallyimportant in the duplication and storage procedures, as poorly devisedlocation inventories may cause the future retrieval of individual negativesto be problematic. With this in mind it would be sensible to run a pilotproject on the entire procedure using a small but representative group ofnegatives. In the pilot stage any bugs in the operation can be worked outwell in advance of attempting a large collection of negatives. ^It goeswithout saying that any perceived problems may be rectified more easily98in a situation where the sample is manageable.(7) Any quantity of nitrate negatives should be destroyed under theauspices of the local fire safety inspector. Because of the extreme volatilityof the material, nitrate should not be destroyed either privately or on ado-it-yourself basis, for reasons of personal and environmental safety.(8) If a copying program is not yet in place, or if the quantity ofnitrate negatives is such that copying and destruction must be carried outover an extended period of time, it is advisable that the institutionimplement procedures whereby a survey of the existing nitrate in storageis performed on a regular basis. Because of the unpredictable way inwhich nitrate deteriorates, a survey carried out over one or two yearswould be sufficient to determine if any particular image is in danger ofdeteriorating past the reproduction stage. This of course would not benecessary where long term cold storage procedures are in place. However,in instances where the cold storage is not state-of-the-art, the closemonitoring of any temperature and humidity fluctuation is important.(9) A common sense approach to the implementation of a copyingprogram would be to build up case files on particular fonds which arepartially or entirely made up of nitrate. The necessary accessioninformation would be included with an initial report as to the state inwhich the material was acquired; this would serve as the basic informationon which a tracking system might be based. This case file, in conjunctionwith a regular survey, would greatly facilitate the organisation of a logical99copying program.(10) In any copying program, it is necessary to prioritize photographcollections; this can be done by balancing the factors of historicalsignificance and stage of deterioration. In some instances this mayconstitute little more than an archival gamble. ^Realistically, groups ofnegatives of greater significance should be copied ahead of those of lessimportance. However, an archives may choose to postpone the copying ofa group of historically important negatives in a fresh, undeterioratedcondition in favour of a less significant group which is showing signs ofprogressive deterioration.^This is an institutional prerogative.^In caseswhere a group of negatives documents the activities of a well knownphotographer, the institution may deem the artifactual value of thenegatives offsets the historical value of other collections and it may becopied first.(11) Finally, it is very important that guidelines produced as part ofa rational approach to the administration of nitrate negatives beincorporated into the overall procedures of the institution. ^A manualshould be compiled, agreed upon and published as a standing documentwithin the archives. This would ensure the program's continuity throughchanges in personnel and administration, and would allow for moreefficient revision of the guidelines where ongoing research or changes intechnique may dictate.Following the above recommendations would certainly be a first100important step towards the preservation of historical images on nitratefilm and the protection of the total holdings of archival institutions whichhave acquired nitrate material. Furthermore, by ensuring the physicalintegrity of nitrate negatives, the health of those people who work themwill also be safeguarded.Archivists must become aware of the fact that the dangerous natureof nitrate negatives does not require their complete destruction, somethingwhich would not only be unnecessary but also unfeasible, given theubiquity of the material. The danger needs to be demystified as much as itneeds to be known. Ultimately, this too is a question of education.1 01' Luciana Duranti, "Diplomatics: New Uses for an Old Science," Archivaria28 (Summer 1989): 15.2 Ibid.I bid . , p. 20.Ibid.5 Ibid.6 "A Picture is Worth^ ?", ACA Bulletin, January 1993, 15. In thisarticle the conclusion is reached that the destruction of Mr. Weston'snegatives was not indeed the destruction of his work, but an act designedto ensure that his work would never be misrepresented.7 In the case of aerial photographs, it would not be appropriate to keepa simple representative sample. If one negative is to be kept after copyingthen