Low coating weight silver halide element using mix sensitization techniques
AssigneeE. I. Du Pont de Nemours and Company
InventorAllan R. Schoenberg
Life of this patent
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Abstract
The sensitivity of a gelatino-silver halide emulsion is improved by adding glutaraldehyde bisulfite in combination with benzene sulfinic acid during the preparation of the silver halide, viz. when a silver salt is mixed with a halide to precipitate a silver halide.
Claims8
A process for preparing a photosensitive gelatino-silver halide emulsion, characterized in that glutaraldehyde (GDA) bisulfite or substituted GDA-bisulfite are added thereto in concentrations of 0.016-1.6% by weight based on the weight of the silver halide, in combination with an aromatic sulfinic acid or a water-soluble salt thereof, at the silver halide precipitation stage.
A process for the sensitization of a light-sensitive gelatino-silver halide emulsion prior to coating it upon a support, in which process the gelatino-silver halide emulsion is made up in a silver halide precipitation step by mixing silver nitrate with an alkali metal halide in the presence of gelatin, and is subsequently introduced into a coater for application to a film support, characterized in that the emulsion is mix-sensitized by adding thereto in the silver halide precipitation stage (1) either glutaraldehyde bisulfite, succinaldehyde bisulfite, or a substituted glutaraldehyde bisulfite, in a concentration of 0.016-1.6% by weight, based on the weight of silver halide in the emulsion, and (2) an aromatic sulfinic acid, or a water-soluble salt thereof, in a concentration of 0.018 to 1.8% by weight, based on the weight of silver halide in the emulsion.
A process for the sensitization of a light-sensitive gelatino-silver halide emulsion prior to coating it upon a support, in which process the gelatino-silver halide emulsion is made up in a silver halide precipitation step by mixing silver nitrate with an alkali metal halide in the presence of gelatin, and is subsequently introduced into a coater for application to a film support, characterized in that the emulsion is mix-sensitized by adding thereto in the silver halide precipitation stage (1) either glutaraldehyde bisulfite, succinaldehyde bisulfite, or a substituted glutaraldehyde bisulfite, in a concentration of 0.016-1.6% by weight, based on the weight of silver halide in the emulsion, and (2) an aromatic sulfinic acid, or a water-soluble salt thereof, in a concentration of 0.018 to 1.8% by weight, based on the weight of silver halide in the emulsion,
- and further characterized in that the process comprises the further steps of washing the precipitated and sensitized light-sensitive gelatino-silver halide emulsion, adding to the emulsion:
- (1) a gold or sulfur sensitizer, followed by a digestion step, (2) glutaraldehyde bisulfite and the sodium salt of benzene sulfinic acid in the range of concentration set forth above;
- pumping the resulting sensitized emulsion to a coating station;
- preparing in a separate vessel a solution of gelatin and formaldehyde hardener, and pumping said solution to the coating station;
- applying from the latter a continuous layer of the sensitized gelatino-silver halide emulsion to a support film;
- and then applying over the silver halide emulsion layer as an abrasion layer said gelatin solution containing formaldehyde hardener.
Dependencies are inferred from the claim text.