USER'S GUIDE - Image Permanence Institute
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1. of life expectancy in the PI Storage Guide for Acetate Film Although the majority of films at this acidity level are still quite usable films that give a strip reading somewhere between levels 1 5 and 3 should be given priority for duplication or segregation A D Strip test results in this range should be strong incentive to improve storage conditions Figure 4 shows the direct correlation between A D Strip levels and the state of preservation of the film Note that the curve becomes markedly steeper after it reaches the autocatalytic point indicating the rapid increase in the rate of film decay Films that turn the strip yellow i e level 3 are probably quite smelly already These should top the priority list for duplication before they warp or shrink irretrievably Such films may also pose a handling hazard and should be treated with caution 12 Correlation with Laboratory Tests A D Strip color levels relate to free acidity values as determined through laboratory tests in which free acidity is expressed in milliliters of 0 1N NaOH per gram of film see Table 3 A D Strips are semi quantitative they give an indication in line with the bench marks in Table 3 Note These bench mark acidity values for the color bands on the pencil apply only to acetate films when tested in a confined space Survey Techniques Statistical Treatment of Data Recording a random sample of val ues then calculating mean standard de placed2. possible levels 0 0 5 1 etc results of the initial survey and partl y P y Film Storage How Often to upon the environmental conditions Temperature Recheck in which the collection is stored Table 4 provides some general guide At or near room lines for determining monitoring fre temperature quency with the assumption that 72 F 21 C part of the collection has already Cool started to decay whichis very likely less than and is producing A D Strip readings 72 F 21 C years of around level 1 5 A Cold 50 F 10 C At least every 10 What Do I Do with the Results to 41 F 5 C Be prepared to act on your sur vey results Ithas been demonstrated Very cold or At least every 25 that the only way to effectively mini dr than mize the decay of acetate collec e tions is to provide suitable storage Table 4 Recommended monitoring conditions Just how urgently one frequency based on collection storage proved conditions are neededis dic temperature tated by the current condition of the film A general outline of actions that can be taken based on film condition is provided in the table in the Basic Instructions section at the beginning of this booklet These actions briefly are e Improve storage conditions This is the most important action and by far the most effective when cold storage temperatures are used At least every 2 years A least every 5 years e Prioritize materials for duplication Ma
3. SMPTE Journal 85 July 1976 493 495 Horvath D G The Acetate Negative Survey Louisville Kentucky Ekstrom Library Uni versity of Louisville February 1987 Jenkins R V Images and Enterprise Tech nology and the American Photographic In dustry 1839 to 1925 Baltimore The Johns Hopkins University Press 1975 Kopperl D F and C C Bard Freeze Thaw Cycling of Motion Picture Films SMPTE Journal 94 August 1985 826 827 Lavedrine B R Duverne M Leroy M Aubert and J L Cot Analyse statistique de l tat de conservation d une collection de films sur support en triacetate de cellulose M Aubert and R Billeaud eds Image and Sound Archiving and Access The Challenges of the 3rd Millennium Proceedings of the Joint Technical Symposium Paris 2000 44 53 Mees C E K History of Professional Black and White Motion Picture Film Journal of the Society of Motion Picture and Television Engineers 63 October 1954 125 140 Ram A T Archival Preservation of Photo graphic Films A Perspective Polymer Deg radation and Stability 29 1 3 29 Ram A T D F Kopperl R C Sehlin S Musary K Morris J L Vincent and P Miller The Effects and Prevention of the Vinegar Syndrome Journal of Imaging Science and Technology 38 3 249 261 Ram A T and J L McCrea Stability of Processed Cellulose Ester Photographic Films Journal of the Soci
4. USER S GUIDE Pe STRIPS FILM BASE DETERIORATION MONITORS Awarded a Certificate of Technical Achievement in 1998 by the Academy of Motion Picture Arts and Sciences The Safe and Accurate Way to Check Film for Vinegar Syndrome Basic Instructions En Espa ol Auf Deutsch En Frangais Detailed Instructions Bibliography The development of A D Strips was made possible by funding from the Division of Preservation and Access of the US National Endowment for the Humanities the National Archives of Canada the Canadian Council for Archives and the National Film Board of Canada 2001 Image Permanence Institute Important Keep A D Strips in the dark ina sealed plastic bag until ready to use 1 Open can box bag or drawer containing film and lay an A D Strip on top of film within Reclose 2 Wait for the length of time recommended for the temperature and RH conditions in the test area See Table I on page 9 3 Remove strip and immediately compare to color bands on reference pencil Place strip directly on band for best color judgment 4 Record the number of the reference band that most closely resembles strip 5 Discard A D Strip after one use See pages 5 15 for more information Basic INSTRUCTIONS FOR Fitm TESTING Interpretation Acetate Roll and Sheet Films Level Film Condition Recommended Actions 0 Good No deterioration Coolcold storage 1 Fair to good Deteriorati
5. ch Schrumpfing und Wellenbildung bevorstehend Handhabung kann Gef hrdung f r Filmmaterial darstellen Sofor tiefk hlen Kopie anfertigen Mope p EMmPLOI Important Conserver les A D Strips a l abri de la lumi re dans une enveloppe plastique sc ll e jusqu a utilisation 1 Ouvrir container boite ou enveloppe contenant le film et placer un A D Strip sur le film Refermer le contenant 2 Attendre pour une dur e d termin e en fonction des conditions de temperature et HR se reporter Table 1 page 9 3 Retirer le papier indicateur et le comparer aussit t a la charte de r f rence Pour une meilleure appr ciation de la couleur placer directement le papier indicateur sur la couleur de r f rence 4 Noter la r f rence correspondant le mieux a la couleur du papier indicateur 5 Ne pas r utiliser le papier indicateur Se reporter pages 5 15 pour des informations plus compl tes Interpr tation plan films et film en bobines sur support ac tate Niveau Etat de conservation du film Recommandations 0 Bon Pas d alt ration d tectable Stockage basse temp rature st 5 RE Stockage a basse temp rature 1 Satisfaisant Debut d alt ration g ee contr le p riodique Point autocatalytique du processus 1 5 FR tockage basse temp rature d alt ration Stockage basse temper er Congelation reproduction 2 Mauvais Alt ration rapide a y ee conseill e Etat crit
6. confined space and significant change can occur within a few minutes To preserve the color of the strips for later review 2 Even though the strips revert to a blue color after removal from a can box or bag they should not be reused they will not give an accurate reading a second time 11 YELLOW Noticeable physical property changes Level 3 2 0 a Autocatalytic A 4 10 Level 2 No noticeable physical 0 5 ze y Level 1 5 0 1 Level 1 BLUE Time Figure 4 Relationship between A D Strip levels free acidity and film condition attach the strips to a sheet of clear plastic with clear plastic tape being sure to cover the strips completely with the tape and store the sheet in the dark Strip color can be preserved for months in this way Acetate films in good condition will generally turn the strips somewhat blue green somewhere between bands 0 and 1 on the reference pencil This means they are doing well they are in close to original condition and have a long life ahead of them Green colors between levels 1 and about 1 5 indicate that there is some degradation butitis not yet serious This is a signal to watch the films more closely in coming years Such films can still have a long life providing they are stored in cold conditions At level 1 5 or greater film is seriously degrading Level 1 5 corresponds to an acidity value of around 0 5 This is the autocatalytic point that is the basis for predictions
7. e 2 A D Strip levels and related amount of acetic acid in the air in parts per million Figure 2 To test films stored in a box place strip on top of stack and reclose box Figure 3 For film stored in a metal cabinet strips are placed on top of film stacks and drawer is closed for the required exposure period 10 while the strip is inside The time required for a complete color change will be similar to that required for roll films and will depend on environmental conditions and the acid level present see Table 1 Testing room conditions Used as a quick short term test A D Strips can provide a rough estimate of the level of atmospheric acidity in a storage area Table 2 shows A D Strip levels as they relate