A Year in the Life of Audiovisual/Media Preservation in Illinois: Still Photographs and Photographic Formats

Jenny Dunbar, Archivist, College of DuPage​

Photographs were not always well regarded as historical documents. In the early stages of the development of archives, many archivists did not consider photographs as primary source material and relegated any visual material to a more subordinate position. Now, the value of photographs is appreciated, and they play a significant role in cultural heritage collections. It is imperative that these materials be preserved.

Like most audiovisual material, the preservation of still images is a complex one. Heliographs, daguerreotypes, cyanotypes, tintypes, albumen, silver gelatin prints, calotype paper negatives, glass plate negatives, nitrate, diacetate and polyester negatives, lantern slides, autochromes, film slides, digital photographs – the list goes on and on. The preservation of this multitude of formats is a daunting task that presents significant concerns, necessitating a variety of storage conditions and techniques. Additionally, photographic collections are usually heavily used, a factor that increases their susceptibility to damage.

Considerations in the preservation of still images and photographic media


Inventory is an important first step in preserving still photographs. During the inventory, an assessment of the collection can be done identifying at risk items that need immediate conservation treatment. Items with condition issues may likely need the attention of a trained conservator. Additionally, housing or storage issues may become evident.

Environmental considerations

A key factor in the preservation of still images is that of the environment. Different types of media require different environmental conditions. The tables below indicate the optimal environmental temperature and relative humidity as recommended by the International Standards Organization (ISO) for various print media:

Storage Conditions for Prints
ISO 18920:2000 (E)
Imaging Materials – Processed Photographic Reflection Prints – Storage Practices

Black-and-white silver-gelatin, dye/silver diffusion transfer (instant), etc. on opaque supports (fiber-based and RC paper and plastic film)

64.4° F

30 – 50% RH

Chromogenic dye on opaque supports

35.6° F

30-40% RH

Storage Conditions for Films
ISO 18911:2000 (E)
Imaging Materials – Processed Safety Photographic Films – Storage Practices

Black-and-white silver-gelatin on a cellulose ester base (each of the three options will achieve a similar life expectancy)

36.5° F

41° F

44.6° F

20-50% RH

20-40% RH

20-30% RH

Black-and-white silver-gelatin on a polyester base

69.8° F

20-50% RH

Color (chromogenic) on a cellulose ester or paper base (each option will achieve a similar life expectancy)

14° F

26.6° F


20-50% R

20-40% RH


Color (chromogenic) on a polyester base

35.6° F

20-30% RH

Storage Conditions for Plates
ISO 18918:2000 (E)
Imaging Materials – Processed Photographic Plates – Storage Practices

Black-and-white silver on a glass or metal support

64.4° F

30-40% RH

In an ideal setting, one would want to have media isolated by type and stored in conditions specifically designed for optimal preservation. However, in an archival environment that contains mixed media formats, it may not be feasible to do this. A temperature range of 65° to 68° F and relative humidity between 30% - 40% is an acceptable compromise, but one should be aware that this will cause certain material to deteriorate more rapidly. Collection managers with collections of cellulose film and color photographs (pre-1990) may want to investigate cool or cold storage units if economically possible.

Temperature and relative humidity in archival storage areas should be monitored. There are a number of environmental monitoring devices available, ranging from recording hygrothermographs and datalogers to more simple non-recording hygrometers. Regardless of the equipment used, it is important to check continuously to keep the environment at a stable level and identify possible HVAC problems.

Protecting photographic material from ultraviolet light is another environmental issue that needs to be addressed. The main sources of UV light are fluorescent lights and sunlight. Storage areas should ideally have no windows, but if this is not the case, the windows should be blocked. Shutting off lights in storage areas when staff are not present and housing photographs in closed containers are two other steps that are essential to guarding against UV damage.

Storage considerations

Storage considerations encompass a number of issues such as storage containers, enclosures, shelving units, and horizontal or vertical storage.

All storage enclosures should pass the photographic activity test (PAT) as outlined by the International Organization for Standardization (ISO). Enclosures should be made of high quality paper or one of several stable plastic materials.

Enclosure material – pros, cons, and specifications

Paper enclosures

Pro – good light protection, typically less expensive than plastic

Con – opacity of paper envelopes requires photos to be removed for viewing, risking abrasion, edge damage, fingerprinting

Smooth surface; pH between 7.0 – 9.5 with alkaline reserve of at least 2% calcium carbonate; minimal sizing; any dyes should be tested for bleeding or transfer

Plastic enclosures

Pro – transparency allows viewing access without physical contact with photo

Con – buildup of static electricity attracts dirt and dust; not recommended for photos that have flaking or lifting emulsions

Acceptable plastics include polyester (polyethylene terephthalate), polyethylene, polypropylene, polystyrene, and spun-bonded polyolefins


ISO 18916:2007 Imaging materials – Processed imaging – Photographic activity test for enclosure materials.