all should be retained as the loss of one link in the chain ofinformation renders the entire fond extremely diminished in information.Furthermore, the aerial photo is one of the few cases where the negativeand the first original print contain identical informational elements; thewill of the photographer in taking the photograph is representedcompletely in the finished print. The principle of Respect des Fonds m a ytherefore encourage institutions to retain all aerial photos on nitrate baseif proper conditions are maintained for their storage.6 "Principles of Institutional Evaluation (proposal)", SAA Newsletter, July1992, 17.102Appendix IThe SurveyThe survey instrument consisted of a very basic questionnaire in anopen-ended form; it was initially intended by the Provincial Archives ofManitoba to gather information about the procedures used by otherinstitutions for the preservation and administration of nitrate negatives.There was never any intent to analyse statistically the informationgathered; rather the questionnaire was seen merely as an instrument forthe qualitative representation of the procedures in place at a number ofinstitutions. The sampled population was non-random and wasdetermined by consideration of the type of material which might beacquired by the various archives and museums. A concerted effort wasmade to poll a broad spectrum of institutions: from large institutions withsignificant budgets, to small ones with much more restricted resources.The goal was to learn how archival institutions were coping with nitratefilm, and to what degree budgetary considerations had a role to play inthe type of program chosen; the method of copying; the type of storage;and whether there were any particularly innovative procedures beingfollowed.The questionnaire was sent to twelve preselected institutions;and the response rate was 100%. The responses were generally in theform of written letters, although Toronto City Archives phoned in a reply.103Some institutions included with their replies some additional technicalinformation in the form of pamphlets and product advertisements.The questionnaire was sent to these institutions: NotmanPhotographic Archives; National Archives of Canada; Provincial Archivesof Alberta; Provincial Archives of New Brunswick; City of VancouverArchives; Saskatchewan Archives Board; Provincial Archives ofNewfoundland and Labrador; Glenbow Museum Archives; Archives ofOntario; Public Archives of Nova Scotia; Les Archives Nationales du Quebec;and the Toronto City Archives.The following is a more detailed description of the courses of actiontaken by the various institutions involved in the survey. The report,which was compiled under the auspices of Betty Blight and the ProvincialArchives of Manitoba, was titled, "A Report in Conjunction with theProvincial Archives of Manitoba Regarding Nitrate Collections," (Winnipeg,Manitoba: 1990) .Both the Archives of Ontario and the Glenbow Museum Archiveshave expressed an interest in a responsible administrative program for theproper appraisal, preservation, and access to nitrate negatives.Unfortunately, circumstances have been such that implementing a programhas proven to be difficult. The Glenbow is still using nitrate negatives toproduce research copies; occasionally, when a particular negative is foundto be significantly deteriorated, a new negative is made from a referenceprint. Whether or not the negative is retained depends on the degree of1 04deterioration, but generally the Archives would tend to retain it. Nomention was made as to whether the nitrate negatives are retainedseparate from the rest of the holdings. If funding is secured in the future,the Glenbow will institute a duplication program using the interpositivemethod, while no plans have been made for cold storage.Until recently, the nitrate problem was not considered at theArchives of Ontario; there has been no selective retention of nitratematerial, and CN negatives have not been separated from the existingfonds when the images had any archival value. Some items were in thepast copied on to safety film, but the original was not destroyed. Thearchives has recommended that nitrate material be preserved only until itbegins to show signs of serious deterioration. Preservation negatives areto be made while the nitrate is still in good condition, and a periodic andsystematic evaluation is made to record the process of deterioration. Thearchives has stated that the artifactual nature of the negatives becomesirrelevant when the material poses a threat to the other holdings .The policy of the Provincial Archives of Alberta (PAA) has been tocopy all its nitrate negatives and dispose of the originals, but budgetaryconstraints have not allowed for the