to the concentration of acid vapors in the air in parts per million ppm This relationship was defined in the laboratory by estimating the concentration of acetic acid in the air inside pouches containing films at various stages of degradation using simulta neously Draeger diffusion tubes and A D Strips Tests were conducted at temperatures ranging from 0 C to 5 C The values are approximate but they indicate a direct correlation between the two methods of measurement Evaluating and Recording Color Changes After the strip has been in a confined space on or next to the film for the appropriate length of time examine its color and immediately compare it to the color bands on the reference pencil The color bands on t
8. eral weeks without compromising the results However if the strip is left inside the enclosure for several months its color may shift and therefore may not give a true indication of film condition A D Strips Are Not Currently Recommended for Use with Nitrate Film Nitrate film degradation produces volatile nitrogen oxides which are not immediately acidic in nature they must react with oxygen and water before forming acids In any case the response of A D Strips to degrading nitrate film can be slower than with acetate film and the strips may show uneven color changes Ifa color change does occur with nitrate film it can be viewed as a reliable indicator of deterioration but no change does not necessarily mean that the film is in good condition Pending further research IPI recommends using A D Strips primarily for acetate film Figure 1 To test roll film in a can place a strip on top of the film and reclose the can Minimum Exposure Time Room 24 hrs 55 F 13 C 1 2 wks Temperature 41 F 5 C 3 wks 35 F 2 C 4 wks 25 F 4 C 6 wks Table 1 Recommended minimum exposure times for A D Strips based on temperature in testing area and moderate RH 30 to 50 Use and Placement of Strips with Roll Films A D Strips should always be used inside a closed confined space Rolls of cinema or microfilm can be evalu ated in a closed can vented or unvented in a box or in a plastic bag Place a test stri
9. ety of Motion Pic ture and Television Engineers 97 June 1988 474 483 Reilly J M IPI Storage Guide for Acetate 17 Film Rochester NY Image Permanence In stitute Rochester Institute of Technology 1993 Reilly J M P Z Adelstein and D W Nishimura Preservation of Safety Film Final Report to the Office of Preservation National Endowment for the Humanities Grant PS 20159 88 Rochester NY Image Perma nence Institute Rochester Institute of Tech nology March 1991 ANSI and ISO Film Storage Standards American National Standard for Imaging Media Processed Safety Photographic Film Storage PIMA IT9 11 1997 revision and redesignation of ANSI NAPM IT9 11 1993 New York American National Stan dards Institute 1997 ISO 18911 Photography Processed Safety Photographic Films Storage Practices for merly ISO 5466 Switzerland International Organization for Standardization THE IMAGE PERMANENCE INSTITUTE The Image Permanence Institute is a private nonprofit academic research institute dedicated to the preservation of imaging media It is a part of the College of Imaging Arts and Sciences of Rochester Institute of Technology IPI is cosponsored by the Society of Imaging Science and Technology Proceeds from the sale of A D Strips go toward the continuation of preservation research programs at IPI The IPI Storage Guide for Acetate Film An essential four part publication tha
10. from cold storage under cold conditions not only is the film base stabilized but the rate of color dye fading is minimized as well Recom mended storage conditions for photographic films can be found in ISO Standard 18911 2000 Overall management of the vinegar syndrome problem in a film collec tion involves knowledge of the deterioration process the provision of a good storage environment and the safe monitoring of film condition using A D Strips Using A D Strips Storage and Handling A D Strips will remain in good condition for at least one year after purchase if the heat sealed outer package is not opened After opening keep A D Strips inside their resealable polyethylene bag and within the opaque outer bag when not in use The strips should not be allowed to become too dry A D Strips are somewhat light sensitive they will fade if exposed to room light for several days The strips contain the dye bromocresol Health Hazards Related to Degrading Film Close contact with severely degraded green sodium salt The dye is not toxic but it is water and alcohol soluble and will run if it gets wet Use Conditions and Response Time The time required for A D Strips to reliably indicate the presence of acidic vapors varies with the acid level of the film and the ambient temperature and RH At room tem perature and moderate RH the strips begin to change color within a few minutes when the film is very acidic If film is le
