Reading 3

Wilhelm, H. (1993). Chapter 7: Monitoring the Long-Term Fading and Staining of Color Photographs in Museum and Archive Collections. The Permanence and Care of Color Photographs: Traditional and Digital Color Prints, Color Negatives, Slides, and Motion Pictures (pp. 239-266). Grinnell, Iowa: Preservation Publishing Company.
ISBN: 0-911515-00-3

This is another chapter Brad recommended I read. It is very relevant to the concerns of archives, since archives often put on exhibits of materials in their collections, including photographic prints. Overall, the chapter's conclusions about the preservation of color prints are a bit bleak--the author indicates that, "Compared with most other types of artistic media, color photographs generally fade and/or stain fairly rapidly when exposed to light on display. And, unlike the dyes and pigments in watercolors, paints, and fabrics... most kinds of color photographs slowly fade and develop overall yellowish stains even when kept in the dark" (239). Since the fading of photographic prints is inevitable under all but the best conditions, this chapter is devoted to determining the limit of tolerable fading and staining on photographs, the monitoring of that deterioration, and the best ways to exhibit photographs in light of these facts. Once the staining and fading limits on a print are reached, Wilhelm indicates that the original print should be permanently stored in dark, cold, humidity-controlled storage and only copies used for display purposes.

Wilhelm notes that carefully monitoring the deterioration of the colors in photographic prints is particularly important since it is often difficult for photographs curators to detect this fading and staining when they view the image repeatedly over the course of their career. While Wilhelm indicates that is is most important that museums and archives monitor the fading of color photographs, he writes that black and white prints should ideally be monitored, as well. Additionally, he writes that any photographs made with processes known to produce unstable prints should be monitored.

The author includes a table on page 258 which provides recommendations for the limits of tolerable fading in color photographs. The density of cyan dye should not change by more than 9%, the density of magenta dye should not change by more than 9%, and the density of yellow dye should not change by more than 13%. (Shifts in the density of the yellow dye do not have as much of an impact on the contrast of the image as do shifts in cyan and magenta, making slightly larger shifts tolerable.)

In order to monitor this deterioration, Wilhelm recommends the use of densitometers and provides instructions on how to calibrate and use these devices. He also gives guidance on how to begin a program for the long-term monitoring of the fading and staining of photographic prints using densitometers. This approach might be useful for large museums and archives, but, while Wilhelm does not give the prices of these devices or filters they use, it seems likely that such devices are outside the budget of the vast majority of archives. To provide examples of monitoring programs using these devices, Wilhelm describes programs at the Art Institute of Chicago and the National Archives, both of which have far more resources than most archives. This limits the usefulness of this section of the chapter to most archivists and curators.

However, the chapter also includes some basic advice which is useful to any photographs curator interested in displaying original prints. Obviously, the prints should be displayed in temperature and humidity-controlled conditions, and a balance must be struck between displaying the photographs under as low a level of light as possible and illuminating them enough to make their details visible to exhibit visitors. In an exhibit put together by the Art Institute of Chicago, the conservator adopted the interesting solution of displaying the most fragile print behind a curtain which the visitors could lift in order to examine the image, minimizing the exposure of the photograph to light as much as possible. Wilhelm also notes that, in the case of traveling exhibits or photographs which have been loaned to another institution, the prints are most vulnerable to fading and staining while they are in transit, when conditions are often not controlled as carefully as they are when the prints are actually on display.

Wilhelm indicates that the available "display time" of a particular print (the amount of time for which it can be exhibited under a particular set of conditions before the limits of tolerable fading and staining are reached) should not be used up under the tenure of one curator--rather, the curator should strive to leave as much display time as possible available for the future. Since some prints may have already undergone significant amounts of staining or fading before they come into the care of a museum or archive, photographs curators may not always have a pristine baseline to which the images can be compared as they deteriorate over time. In this case, Wilhelm recommends that prints which may have reached their fading or staining limit not be exhibited at all and facsimile prints used for display and study.

The author recommends that facsimile copies of prints be made before any fading or staining becomes noticeable. This will extend the lifetime of the original, since the facsimile can sometimes be used for display and research purposes. Wilhelm believes that archives and historical institutions are in a slightly better position than art museums when it comes to displaying photographs, since it is more likely that a facsimile will be acceptable in the context of a historical exhibit--where the content of the image is of greatest interest to the visitor--than in an art museum, where the print itself is the object of interest.

This chapter includes some useful guidelines and common-sense advice for the display of photographs in archives and museums. For those institutions with the resources to monitor the deterioration of images with densitometers, the author also provides detailed guidelines on the use of these devices. For institutions with more limited resources, following the general guidelines provided by the author can allow photographs curators to be reasonably sure that they are exhibiting their materials responsibly.