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US 4,383,022 AGranted
Diffusion transfer film unit with protective layer of water soluble copper salt, chitosan and gelatin
AssigneePolaroid Corporation
InventorMichael Berger
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Abstract
A silver diffusion transfer film unit which comprises, in order, a support carrying a silver precipitating layer, a protective layer comprising chitosan having a copper salt and gelatin disposed therein, a release layer and a photosensitive silver halide layer. In a particularly preferred embodiment, the film unit is an additive color diffusion transfer film unit.
Claims19
A silver diffusion transfer film unit which comprises a support carrying, in order, a layer comprising silver precipitating nuclei;
- a protective layer comprising a water soluble copper salt, chitosan and gelatin wherein said gelatin is at least about 11/2 times, by weight, of the level of chitosan;
- a release layer;
- and a photosensitive silver halide emulsion layer.
A photographic process which comprises the steps of:
- (a) exposing a film unit which comprises a support carrying, in order, a layer comprising silver precipitating nuclei;
- a protective layer comprising a water soluble copper salt, chitosan and gelatin said gelatin being at least about 11/2 times, by weight, of the level of chitosan;
- a release layer;
- and a photosensitive silver halide emulsion layer;
- (b) contacting said exposed film unit with a processing composition containing a silver halide developing agent and a silver halide solvent adapted to provide a positive silver image in said layer comprising silver precipitating nuclei;
- and
- (c) detaching said emulsion subsequent to positive image formation.
4 more elements
Dependencies are inferred from the claim text.