AIC's 52nd Annual Meeting

During a 2023 characterization study of Robert Mapplethorpe prints at the Solomon R. Guggenheim Museum, NY, four gelatin silver prints on resin coated (RC) paper from the 1970s were found to have small blue and magenta colorants scattered throughout the resin layer of the recto.  When observed under ultraviolet radiation, all four prints had significant transfer of optical brightening agents (OBAs) to the Phototex folders used in housing despite being stored under optimal environmental conditions. It was further found that OBAs readily transferred from the verso when lightly brushed with a dry cotton swab.
While the modes of deterioration for RC prints have been well documented in conservation literature, unique aspects of their structure and manufacturing have not.  In addition, the materials used in mass produced photographic papers from the late 20th century are often difficult to research due to lack of publicly available information from manufacturers.  To further investigate the phenomena observed in the Mapplethorpe prints, 63 samples of RC paper from the 1960s to the 2010s were examined to look for the presence of colorants in the resin layer and dry OBA transfer.  Samples were chosen from the collection of gelatin silver and chromogenic papers collected by Paul Messier and currently held by the Lens Media Lab at Yale University’s Institute for the Preservation of Cultural Heritage.  Only Kodak papers from between the 1970s and 1980s had both blue and magenta colorants.  About two thirds of the paper samples exhibited dry transfer of OBAs to non-optically brightened surfaces.
 The observation of colored additives as well as the issue of OBA transfer is supported through research into manufacturers’ patent histories.  Patents provide a rich source of information on materials and manufacturing techniques and reveal an intricate network of challenges and developments in the production of RC papers throughout the 20th and 21st centuries.  In addition, these patents speak to the structural and material complexity of photographic papers that cannot always be adequately investigated with nondestructive analytical techniques or imaging.
 This talk will explore the varied manufacturing techniques and additives used in the production of RC paper and their implications for preservation, identification, and dating.  This talk will also explore the potential of patent research in investigating the development of late 20th century photographic materials, and how manufactured photographic papers can often belie binary material categorizations.