REDUCTION SENSITIZATION METHOD FOR SILVER HALIDE PHOTOGRAPHIC EMULSION AND SILVER HALIDE PHOTOGRAPHIC SENSITIVE MATERIAL USING THIS EMULSION

摘要

PROBLEM TO BE SOLVED: To obtain the silver halide photographic emulsion high in sensitivity by depositing silver halide having a sliver chloride content of a specified value or more by mol.% and not having a clear epitaxial form on the surfaces of base silver halide grains specified in a silver bromide content or more by mol.% at the time of reduction sensitization of the base silver halide grains. SOLUTION: The base silver halide grains to be subjected to the reduction sensitization comprise =60 mol.% silver bromide, and/or silver iodobromide, silver chlorobromide, or chloro-iodobromide. The content of the silver chloride grains to be deposited during or after the reduction sensitization is, preferably, =50 mol.%, especially, 100 mol.%. The silver chloride grains to be deposited exhibits no clear epitaxial forms, because they are deposited not only on the specified positions of the base silver halide grains, such as their corners or fringes, and it is preferred that they are deposited so as to cover =30% of the base grain surfaces, even if they are rugged on the surfaces.