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US 3,941,597 AGranted
Application of protective polymer to processed diffusion transfer light sensitive element
AssigneePolaroid Corporation
InventorMonis J. Manning
Life of this patent
Estimating the term…
Abstract
A developed and fixed unwashed negative component of a diffusion transfer photographic film unit is protected and preserved for an extended period.
Claims8
In a process for forming a diffusion transfer negative element capable of being employed to provide reflection images which comprises:
- a. exposing a diffusion transfer photosensitive element comprising a silver halide layer to actinic radiation;
- b. providing a layer of processing composition including a developing agent whose adherence to said negative element after the development and fixing of said negative element would adversely affect the quality of the negative image, a silver halide solvent, and a film-forming polymer between said exposed diffusion transfer photosensitive element and a diffusion transfer silver receptive stratum in face-to-face relationship therewith;
- c. developing said exposed diffusion transfer photosensitive element to provide a negative image and forming a positive image thereof in said silver receptive stratum by silver diffusion transfer as a function of point-to-point degree of exposure of said photosensitive element;
- d. separating said silver receptive stratum from said negative image which has said layer of processing composition adhered thereto;
- e. washing said developed negative image with aqueous sodium sulfite, and
- f. washing said negative with water, the improvement which comprises applying to the surface of said layer of processing composition while said surface remains moist and before washing with aqueous sodium sulfite a uniform layer of a vapor-permeable polymeric macromolecule whereby washing of said negative image may be delayed for an extended period without injury to it.
3 more elements
In a process for forming a diffusion transfer negative element capable of being employed to provide positive reflection images which comprises:
- a. exposing a diffusion transfer photosensitive element comprising a silver halide layer to actinic radiation;
- b. providing a layer of processing composition including a developing agent whose adherence to said negative element after the development and fixing of said negative element would adversely affect the quality of the negative image, a silver halide solvent, and a film-forming polymer between said exposed diffusion transfer photosensitive element and a diffusion transfer silver receptive stratum in face-to-face relationship therewith;
- c. developing said exposed diffusion transfer photosensitive element to provide a negative image and forming a positive image thereof in said silver receptive stratum by silver diffusion transfer as a function of point-to-point degree of exposure of said photosensitive element;
- d. separating said silver receptive stratum from said negative image which has said layer of processing composition adhered thereto;
- e. washing said developed negative with aqueous sodium sulfite;
- and
- f. washing said negative with water,
- the improvement which comprises removing said processing composition layer while still moist and before washing with aqueous sodium sulfite by swabbing said negative image with a solution of a vapor-permeable polymeric macromolecule;
- and applying to the surface of said developed negative image while said surface is still moist a uniform layer of said vapor-permeable macromolecule whereby washing of said negative image may be delayed for an extended period without injury to it.
6 more elements
Dependencies are inferred from the claim text.