Volume 22, Number 2
1998

Review

Storage Guide for Color Photographic Materials: Caring for Color Slides, Prints, Negatives, and Movie Films by James M. Reilly. Albany, NY: University of the State of New York, 1998. 48 pp. Available from NY State Education Dept., 16-C 47 Cultural Education Center, Albany, NY 12230. (phone: 518/486-5354.)

With billions of photographs made every year, it is probably essential for the survival of the human species that most of them will fade and be discarded. It has been estimated that one billion photographs per year are taken at Disney properties alone. If 4x6 prints were made of each exposure, and they were laid end to end along the equator, the line of prints would extend 94,696 miles, almost four times around the globe. (A challenging project for Christo!) If all of these photographs had to be stored in the Disney Archives, about 250,000 cubic foot record cartons would be required. Alternatively, for about $95,238,000 these photos could be kept in 4,761,904 archival binders (1.75 inch), each with 35 page protectors (six photos per page), on 131.5 miles of shelves or in 77,160 four-drawer file cabinets. Apparently, the world's natural resources are being converted into photographs and we can only hope that digital imaging will save us from this calamity.

Some contemporary photographs, of course, deserve long-term preservation. This very useful and impressive Storage Guide, authored by the director of the Image Permanence Institute at the Rochester Institute of Technology, constitutes a companion to the IPI Storage Guide for Acetate Film (IPI, 1993). Like that earlier effort, the Storage Guide for Color Photographic Materials includes an informative text and a laid-in cardboard wheel which distills new research on contemporary color materials compiled from 1993 to 1996, most of it previously unpublished, and provides practical recommendations for collections managers.

The wheel is used by turning a dial to select a storage temperature; data in a window are provided with the approximate number of years to significant dye fading at various levels of relative humidity. (Dark storage is assumed.) IPI's research indicates that, even with the increased stability afforded by contemporary products, cold storage is necessary for long-term preservation. At 70°F (21°C) and 40% relative humidity, the approximate time to significant dye fading is 60 years, while at 75°F (24°C) and 60% RH, the time is only 19 years. To prevent such fading for 450 years, storage at 45°F (7°C) and 40% RH could be used. Most pre-1990 color materials would require substantially colder and/or drier storage for comparable results. No particular combination is recommended, but the longest time period given before significant fading is 8,000 years for 30°F (-1°C) at 20% RH.

"Significant" dye fading is defined by Reilly as a 30% loss in the least stable dye in chromogenic color slides, negatives, and prints, which in all dark fading tests turned out to be yellow. (Although the wheel refers only to the least stable dye, other dyes will also fade to a lesser degree during the same time period.) Thirty percent is well beyond a just barely visible change, which is about a 10% dye loss.

Although individual products differ in fading rates, a single scale is used on the wheel. Henry Wilhelm, in his classic Permanence and Care of Color Photographs (1993), reported substantial differences in fading rates among Agfa, Kodak, Konica, and Fuji color papers and other materials. Reilly does not report here the extent to which IPI's results were consistent with Wilhelm's earlier findings, but states that, for contemporary color materials, storage conditions are a more important factor than product selection in determining longevity.

The other side of the wheel provides a Time-Out-of-Storage Table which indicates the damaging effects of removing color photographic materials from a preferred storage environment and exposing them for various numbers of days each year to office conditions (75°F [24°C] and 60% RH). This table has particular implications for museums that store and occasionally exhibit color photographs valued highly as works of art, but it has practical value for other repositories as well.

While removing a photograph from a storage environment that differs little from that of the office will have only a minor impact on stability, withdrawal from cold storage even for a few days per year has a substantial effect. For example, an item removed from storage at 40°F (4°C) and 40% RH for only ten days per year would fade twice as fast as one kept under those excellent conditions (700 years vs. 350 years for 30% density loss in the least stable dye). Keep in mind that the Time-Out-of-Storage Table does not account for the additional deleterious effects of light during time out of storage.

Unlike the front side of the wheel, the Time-Out-of-Storage Table on the back gives fading rates for temperatures well below freezing, down to -15°F (-26°C). The table indicates that deep-freeze storage does not provide a significant advantage over storage just below freezing temperatures, provided the humidity is kept below 40%. Older materials, however, would benefit more from deep-freeze storage than the 1990s photographs for which data are presented, because recent color photographs have been fairly stable.

Reilly's text is divided among ten clearly written chapters and a bibliography. The first three chapters provide an overview of the history of color stability, the technology of color photography, and an explanation of the causes of fading in dark storage. (Light fading stability is mentioned but not addressed, presumably because it is not a factor in storage). Reilly then explains the effects of different factors that influence stability, including storage enclosures, air pollution, and environmental controls. One example of useful information here is that oxidizing air pollutants are not as significant a threat to color images as they are to silver-based black-and-white films and papers.

The final chapters deal with practical aspects of cool and cold storage considerations, including discussions of facilities and equipment for both large and small collections, the control of condensation, and the use of sealed packages. This section should be required reading for all who have professional responsibility for storing color images. The annotated bibliography cites a number of key works, although surprisingly it omits reference to New Tools for Preservation, another publication by Reilly et al., that is discussed in the text. Although the table of contents is fairly detailed, an index would have made the guide easier to use.

In summary, Storage Guide for Color Photographic Materials is among the handful of essential publications in this important aspect of conservation.