11. hanges in condition over time can be monitored The Need for Proper Storage A diagnostic tool like A D Strips is only one part of managing the vinegar syndrome problem The most important aspect of preserving acetate film is proper storage All acetate and nitrate films not just certain types or brands are prone to degrade The process of deterioration goes on every day slowly or rapidly depending on the temperature and relative humidity RH of the storage environment It is a simple fact of life that acetate film will begin to seriously degrade in about 50 years at room temperature and moderate RH Periods of higher See Mary Kaldany et al Evaluating the Stability of Commercially Available Artists Coloring Materials Used to Create Compensation Infills for Losses in Textiles JAIC 38 3 Fall Winter 1999 pp 443 458 and Catherine Nicholson and Elissa O Loughlin Screening Conservation Storage and Exhibit Materials Using Acid Detection Strips Collections Caretaker a publication of the Northern States Conservation Center 1 4 Winter 1998 1999 pp 4 5 temperature and dampness will accelerate the process and cold and dry periods will slow it down Newly processed film stored in cool less than 72 F 21 C or cold less than 50 F 10 C conditions at moderate RH 20 to 50 can be expected to last for centuries Film stored under poor conditions may become degraded within a few decades Color film benefits doubly
12. he pencil are designed to be evaluated under cool white fluorescent lamps If the color change is not yet complete i e if the strip color is not uniform leave the strip in place for a longer time When no acidity is present the paper remains blue An increasing concentration of acid vapor turns the strip color gradually from blue to green and then to yellow the lighter and yellower the color the higher the acidity In the presence of very high levels of acid the strip turns bright yellow The best color judgment is achieved when the strip is examined directly on or beside the pencil s color bands Because the strips change from blue to yellow on a gradual scale in an infinite number of steps the strip color often does not exactly correspond to one of the four colors represented on the reference pencil Use the following method to record your A D Strip test results If the color of the strip is fairly close to that of one of the color bands record the number of that band If the color of a strip falls between two of the bands give it a number halfway between the two for example if the strip is not as blue as band 0 but not as green as band 1 record the level as 0 5 Thus there can be seven possible color levels 0 0 5 1 1 5 2 2 5 and 3 Using this standard notation will make it easier to gather statistics about a film collection Strip color should be evaluated promptly The color reverts to blue very soon after removal from the
13. hic film including sheet and roll films cinema film and micro film They provide a nondestructive method of determining the extent of vinegar syndrome in film collections The strips were developed specifically for acetate films but they may also be used for testing other materials that release acidic compounds when they decay for example cardboard adhe sives textiles wood and other materials commonly encountered in museum environments The A D Strip color scale applies only to acetate however it will not give accurate quantitative results for other materials A D Strips ano F Lm COLLECTION PRESERVATION A D Strips are a diagnostic tool for vinegar syndrome They can be used to determine the approximate extent of acetate support degradation in individual films and they can also be used as a survey tool for gaining an overview of the condition of films in an entire collection Using statistical sampling techniques it is possible to obtain such an overview by testing the condition of only a small percentage of the total collection see footnote 4 on page 13 Although it is often not possible or practical testing every film in a collection and entering the data into a computerized database will produce a very accurate picture of the storage and duplication needs of a collection Testing individual films whenever they are accessed is another approach If A D Strips are routinely used when a film is removed from storage for any reason c
