USER’S GUIDEFORAwarded 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 ........................................................ 1
En Español ........................................................... 2
Auf Deutsch ......................................................... 3
En Français .......................................................... 4
Detailed Instructions .............................................. 5-15
Bibliography ......................................................... 16-17

The development of A-D Strips was made possible by funding from the Division ofPreservation 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 Institute16

Important: Keep A-D Strips in the dark in asealed 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 forthe temperature and RH conditions in thetest area. (See Table I on page 9.)
3. Remove strip and immediately compare tocolor bands on reference pencil. Place strip
directly on band for best color judgment.
4. Record the number of the reference bandthat most closely resembles strip.
5. Discard A-D Strip after one use.

BASIC INSTRUCTIONS FOR
FILM TESTING

See pages 5-15 for more information.

Interpretation (Acetate Roll and Sheet Films)
Le ve lFilm Condition

Re comme nde d Actions

0

Good - No deterioration

Cool/cold storage

1

Fair to good - Deterioration starting

Cold storage
Monitor closely

1.5

Rapid degradation starting - point of
autocatalytic decay (see figure on page 12)

Cold storage or freeze

2

Poor - Actively degrading

FreezeCopying advisable

3

Critical - Shrinkage and warping imminent;
possible handling hazard

Freeze immediately
C opy

1

INSTRUCCIONES BASICASPARA EL TEST DE PELICULA

Importante: Conserve las A-D Strips en su
bolsa de plástico bien cerrada. Abra la bolsa
sólo cuando esté usted preparado para usar
las tiras.
1. Coloque la A-D Strip encima del rollo depelícula y tape muy bien la caja, contenedor,o lata. Si se emplea una bolsa asegurese decerrarla completamente.
2. Espere por el lapso de teimpo recomendado
para las condiciones de temperatura y
humedad relativa (RH) correspondientes alárea donde se realiza el test. (Refiérase Tabla
1 en la página 9.)
3. Extraiga la tira del contenedor e
inmediatamente compare con las bandas decolores del lápiz de referencia. Coloque latira directamente encima de la banda para un
juicio más preciso del color.
4. Registre el número del color (en la tabla dereferencia) que más se asemeje al color de latira.
5. Deseche las A-D Strips una vez usadas.
Para mayor información diríjase a laspáginas 5 a 15.

Interpretación (Película de Acetato en Rollo y en Hojas)
Nive l Condicione s de la Pe lícula

Accione s Re come ndadas0

En buen estado - Sin deterioro

Almacenamiento fresco/frío

1

Regular a bueno - Inicio de deterioro

Almacenamiento frío
Inspección continua

1.5

Inicio de degradación rápida - puntode deterioro autocatlítico (página 12)

Almacenamiento frío o congelamiento

2

Pobre - Degradando activamente

Congelar para preservar
Se recomienda duplicar

3

Condiciones críticas - encojimiento,
distorsión inminente. Posible riesgo
para la salud durante su manejo

Congelar inmediatamente
Duplicación inmediata2

Wichtig: A-D Streifen bis zum Gebrauch inverschlossener Verpackung im Dunkeln
aufbewahren!
1. A-D Streifen auspacken und auf das
Filmmaterial in der Dose, der Schachtel, im
Beutel oder in der Schublade legen; diesegut verschliessen.
2. Warten; Wartezeit entsprechend derTemperatur und Luftfeuchtigkeit im
Testraum wählen. (Siehe Tabelle I, Seite 9.)
3. Streifen herausnehmen und sofort mit den
Farbbändern auf dem Referenzstift
vergleichen. Für den Farbvergleich Streifen
direkt auf oder neben das Farbband legen.
4. Die Nummer des mit der Farbe des Streifens
am besten übereinstimmenden
Referenzfarbbandes notieren.
5. A-D Streifen nach einmaligem Gebrauch
entsorgen.

KURZANLEITUNG FÜR DASTESTEN VON FILMEN

Für weitere Informationen siehe Seiten 5–15.

