Precipitation of Monodispersed Silver Halide Emulsions Using Water‐Soluble Ortho‐Substituted Aryl Disulfides

Abstract

Silver bromoiodide photographic emulsions were precipitated using water‐soluble aryl disulfides. The emulsions studied were sub‐micron regular (nontabular) crystals containing less than 5% iodide, precipitated with ammonia and/or thioether. When compared to their para‐substituted counterparts, water‐soluble ortho‐substituted aryl disulfides provided improved monodispersity along with no observed formation of large tabular grains. A proposed mechanism for the decreased ripening effect of the ortho‐substituted isomer involved an in situ reduction of the disulfide to a ring‐closed species that did not interact with silver ion.

Keywords:

• Silver halide emulsions
• Monodispersed crystals
• Ortho‐substituted aryl disulfides
• Grain‐size distributions

Acknowledgment

We thank our colleagues at Eastman Kodak Company, Research & Development Laboratories for supporting this work.