# US 5,700,608 A · Process for making photographic emulsions and photographic elements and emulsions containing latent image forming units internally containing sensitizing dye > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,608 A - Document ID: US5700608A - Status: Granted - Kind: A - Application number: 08/618,481 - Filed: 1996-03-19 - Granted: 1997-12-23 - Earliest claimed: 1996-03-19 - Assignees: Eastman Kodak Company - Inventors: Lyn Marie Eshelman; David Darrell Miller; David Howard Levy - Web page: https://patentgrep.com/patent/US5700608A ## CPC - G03C 1/12: Methine and polymethine dyes - G03C 1/035: characterised by the crystal form or composition, e.g. mixed grain - G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G) ## Abstract A photographic element is described which comprises a silver halide emulsion having incorporated therein a latent image forming unit, said unit being comprised of an agglomeration of silver halide in conductive contact with a light absorbing center, wherein the center is comprised of: (i) an amorphous or liquid crystalline spectral sensitizing dye; or (ii) a plurality of spectral sensitizing dye crystals. Also described is a process for forming a silver halide emulsion and the emulsion prepared by such process. ## Claims ### Claim 1 A photographic element comprising a silver halide emulsion having incorporated therein a latent image forming unit, said unit being comprised of an agglomeration of silver halide in conductive contact with a light absorbing center, wherein the center is comprised of: (i) an amorphous or liquid crystalline spectral sensitizing dye; or (ii) a plurality of spectral sensitizing dye crystals; and wherein the light absorbing center further comprises a binder, surfactant or stabilizer. ### Claim 2 (depends on 1) A photographic element according to claim 1 wherein the silver halide substantially encapsulates the light absorbing center. ### Claim 3 (depends on 2) A photographic element according to claim 2 wherein the latent image forming unit has an equivalent circular diameter of from about 0.1 to about 10 .mu.m. ### Claim 4 (depends on 3) A photographic element according to claim 3 wherein the spectral sensitizing dye is selected from the group consisting of methine, cyanine and merocyanine dyes. ### Claim 5 (depends on 1) A photographic element according to claim 1 wherein the latent image forming unit contains an amount of spectral sensitizing dye from about 0.5 to about 5000 millimoles per mole of silver. ### Claim 6 (depends on 5) A photographic element according to claim 5 wherein the latent image forming unit contains an amount of spectral sensitizing dye from greater than 1 to about 1000 millimoles per mole of silver. ### Claim 7 (depends on 6) A photographic element according to claim 6 wherein the latent image forming unit contains an amount of spectral sensitizing dye from about 2 to about 500 millimoles per mole of silver. ### Claim 8 (depends on 1) A photographic element according to claim 1 wherein the light absorbing center is comprised of a plurality of spectral sensitizing dye crystals substantially encapsulated by an agglomeration of silver halide wherein the dye is in an amount from greater than 1 to about 1000 millimoles per mole of silver. ### Claim 9 (depends on 8) A photographic element according to claim 8 wherein the latent image forming unit has an equivalent circular diameter of from about 0.1 to about 10 .mu.m. ### Claim 10 A process of preparing a photographic emulsion having incorporated therein a plurality of latent image forming units, each of said units being comprised of an agglomeration of silver halide in conductive contact with a spectral sensitizing dye, the process comprising: dispersing a spectral sensitizing dye in an organic medium to form an organic dispersion; contacting the organic dispersion with an aqueous colloidal dispersion of silver halide grains and providing sufficient agitation to the dispersions to form a series of interfaces between the organic and aqueous phases; and providing to the dispersions a promoter which facilitates the adsorption of the silver halide grains to the interfaces between the organic and aqueous phases to form the latent image forming units. ### Claim 11 (depends on 10) A process of preparing a photographic emulsion according to claim 10 wherein the silver halide is adsorbed to the interfaces of the organic and aqueous phases in an amount sufficient to substantially encapsulate the spectral sensitizing dye. ### Claim 12 (depends on 11) A process of preparing a photographic emulsion according to claim 11 wherein the spectral sensitizing dye is an amorphous or liquid crystalline spectral sensitizing dye, or is in the form of a plurality of spectral sensitizing dye crystals. ### Claim 13 (depends on 12) A process of preparing a photographic emulsion according to claim 12 wherein the spectral sensitizing dye is in the form of a plurality of spectral sensitizing dye crystals. ### Claim 14 (depends on 13) A process of preparing a photographic emulsion according to claim 13 wherein the organic medium is ethyl acetate. ### Claim 15 (depends on 14) A process of preparing a photographic emulsion according to claim 14 wherein the promoter is an anionic or cationic salt containing from 1 to 20 carbon atoms. ### Claim 16 A process of preparing a photographic emulsion according to 15 wherein at least 50 percent of the latent image forming units have an equivalent circular diameter of from about 0.1 to about 10 .mu.m. ### Claim 17 (depends on 16) A process of preparing a photographic emulsion according to claim 16 wherein the spectral sensitizing dye is selected from the group consisting of methine, cyanine or merocyanine dyes. ### Claim 18 (depends on 17) A process of preparing a photographic emulsion according to claim 17 wherein the latent image forming units contain an amount of spectral sensitizing dye from about 0.5 to about 5000 millimoles per mole of silver. ### Claim 19 (depends on 10) A process of preparing a photographic emulsion according to claim 10 further comprising removing the organic medium from the latent image forming units by evaporation, dialysis or washing. ### Claim 20 (depends on 19) A process of preparing a photographic emulsion according to claim 19 further comprising adding to the organic dispersion a hydrophobic stabilizer and hydrophobic binder. ### Claim 21 (depends on 20) A process of preparing a photographic emulsion according to claim 20 further comprising adding to the emulsion a hydrophilic colloid after contacting the organic dispersion with the aqueous colloidal dispersion of silver halide grains. ### Claim 22 (depends on 10) A process of preparing a photographic emulsion according to claim 10 further comprising ripening additional silver halide onto the surfaces of the latent image forming units.