Auswertung (Azetat-Roll- und Planfilme)
Numme rZus tand de s Filme s

Empfohle ne M as s nahme n0

Gut - Keine Zersetzung

Kühl- /Kaltlagerung

1

Mittelmässig bis gut - BeginnendeZersetzung

Kaltlagerung
Sorgfältig überwachen

1.5

Beginnende schnelle Zersetzung Autokatalytische Zersetzung beginnt (Seite
12)

Kaltlagerung oder Tiefkühlen

2

Schlecht - Schnell fortschreitende Zersetzung

Tiefkühlen
Kopieren empfohlen

3

Kritisch - Schrumpfung und Wellenbildung
Sofor tiefkühlen
bevorstehend; Handhabung kann Gefährdung
Kopie anfertigen
für Filmmaterial darstellen
3MODE D’EMPLOIImportant: Conserver les A-D Strips à l’abri
de la lumière dans une enveloppe
plastique scéllée jusqu’à utilisation.
1. Ouvrir container, boîte ou enveloppe
contenant le film et placer un A-D Strip surle film. Refermer le contenant.
2. Attendre pour une duré e déterminée en
fonction des conditions de temperature etHR (se reporter Table 1, page 9).
3. Retirer le papier indicateur, et le comparer
aussitôt à la charte de référence. Pour une
meilleure appréciation de la couleur, placer
directement le papier indicateur sur lacouleur de référence.
4. Noter la référence correspondant le mieux à
la couleur du papier indicateur.
5. Ne pas réutiliser le papier indicateur.
Se reporter pages 5-15 pour des informations
plus complètes.

Interprétation (plan-films et film en bobines sur support acétate)
Nive au

Etat de cons e rvation du film

Re commandations

0

Bon - Pas d'altération détectable

Stockage à basse température

1

Satisfaisant - Début d'altération

Stockage à basse température,contrôle périodique1.5

Point autocatalytique du processusd'altération

Stockage à basse température2

Mauvais - Altération rapide

Congelation, reproduction
conseillée

3

Etat critique. Rétraction et déformation
du support imminentes; manipulation
pouvant entraîner des altérations

Congelation et reproduction

4

ACETATE FILM 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 baseto become acidic, to shrink, and to give off the characteristic vinegary odorof acetic acid. Chemical reactions influenced by heat, moisture, and/or thepresence of acidic vapors from nearby degrading film cause acid to begenerated within the cellulose acetate support. From there it diffuses into thegelatin 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 decomposition, A-D Strips are primarily designed for use with acetate film. Theiruse 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 ofpolyester film base.
Research at Image Permanence
Photographic film has three principal
Institute, Eastman Kodak Comcomponents: a support made of a sheet
pany, and Manchester Metropoliof transparent plastic, a gelatin emultan University in the UK has consion, and an image of color dyes ormetallic silver (see below). Three differtributed to a better understanding
ent types of plastic have been used inof film base deterioration. A biblifilm manufacture to date: nitrate (fromography of writings on film dete1890 to 1950), acetate (from 1925 torioration can be found at the end of
the present), and polyester (from 1960
this booklet.
to the present).*

What Are A-D Strips?
A-D Strips are acid-base indicator papers that turn from blue,
through shades of green, and finally to yellow in the presence ofincreasing amounts of acid. (TheA-D stands for “acid-detecting.”)
They measure film deterioration indirectly by reacting to the amountof acidic vapor present in a confined air space around the film.
After the strips are exposed, theircolor changes are compared to acolor scale printed on the reference
pencil provided in each package.
This information can be used in

Image
Material
Gelatin
Emulsion

Plastic
Support* For a full discussion of film history, identificationof film type, film deterioration, and storage recommendations, see J. M. Reilly, IPI Storage Guide for
Acetate Film, revised (Rochester, NY: Image Permanence Institute, 1996).

5judging the adequacy of existing storage conditions for film preservation andalso for prioritizing films for duplication based on their level of deterioration.
A-D Strips were created to aid in the preservation of collections ofphotographic film, including sheet and roll films, cinema film, and microfilm. They provide a nondestructive method of determining the extent ofvinegar syndrome in film collections. The strips were developed specificallyfor acetate films, but they may also be used for testing other materials that
release acidic compounds when they decay—for example, cardboard, adhesives, textiles, wood, and other materials commonly encountered in museum
environments.1 The A-D Strip color scale applies only to acetate, however;it will not give accurate quantitative results for other materials.