completion of this program There areno cold storage capabilities in place at present, but they are included in theplans for a proposed new facility. Separate storage is provided only forthe working copies of cinefilm, while none of the original stills (includingnitrate) are available for public consultation; reference copies are produced1 05for this purpose. The staff has expressed some concern over the evidenceof silver migration and instability in direct duplication film, and this hasresulted in the holding back for destruction of recently copied material.The PAA does not, however, see any intrinsic or artifactual value in theoriginal nitrate negatives which would justify their continued preservationif an acceptable method of archival copying is determined.The Saskatchewan Archives Board maintains its collection of nitratenegatives separate from the rest of its holdings, and stores them in a frost-free refrigerator with a temperature of 3 C and a relative humidity of 34%.The respondent to the questionnaire expressed reservations about sealingthe Kodak envelopes, expressing the opinion that the gases emitted by thedecomposing nitrate should be vented from its confines.The City of Vancouver Archives is currently in the initial stages ofdeveloping policies to deal with the problem of nitrate preservation. Thecurrent holdings of nitrate negatives have been separated from the rest ofthe photographic material, and are maintained in one central location inthe stacks at a temperature of 19.5 C and 52% relative humidity; thiswould appear to be an interim measure on the part of the archives asplans for a cold storage unit are being considered, but it has yet to bedetermined what type of cold storage would be best suited to the needs ofthe institution. For the most part, copy prints have been produced fromthe nitrate negatives and, as reprints are required, a copy negative is madefrom the copy print. The City of Vancouver Archives hopes to develop106criteria for determining more appropriate duplication priorities based onstandard appraisal techniques for intrinsic and informational value. Ahigh priority for duplication would be given to those negatives which are'showing obvious signs of deterioration: those showing signs of extremedegradation would be destroyed upon duplication. The archives feels thatthe best method of duplication is an interpositive/negative method .The National Archives of Canada retains the nitrate negatives,provided that they are not showing significant signs of deterioration;copies are made of those negatives which it is physically possible to copy,and which are of sufficient historical significance. The archives destroysthose negatives which have reached greater deterioration than stage two.NAC uses the interpositive/negative method of duplication; thephotographic laboratory retains the copy negative in order to respond torequests for reproductions, while the photographs division retains theinterpositive as an additional preservation copy. Negatives which areselected for preservation copying are coded, resleeved in acid-freeenclosures and then copied. Duplicated originals which show signs ofserious deterioration are destroyed, while those which are to be sent tocold storage are placed in acid-free archival boxes and sent to theRockcliffe Vault location where they are kept at 10 C and 50% relativehumidity. Information on the contents of each box and its location ismaintained in an automated box label/home location data base, which isused to generate box labels and a location inventory list. NAC is currently107performing a survey of existing negative collections in an attempt to locateand segregate nitrate material. The negatives so identified are separatedfrom the existing collections, copied and sent to the Rockcliffe vaults forpermanent storage. These vaults are used for material which is stillcirculating on a regular basis, while another storage area at Tunney'sPasture is used for essentially dead storage. The material currently beingheld at the Rockcliffe location is in varying stages of archival processing;the system is currently undergoing something of an overhaul, as there hasnot been a full-time collections manager at the NAC for some time .The Provincial Archives of Newfoundland and Labrador retains allnitrate negatives, and stores them in deep-freeze units: retrieval time isapproximately 24 hours. Most of the negatives are in individual acid-freeenvelopes, and contained in sealed acid-free Hollinger boxes. Some of thenitrate negatives have been copied to print format and, when this is done,a safety negative is also produced, so that the original nitrate negative willnot have to be used, but will remain available in case it has to be viewedin specific