14. ique R traction et d formation 3 du support imminentes manipulation Congelation et reproduction pouvant entra ner des alt rations Acetate F Lm BASE DETERIORATION THE VINEGAR SYNDROME Celluose acetate film is susceptible to a slow form of chemical decay known as the vinegar syndrome This decay process causes plastic film base to become acidic to shrink and to give off the characteristic vinegary odor of acetic acid Chemical reactions influenced by heat moisture and or the presence of acidic vapors from nearby degrading film cause acid to be generated within the cellulose acetate support From there it diffuses into the gelatin emulsion and often into the air creating a sharp acidic odor The utility of A D Strips is based on this phemonenon Although both nitrate and acetate plastics are prone to chemical decom position A D Strips are primarily designed for use with acetate film Their use with nitrate film requires further investigation see page 8 Polyester plastic is much more chemically stable than acetate or nitrate plastics A D Strips do not provide useful information about the state of preservation of polyester film base Research at Image Permanence Photographic film has three principal Institute Eastman Kodak Com components a support made of a sheet of transparent plastic a gelatin emul sion and an image of color dyes or metallic silver See below Three differ ent types of plastic ha
15. lly D W Nishimura and C J Erbland Stability of Cellulose Ester Base Photographic Film Part I Prac tical Storage Considerations SMPTE Jour nal 101 May 1992 347 353 Adelstein P Z J M Reilly D W Nishimura and C J Erbland Stability of Cellulose Ester Base Photographic Film Part II Mea surement of Film Degradation SMPTE Jour nal 104 May 1995 281 291 Adelstein P Z J M Reilly D W Nishimura C J Erbland and J L Bigourdan Stability of Cellulose Ester Base Photographic Film Part V Recent Findings SMPTE Journal 104 July 1995 439 447 Allen N S and M Edge Initiation of the Degradation of Cellulose Triacetate Base Mo tion Picture Film Journal of Photographic Science 38 2 54 59 Allen N S M Edge J H Appleyard T S Jewitt and C V Horie Degradation of His toric Cellulose Triacetate Cinematographic Film Influence of Various Film Parameters and Prediction of Archival Life Journal of Photographic Science 36 6 194 198 Bigourdan J L Vinegar Syndrome An Action Plan The Vinegar Syndrome A Hand book Prevention Remedies and the Use of New Techniques Bologna The GAMMA Group 2000 Bigourdan J L Preservation of Acetate Base Motion Picture Film From Stability Studies to Film Preservation in Practice The Vinegar Syndrome A Handbook Prevention Remedies and the Use of New Techniques Bologna The GAMMA Grou
16. miento fresco frio Almacenamiento fr o Inspecci n continua Almacenamiento fr o o congelamiento Congelar para preservar Se recomienda duplicar Condiciones cr ticas encojimiento 3 distorsi n inminente Posible riesgo para la salud durante su manejo Congelar inmediatamente Duplicaci n inmediata Wichtig A D Streifen bis zum Gebrauch in KURZANLEITUNG FUR DAS verschlossener Verpackung im Dunkeln TESTEN VON FILMEN aufbewahren AA eee 1 A D Streifen auspacken und auf das Filmmaterial in der Dose der Schachtel im Beutel oder in der Schublade legen diese gut verschliessen 2 Warten Wartezeit entsprechend der Temperatur und Luftfeuchtigkeit im Testraum w hlen Siehe Tabelle I Seite 9 3 Streifen herausnehmen und sofort mit den Farbb ndern auf dem Referenzstift vergleichen F r den Farbvergleich Streifen direkt auf oder neben das Farbband legen 4 Die Nummer des mit der Farbe des Streifens am besten bereinstimmenden Referenzfarbbandes notieren 5 A D Streifen nach einmaligem Gebrauch entsorgen F r weitere Informationen siehe Seiten 5 15 Al Auswertung Azetat Roll und Planfilme Nummer Zustand des Filmes Empfohlene Massnahmen EN Gut Keine Zersetzung K hl Kaltlagerung 1 Mittelm ssig bis gut Beginnende Kaltlagerung Zersetzung Sorgf ltig berwachen Beginnende schnelle Zersetzung Autokatalytische Zersetzung beginnt Seite Kaltlagerung oder Tiefk hlen 12 Kritis