A-D STRIPS AND FILM 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 statisticalsampling techniques, it is possible to obtain such an overview by testing thecondition of only a small percentage of the total collection (see footnote 4 onpage 13). Although it is often not possible or practical, testing every film ina collection and entering the data into a computerized database will producea 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, changes 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 isproper 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 thestorage environment.
It is a simple fact of life that acetate film will begin to seriously degradein about 50 years at room temperature and moderate RH. Periods of higher
1

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.
6

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 from cold storage: under cold conditions, not only is the film basestabilized, but the rate of color dye fading is minimized as well. Recommended storage conditions for photographic films can be found in ISO
Standard 18911:2000.
Overall management of the vinegar syndrome problem in a film collection involves knowledge of the deterioration process, the provision of a goodstorage 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 beallowed to become too dry.
A-D Strips are somewhat lightsensitive; they will fade if exposed
Health Hazards Related toto room light for several days. The
Degrading Film
strips contain the dye bromocresol
Close contact with severely degradedgreen, sodium salt. The dye is notacetate and nitrate films (touching or
toxic, but it is water- and alcoholsniffing) may be a health hazard.
soluble and will run if it gets wet.
Acetic acid and other acidic products
emitted by degraded film have been
known to produce contact burns, skinand mucous-membrane irritations,and other physiological effects. When
handling degraded films, protective
gloves and adequate ventilation arestrongly recommended. Use of A-D
Strips eliminates the dangers of “sniffing” degraded film and also provides
a more objective and accurate determination of the presence of degradation products.

Use Conditions and Response TimeThe time required for A-D Strips
to reliably indicate the presence ofacidic vapors varies with the acidlevel of the film and the ambient
temperature and RH. At room temperature and moderate RH, the strips
begin to change color within a few
minutes when the film is very acidic.
If film is less acidic more time isneeded, but the change is usuallycomplete in about 24 hours. Response7

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. (Ofcourse, the goal in testing should be accuracy, not speed.) In order to establish
the minimum exposure time required for a particular storage vault, the usermight test a series of films at both room conditions and vault conditions todetermine how long the exposure time must be in each case to achieve thesame results. The resulting minimum exposure time can then be the standardpractice 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 several 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 notimmediately 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 unevencolor changes. If a color change does occur with nitrate film, it can be viewed
as a reliable indicator of deterioration, but no change does not necessarilymean 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.
8Use and Placement of Strips with
Roll Films
A-D Strips should always be used
inside a closed, confined space. Rolls
Room
24 hrs.
of cinema or microfilm can be evalu55°F/13°C
1 - 2 wks.
ated in a closed can (vented orunvented), in a box, or in a plastic
41°F/5°C
3 wks.
bag. Place a test strip on the film rollas shown in Figure 1. (Placing it on
35°F/2°C
4 wks.
the reel will work, but color changes
fastest when the strip is placed di25°F/- 4°C
6 wks.
rectly on the film.) The strip should
not be placed under the film; it must
Table 1. Recommended minimum be exposed to the atmosphere insideexposure times for A-D Strips, based on the confined space of the enclosure.
temperature in testing area and moderate Close the can, box, or bag and wait
RH (30% to 50%).
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 thanremoving 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 andmagnetic 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,
two rolls 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 responsetime (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 Strip reading is possible. For testing a small mass of film thatis stored in a large enclosure, it is better to place both the film and the strip
inside a plastic bag.
Te mpe rature

