A process for the preparation of a grain - stabilized photographic emulsion comprising tabular grains of a high chloride content (iv)

摘要

A process is disclosed of preparing an emulsion for photographic use comprised of silver halide grains and a gelatino-peptizer dispersing medium in which morphologically unstable tabular grains having {111} major faces account for greater than 50 percent of total grain projected area and contain at least 50 mole percent chloride, based on silver. The emulsion additionally contains at least one 2-hydroaminoazine adsorbed to and morphologically stabilizing the tabular grains. A silver salt is epitaxially deposited epitaxially at one or more corners of the tabular grains. Protonation releases 2-hydroaminoazine from the tabular grain surfaces into the dispersing medium. Released 2-hydroaminoazine is replaced on the tabular grain surfaces by adsorption of a photographically useful compound selected from among those that contain at least one stabilizing chalcogen atom or at least one 5-iodobenzoxazolium nucleus or a photographically useful cationic benzimidazolium dye, thereby concurrently morphologically stabilizing the tabular grains and enhancing their photographic utility, and the released 2-hydroaminoazine is removed from the dispersing medium. IMAGE