Research Techniques in Photographic Conservation:
Proceedings of the Conference in Copenhagen, 14-19 May 1995.
Mogens S. Koch, Tim Padfield, Jesper Stub Johnsen and Ulla
Bøgvad Kejser, eds. Copenhagen: Royal Danish Academy of Fine
Arts, 1996. Available from National Museum of Denmark, Department of
Conservation, Attn: Jesper Stub Johnsen, Box 260, DK-2800 Lyngby,
250 DKK (about $45). Hardcover, 116 pp., with numerous illus.
The Copenhagen conference organized by J.S. Johnson attracted an impressive roster of speakers, including many of the leading photographic conservation scientists and administrators from North America and Western Europe. Although not as voluminous as the fifty papers in the proceedings of the April 1992 Windermere conference (published as The Imperfect Image and reviewed in CAN 56, January 1994), the quality of the twenty papers here is excellent.
Several speakers at Copenhagen addressed broad issues in the field of photographic conservation. The late Klaus B. Hendriks in "Evaluation of Conservation Treatments," and Debbie Hess Norris in "Current Research Needs in the Conservation Treatment of Deteriorated Photographic Print Materials," both attempted to formulate a research agenda. Particularly needed is research that will resolve questions concerning appropriate storage conditions as raised by the Conservation Analytical Laboratory of the Smithsonian Institution, the development of better treatments for flaking binder layers, and improved methods for surface cleaning; humidification and flattening; and mounting. The ethics of irreversible chemical treatments is another unresolved problem. Norris also notes the need for better differentiation between the practices of paper conservation and photographic conservation. Other papers which dealt with broad issues were P.Z. Adelstein's "Standards on the Permanence of Imaging Materials," which includes a useful table listing related ANSI and ISO standards, and J. Rosvall's "Scholarly-Scientific Research, Networks and Standards in Conservation."
Most of the other papers at Copenhagen fell into three categories: preservation planning, analytical techniques, and methods used to predict deterioration. The first category addressed issues of preservation planning in Scandinavia and would be of interest to most individuals in the field of conservation of cultural materials. E.K. Nielsen outlines the strategic five-year plan at the Royal Library of Denmark and issues concerning its print and photographic collections, including planning for storage in new buildings and compromises that have to be made between "standards and reality." R. Koskivirta provided an overview of the situation in Finland, including the conservation activities at the National Museum and the Photographic Museum.
R. Erlandsen outlined the missions of several of Norway's institutions involved in photographic conservation. Erlandsen then discussed how the conservation of photographs fits into the national conservation project initiated by the Norwegian Council of Cultural Affairs that is being implemented by the Institute for Historical Photography. The Institute is in the first phase of the project, involving a survey of about nine million photographs at fourteen institutions; this will be followed by recommendations and guidelines. Another paper by Karl-Espen Antonsen describes the preservation work on audiovisual materials at the recently established Rana Branch of the National Library of Norway and includes photographs of the underground cold storage facility and above-ground nitrate film vault.
Sweden also has a national plan for preservation of photographic materials, as described by E. Dahlman. In December 1993, Sweden created the Swedish Secretariat for Photographic Collections which coordinates activities and provides advisory services. One of four working groups attached to the Secretariat deals with preservation; another with photographic archives and registers of photographers; a third with access issues, and the fourth with "registration." A national database indexing photographers and photographic collections is a planned component of the national preservation plan.
The second category of papers, concerning analytical techniques, is much more technical in nature than the first. C. McCabe and L.D. Glinsman's presentation, "Understanding Alfred Stieglitz's Platinum and Palladium Prints: Examination by X-Ray Fluorescence Spectrometry," describes a useful method to help distinguish print processes that may appear indistinguishable on visual examination alone. U.B. Kejser in "Examination of Photographs with TEM--Sample Preparation and Interpretation of the Image" describes how to create a slice of an image 1/10,000 mm thin in order to study it with transmission electron micrography. Kejser is using TEM to study deterioration of silver gelatin images and his paper includes a number of impressive microphotographs.
The third category includes papers primarily related to methods used to predict useful life of photographic materials under varying storage conditions. T. Padfield and J.S. Johnsen, in "The Breath of Arrhenius: Air Conditioning in Photographic Archives," assess in an innovative way a variety of factors causing deterioration and, from a practical viewpoint based on survey evidence, provides guidance on setting a climate specification for the bulk of a photographic collection.
Mark H. McCormick-Goodhart summarizes a study of the moisture content of photographic gelatin under varying temperature and humidity conditions. In an encouraging finding, he reports that, in a cold storage vault, photographs sealed in a package with "little free air space naturally move towards the desired lower relative humidity conditions when the temperature is reduced." (McCormick-Goodhart has also developed a packaging method for cold storage, which he described at the 1995 annual meeting of the Society of American Archivists.) Also interesting here (but difficult to summarize) is his discussion of the implications of his research on two methods of accelerated aging tests (sealed vs. unsealed test samples).
Accelerated aging tests, based on the work of the Swedish chemist Arrhenius in the 19th century, are necessary for long-term prediction of the longevity of photographic materials and for research on the behavior of these materials under different environmental conditions. James M. Reilly, who directs many such tests at the Image Permanence Institute in Rochester, New York, provides a detailed explanation of the experimental techniques used today and the factors that affect the accuracy of the results. In a complementary paper, D.W. Nishimura describes issues of interpretation and presentation of accelerated aging test results, including issues surrounding The IPI Storage Guide for Acetate Film (reviewed in this newsletter, October 1993, p. 71c).
Only recently has it been possible to assess empirically the accuracy of Arrhenius tests by comparison with naturally aged samples of photographic materials. One such study is reported here by Bertrand Lavédrine, who studied the dark stability of twelve color chromogenic films produced by five manufacturers. Lavédrine compared actual density changes after ten years with predicted changes based on accelerated aging ten years previously. He found that while there was "some concordance" between natural aging and predicted density changes, the results are not always consistent, particularly for yellow dyes.
A related paper was that by Michele Edge, "Lifetime Prediction: Fact or Fantasy?" which explored a number of reasons why accelerated aging can only provide a "rough guide." One reason she mentions is that extreme conditions may cause secondary reactions that would not occur at room temperature. Another paper on aging was presented by J. Glastrup, who reported on a study of the gases released during accelerated aging of cellulose acetate film. He found that there were at least two independent chemical reactions in the product during aging. Since extrapolated data using Arrhenius methods is based on the assumption of one reaction, this finding could help explain the limitations of some accelerated aging tests.
Finally, a brief overview of research in Stockholm on digital restoration of photographs was presented by J. Pal and M.S. Koch, with an impressive illustration of how they reassembled and enhanced an image on a computer from scanned emulsion flakes found in the bottom of an envelope. We can expect much more in the future from this new branch of photographic conservation.
Collectively, all these fine papers leave the impression that while much more work needs to be done to improve photographic conservation methods, considerable progress is being made.
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