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US 3,970,458 AGranted
Imagewise hardening with inert transition metal complex oxidizing agents
AssigneeEastman Kodak Company
InventorVernon Leon Bissonette
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AssigneeEastman Kodak Company
InventorVernon Leon Bissonette
Estimating the term…
An improvement is provided in processes wherein an oxidation-reduction reaction is utilized to form an image. In one aspect of this invention, the improvement comprises employing an oxidizing agent and a reducing agent which undergo imagewise redox reaction in the presence of catalytic material, the oxidizing agent and the reducing agent being so chosen that the reaction products are noncatalytic for the oxidation-reduction reaction. In another aspect of this invention, a substitution inert metal complex is utilized as the oxidant in oxidation-reduction image-forming processes. Novel processing compositions and photographic materials are also described. In a specific aspect, this divisional application relates to processes for tanning a crosslinkable colloid with the reaction products of the above redox reaction.
In a process of imagewise-hardening at least one layer of a photographic element which contains a crosslinkable colloid, the improvement comprising reacting an inert transition metal ion complex oxidizing agent having a coordination number of 6 and which is capable of existing in at least two valence states with a reducing agent in the presence of a catalytic metal material or catalytic activated carbon material in a processing solution which is substantially free of silver halide solvents, wherein said catalytic material is provided in an imagewise distribution and wherein said oxidizing agent and said reducing agent are chosen so that the reaction products thereof are essentially noncatalytic for an oxidation-reduction reaction with said oxidizing agent and said reducing agent, and said oxidizing agent and said reducing agent are essentially inert to oxidation-reduction reaction in the absence of said catalytic material.
In an image-forming process wherein a photographic element containing at least one layer of an imagewise-exposed silver halide emulsion is processed in a processing solution which is substantially free of silver halide solvents to provide an imagewise distribution of tanned crosslinkable colloid in a layer of crosslinkable colloid, the improvement comprising employing in said process in reactive association (a) an inert transition metal complex oxidizing agent having a coordination number of 6 and which is capable of existing in at least two valence states and (b) a reducing agent which is capable of reducing exposed silver halide to metallic silver, wherein said oxidizing agent and said reducing agent undergo redox reaction in the presence of metallic silver and are essentially inert to oxidation-reduction reaction in the absence of said metallic silver, said oxidizing agent and said reducing agent being chosen so that the reaction products thereof are essentially noncatalytic for an oxidation-reduction reaction with said oxidizing agent and said reducing agent.
In a photographic process wherein an imagewise-exposed photographic element comprising a support having coated thereon silver halide grains dispersed in a crosslinkable colloid is developed to produce a metallic silver image and said colloid is crosslinked imagewise in the areas where metallic silver develops, the improvement which comprises conducting said photographic development with the combination of (a) a photographic developer and (b) an inert transition metal ion complex having a coordination number of 6 and which is capable of existing in at least two valence states, which is reduced by said photographic developer in the presence of metallic silver, the reduced form of said transition metal ion complex being a crosslinking agent for said colloid, wherein said photographic developer and said inert transition metal ion complex are essentially inert to oxidation-reduction reaction in the absence of said metallic silver.
Dependencies are inferred from the claim text.