Multicolor dye developer systems

Claim 2

In a photographic element comprising a support having coated thereon at least two dye image-forming units with an alkali-permeable, water-insoluble salt stratum positioned between at least two of said dye image-forming units, said dye image-forming units comprising a silver halide emulsion layer and a dye developer contiguous to silver halide of said emulsion, and said salt stratum comprising an alkali-permeable, water-insoluble salt of an alkaline earth metal and a film-forming, alkali-permeable, water-soluble polymer having free carboxylic acid groups, said salt stratum being less permeable to dye developers comprising said dye image-forming units in aqueous alkaline solution than said water-soluble polymer used to prepare said salt stratum, the improvement which comprises having coated on the salt stratum side of the photographic element a catechol which develops silver halide and is a chelating agent for said polyvalent metal.

Claim 3

A photographic element as defined by claim 3 wherein the salt stratum is calcium alginate.

Claim 4

A photographic element as defined by claim 3 wherein the catechol has the formula:

Claim 5

A photographic element as defined by claim 4 wherein the catechol is 4-phenylcatechol.

Claim 6

A photographic element comprising superposed on a photographic support three dye image-forming units in layers capable of recording red, green and blue light respectively, the dye image-forming unit recording blue light being furthest from the support and the dye image-forming unit recording red light being most proximate to the support, and an alkali-permeable, water-insoluble stratum of calcium alginate positioned between each of the said image-forming units, said dye image-forming units comprising a gelatino-silver halide emulsion layer and an underlying contiguous layer containing a dye developer substantially complementary in color to the color of light recorded in the contiguous silver halide emulsion layer, and a catechol which develops silver halide and is a chelating agent for calcium ions being positioned between said support and said stratum of calcium alginate, said catechol being present in an amount sufficient to increase the permeability of said stratum in just the unexposed areas.

Claim 7

A photographic element comprising superposed on a photographic support three dye image-forming units in layers capable of recording red, green and blue light respectively, the dye image-forming unit recording blue light being furthest from the support and the dye image-forming unit recording red light being most proximate to the support, and an alkali-permeable, water-insoluble stratum of calcium alginate positioned between the said image-forming units recording red and green light, said dye image-forming units comprising a gelatino-silver halide emulsion layer and an underlying contiguous layer containing a dye developer substantially complementary in color to the color of light recorded in the contiguous silver halide emulsion layer, and a catechol which develops silver halide and is a chelating agent for calcium ions being positioned between said support and said stratum of calcium alginate, said catechol being present in an amount sufficient to increase the permeability of said stratum in just the unexposed areas.

Claim 8

In the processing of an imagewise exposed photographic element comprising a support having coated thereon at least two dye image-forming units with an alkali-permeable, water-insoluble salt stratum positioned between at least two of said dye image-forming units, said dye image-forming units comprising a silver halide emulsion layer and a dye deVeloper contiguous to silver halide of said emulsion, and said salt stratum comprising an alkali-permeable, water-insoluble salt of a polyvalent metal and a film-forming alkali-permeable, water-soluble polymer having free carboxylic aid groups, said salt stratum being less permeable to dye developers comprising said dye image-forming units in aqueous alkaline solution than said water-soluble polymer used to prepare said salt stratum, which comprises treating the photographic element with an alkaline processing liquid, developing latent images in the regions of exposure of the silver halide emulsion layers and thereby immobilizing dye developers in said regions of exposure, dye developers in undeveloped regions diffusing imagewise in register to a reception layer for dye developer images, the improvement which comprises carrying out said treating of the photographic element in the presence of a material that is a chelating agent for said polyvalent metal, the chelating function of said material being destroyed imagewise in just exposed areas as a function of development.

Claim 9

The process as defined in claim 9 wherein said material is an auxiliary developer coated in a layer on the salt stratum side of the photographic element.

Claim 10

In the processing of an imagewise exposed photographic element comprising a support having coated thereon at least two dye image-forming units with an alkali-permeable, water-insoluble salt stratum positioned between at least two of said dye image-forming units, said dye image-forming units comprising a silver halide emulsion layer and a dye developer contiguous to silver halide of said emulsion, and said salt stratum comprising an alkali-permeable, water-insoluble salt of an alkaline earth metal and a film-forming alkali-permeable, water-soluble polymer having free carboxylic acid groups, said salt stratum being less permeable to dye developers comprising said dye image-forming units in aqueous alkaline solution than said water-soluble polymer used to prepare said salt stratum, which comprises treating the photographic element with an alkaline processing liquid, developing latent images in the regions of exposure of the silver halide emulsion layers and thereby immobilizing dye developers in said regions of exposure, dye developers in undeveloped regions diffusing imagewise in register to a reception layer for dye developer images, the improvement which comprises carrying out said treating of the photographic element in the presence of a catechol which develops silver halide and is a chelating agent for said polyvalent metal.

Claim 11

The process as defined in claim 11 wherein the catechol is coated in a layer on the salt stratum side of the photographic element.

Claim 12

The process as defined in claim 11 wherein the catechol is present in the alkaline processing liquid.

Claim 13

The process as defined in claim 11 wherein the salt stratum is calcium alginate.

Claim 14

The process as defined in claim 11 wherein the catechol has the formula:

Claim 15

The process as defined in claim 11 wherein the catechol is 4-phenylcatechol.