Browse Prior Art Database

Silver Halide Grains of Preselected Size

IP.com Disclosure Number: IPCOM000075082D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Wheelock, CE: AUTHOR

Abstract

Silver halide grains of preselected size are obtained by preparing a soluble silver halide-ammonia complex in water, with or without a carrier, and then depositing solution drops of controlled size into a chilled non-aqueous immiscible fluid. This results in the formation of discrete spheres of silver halide solution, which spheres are subsequently treated to remove the ammonia, and precipitate discrete grains of silver halide having a preselected size. Where a carrier is not present in the original solution, subsequent dispersion of the silver halide grains in a carrier, such as gelatin, forms a photographic emulsion. The practice of this invention is especially useful in producing silver halide grains of substantially uniform size for use in a light-sensitive emulsion having excellent contrast, and sensitivity.

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Silver Halide Grains of Preselected Size

Silver halide grains of preselected size are obtained by preparing a soluble silver halide-ammonia complex in water, with or without a carrier, and then depositing solution drops of controlled size into a chilled non-aqueous immiscible fluid. This results in the formation of discrete spheres of silver halide solution, which spheres are subsequently treated to remove the ammonia, and precipitate discrete grains of silver halide having a preselected size. Where a carrier is not present in the original solution, subsequent dispersion of the silver halide grains in a carrier, such as gelatin, forms a photographic emulsion. The practice of this invention is especially useful in producing silver halide grains of substantially uniform size for use in a light-sensitive emulsion having excellent contrast, and sensitivity. Where the silver halide particles are uniformly large the resulting emulsion is also capable of high-speed exposure.

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