MANUFACTURE OF PLANAR PARTICLE EMULSION HAVING LOW DISPERSION DEGREE

摘要

PURPOSE: To provide a method for producing a photographic emulsion contg. plate-like silver halide particles exhibiting low total particle dispersion. CONSTITUTION: A group of the silver halide particle cores having a parallel twin plane is formed, and then a part of the cores are aged. Subsequently, the remaining cores having a parallel twin plane are grown to form a plate-like silver halide particle. The total dispersion of this emulsion is lowered by incorporating bromine ion into a dispersion medium before the cores are formed and further incorporating a polyalkylene oxide block copolymer surfactant contg. at least two end oleophilic alkylene oxide block units connected by the hydrophilic alkylene oxide block units occupying at least 4% of the mol.wt. of the copolymer at a concn. where the particle dispersion is decreased when a parallel twin plane is formed in the core.