Light-sensitive material for tanning development comprising pretreated carbon
AssigneeE. I. Du Pont de Nemours and Company
InventorHorst Friedel
Life of this patent
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Abstract
In a light-sensitive material for tanning development containing unhardened or only slightly hardened gelatin silver halide emulsion layers, the silver content required to obtain maximum density is reduced by incorporating carbon black pretreated with water-miscible compounds which have a higher affinity for carbon black than gelatin. Suitable treatment may be provided by at least two of the following: poly-n-vinyl lactams, polyalkylene oxide derivatives, water-miscible compounds containing at least two OH groups, and polyalkylene oxides with a molecular weight of at least 400.
Claims12
In a light-sensitive material for tanning development consisting of a support, an unhardened or only slightly hardened gelatin-containing silver halide emulsion layer and, if desired, an auxiliary layer, wherein at least one layer contains a carbon black participating in forming an image, the improvement comprising employing a carbon black pretreated with at least two water-miscible compounds which have a higher affinity for carbon black than gelatin, said compounds being selected from at least two of the following compound classes,
- (a) Poly-N-vinyl lactams
- (b) Polyalkylene oxide derivatives
- (c) Low volatility water-miscible compounds containing at least two OH groups
- (d) Polyalkylene oxides with a molecular weight of at least 400.
The light-sensitive material of any one of the aforementioned claims, characterized in that the carbon black was pretreated with polyvinyl pyrrolidone and polyethylene oxide with a molecular weight of at least 400.
The light-sensitive material of any of the foregoing claims wherein the pretreated carbon black is contained in the silver halide emulsion layer.
In a light-sensitive wash-off material for tanning development comprising an emulsion support which is coated on one side with an unhardened, or only slightly hardened, gelatino-silver halide emulsion layer, the latter containing carbon black and a tanning developing agent, the improvement wherein (1) the carbon black is one which has been pretreated with at least two compounds selected from at least two of the following compound classes
- (a) Poly-N-vinyl lactams
- (b) Polyalkylene oxide derivatives
- (c) Low volatility water-miscible compounds containing at least two OH groups
- (d) Polyalkylene oxides with a molecular weight of at least 400,
- and (2) the emulsion contains a polymer dispersion of polyacrylate and an oxidation-preventive agent.
Dependencies are inferred from the claim text.