instances. The archives hopes to render their collections ofnitrate negatives more accessible to the public through a program ofduplication in the near future.The British Columbia Archives and Records Service has in the pastperformed a general culling, and has destroyed those negatives which arein poor condition. It only intends to destroy more if and when theydeteriorate to the point at which they become a hazard. No mention was108made of the stage at which the negatives were destroyed, and there is nopolicy for routine destruction. The criteria for evaluating the negativesremain the same used for other forms of archival material, but with specialconsideration for the medium.The Toronto City Archives is currently in the process of copying itscollection of negatives from the Globe and Mail; this is a project for whichspecific funding has been obtained, and there are no other plans in placefor the balance of the nitrate material in the holdings of the archives. Thisproject is being carried out on a twelve week basis every year andapproximately 600 photographs are copied each time and the originalsdestroyed.The Notman Photographic Archives at the McCord Museum retainsthe original nitrate negatives, and bases its appraisal of the image onintrinsic and artifactual value. The negatives are copied as 4x5 negatives.There are no cold storage facilities, and the negatives are stored loosely onopen shelves. The only time the Museum destroys nitrate negatives iswhen they show serious signs of deterioration.Les Archives Nationales du Quebec acquires nitrate material in theform of nitrate based audio and visual tapes and several thousands of stillimages. The Archives copies nitrate material before disposing of it througha Quebec firm which specialises in its destruction. For audiotape,budgetary considerations have dictated that the copying process be donein stages. A laboratory in Montreal is contracted to copy an optical1 09positive soundtrack off the original negative and transfer it to 35 mmsafety base. After the soundtrack has been properly mixed and correctedfor sound quality, another optical copy is made. For film, the archivesproduces master-positives from which it makes duplicate negatives forcopying purposes. The archives has many thousands of still images in avariety of formats; they are stored in a refrigerated vault in acid-freeenvelopes. It is not foreseen that these still images will be disposed of asthe refrigeration decreases the risk of deterioration substantially.Certainly there is a great deal of variation as to how variousinstitutions deal with nitrate material, and these differences of approachseem to be dependent primarily on financial matters rather than onarchival concerns and theory. It is still important, however, to formulate aset of guidelines for the proper administration of nitrate collections.110Appendix II:CD ROM Technology and its Application to the Storage ofVisual ImagesCD ROM represents an exciting new breakthrough in informationstorage technology. It constitutes a new publishing medium, the centre ofa new genre of computer applications, and an educational tool ofunprecedented power; it allows for the efficient manipulation ofextremely large databases and allows almost any organisation to exchange,sell, buy and use these databases through the implementation of certainspecialised technologies.' Each CD ROM disc can carry at least 550megabytes of digital data with the accuracy and reliability of the best incomputer peripheral devices; and can hold the equivalent of 150,000printed pages, 15,000 document pages, 1200 standard 5.25-inch floppydisks; and can provide a crisp colour picture and ten seconds of narrationfor each 3,000 segments of an educational or reference program,equivalent to eight hours of content. 2Despite all its impressive capabilities, CD ROM is not the multi-purpose storage medium which will render all others obsolete: this newtechnology still requires the support of conventional systems such as disc,tape, and RAM products. One of its greatest limitations is that it is a read-only medium, therefore it is especially suited for large and unchangingdatabases, but not for those which are evolving. CD ROM can, however, be1 1 1used in changing archival databases, if smaller sub-units of the largerdatabase are created as more material is acquired. This would involve thecreation of subsequent CD ROM discs. The new material is digitised onto anapplicable format, for example a storage tape, and then sent to a companyspecialising in the creation of CD ROM master discs containing the "archivedinformation". This process can prove to be rather cumbersome, and inevolving collections, technical and specialised cross-indexing softwarewould be required to deal with several discs carrying related information.For rapidly evolving databases, a high-capacity writeable medium such asthe optical disc WORM could prove more suitable. The advent of CD ROMcould indeed be a boon for the storage of copies of fragile photographs, ifsome drawbacks to the system, not the least of which is the high cost ofthis technology, can in some way be circumvented.Much of the excitement surrounding the advent of CD ROM can beattributed to the compact audio disc, or CD. As it is well known, the CD hasproven to be enormously successful in the music marketplace, supplantingthe vinyl record as a means of distributing music. The great success of thismedium has raised hopes within the industry that its progeny, the CD ROM,will be equally successful. The technology behind all of today's opticalstorage of digital data comes not from the computer industry but from theconsumer electronics industry.' The concept of the CD ROM grew up duringthe eighties; and as the CD matured and became accepted by the consumer,it became apparent to some that the CD ROM could be used as a medium112for the storage and distribution of digitally encoded data.A CD ROM disc is 120 mm in diameter, 1.2 mm thick and has a hole15 mm across in the centre. The information on the disc is represented bya spiral series of small pits moulded onto the surface. The surface iscoated with a reflective metal layer, which is then coated with a protectivelacquer. The structure of the disc is such that the total length of the trackon the CD ROM disc is almost three miles, and the total number of pitswhich represent information is almost 2 billion.' The information isencoded on the disc by a process called mastering. Mastering begins whenthe information to be encoded is transferred from magnetic tape to apowerful laser beam which then passes over the surface of the disc,burning a spot on the coating of the disc. In order to read the informationfrom the disc, a laser beam is focused on the spiral track of the pits andthe light is reflected back into an objective lens. When the beam hits apit, most of the light is refracted and very little light is reflected back intothe objective lens. Conversely, when the light beam strikes a clear spot onthe track, most of the light is reflected back into the objective lens. Thismodulated beam of light entering the lens represents the digitalinformation stored on the disc, which is then converted into an electricalcurrent which is read by the computer as a series of 0's and l's, the basisof computerised digital information.There are several important criteria to be considered whendeveloping CD ROM applications for the storage of images; they are also113determining factors in the scanning and processing technology. Thecriteria are: the frequency of update of the information base; thesuitability of the content for image capture and processing; the number ofcopies needed to meet the market demand; the value of the informationcontent to the user as measured by the cost and availability of othersources; and the degree of sophisticated search and retrieval required bythe user. All these factors have a bearing on the resources needed; it istherefore important that the necessary planning be done far in advance ofimplementing a CD ROM program for the storage of images.Image scanning and processing consists of five basic elements: imagecapture, data manipulation, storage and retrieval, and display and printing.Capturing an image requires that it be converted into a set of digital data.This implies that: (i) the image is to be moved into a position to bescanned; (ii) an optical system forms the image of the document onto thephoto-detection system; and (iii) the photodetector converts the light into adigital signal which can be stored. Data manipulation is generally onlyincluded in the more expensive packages; manipulation may be needed ininstances where large quantities of images are stored, and some need to berecaptured for the sake of quality control. Manipulation of the digitisedimage also has some interesting possibilities, as deteriorated or poorlyexposed areas of the original image can be enhanced to a certain degree inthe database, thereby saving possible labour intensive work on theoriginal. In CD ROM, there are two steps involved in storage: a master disc1 1 4is made for the process of duplication, and then the copies of the masterare made. Retrieval usually involves some form of database managementsystem, with a separately maintained indexing system. Display andprinting can be discussed together. There are some technical problemsassociated with the printing and display of digitised images, the mostserious of which lies in converting the images into a