NOTES

1.. An original petition of Matthew B. Brady, in the custody of the National Archives, requests that Congress purchase his collection of Civil War photographs. In this document, which bears his signature, Brady's given name is spelled “Matthew” (with a double “t”). While his given name is customarily spelled with only one "t," it seems reasonable in this article to follow the spelling in Brady's petition.

2.. Coe and Haworth-Booth also describe albumen negatives as “creamy or milky” in color. When they usually appear reddish brown in hue.

3.. The term “emulsion coating” seems to describe the varnish layer. However, gelatin plates may be varnished with uneven coatings as well.

4.. This description may be considered accurate from a technical standpoint. however, it may be misleading to those unfamiliar with collodion collections and the process by which they are made. The term “flow marks” and “varing thickness” imply a three dimensionality associated with the collodion layer. The three-dimensional surface character of collodion plates observed by the naked eye is primarily a result of the thicker varnish layer.

5.. To achieve the desired three-dimensional effect, the position of two camera-generated stereo images must be laterally swapped. In production shops, stereo plates were often cut in half and the positions swapped and mounted with gummed paper tape to a secondary glass support to facilitate contact printing. This single procedure eliminated the need to trim numerous prints before mounting.

6.. The secondary effect described by Brems is apparently more relevant to collodion negative deterioration than the primary effect seen in the degradation of cellulose nitrate-based negatives.

7.. The use of organic solvents, such as Kodak Film Cleaner (1,1,1 trichloroethane) on collodion plates is not recommended. The varnish layer, as well as the underlying collodion binder layer, are soluble in most organic solvents. Treatment with organic solvents may result in loss of image.

REFERENCES

ANSI. 1986. American national standard for photography (processing): Processed films plates, and papers—Filing enclosures and containers for storage. ANSI PHI.53-1986. New York: American National Standards Institute.

Archer, F. S.1854. The collodion process on glass. 2d ed.London: Printed for the author.

Barger, M. S.1985. Characterization of deterioration of glass supported photographic images. Printing of Transcript Summaries, Second International Symposium: The Stability and Preservation of Photographic Images, Society of Photographic Scientists and Engineers, Ottawa, Canada, August 25–28, 1985.

Barger, M. S., D. K.Smith, and W. B.White. 1989. Characterization of corrosion products on old protective glass, especially daguerreotype cover glasses. Journal of Materials Science 24: 1343–56.

Brems, K.A.H. 1988. The archival quality of film bases. Journal of the Society of Motion Pictures and Television Engineers (December):991–93.

Brill, Robert H. 1978. The use of equilibrated silica gel for the protection of glass with incipient crizzling. Journal of Glass Studies 20: 100–118.

Coe, B., and M. Haworth-Booth. 1983. A guide to early photographic processes. London: Victoria and Albert Museum.

Eastman Kodak Co. 1979. Preservation of photographs. Rochester, N.Y.: Eastman Kodak Co.

Eastman Kodak Co. 1985. Conservation of photographs. Rochester, N.Y.: Eastman Kodak Co.

Feldman. L. H. 1981. Discoloration of black-and-white photographic prints. Journal of Applied Photographic Engineering 7(1): 1–9.

Gill, A. T. 1978. Photographic processes: A glossary and chart for recognition. Museums Assocation Information sheet 21. London: Museums Assocation.

Gillet, M., C. Garnier, and F. Flieder. 1986. Glass plate negatives: Preservation and restoration. Restaurator 7(2):49–80.

Lavedrine, B., and C. Garnier. 1989. Analysis and restoration of negatives intensified with mercuriclodide. In Topics in Photographic Preservation, Vol. 3. Washington, D.C.: Photographic Materials Specialty Group of the American Institute for Conservation of Historic and Artistic Works.

Lea, M. C. 1871. A manual of photography. 2d ed. Philadelphia: Printed for author.

Moser, F. 1961. A study of glass surface deterioration by moisture. The Glass Industry 42 (May):244–86.

Munson, D. 1982. Duplication of glass negatives. Picturescope (Spring):19–23

Ostroff, E. 1974. conserving and restoring photographic collections. Part 3. Museum News (November) 42–45.

Ram, A. T., and J. L. McCrea. 1988. Stability of processed cellulose ester photographic films. Journal of the Society of Motion Picture and Television Engineers June.

Reilly, J. M. 1979. The albumen and salted paper book. Rochester, N.Y.: Light Impressions.

Reilly, J. M. 1986. Care and identification of 19th-century photographic prints. (with C. McCabe) Kodak Publication G-2S. Rochester, N.Y.: Eastman Kodak Co.

Rempel, S. 1979. The care of black-and-white photographic collections: Identification of processes. Canadian Conservation Institute Technical Bulletin 6. Ottawa: Canadian Conservation Institute.

Rempel, S. 1987. The care of photographs. New York: Nick Lyons Books.

Segal, V. M., I. E. Bolotov, L. V. Rabinovich, R. Ya. Liberman, and L. P. Zhukova. 1976. Crystalline deposit on polished surfaces. Soviet Journal of Optical Technology. 43(10):607–10.

Simpson, H. E. 1958. Study of surface structure of glass as related to its durability. Journal of the American Ceramic Society. 41(2):43–49.

Simpson, H. E. 1959. Study of surface durability of container glasses. Journal of the American Ceramic Society 42(7):337–43.

Time Life Books 1972. Cuting for photographs New York: Time Life Books.

Towler, J.M.D. 1879. The silver sunbeam, 9th ed.New York: E. and H. T.Anthony.

Weinstein, R. A., and L. Booth. 1977. Collection, use and care of historical photographs. Nashville: Tenn.: American Association for State and Local History.

Wilkin, L. D., and B. London. 1979. The photograph collector's guide. Boston: New York Graphic Society.

AUTHOR INFORMATION

CONSTANCE MCCABE received her MFA in 1982 at Rochester Institute of Technology in the School of Photographic Arts and Sciences' Museum Practice Program and served internships with the George Eastman House and the Image Permanence Institute. At the time of writing this article, she was senior photograph conservator at the National Archives in Washington, D.C. She is currently working as a photograph preservation consultant and is president of Photo Preservation Services, Inc., a negative duplication service, Address: 409 Constitution Avenue, N.E. #4, Washington, D.C. 20002.