M inimum
Expos ure TimeTips 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 ofseveral sheets of film inside a plastic bag, placing the strip directly on the9film. Close the bag. Do not squeeze
A-D Strip
Ace tic Acidthe bag flat, but allow some free air
Le ve ls(ppm)
space to remain around the strip. If
sheet or roll films are already in
1
1-2
plastic sleeves, strips can be placed
inside the sleeves. A complete color
1. 5
3-5change takes longer with a single
sheet of film than with a roll ofcinema film under similar test con2
6-8
ditions. At room temperature, allow
four days for single sheets.
2.5
18 - 20
Testing microfilm collections.
For 100-ft. rolls of 16mm and 35mm
Table 2. A-D Strip levels and related
microfilm, strips may be used inside
amount of acetic acid in the air in parts
cardboard boxes if desired, but more per million.
accurate measurements are obtained
when the roll is removed from its box and placed in a plastic bag. Place thestrip directly on the roll of film. For film in cassettes or cartridges, put theentire cartridge and the strip in a plastic bag.
Testing film in storage cabinets. A-D Strips can be used to detect thepresence 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

Figure 2. To test films stored in abox, place strip on top of stack andreclose box.

Figure 3. For film stored in a metal cabinet, strips
are placed on top of film stacks and drawer isclosed 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 canprovide 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 acidvapors 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 insidepouches containing films at various stages of degradation using, simultaneously, Draeger diffusion tubes and A-D Strips. Tests were conducted attemperatures 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 theappropriate length of time, examine its color and immediately compare it to
the color bands on the reference pencil. The color bands on the pencil aredesigned 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 thestrip 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 thecolor 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 makeit easier to gather statistics about a film collection.
Strip color should be evaluated promptly. The color reverts to blue verysoon after removal from the confined space, and significant change can occur
within a few minutes.2 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

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. Thismeans they are doing well; they are in close to original condition and havea long life ahead of them. Green colors between levels 1 and about 1.5
indicate that there is some degradation, but it is not yet serious. This is a signal
to watch the films more closely in coming years. Such films can still have along 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 thebasis for predictions of life expectancy in the IPI 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 begiven priority for duplication or segregation. A-D Strip test results in thisrange should be strong incentive to improve storage conditions. Figure 4
shows the direct correlation between A-D Strip levels and the state ofpreservation of the film. Note that the curve becomes markedly steeper after
it reaches the autocatalytic point, indicating the rapid increase in the rate offilm 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 shouldbe treated with caution.
12

Correlation with Laboratory Tests
A-D Strip color levels relate to free
acidity values as determined throughlaboratory tests, in which free acidity isexpressed in milliliters of 0.1N NaOH
per gram of film (see Table 3).3 A-D
Strips are semi-quantitative; they givean indication in line with the benchmarks in Table 3. NOTE: These benchmark acidity values for the color bandson the pencil apply only to acetate films
when tested in a confined space.

A-D Strip
Re adings

Film Acidity(ml 0.1 N NaOH/g)

Level 00 to 0.1

Level 1

About 0.2

Level 1.5

About 0.5

Level 2

About 1

Level 3
About 2 or above
Survey Techniques—StatisticalTreatment of Data
Table 3. A-D Strip levels as they relate
Recording a random sample of val- to the amount of free acidity in acetate
ues, then calculating mean, standard de- film.
viation, and median, will help give an idea of the status of collections or
subcollections.4 After the data are recorded, a frequency histogram, like thatshown 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
placed near the film, read on thesame time schedule, and interpreted
similarly.

Monitoring the Condition of aCollection
Acetate base decay is a continuing chemical process; therefore, film
condition should be rechecked periodically. How often a collection isrechecked depends partly upon the3

See bibliography for P. Z. Adelstein, et al.,“Stability of Cellulose Ester Base Photographic Film—Parts I and II.”
4
Described in B. Lavedrine, et al., “The Useof a Statistical Approach to Evaluate Accurately the Spread of the Vinegar Syndrome ina Large Collection.”

Figure 5. A frequency histogram showing
the percentage of films in a test samplingat each of the seven possible levels (0,0.5, 1, etc.).
13

results of the initial survey and partly
upon the environmental conditions
in which the collection is stored.
Table 4 provides some general guidelines for determining monitoring frequency, with the assumption thatpart of the collection has alreadystarted to decay (which is very likely)
and is producing A-D Strip readingsof around level 1.5.