displayable formwhich takes into account the differences in resolution, aspect ratio, andpixel geometry of the various kinds of display devices which are available'.There are three basic scanner designs which are currently used inimage capture. These are camera based systems, flatbed systems, andpaper moving systems. Camera systems are particularly flexible in theirapplication, because camera emulation and lenses can be selected for aparticular application. The type of camera which is used in thesesituations is of broadcast quality, with very high resolution andcorrespondingly high cost. Resolution can be increased or decreased bymoving the lens either closer to or farther away from the image to bescanned. Camera systems tend to be somewhat more expensive and moreobtrusive than other systems, but their flexibility makes up for this.Flatbed systems are derived from photocopier technology, where thedocument is held in one place and the scanning device creates an opticalpath over the surface of the document. This allows for precise positioningof the document. Fixed optics in these systems allow for the simplificationof the process with an associated decrease in the cost.1 15Paper-moving systems are essentially the opposite of flat-bed in thatthe optical path is kept in the same place but the document is moved, in away analogous to facsimile technology. The result is an even simplermechanism and reduced costs. 6 Flatbed and paper-moving systems have amuch greater resolving power than camera systems, but they are muchless flexible and cannot scan three-dimensional objects. Furthermore, as inthe case of paper-moving systems, sensitive or fragile documents may bedamaged. Once the information is scanned into the machine, somemanipulations, such as thresholding, halftoning, and windowing, can beused to maintain basic control over the image captured, and to enhanceareas of the scanned image where there might be problems in clarity ortone, and where there is a need for resolution compensation in instances inwhich a picture and text are joined together.' To be added to theseconcerns for the preservation and accessibility of images is the need forthe necessary display technology for the database being created; highresolution displays tend to be very expensive, but the cost has beencoming down over the last few years as greater emphasis has been placedon the need for high quality graphics for business applications.A document retrieval system must, of course, attempt to capture allthe significant elements in an image without requiring a large amount ofstorage; images tend to occupy more memory space at a much greater ratethan the written page, because the amount of information to be digitised inan image is much greater than that in a page. Therefore, any attempt to1 1 6convert an infinitely variable, continuous image into a discrete form cancause some undesirable changes in the image due to a necessarily finitememory capacity. These changes are known as quantization effects, andcan have an effect on the resolution of the image, its pixel geometry, and inthe scaling of the image. Resolution in an image can be adversely effectedby digitisation, and in situations where images are electronicallycommunicated between users, some standard resolution must bemaintained, so that the users can see the image in its totality at the desiredresolution. In terms of pixel geometry, pixels themselves have a definitesize and shape associated with them, and if the size and shape of thecaptured pixels do not correspond to that of the displayed pixels, thenchanges will occur in the appearance of the image. Scaling is a processwhereby the user can change the effective pixel spacing in order toenhance a portion of the image for greater analysis; there are severalmethods for doing this, but they can effectively degrade the image if thereis no recourse to the original. No method of enhancement will improveupon the quality of the first image taken and digitised in the scanningprocess therefore the scanning process must be of the highest quality forpreservation and for reproduction on a display screen or on hard copy.'Some new copying and storage technologies other than CD ROM arenow available and may prove to be of greater use for archives in the nearfuture. One such technology is the WORM (write once read many) driveunits, in which the laser effectively burns a non-eraseable spot on the disc1 1 7to record a data bit.' This is a more flexible system, which allows for theconversion of rapidly expanding databases into digital storage units. Other,more recent units, such as multi-function and erasable/WORM drives areopening up the horizons of digital storage for the archivist."The technologies available to the potential