17. near the film read on the same time schedule and interpreted similarly Monitoring the Condition of a Collection Acetate base decay is a continu ing chemical process therefore film condition should be rechecked peri odically How often a collection is rechecked depends partly upon the 3 See bibliography for P Z Adelstein et al Stability of Cellulose Ester Base Photo graphic Film Parts I and II OF COLLECTION A D Strip Film Acidity Readings ml 0 1 N NaOH g Level 0 0 to 0 1 Level 1 About 0 2 Level 1 5 About 0 5 Level 2 About 1 Level 3 About 2 or above Table 3 A D Strip levels as they relate to the amount of free acidity in acetate film viation and median will help give an idea of the status of collections or subcollections After the data are recorded a frequency histogram like that shown in Figure 5 can be created This is a helpful way to illustrate the distribution of vinegar syndrome within the sampled portion of a collection or collections The data will be most accurate if the strips are consistently 100 o o o E o N o 0 05 1 A D STRIP LEVELS 15 2 25 4 4 Described in B Lavedrine et al The Use of a Statistical Approach to Evaluate Accu rately the Spread of the Vinegar Syndrome in a Large Collection 13 Figure 5 A frequency histogram showing the percentage of films in a test sampling at each of the seven
18. on starting Cold storage Monitor closely Rapid degradation starting point of possible handling hazard il autocatalytic decay see figure on page 12 Sen Oti Freeze 2 Poor Actively degrading Copying advisable 3 Critical Shrinkage and warping imminent Freeze immediately Copy INSTRUCCIONES BASICAS Importante Conserve las A D Strips en su PARA EL TEST DE PELICULA bolsa de pl stico bien cerrada Abra la bolsa TT slo cuando est usted preparado para usar las tiras 1 Coloque la A D Strip encima del rollo de pel cula y tape muy bien la caja contenedor O lata Si se emplea una bolsa asegurese de cerrarla completamente 2 Espere por el lapso de teimpo recomendado para las condiciones de temperatura y humedad relativa RH correspondientes al rea donde se realiza el test Refi rase Tabla 1 en la p gina 9 3 Extraiga la tira del contenedor e inmediatamente compare con las bandas de colores del l piz de referencia Coloque la tira directamente encima de la banda para un juicio m s preciso del color 4 Registre el n mero del color en la tabla de referencia que m s se asemeje al color de la tira 5 Deseche las A D Strips una vez usadas Para mayor informaci n dir jase a las p ginas 5 a 15 Interpretaci n Pel cula de Acetato en Rollo y en Hojas Nivel Condiciones de la Pel cula Acciones Recomendadas 0 En buen estado Sin deterioro Almacena
19. p 2000 Bigourdan J L P Z Adelstein and J M Reilly Use of Microenvironments for the Preservation of Cellulose Triacetate Photo graphic Film Journal of Imaging Science and Technology 42 2 155 162 Bigourdan J L and J M Reilly Effective ness of Storage Conditions in Controlling the Vinegar Syndrome Preservation Strategies for Acetate Base Motion Picture Film Col lections M Aubert and R Billeaud eds Image and Sound Archiving and Access The Challenges of the 3rd Millennium Proceed ings of the Joint Technical Symposium Paris 2000 14 34 Bigourdan J L and J M Reilly Environ ment and Enclosures in Film Preservation Final Report to the Office of Preservation National Endowment for the Humanities Grant PS 20802 94 Rochester NY Image Permanence Institute 1997 Brems K A H The Archival Quality of Film Bases SMPTE Journal 97 December 1988 991 993 Edge M N S Allen T S Jewitt J H Appleyard and C V Horie The Deteriora tion Characteristics of Archival Cellulose Tri acetate Base Cinematograph Film Journal of Photographic Science 36 6 199 203 Edge M N S Allen T S Jewitt and C V Horie Fundamental Aspects of the Degra dation of Cellulose Triacetate Base Cinemato graph Film Polymer Degradation and Sta bility 25 1989 345 362 Fordyce C R Motion Picture Film Sup port 1889 1976 An Historical Review
20. p on the film roll as shown in Figure 1 Placing it on the reel will work but color changes fastest when the strip is placed di rectly on the film The strip should not be placed under the film it must be exposed to the atmosphere inside the confined space of the enclosure Close the can box or bag and wait for the length of time recommended in Table 1 As long as the minimum recommended exposure time is observed materials can be tested in situ This is a far more practical procedure than removing films to another area for testing and then returning them to storage especially when many films are involved as during a survey Cinema collections A D Strips may be used with both picture and magnetic track elements on acetate base Interpretation for magnetic track film is similar to that for pictorial films Does the length of the film roll matter In general the mass of film being tested has little bearing on the accuracy of the reading In a laboratory test tworolls of the same film one a 25 foot roll and one a 400 foot roll enclosed in matching cans gave identical readings after 48 hours at room conditions a 400 foot roll holds sixteen times more film than a 25 foot roll However it has been observed that in cold conditions film mass may affect response time the greater the mass of film the faster the response of the strip Also in the extreme case of a very small roll of film inside a very large can an inaccurate A D Stri
