Silver halide emulsions precipitated in the presence of ortho-substituted water-soluble disulfides

Abstract

A method of making a monodisperse regular grain silver halide high bromide emulsion is described comprising precipitating regular silver halide grains comprising greater than 50 mole percent bromide, based on total silver, in a reaction vessel, and adding to the reaction vessel before or during precipitation a disulfide compound represented by the following formula (I): 1 where Y and Z are H atoms or substituents, which may be connected to form a carbocyclic or heterocyclic ring; X is —O—, —NH— or —NR—, where R is a substituent; M is —H— or a cationic species; and L is a linking group, where p is 0 or 1. The invention further provides a silver halide emulsion prepared by the method, and a photographic element comprising a silver halide emulsion prepared by the method. The use of water soluble disulfide compounds of the above formula in the preparation of regular grain high bromide emulsions provides the antifoggant advantages of water soluble disulfide compounds in a monodisperse emulsion, while avoiding the problem of large grain contamination in such emulsions.

Dependencies are inferred from the claim text.