user of mass storage areexpanding rapidly in complexity and dynamism. Moreover, their costs aredecreasing and will probably continue to do so over time. This havingbeen said, it is still important to note that the costs will remain prohibitiveto all but the most affluent archives for some time to come." Thus, it isunlikely that this technology will be pervasive in archival work. It is,however, foreseeable that, as archivists continue to embrace technologiesas copying, storage, and retrieval tools, as opposed to simply officeresources, they will increasingly use mass storage techniques in thepreservation of a variety of archival materials.118' Leonard Laub, "What is CD ROM," CD ROM. The New Papyrus, SteveLambert and Suzanne Ropiequet eds., (Redmond: Microsoft Press, 1986) 47.2 Ibid.3 Ibid., p. 53.• Ibid., p. 58.5 Truett Lee Smith, "Compressing Digitised Images," CD ROM, The NewPapyrus , 260-261.6 James P. McNaul, "Image Capture and Processing for CD ROM," CD ROM, The New Papyrus , pp. 246-247.7 Ibid., pp. 248-249.6 Smith, pp. 263-269.9 Charles Seiter, " Optical Outlook," MacWorld, (June 1991): 148.10 Ibid., p. 145." Ibid., p. 141. A single drive costs on the order of between $4 000 and$7 000, while the drive cartridges cost between $200 and $300.Appendix IIIBrand Names of Cellulose Nitrate Products119AmberloidAmbroid (glue, US)Amerinth (Celanese Corp., US)Celluloid (Celanese Corp., US)Chrolitihion (Collar & Cuff)Duco (glue, DuPont US)Duro (glue, US)Durofix (glue, England)Ercalene (cellulose nitrate lacquers,England)FibrolithoidFiberloid (Fiberloid Co., MonsantoCorp., US)Frigelene (cellulose nitrate lacquers,England)HMG (glue, England)IvoroidLixothyl (US)Nitrocellulose (generic misnomer)Nitron (Monsanto Corp., US)Nixonoid (Monsanto Corp., US)Parkesine (Parkes, England)Pasbosene (Marchant's Manu. Co.,US)Pyralin (DuPont-Arlington Manu.Co., US)Pegamoid (Leathercloth with castoroil, Anison, England)Pyroxilin(e) (Bracannot, France)Randolph's Universal Cement (glue,USA)UHU Hart (glue, West Germany)Viscoloid (US)Xylonite (US)Xylonith (US)Xyloidine (US)Zapon (glue)120Appendix IVSome Trade Names for Cellulose NitrateTrade Name^ ManufacturerAceloid American Cellulose Co., Indianopolis,Ind.Amerith^ Celanese Corp of America., New YorkCelluloid Celanese Corp of America., New YorkDurakalf Respro Inc., Rhode IslandDuralin^ Respro Inc., Rhode IslandFabrikoid DuPont & CO., DelawareFebroid Textron Inc., Belleville N.J.Gemlike^ Gemloid Corp., Elmhurst, N.Y.Gemloid CN Gemloid Corp., Elmhurst, N.Y.Herculoid Hercules Powder Co., DelawareHycoloid^ Celluplastic Corp., Newark, N.J.Inceloid N American Products Manufacturing,New Orleans, LouisianaKoda^ Joseph Davis Plastics Co., Arlington,NJ.Kodaloid Eastman Kodak Co., Rochester NewYorkMacoid^ Detroit Macoid Corp., DetroitMiracle Miracle Adhesives Co., New YorkMultipruf Elm Coated Fabrics Co., New YorkNitron^ Monsanto Chemical Co., Springfield,Mass.Nixon C/N Nixon Nitration Works; Nixon N.J.Plastite^ Adhesives Plastics Mastic Co.,ChicagoPolybond Polymer Industries Inc., Springdale,ConnPyraheel^ DuPont & CO., DelawarePyralin DuPont & CO., DelawareReskraf Respro Inc., Rhode IslandResyn^ National Starch & Chemical Co., NewYorkTan-O-Tex Columbia Mills Inc., Syracuse NewYorkTerek^ Athol Manufacturing Co., Athol,Mass121Appendix IVSome Trade Names for Cellulose NitrateTrade Name^ ManufacturerTextileather Textileather Corp., Toledo, OhioTexiloid Textileather Corp., Toledo, OhioTuflex^ Respro Inc., Rhode IslandTufskin Respro Inc., Rhode IslandWopaloid Worbla Ltd., Papiermuhle-Bern,Switz.122Bibliography"A Picture is Worth ^ ?", ACA Bulletin, (January 1993).Booth, Larry and Booth Jane. "Duplication of Cellulose Nitrate Negatives."Picturescope Vol. 30 No.1 (Spring 1982): 12-18.Calhoun, J.M. "Storage of Nitrate Amateur Still-Camera Negatives." Journalof the Biological Photographic Association Vol. 21 No. 3 (August1953): 1-11."Care of Black and White Photographic Negatives on Film," CCI Notes,Ottawa: Canadian Conservation Institute, 1986.Carroll, Ann Elizabeth. "Acquisition of Photographs Determining ArchivalQuality." Masters of Archival Studies thesis ., The University ofBritish Columbia, 1989.Cellulose Nitrate and Safety-Base Photographic Film.  (nd)Coe, Brian. George Eastman and the Early Photographers. London: PrioryPress, 1973.Collard, Paul. "Pictures for Posterity." Image Technology (March 1990)94-99.Conservation Resources. Archival Storage Materials and Conservation Supplies (February 1990): 2-7.Duranti, Luciana. "Diplomatics: New Uses for an Old Science (Part I)."Archivaria 28 (Summer 1989): 7-27.Duranti, Luciana. "Diplomatics: New Uses for an Old Science (Part II)."Archivaria 29 (Winter 1989-90): 4-17.Duranti, Luciana. "Diplomatics: New Uses for an Old Science (Part III)."Archivaria 30 (Summer 1990): 4-20.Eastman Kodak. Preservation of Photographs Rochester: Eastman Kodak,1979, 29-35.Fenn, Julia. Ethnographic Conservator for the Royal Ontario Museum, apreliminary draft of a monograph on plastics and polymers, May1989.   