US3859093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fogged, direct positive emulsion containing composite silver halide grains protected with silver halide layer and the use thereof in reversal process
Assignee: Agfa Gevaert AG
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Filing: 1973-03-26
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Granted: 1975-01-07
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Expires: 1993-03-26
Abstract
Abstract A direct positive photographic image material made up of silver halide grains on which development nuclei are formed by preexposure fogging are contained in a supported light-sensitive emulsion with a binding agent. The silver halide grains are covered with a protective layer of a silver salt, which silver salt is soluble in a solvent applied to the emulsion with the developer after imagewise exposure. The protective coating of silver salt stabilizes the fogged emulsion against sensitivity loss.
Inventors
- 👤 Manfred Becker
- 👤 Otto Lapp
- 👤 Erik Moisar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:50
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48515
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
89 words
A LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL COMPRISING A SUPPORTED DIRECT POSITIVE SILVER HALIDE EMULSION LAYER CONTAINING SILVER HALIDE GRAINS OF COMPOSITE STRUCTURE, THE SAID GRAINS COMPRISING A CORE OF SILVER HALIDE WHICH IS CHEMICALLY SENSITIZED, THE SAID CORE IS COATED BY A SILVER HALIDE SHELL WHICH AT THE SURFACE CONTAINS SPONTANEOUSLY DEVELOPABLE FOG AND AN OUTER PROTECTIVE LAYER OF SILVER HALIDE WHICH ENVELOPS THE SHELL AND COVERING THE DEVELOPABLE NUCLEI PROTECTS THE NUCLEI FROM DESENSITIZATION THE THICKNESS OF SAID PROTECTIVE LAYER IS BETWEEN 5 AND 100 LATTICE PLANES OF SILVER HALIDE.
Claim 2
Dependent Claim
89 words
A LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL COMPRISING A SUPPORTED DIRECT POSITIVE SILVER HALIDE EMULSION LAYER CONTAINING SILVER HALIDE GRAINS OF COMPOSITE STRUCTURE, THE SAID GRAINS COMPRISING A CORE OF SILVER HALIDE WHICH IS CHEMICALLY SENSITIZED, THE SAID CORE IS COATED BY A SILVER HALIDE SHELL WHICH AT THE SURFACE CONTAINS SPONTANEOUSLY DEVELOPABLE FOG AND AN OUTER PROTECTIVE LAYER OF SILVER HALIDE WHICH ENVELOPS THE SHELL AND COVERING THE DEVELOPABLE NUCLEI PROTECTS THE NUCLEI FROM DESENSITIZATION THE THICKNESS OF SAID PROTECTIVE LAYER IS BETWEEN 5 AND 100 LATTICE PLANES OF SILVER HALIDE.
Claim 3
Dependent Claim
128 words
A PROCESS FOR THE PRODUCTION OF DIRECT POSITIVE PHOTOGRAPHIC IMAGES COMPRISING THE STEPS OF A. PREPARING A LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL COMPRISING A SUPPORTED DIRECT POSITIVE SILVER HALIDE EMULSION LAYER CONTAINING SILVER HALIDE GRAINS OF COMPOSITE STRUCTURE, THE SAID GRAINS COMPRISING A CORE OF SILVER HALIDE WHICH IS CHEMICALLY SENSITIZED THE SAID CORE IS COATED BY A SILVER HALIDE SHELL WHICH AT THE SURFACE CONTAINS SPONTANEOUSLY DEVELOPABLE FOG AND AN OUTER PROTECTIVE LAYER OF SILVER HALIDE WHICH IS COVERING THE DEVELOPABLE NUCLEI PROTECTING THE NUCLEI FROM DENSITIZATION THE THICKNESS OF SAID PROTECTIVE LAYER IS BETWEEN 5 AND 100 LATTICE PLANES OF SILVER HALIDE; B. IMAGEWISE EXPOSURE AND C. DEVELOPMENT OF THE EXPOSED LAYER WITH A DEVELOPER SOLUTION CONTAINING A SOLVENT FOR THE SILVER HALIDE OF THE SAID PROTECTIVE LAYER.
Claim 4
Dependent Claim
128 words
A PROCESS FOR THE PRODUCTION OF DIRECT POSITIVE PHOTOGRAPHIC IMAGES COMPRISING THE STEPS OF A. PREPARING A LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL COMPRISING A SUPPORTED DIRECT POSITIVE SILVER HALIDE EMULSION LAYER CONTAINING SILVER HALIDE GRAINS OF COMPOSITE STRUCTURE, THE SAID GRAINS COMPRISING A CORE OF SILVER HALIDE WHICH IS CHEMICALLY SENSITIZED THE SAID CORE IS COATED BY A SILVER HALIDE SHELL WHICH AT THE SURFACE CONTAINS SPONTANEOUSLY DEVELOPABLE FOG AND AN OUTER PROTECTIVE LAYER OF SILVER HALIDE WHICH IS COVERING THE DEVELOPABLE NUCLEI PROTECTING THE NUCLEI FROM DENSITIZATION THE THICKNESS OF SAID PROTECTIVE LAYER IS BETWEEN 5 AND 100 LATTICE PLANES OF SILVER HALIDE; B. IMAGEWISE EXPOSURE AND C. DEVELOPMENT OF THE EXPOSED LAYER WITH A DEVELOPER SOLUTION CONTAINING A SOLVENT FOR THE SILVER HALIDE OF THE SAID PROTECTIVE LAYER.
Claim 5
Dependent Claim
23 words
The photographic material of claim 1, wherein the soluble silver salt is silver bromide which may contain up to 10% of silver iodide.
Claim 6
Dependent Claim
51 words
The photographic material of claim 1, wherein the silver halide grains with development nuclei are the product of fogging the silver halide grains with a reducing fogging agent in the presence of a compound of a metal selected from the group consisting of gold and a metal more electropositive than silver.
Claim 7
Dependent Claim
12 words
The photographic material of claim 1, wherein the emulsion is optically sensitized.
Claim 8
Dependent Claim
18 words
The process of claim 2, wherein the protective layer has a thickness of 15 to 50 lattice planes.
Claim 9
Dependent Claim
25 words
The process of claim 2, wherein the silver halide is silver bromide or silver iodobromide with an iodide content of up to 10 mols percent.
Claim 10
Dependent Claim
27 words
The process of claim 2, wherein the developer contains a silver halide solvent selected from the group consisting of sulfite ions, thiocyanate ions, thiosulfate ions and triethanolamine.
Claim 11
Dependent Claim
75 words
A light-sensitive photographic material comprising a supported direct positive silver halide emulsion layer containing silver halide grains of composite structure having spontaneously developable nuclei on the surface of the grain, the said surface containing the spontaneously developable nuclei being enveloped by a covering layer consisting essentially of a soluble silver salt so as to be protected from desensitization the thickness of the said protective layer is between 5 and 100 lattice planes of silver halide.
Claim 12
Dependent Claim
75 words
A light-sensitive photographic material comprising a supported direct positive silver halide emulsion layer containing silver halide grains of composite structure having spontaneously developable nuclei on the surface of the grain, the said surface containing the spontaneously developable nuclei being enveloped by a covering layer consisting essentially of a soluble silver salt so as to be protected from desensitization the thickness of the said protective layer is between 5 and 100 lattice planes of silver halide.
Claim 13
Dependent Claim
19 words
The photographic material of claim 1, wherein the protective layer has a thickness of 15 to 50 lattice planes.
References Cited (Backward Citations)
US3367778A
Cited
US3477852A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |