Chemical sensitization of photothermographic silver halide emulsions
AssigneeImation Corp.
InventorsJohn M. Winslow, Gary L. Featherstone, Doreen C. Lynch, James R. Miller, Sharon M. Simpson, Mark C. Skinner
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Abstract
Chemical sensitization of silver halide photothermographic emulsions used in photothermographic elements, can be effected by the decomposition of sulfur containing compounds on or around the surface of the silver halide grains, usually under oxidizing conditions at elevated temperatures. Alignment of the sulfur containing compounds on the surface of the grains, can be accomplished with spectral sensitizing dyes and appears to be particularly effective in providing strong chemical sensitization effects.
Claims19
A method for preparing a photothermographic emulsion comprising the steps of:
- (a) providing a photothermographic emulsion comprising silver halide grains and a non-photosensitive silver source;
- (b) providing an organic sulfur-containing compound positioned on or around the silver halide grains;
- and
- (c) chemically sensitizing the silver halide grains by decomposing the organic sulfur-containing compound on or around the silver halide grains in an oxidizing environment.
A method for preparing a photothermographic emulsion comprising the steps of:
- (a) providing a photothermographic emulsion comprising silver halide grains and a non-photosensitive silver source;
- (b) providing a sulfur-containing spectral sensitizing dye positioned on or around the silver halide grains;
- and
- (c) chemically sensitizing the silver halide grains by decomposing the spectral sensitizing dye on or around the silver halide grains.
A method for preparing a photothermographic emulsion comprising the steps of:
- (a) providing a photothermographic emulsion comprising silver halide grains and a non-photosensitive silver source;
- (b) providing a sulfur-containing compound comprising a thiohydantoin nucleus, a rhodanine nucleus, or a 2-thio-4-oxo-oxazolidine nucleus positioned on or around the silver halide grains;
- and
- (c) chemically sensitizing the silver halide grains by decomposing the sulfur-containing compound on or around the silver halide grains.
A method for preparing a photothermographic emulsion comprising the steps of:
- (a) providing a photothermographic emulsion comprising silver halide grains and a non-photosensitive silver source;
- (b) providing a sulfur-containing compound positioned on or around the silver halide grains;
- and
- (c) chemically sensitizing the silver halide grains by providing an oxidizing compound which causes the decomposing of the sulfur-containing compound on or around the silver halide grains.
A method of forming a sensitized photothermographic emulsion comprising the steps of:
- (a) providing a photothermographic emulsion comprising silver halide grains and a non-photosensitive silver source;
- (b) providing a sulfur-containing spectral sensitizing dye on or around the silver halide grains;
- (c) decomposing the spectral sensitizing dye in an oxidizing environment at a temperature between about 20.degree. C. and about 40.degree. C.;
- (d) adding a second spectral sensitizing dye to said photothermographic emulsion to spectrally sensitize said emulsion.
A method for chemically sensitizing silver halide grains comprising the steps of:
- (a) providing a silver halide grains;
- (b) providing a sulfur-containing sensitizing dye on or around the surface of silver halide grains;
- and
- (c) oxidatively decomposing the sulfur-containing sensitizing dye thereby chemically sensitizing said grains.
Dependencies are inferred from the claim text.