Gernsheim, Helmut and Gernsheim, Alison. The History of Photography 16 8 5 -1914.  New York: McGraw-Hill, 1969.Gobel, Rudolph W. "Fire Risk by Storing Nitrocellulose and its BehaviourDuring Combustion- A Contribution to Film Preservation by theFIAF."^Deutsches Institut fur Filmkunde (nd).Haas, Pamela. "The Conservation of Photographic Collections." Curator.Vol. 26 No. 2 (1983): 89-105.Hager, Michael. "The History of Nitrate Film." Image. Vol. 26 No.4(December: 1983): 2-9.Hodsoll, Frank. "Our Heritage Must be Saved." Variety, January 19, 1983,132.Hollinshead, Patricia et al. Deteriorating Negatives: A Health Hazard in Collection Management. Tuscon: Arizona State Museum, 1987.Jones, G. William. "Nitrate Film: Dissolving Images of the Past."Conservation Administration News No. 31 (October 1987): 1-31.Karr, Lawrence F. "Film Preservation Why Nitrate Won't Wait." I.A.T.S.E.Official Bulletin. (Summer 1972): 1-4.Laub, Leonard. "What is CD ROM?" "Image Capture and Processing for CDROM." CD ROM the New Papyrus. Steve Lambert and SuzanneRopiequet eds. Redmond: Microsoft Press, 1986, 47-71.Lautenbach, Adrian. "The Disintegrating Image." Australian Photography Conference: Working Papers on Photography. (1980): 77-79.Lazar, M, Bleha, T, and J. Rychly, Chemical Reactions of Natural and Synthetic Polymers. New York: John Wiley and Sons, 1989.123124Leary, William H. The Archival Appraisal of Photographs: A Ramp Study With Guidelines. Paris: UNESCO, 1985.Maynor, Catherine J. and Vand der Reyden, Diane. Paper Conservation Catalog, Washington: American Institute of Conservation of Historicand Artistic Works, 1989, 38-41.Meidl, James H. "Plastics: Cellulose Nitrate. (Cellulose Nitrate Fire Hazards;Shipping and Storage)." Flammable Hazardous Materials. BeverlyHills: Glencoe Press, 1970, 218-229."Motion Picture Films of the National Archives of the United States,"Science, Vol 82, No. 2123 (1985).McNaul, James P. "Image Capture and Processing for CD ROM." CD ROM theNew Papyrus. Steve Lambert and Suzanne Ropiequet eds.Redmond: Microsoft Press, 1986, 239-254.National Archives and Records Society. "NARS Responds to GAO Report onFilm Program." SAA NewsLetter (1979): 4-5.Nitrocellulose Film Identification. (nd)Ostroff, Eugene. "Rescuing Nitrate Negatives." Museum News (September/October 1978):^34-40."Poison Gas Kills 100 in Cleveland Clinic; Explosion Spreads Fumes, FireFollowing; Patients, Nurses, Doctors Die in Flight." The New York Times, May 16, 1929."Principles of Institutional Evaluation (proposal)", SAA Newsletter, (July1992), 17.Puglia, Steven. "A Short Guide to Nitrate Negatives: History, Care, andDuplication." Northeast Document Conservation Centre Technical Paper. (1986).Rattee, Colin. "Conference Report Nitrate 2000." Journal of PhotographicScience. Vol. 36 No. 1 (1988): 31.125Reid, Scott, "Report to the Provincial Archives of Manitoba on thePreservation and Administration of Nitrate Negative Collection."Manitoba, 1989.Reilly, James et al. "Stability of Black-and-White Photographic Images, withSpecial Reference to Microfilm." Presentation at the "Conservation inArchives Symposium". National Archives of Canada. (May 1988).Reilly, Julie A. "Celluloid Objects: Their Chemistry and Preservation."Journal of the American Institute of Conservation  No. 30 (1991):1 4 5-1 6 2.Ritzenhaler, Mary Lynn, Munoff, Gerald F., and Margery S. Long.Administration of Photographic Records. Chicago: Society ofAmerican Archivists, 1984.Schellenberg, Theodore. Modern Archives: Principles and Techniques. Chicago: University of Chicago Press, 1956.Seiter, Charles. "Optical Outlook." MacWorld, June 1991, 138.Smith, Anthony. "Mixing Chemistry with Culture." Screen Digest (London).May 1981).Smith, Truett Lee. "Compressing Digitised Images." CD ROM the New Papyrus. Steve Lambert and Suzanne Ropiequet eds. Redmond:Microsoft Press, 1986, 255-270.Soupcoff, Murray. "CD-ROM Technology Chasing Paper Blues Away." TheGlobe and Mail, Wednesday, January 29, 1992."Strict Rules Govern Hospital Film Here." The New York Times, May 16,1929Westerblom, Hans. "City of Toronto Nitrate Negative Conversion Project atRyerson, Summer 1986." Report to the Department of the City Clerk, Toronto 1986.Williams, R. Scott. "Display and Storage of Museum Objects ContainingCellulose Nitrate." CCI Notes (April 1988).126Young, Christine. "Nitrate Films in the Public Institution." History News.Vol. 44 No.4 (July/August 1989) .

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