Nucleating agents for photographic reversal processes

Claim 2

In a photographic reversal color process wherein a photographic element containing at least two silver halide emulsion layers differentially sensiTized to different spectral regions and color forming coupler compounds is exposed to a colored image, images are developed in the emulsion layers in the regions of exposure using a first silver halide developing solution, and reversal positive colored images are obtained by nucleating the unexposed silver halide of the emulsion layers by contacting the layers with a chemical nucleating agent to render them developable with a second silver halide color developing solution, and developing the resulting nucleated silver halide to form the positive colored images, the improvement for obtaining better color reproduction and definition comprising nucleating the unexposed silver halide by contacting it with an aqueous solution of organo phosphorous chelated stannous ion silver halide nucleating agent.

Claim 3

The process of claim 3 wherein the unexposed silver halide is nucleated by treatment with an acid solution of the chelated stannous ion prior to treatment of the emulsion layers with the color developing solution.

Claim 4

The process of claim 3 wherein chelated stannous ion is present in a developing solution containing color developing agent to nucleate the unexposed silver halide and render it developable by the color developing agent.

Claim 5

In a photographic reversal color process wherein a photographic element containing at least two silver halide emulsion layers differentially sensitized to different spectral regions and free of color-forming coupler compounds is exposed to a colored image, silver images are developed in the emulsion layers in the regions of exposure using a first silver halide developing solution, reversal positive colored images are obtained by consecutive reversal reexposure of the emulsion layers except for the last one and developing the reexposed layers separately with color developing solutions containing color-forming coupler compounds, and the unexposed silver halide of said one emulsion layer is then nucleated by contacting it with a chemical nucleating agent followed by developing the resultant nucleated silver halide with a color developing solution containing a color-forming coupler compound, the improvement for obtaining better color reproduction and definition comprising using organo phosphorous chelated stannous ion as the chemical nucleating agent.

Claim 6

The process of claim 6 wherein the chelated stannous ion is present in the color developing solution used for development of the nucleated silver halide.

Claim 7

The process of claim 3 wherein the photographic element contains three superimposed silver halide emulsion layers sensitive respectively to the red, green and blue regions of the spectrum and each emulsion layer contains a coupler compound for formation of a dye image in the layer of a color complementary to the sensitivity of emulsion layer, and the nucleation of the silver halide is effected by the use of an organo phosphorous stannous ion silver halide nucleating agent present in the color developing solution.

Claim 8

An aqueous solution for the nucleating of photographic silver halide emulsion layers containing organo phosphorous chelated stannous ion silver halide nucleating agent and sufficient organic acid to give a pH of about 2 to 7 and provide buffering capacity.

Claim 9

A solution for nucleating and developing photographic silver halide emulsion layers comprising alkali, a silver halide developing agent and organo phosphorous chelated stannous ion silver halide nucleating agent.

Claim 10

The developing solution of claim 10 wherein the developing agent is a primary aromatic amino silver halide developing agent.

Claim 11

The developing solution of claim 11 further containing a coupler compound reactive with the oxidation product of the developing agent to form a dye.