posted on 11 Nov 2013 19:26 by Gabrielle Berlinger
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The "Cultures of Conservation" class met on October 8, 2013 with Nora Kennedy, Conservator of Photographs at the Metropolitan Museum of Art. Class member Antonia Behan offers the follow report of a fascinating behind-the-scenes site visit:
When conservators and non-conservators talk, we often begin with what we have in common. Questions of mutual interest, such as how decisions made during a treatment about an artifact’s material substance affect its interpretation, are a natural place to start. But though we speak a common language, we can often forget the differences in skills and expertise that bring us together. Conservators, for instance, speak a second language, that of science and technique. Our visit to the Metropolitan Museum of Art’s Sherman Fairchild Center for the Conservation of Photography was especially exciting and important since our hosts brought us into their world, demonstrating a number of analytic tools that are fundamental to their everyday practice.
Nora Kennedy, Sherman Fairchild Conservator of Photographs, began our session with a short history of photography through its technical forms, from the Daguerreotype to the digital photograph. We discussed how the material and chemical composition of each type of photography make it prone to certain types of problems. One issue that came up quickly and resurfaced often through our visit was the need for conservators of the rapidly expanding field of digital works.
Janka Krizanova, a postdoctoral research fellow at he MET (Paper and Photograph Conservation, Academy of Fine Arts and Design, Bratislava), introduced us to some basic tools in conservation, guiding us through the various ways one can “see” photographs. We began with looking at photographs with the naked eye, and looked closer and closer with the aid of loupes and then microscopes. Janka then showed us analytical tools: FTIR and XRF. These tools work on the same principle, but are suited to different types of detection. FTIR, working with the infrared range of the electromagnetic spectrum, is used to identify organic material such as albumen or cellulose binders. XRF operates in the X-ray range and is used to identify inorganic components of photographs, such as silver. Each machine sends pulses of a range of electromagnetic radiation through the sample—imagine scanning slowly through the frequencies of an analog radio. Each chemical compound will absorb characteristic amounts of energy at characteristic wavelengths, creating a signature pattern of response. The conservator can compare the results from their sample with known response patterns, or spectra, to identify the substances. It is essential to understand what the photograph is made of in order to understand how to care for it.
Understanding the composition of a photograph also helps us date it. Krista Lought, Third Year Intern at Photograph Conservation and graduate student in SUNY Buffalo's Conservation Program, demonstrated another essential tool in the conservator’s arsenal: the UV lamp. UV A and UV C detection works on the same principle as FTIR and XRF, but the visual display of results is different. The response of chemical compounds to infrared and X-ray are displayed in a graph, visible to us only when detected and interpreted by graphical analysis. The energy released by the compounds during their interaction with UV, however, falls in the range of visible light. In other words, the compounds fluoresce, and are visible to the naked eye. Kristin showed us a pile of black and while snapshots: they all looked the same. But under UV A light, some fluoresced bright white, betraying the presence of optical brighteners that were used in photography only after 1950.
We finished our session with Katie Sanderson, Sherman Fairchild Assistant Conservator of Photographs, who spoke about color photography. She gave us a light-show demonstration of additive and subtractive color matrices. We also discussed her treatment of intentional decay in the work of contemporary photographer Stephen Shore, decay that is both a terrifying and fascinating revelation of the layers of photographs.
The MET Photography Conservation team took us “behind the scenes” of their analytical process. They introduced us to some basic vocabulary of scientific analysis, defining frequently encountered but often opaque technical terms. Hopefully, this primer on scientific instrumentation and language will help make our conversations richer, even when we come together with shared questions.