Film Storage
Te mpe rature

How Ofte n to
Re che ck

At or near room
temperature(72°F/21°C)

At least every 2
years

C ool
(less than
72°F/21°C)

A least every 5
years

Cold (50°F/10°C

At least every 10

What Do I Do with the Results?
to 41°F/5°C)
years
Be prepared to act on your surVery cold or
vey results. It has been demonstrated
At least every 25
freezing (less thanthat the only way to effectively miniyears
41°F/5°C)
mize the decay of acetate collections is to provide suitable storage Table 4. Recommended monitoring
conditions. Just how urgently im- frequency based on collection storage
proved conditions are needed is dic- temperature.
tated by the current condition of thefilm. 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:
• Improve storage conditions. This is the most important action, and by far
the most effective when cold storage temperatures are used.
•

Prioritize materials for duplication. Materials in an advanced state ofdecay should be duplicated first.

•

Periodically recheck the condition of the collection (see Table 4). Monitoring 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 notwork. But this volatility means that acidic vapors from degrading film canreadily 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 thefilm 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 deteriorated 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 polyester is less threatened by acidity thanacetate is. (Acidity does have a detrimental impact on the stability of colordyes, 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 tohave a close intermixing of acetate and polyester films. A simple way toidentify 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 filmin this condition is deteriorated. This phenomenon is observed mostly insheet films that have been handled a great deal.

15

BIBLIOGRAPHY
Preservation of Cellulose Triacetate Photographic Film,” Journal of Imaging Scienceand Technology 42 (2): 155-162.
Bigourdan, J.-L., and J. M. Reilly, “Effectiveness of Storage Conditions in Controlling theVinegar Syndrome: Preservation Strategies
for Acetate Base Motion-Picture Film Collections,” 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): 14-34.
Bigourdan, J.-L., and J. M. Reilly, Environment 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 ofFilm Bases,” SMPTE Journal 97 (December
1988): 991-993.
Edge, M., N. S. Allen, T. S. Jewitt, J. H.
Appleyard, and C. V. Horie, “The Deterioration Characteristics of Archival Cellulose Triacetate Base Cinematograph Film,” Journalof Photographic Science 36 (6): 199-203.
Edge, M., N. S. Allen, T. S. Jewitt, and C. V.
Horie, “Fundamental Aspects of the Degradation of Cellulose Triacetate Base Cinematograph Film,” Polymer Degradation and Stability 25 (1989): 345-362.
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SMPTE Journal 85 (July 1976): 493-495.
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Louisville, Kentucky: Ekstrom Library, University of Louisville, February 1987.
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Hopkins University Press, 1975.
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Cycling of Motion-Picture Films,” SMPTE
Journal 94 (August 1985): 826-827.
Lavedrine, B., R. Duverne, M. Leroy, M.
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Adelstein, P. Z., J. M. Reilly, D. W. Nishimura,and C. J. Erbland, “Stability of Cellulose
Ester Base Photographic Film: Part I—Laboratory Testing Procedures,” SMPTE Journal
101(May 1992): 336-346.
Adelstein, P. Z., J. M. Reilly, D. W. Nishimura,and C. J. Erbland, “Stability of Cellulose
Ester Base Photographic Film: Part II—Practical Storage Considerations,” SMPTE Journal 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 III—Measurement of Film Degradation,” SMPTE Journal 104 ( May 1995): 281-291.
Adelstein, P. Z., J. M. Reilly, D. W. Nishimura,
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17

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 ofImaging Arts and Sciences of Rochester Institute of Technology. IPI is cosponsoredby 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-partpublication that will givecollection managers a general
understanding of how
temperature and humidity affectthe rate of film base degradationand help them evaluate and planstorage environments for theiracetate base photographic film,
cinema film, and microfilm
collections. The booklet provides
an overview of environmental
specifications for film storage andexplains 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 priceand 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 thisproduct.

Image Permanence InstituteRochester Institute of Technology
70 Lomb Memorial Drive, Rochester, NY 14623-5604
Phone: 585-475-5199 • Fax: 585-475-7230

Made in USA
Second Edition 11/01