5 CONCLUSIONS

This research quantitatively establishes that the aqueous treatment of albumen photographs has serious consequences. Pre-existing cracks in albumen photographs are measurably wider after treatment, and there are additional cracks after treatment. Print gloss is reduced after treatment. Print color, particularly highlight yellowing, is not improved by aqueous treatment. Removal from a mount by aqueous immersion appears to result in some transfer of soluble colored material from the mount to the print.

A practicing conservator must judge the potential merits of the aqueous treatment of albumen prints against the drawbacks. It is clear that application of water to the surface of albumen photographs causes damage. Although this damage is largely on a microscopic level, it is visually perceptible in terms of reduced gloss. In many cases this damage may be acceptablexs, if a greater preservation aim is served. The aqueous surface cleaning of an extremely soiled print, for example, may achieve a greater image clarity that outweighs the damage created by increased overall cracking.

Aqueous treatment of albumen prints should not be considered routine or noninvasive. The benefits and risks of aqueous treatment need to be assessed for each individual albumen photograph prior to treatment. Alternatives to aqueous treatment, such as surface cleaning with solvents or crumbled eraser particles, warrant investigation. These alternatives may also have potential hazards. The use of polar solvents may cause excessive swelling, and rapid evaporating solvents may result in dramatic dimensional changes. The use of eraser particles may cause abrasion, and there is the risk of leaving particles in existing albumen cracks. Further work is needed to develop and assess nonaqueous treatment alternatives for albumen prints.

ACKNOWLEDGEMENTS

We are indebted to Marion Mecklenburg, assistant director for conservation research at the Conservation Analytical Laboratory, Smithsonian Institution (CAL), who provided insightful guidance, read the manuscript, and made many valuable contributions. Mark McCormick-Goodhart, photographic scientist, CAL, also offered valuable advice and insights into photographic technology. Carol Grissom, chief of objects conservation, CAL, served as a tireless proofreader and made many valuable suggestions that spared the reader considerable duress.

We thank Richard Harold, head of training, Hunter Laboratories, for his interpretation of our color data, especially the effects of dirt removal on color, and for fielding many general inquires about color measurement. Paula Flemming, supervisory museum specialist, Department of Anthropology, National Museum of Natural History, provided several of the prints used in the experiment; they were treated and returned. Douglas Munson of the Chicago Albumen Works provided samples of his work and valuable insight on the manufacture of albumen photographs. Our special thanks are extended to Jose Orraca, in private practice in New York and Kent, Connecticut, who generously contributed several prints used in the experiment and has provided invaluable support.