21. p reading is possible For testing a small mass of film that is stored in a large enclosure it is better to place both the film and the strip inside a plastic bag Tips for Testing Sheet Film and Other Film Formats Testing individual sheet films and amateur roll films 35mm 120 etc Remove the sheet film from its enclosure and put a single sheet or a stack of several sheets of film inside a plastic bag placing the strip directly on the film Close the bag Do not squeeze the bag flat but allow some free air space to remain around the strip If sheet or roll films are already in plastic sleeves strips can be placed inside the sleeves A complete color change takes longer with a single sheet of film than with a roll of cinema film under similar test con ditions At room temperature allow four days for single sheets Testing microfilm collections For 100 ft rolls of 16mm and 35mm microfilm strips may be used inside cardboard boxes if desired but more accurate measurements are obtained when the roll is removed from its box and placed in a plastic bag Place the strip directly on the roll of film For film in cassettes or cartridges put the entire cartridge and the strip in a plastic bag Testing film in storage cabinets A D Strips can be used to detect the presence of acidic vapor in a film storage cabinet or in a box containing multiple films see Figures 2 and 3 The cabinet or box must remain closed Acetic Acid Tabl
22. ss acidic more time is needed but the change is usually complete in about 24 hours Response acetate and nitrate films touching or sniffing may be a health hazard Acetic acid and other acidic products emitted by degraded film have been known to produce contact burns skin and mucous membrane irritations and other physiological effects When handling degraded films protective gloves and adequate ventilation are strongly recommended Use of A D Strips eliminates the dangers of sniff ing degraded film and also provides amore objective and accurate deter mination of the presence of degrada tion products time is slower at low temperatures or under dry conditions A D Strips may be used at or below freezing temperatures but under such conditions users must allow more exposure time before reading the strip color Table 1 suggests minimum strip exposure times based on climate conditions Of course the goal in testing should be accuracy not speed In order to establish the minimum exposure time required for a particular storage vault the user might test a series of films at both room conditions and vault conditions to determine how long the exposure time must be in each case to achieve the same results The resulting minimum exposure time can then be the standard practice for that particular vault Is There a Maximum Exposure Time Even at room conditions strips may be left in contact with the material being tested for sev
23. t will give collection managers a general understanding of how temperature and humidity affect the rate of film base degradation and help them evaluate and plan storage environments for their acetate base photographic film cinema film and microfilm collections The booklet provides an overview of environmental specifications for film storage and explains the relationship between temperature relative humidity and the time it takes for vinegar syndrome the slow chemical decomposition of acetate plastics to begin to affect fresh film Wheel graphs and table present valuable quantitative data in three practical easy to use forms A valuable tool for anyone responsible for the care of film collections Can be ordered from the IPI web site You also may call fax or write for price and ordering information Visit IPI on the web at www rit edu ipi Product Warranty A D Strips will be replaced if found defective in manufacture or packaging No other warranties expressed or implied are offered in connection with this product IPI Image Permanence Institute O A Rochester Institute of Technology RI T A 70 Lomb Memorial Drive Rochester NY 14623 5604 Made in USA IS amp T Phone 585 475 5199 Fax 585 475 7230 Second Edition 11 01
