Color diffusion transfer employing silver salt transfer reversal and 4-thiohydantoine

A photographic diffusion transfer film unit for producing a dye or dye precursor image, said unit comprising

• 1. a support bearing at least one element comprising
• a. a negative silver halide emulsion containing a 4-thiohydantoine and having associated with said emulsion a chemical developing agent and a ballasted scavenger for oxidized chemical developing agent and
• b. a physical development layer associated with said emulsion layer, said physical development layer comprising cadmium sulfide nuclei, an initially immobile dye-providing substance which can provide diffusible dye or dye precursor, and, associated with said physical development layer, a chemical developing agent, and
• 2. means for applying an alkaline processing medium and a silver halide solvent to the surface of said negative silver halide emulsion layer.

A photographic diffusion transfer film unit for producing a multicolor dye image, said unit comprising a support bearing a dye image receiving layer, a reflecting layer, red;

• green;
• and blue light-sensitive elements capable of producing cyan, magenta, and yellow dye images in response to red, green, and blue light radiation, respectively, and overlying said three light-sensitive elements a rupturable pod containing a liquid processing composition comprising a silver halide solvent and an alkaline processing medium,
• 1. said red light sensitive element comprising
• a. a negative silver halide emulsion layer sensitive to red light having associated therewith a chemical developing agent, a ballasted scavenger for oxidized chemical developing agent, and, incorporated in said emulsion layer, a 5,5-dialkyl-4-thiohydantoine and
• b. a physical development layer associated with said emulsion layer, said physical development layer comprising cadmium sulfide nuclei, an initially immobile dye-providing substance which can provide diffusible dye or dye precursor, and, associated with said physical development layer, a chemical developing agent, said physical development layer located between said support and said negative emulsion layer sensitive to red light,
• 2. said green light sensitive element comprising
• a. a negative silver halide emulsion sensitive to green light having associated therewith a chemical developing agent, a ballasted scavenger for oxidized chemical developing agent, and, having incorporated in said emulsion layer a 5,5-dialkyl-4-thiohydantoine and
• b. a physical development layer associated with said emulsion layer, said physical development layer comprising cadmium sulfide nuclei, an initially immobile dye-providing substance which can provide diffusible dye or dye precursor, and, associated with said physical development layer, a chemical developing agent, said physical development layer located between said support and said negative emulsion layer sensitive to green light, and
• 3. said blue light sensitive element comprising
• a. a negative silver halide emulsion layer sensitive to blue light having associated therewith a chemical developing agent, a ballasted scavenger for oxidized chemical developing agent, and, having incorporated in said emulsion layer, a 5,5-dialkyl-4-thiohydantoine and
• b. a physical development layer associated with said emulsion layer, said physical development layer comprising cadmium sulfide nuclei, an initially immobile dye-providing substance which can provide diffusible dye or dye precursor, and, associated with said physical development layer, a chemical developing agent, said physical development layer located between said support and said negative emulsion layer sensitive to blue light.

In a photographic diffusion transfer process for producing a dye or dye precursor image in a photographic element and transferring said image to an image receiving layer, said element including a support bearing at least one element comprising

• 1. a negative silver halide emulsion layer having associated therewith a ballasted scavenger for oxidized chemical developing agent and
• 2. a physical development layer comprising cadmium sulfide nuclei and an initially immobile dye-providing substance which provides diffusible dye or dye precursor,
• said process including
• a. image-wise exposing said negative emulsion layer
• b. developing said negative emulsion layer with a chemical developing agent in the presence of an alkaline processing medium and a silver halide solvent, whereby unexposed silver halide in said negative emulsion is solubilized and diffuses into said physical development layer,
• c. physically developing said solubilized silver halide in said physical development layer in the presence of a chemical developing agent to obtain oxidized chemical developer which interacts with said initially immobile dye providing substance thereby producing a diffusible dye or dye precursor image, and
• d. transferring said diffusible dye or dye precursor image to said image receiving layer,
• the improvement which comprises carrying out step (b) of said process in the presence of a 4-thiohydantoine.