The photographic image is by nature fragile. Most photographic print images are supported by paper and most commonly employ silver as the light sensitive material. The finely dispersed silver filaments in a photographic emulsion are sensitive in that they are relatively easily oxidized by airborne pollutants, thereby destroying image information - be it data or pictures. The purpose of this project was to investigate protective treatments that would render a black and white image sufficiently stable in order to withstand long exposure to adverse conditions. This could only be achieved by employing a reliable test-method, jointly developed by the Image Permanence Institute and Eastman Kodak Co. Toners were used ever since photography's inception. In the beginning they were mainly utilized to alter images aesthetically. Although their protective qualities were recognized at the time, this concept neither found wide acceptance nor was toning for permanence greatly practiced. Only 25 years ago, several research projects got under way to investigate the benefits of such treatments. Although many scientific papers were published since and the concepts of silver image oxidation reasonably well understood, little information is available on the practical implications of toners, i.e., an identification of treatments and their applications that truly protect the silver image. Commercially available toners are still marketed for the aesthetic qualities they impart on photographs. The limited suggestions regarding image permanence were found to be inadequate or faulty. A ranking of toners is given at the end of this paper in the section Conclusions/Recommendations. Test data is provided in Appendices A and B. These show the marked improvements in image stability that can be accomplished by toning. The optimum toner treatment and concentration is dependent upon the particular brand of photographic paper. However, the polysulfide toners offer advantages over the others that were evaluated.
Department, Program, or Center
School of Photographic Arts and Sciences (CIAS)
Gmuender, Christopher, "On black-and-white paper image-stability enhancement" (1992). Thesis. Rochester Institute of Technology. Accessed from
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