24. ter is less threatened by acidity than acetate is Acidity does have a detrimental impact on the stability of color dyes however It is always advisable to identify the film type as acetate nitrate or polyester before taking any actions based on the use of A D Strips Post 1960s microfilm and sheet film collections are the ones most likely to have a close intermixing of acetate and polyester films A simple way to identify polyester film is to use crossed polarizers see the IPI Storage Guide for Acetate Film for more information The volatility of acetic acid vapors also means that acidity can evaporate from film over time so that testing with an A D Strip sometimes reveals a relatively moderate level of acidity despite the fact that the film is obviously very buckled and degraded One does not need an A D Strip to know that film in this condition is deteriorated This phenomenon is observed mostly in sheet films that have been handled a great deal BIBLIOGRAPHY Books Articles and Reports Adelstein P Z From Metal to Polyester History of Picture Taking Supports Pio neers of Photography Eugene Ostroff ed Springfield Virginia Society for Imaging Science and Technology 1987 pp 30 36 Adelstein P Z J M Reilly D W Nishimura and C J Erbland Stability of Cellulose Ester Base Photographic Film Part I Labo ratory Testing Procedures SMPTE Journal 101 May 1992 336 346 Adelstein P Z J M Rei
25. terials in an advanced state of decay should be duplicated first e Periodically recheck the condition of the collection see Table 4 Moni toring the condition of collection materials enables collection managers to take proactive measures when necessary Things to Watch Out For Acetic acid vapors are volatile if they were not A D Strips would not work But this volatility means that acidic vapors from degrading film can readily be absorbed by storage enclosures and by other film For example high levels of acidity can be measured inside paper envelopes or cardboard microfilm boxes that formerly contained very degraded film even after the film has been removed Plastic bags too can absorb acidity and retain it Bags that have housed degraded films for testing with A D Strips should not be reused Absorbed acidity in a box bag or envelope dissipates with time but a small amount always remains 14 Likewise good undegraded film can absorb acidity from its deterio rated neighbors inside a box or cabinet This is harmful because the absorbed acidity will speed the degradation of the good film The ability of film to absorb acid vapors also means that even polyester films sometimes can be acidic Because of their greater chemical stability these films probably are not in much danger from the absorbed acidity It would therefore be a waste of resources to duplicate polyester film that has absorbed acid vapors because polyes
26. ve been used in film manufacture to date nitrate from 1890 to 1950 acetate from 1925 to the present and polyester from 1960 to the present Image g Material Gelatin Emulsion Plastic Support For a full discussion of film history identification of film type film deterioration and storage recom mendations see J M Reilly IPI Storage Guide for Acetate Film revised Rochester NY Image Per manence Institute 1996 pany and Manchester Metropoli tan University in the UK has con tributed to a better understanding of film base deterioration A bibli ography of writings on film dete rioration can be found at the end of this booklet What Are A D Strips A D Strips are acid base indi cator papers that turn from blue through shades of green and fi nally to yellow in the presence of increasing amounts of acid The A D stands for acid detecting They measure film deterioration in directly by reacting to the amount of acidic vapor present in a con fined air space around the film After the strips are exposed their color changes are compared to a color scale printed on the reference pencil provided in each package This information can be used in judging the adequacy of existing storage conditions for film preservation and also for prioritizing films for duplication based on their level of deterioration A D Strips were created to aid in the preservation of collections of photograp
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