Process of preparing a photothermographic composition of enhanced photosensitivity
AssigneeEastman Kodak Company
InventorsLyn M. Eshelman, Mark E. Irving, David H. Levy, Kathleen R. C. Gisser
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Abstract
A process of preparing a photothermographic composition of enhanced photosensitivity is disclosed comprised of (a) precipitating light-sensitive silver halide grains in the presence of a non-aqueous polymeric peptizer and (b) then combining the silver halide grains with an oxidation-reduction image-forming combination comprised of an organic silver compound and a reducing agent for the silver organic compound. Light-sensitivity of the silver halide grains is enhanced by, prior to step (b), sensitizing the silver halide grains with a gold sensitizer dissolved in an aqueous medium.
Claims8
A process of preparing a photothermographic composition of enhanced photosensitivity comprised of
- (a) precipitating light-sensitive silver halide grains in the presence of a non-aqueous polymeric peptizer and
- (b) then combining the silver halide grains with a non-aqueous polymeric vehicle containing an oxidation-reduction image-forming combination comprised of an organic silver compound and a reducing agent for the organic silver compound,
- wherein light-sensitivity of the silver halide grains is enhanced by, prior to step (b), sensitizing the silver halide grains with a gold sensitizer dissolved in an aqueous medium, the gold compound being chosen from the group consisting of
- gold tetrachloroaurate salts;
- gold dithiosulfate salts;
- gold sulfide;
- gold thiolates;
- gold compounds of the formula {AuL.sub.2 }.sup.+ X.sup.- or {AuLL'}.sup.+ X.sup.- wherein L is a mesoionic cyclic or acyclic thiourea ligand, L' is a Lewis base donor ligand, and X is an anion;
- gold compounds of the formula:
- ##STR6## wherein M is a charge balancing cation and Z is chosen to complete a 5 or 6 membered ring forming an imide nucleus;
- gold compounds containing at least one gold atom linking at least two divalent sulfur or selenium chalcogen atoms in a cyclic thioether or selenoether containing from 12 to 30 ring atoms;
- and
- a gold compound having the formula:
- {AuS.sub.2 X}.sub.n
- wherein X is a dithiophosphinate, a dithiophosphate, a xanthate, a dithiocarbamate, or a dithiocarboxylate, and n is an integer of from 1 to 6.
A process of preparing a photothermographic composition of enhanced photosensitivity comprised of
- (a) precipitating light-sensitive silver halide grains in the presence of a volatile organic solvent and a vinyl butyral polymer containing, on a mole basis, repeating units that are from 80 to 88 percent provided by vinyl butyral monomer, from 10 to 20 percent provided by vinyl acetate monomer, and from 0 to 2.5 percent provided by vinyl alcohol monomer;
- (b) chemically sensitizing the grains by stirring and heating following the addition of a gold sensitizer dispersed in an aqueous medium, the gold sensitizer being chosen from the group consisting of ##STR8## wherein R.sub.1 and R.sub.4 are methyl;
- R.sub.2 and R.sub.3 are independently chosen from among methyl, methoxymethyl, allyl, phenyl, and cyclohexyl;
- and
- X.sup.- is a charge balancing anion, and
- (c) combining the chemically sensitized silver halide grains dispersed in the vinyl butyral polymer with an oxidation-reduction combination comprised of a silver carboxylate and a reducing agent for the silver carboxylate.
Dependencies are inferred from the claim text.