Literature

"Effect of Paper Alkaline Reserve on the Chemical Stability of Acetate Base Sheet Film," by Jean-Louis Bigourdan, Peter Z. Adelstein, and James M. Reilly. Topics in Photographic Preservation v.7, 1997, p. 43-54. That issue of Topics is available from the American Institute for Conservation for $15 + $3.

This is a report of research funded by the NEH and the Institut Français de Restauration des Oeuvres d'Art, Paris. It answers a number of questions that people have been asking for years.

First, do buffered paper enclosures slow down the development of the "vinegar syndrome" (degradation of acetate film base)? Answer: Hardly at all, because calcium carbonate is so slow to react with the acetic acid given off by the film. It did react fairly rapidly over the first two weeks, but more than half of the alkaline reserve was still left at the end of 50 days' exposure, coexisting with the free acid in the fiber of the paper.

Second, are buffered papers more effective acid receptors than plain papers? Answer: Yes. But the practical impact on the film is limited. Third: Do paper enclosures slow the "infection" of sound film by degrading film? Answer: No.

Fourth: Which is better: Paper (buffered or nonbuffered) or plastic envelopes for sheet film? Answer: Neither offers an advantage. Question: Then what shall we do about our acetate film collections? Answer: "Segregation of degrading objects, re-housing, and efficient ventilation are considered important for collection management. The control of temperature and relative humidity remains the most effective and quantified preservation strategy for cellulose acetate film collections." (3F2)

"Shandon Xylene Substitute in Document Examinations," by Gary Licht and Jerry Brown, Iowa Division of Criminal Investigation Laboratory, Wallace Building, Des Moines, IA 50319-0041. This solvent is marketed as a noncarcinogenic substitute for xylenes. It is nondestructive to inks, paper or plastics, less volatile than xylene, and is only a weak solvent of correction fluids. The authors use it mainly to make paper translucent, to allow obliterated writings to be read through the back side of the page, and to permit IR examinations through the paper. It does not affect indented writings, and it evaporates without leaving any odor, discoloration or distortion. (3B2.71)