David Lyon


Hypersensitization using H2 gas is the most recent addition to the techniques available to reduce the effects of low intensity reciprocity law failure. Because of the presence of addenda in all commercially available emulsions, the interactive effects of hydrogen sensitization with a common stabilizer (4-methyl-6-hydroxy-1,3,3a,7-tetraazaindene) and a common form of chemical sensitization (Sulfur Sensitization) alone and together were investigated. A primitive, single jet emulsion was coated with and without the above addenda. Samples were paired and either treated to a hydrogen baking process at 65°C for 20 minutes, or left untreated. Sensitometric exposures were made in a room air environment for 1000, 100, 10, 1, 0.01, and 0.001 seconds. The results of this research indicated that: for exposure times where low intensity reciprocity law failure is minimal, the speed increase with H2 sensitization is only slight; sulfur and H2 sensitization can be partially additive; and, H2 sensitization tends to promote HIRF. Sulfur sensitization was not found to limit the reduction in LIRF by H2 sensitization, and tetraazaindene stabilization was not found to limit the sensitivity incease resulting from H2 sensitization.

Library of Congress Subject Headings

Photographic emulsions

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Department, Program, or Center

School of Photographic Arts and Sciences (CIAS)


Carroll, Burt


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