Konishiroku Photo Industry Co., Ltd.

Konishiroku Photo Ind. Co., Ltd.

Takehisa Kishita

Toshiharu Nagashima

Atsuo Ezaki

Kazuo Takahashi

Takeshi Murakami

Morio Enomoto

A process for manufacturing a silver halide direct positive type emulsion comprising primarily silver bromide prepared in the presence of a water-soluble rhodium salt said process comprising; simultaneously adding and mixing a silver aqueous solution and a halide aqueous solution to form an aqueous solution containing a hydrophilic colloid, said resultant mixture having a silver potential maintained with a range of from 100 mV to 200 mV, the speed at which the solutions are added being not more than the critical growth speed of existing silver halide grains, and fogging said silver halide grains.

Manufacturing process for silver halide photographic emulsion

A method of preparing a silver halide photographic emulsion comprising silver chloride as a principal component, which comprises adding to an aqueous solution of a hydrophilic colloid, an aqueous solution of a water-soluble silver salt and an aqueous solution of a water-soluble halide according to a simultaneous mixing method, and maintaining the rate of addition of the aqueous solution of a water-soluble silver salt and that of the aqueous solution of a water-soluble halide at a level not higher than the critical growth rate of silver halide grains and, at the same time, setting and maintaining the EAg value during the addition of the aqueous solution of a water-soluble silver salt and the aqueous solution of a water-soluble halide to a level not lower than 130 mV and not higher than 160 mV, said silver halide photographic emulsion being prepared in the presence of a water-soluble rhodium salt which is added during the course of emulsification and physical ripening of the emulsion.

Method of preparing silver halide photographic emulsion

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Hino, Japan

Takehisa Kishita