SILVER HALIDE PHOTOGRAPHIC SENSITIVE MATERIAL HAVING IMPROVED RELATION BETWEEN SENSITIVITY AND FOG

摘要

PURPOSE:To increase the sensitivity by providing an at least four-layered structure to silver halide particles and regulating the amount of silver chloride in the compsn. of the silver halide to =50mol% and the difference in silver bromide content between adjacent layers to =20mol%. CONSTITUTION:When silver halide particles are produced, an aq. soln. of alkali metal halide is added in steps to provide an at least four-layered structure. The amount of silver chloride in the average compsn. of the silver halide particles is regulated to =50mol%. The difference in silver bromide content between adjacent layers is also regulated to =20mol%. For example, the difference between the core layer (first layer) and the second layer is regulated to 100mol%, that between the second and the third layers to 60mol% and that between the third and the fourth layers to 40mol%. High sensitivity, reduced fog, improved Dmax and contrast are attained by using the resulting silver halide particles.