A monodisperse silver bromide emulsion was surface sensitized with potassium hexachloroiridate (III). The rate of sensitization and maximum photographic sensitivity were determined at different sensitization conditions. The effects of silver ion concentration (pAg), length of sensitization, and the presence of the thiocyanate onion during sensitization were defined. The highest gain of sensitivity of an Iridium sensitized emulsion over an unsensltized emulsion was 0.43 log H units at pAg 9 after 30 minutes of after-ripening at 70 C. The highest gain of sensitivity of an iridium + thiocyanate sensitized emulsion over an unsensltized emulsion was 0.55 log H units at pAg 9 after minimal after-ripening. The experimental results were used to confirm an existing theory for the action of thiocyanate in iridium sensitization, as well as to optimize the system.
Library of Congress Subject Headings
Photographic sensitometry; Photographic emulsions; Silver halide crystals; Iridium
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Natan, Nimrod, "Factors influencing the rate of sensitization and maximum sensitivity of an iridium (III) surface sensitized silver bromide emulsion" (1987). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus