Process for preparing silver halide emulsion using a sulfur-containing ripening agent
AssigneeEastman Kodak Company
InventorsJames P. Terwilliger, Anthony D. Gingello, Jong-Shinn Wey
Life of this patent
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Abstract
A process is disclosed for the continuous formation of radiation-sensitive silver halide emulsions. In the course of reacting a silver salt with a halide salt in the presence of a peptizer to form a radiation-sensitive silver halide emulsion a portion of the emulsion is withdrawn continuously from the reaction chamber while silver halide grain formation is occurring. The silver halide grains are formed in the presence of a sulfur-containing silver halide ripening agent, while the total halide ion concentration is concurrently controlled and maintained at less than 0.01 molar.
Claims19
In a process of continuously preparing a radiation-sensitive silver halide emulsion wherein
- (1) a silver salt and a halide salt capable of reacting to form radiation-sensitive silver halide grains are concurrently and separately continuously introduced into a reaction chamber in the presence of a peptizer and
- (2) radiation-sensitive silver halide emulsion is withdrawn continuously from the reaction chamber while silver halide grain formation is occurring under steady state operating conditions,
- the improvement comprising
- forming the silver halide grains in the presence of a sulfur-containing ripening agent chosen from the group consisting of thioether and thiocyanate ripening agents for silver halide grains, and
- concurrently controlling and maintaining the total halide ion concentration at less than 0.01 molar.
In a process of continuously preparing a radiation-sensitive silver bromide emulsion wherein
- (1) a silver salt and a bromide salt capable of reacting to form radiation-sensitive silver bromide grains are concurrently and separately introduced continuously into a reaction chamber in the presence of gelatin,
- (2) radiation-sensitive silver bromide emulsion is withdrawn continuously from the reaction chamber while silver bromide grain formation is occurring, under steady state operating conditions and
- (3) thereafter chemically sensitizing the emulsion following removal from the reaction chamber,
- the improvement comprising
- forming the silver bromide grains in the presence of a thioether ripening agent for silver bromide grains and
- concurrently maintaining and controlling the bromide ion concentration in the reaction chamber so that at least a stoichiometric excess of bromide ions as compared to silver ions and less than a 0.010 molar concentration of bromide ions is present.
In a process of continuously preparing a radiation-sensitive silver bromide emulsion wherein
- (1) a silver salt and a bromide salt capable of reacting to form radiation-sensitive silver bromide grains are concurrently and separately introduced continuously into a reaction chamber in the presence of gelatin,
- (2radiation-sensitive silver bromide emulsion is withdrawn continuously from the reaction chamber while silver bromide grain formation is occurring, under steady operating conditions and
- (3) thereafter chemically sensitizing the emulsion following removal from the reaction chamber,
- the improvement comprising
- forming the silver bromide grains in the presence of a thiocyanate silver bromide grain ripening agent and
- concurrently maintaining and controlling the bromide ion concentration within the reaction chamber so that at least a stoichiometric excess of bromide ions as compared to silver ions is present and less than a 0.010 molar concentration of bromide ions is present.
Dependencies are inferred from the claim text.