ISO 18902:2013 Imaging materials – Processed imaging materials – Albums, framing and storage materials

In addition to the material used to house photographic items, shelving and orientation of objects during storage need to be examined. Shelves, drawers, and storage furniture made of wood or wood products should not be used to store photographs. Wood products contain adhesives, formaldehyde, and other substances that will damage photographic material. If wood is unavoidable, it could be sealed with a non-oil based paint or covered with sheets of polyester film. Baked-on enamel for archival shelving and storage furniture is widely used and acceptable, the preferred material being powder-coated.

Format, size, and condition are the primary factors to consider when deciding whether to store material vertically or horizontally. Storing fragile photographs vertically can damage the edge it rests on; large photographs stored in this manner can cause the item to curve. Hanging folders are not recommended for these same reasons.

Horizontal storage is preferred for large or fragile items because they are better supported, but care must be exercised so as not create undue pressure on items at the bottom of a box or drawer. For unusual formats or items at risk, custom folders, boxes, or housing may be indicated.


Photographic collections are often heavily used making them susceptible to damage in handling. Consequently, handling the items in a safe manner, so as not to inflict damage, is crucial. The use of clean dry hands or gloves when handling will help protect items. Training staff, student workers, and volunteers in the proper techniques for handling material is important, as they may not be aware of correct methods.

Due to the diversity of photographic media, the subject of preservation is large and complex. While this is by no means intended to be a comprehensive guide, hopefully it will provide a starting point for collection review. There is a wealth of good information on the preservation and conservation of special photographic material available online. Please consult the additional online resources for further information.

As part of the Preservation Committee’s yearlong look at two libraries, Anne Thomason (Donnelley and Lee Library at Lake Forest College Library) and Patrick Brown (Morris Library at the Southern Illinois University – Carbondale) discuss their collections of photographic material.

Case Study

Questions Anne Thomason from Donnelley and Lee Library, Lake Forest College Patrick Brown from Morris Library, Southern Illinois University Carbondale

Please provide a brief overview of the types of photographic material you have in the collection.


Print photographs, negatives, and slides as well as born digital items.

In the SIU Special Collections and Research Center, we have a variety of still images in many formats. In our general collections, we do not have much photographic material beyond microform. Most still images are found in our University Archives, Manuscripts, and Political Papers Collections. We have a few tintypes, daguerreotypes, and other “special” formats within these collections, but mostly we have more modern black and white gelatin prints, color prints, and acetate negatives. We also have lantern slides and glass plate negatives, including a few panoramic glass plate negatives. We are starting to get born digital photographs, mostly in University Archives.

Have you done an inventory of still images?



We have some manuscript collections with fairly complete image inventories. However I would say the inventory lacks metadata about images that would be good to collect.

We haven’t explicitly done an inventory of still images, but when a collection is processed, still images are noted in finding aids. The level of detail of the finding aid depends on the collection. Digitized images are in CONTENTdm – hosted by CARLI – and have item level description. Other photographic material might be described at the folder or box level.

Are there appraisal steps that you are including of the inventory? Condition assessment or weeding?


We are not weeding, but we are noting preservation challenges as they come up. One of our most important collections is stored improperly, and I’m hoping to go after grant funds to rehouse and reprocess the collection.

While processing, the archivists do look out for condition problems or potential concerns. They are trained to look out for nitrate film, vinegar syndrome, and other issues and bring them to Preservation.

For your different types of media, are there differences in how you store them?

Not presently

With a few exceptions (nitrate film), photographic material is stored in with the rest of its collection. We might house them differently, with different supports, etc. Most photographs and negatives are stored in paper envelopes. Broken or flaking glass plate negatives are stored flat on custom trays.

Do you monitor the environment in your archive and if so, what kind of environmental monitoring systems or procedures do you have in place?

We have a couple of temperature and relative humidity readers in the stacks area and in the reading room. They are not on a network, so I check them regularly. We need a better monitoring system, and that is on a list of things to do this year.




Albright, Gary and Monique Fischer. “Care of Photographs Northeast Document Conservation Center. 

Albright, Gary and Monique Fischer. “Storage Enclosures for Photographic Materials Northeast Document Conservation Center. 

ISO. International Organization for Standardization.

Ritzenthaler, Mary Lynn and Diane Vogt-O’Connor. Photographs: Archival Care and Management. Chicago: Society of American Archivists, 2006. Print.


Image Permanence Institute. Rochester Institute of Technology, 2016. 

Northeast Document Conservation Center.

Teper, Jennifer Hain. “Identification and Preservation of Photographic Collections.” CARLI Preservation Working Group Audio Visual Preservation Forum. 13 Oct. 2009. 

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