US4287296A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct-positive emulsion containing fogged, silver halide grains of silver iodide content
Assignee: Agfa Gevaert NV
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Filing: 1973-11-20
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Granted: 1981-09-01
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Expires: 1993-11-20
Abstract
Abstract Direct positive silver halide emulsions are provided which contain fogged silver halide grains the said grains being heterodisperse and containing silver iodide in an amount of more than 10 mole % and at most 20 mole % relative to the total amount of silver halide. The emulsions have increased sensitivity and reduced gradation which is suitable for continuous tone reproduction.
Inventors
- 👤 Willy J. Vanassche
- 👤 Herman A. Pattyn
- 👤 Erik Moisar
- 👤 Sieghart Klotzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:48
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48515
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
92 words
Photographic material comprising at least one layer of a direct-positive radiation-sensitive emulsion containing fogged silver halide grains, wherein the silver halide grains are heterodisperse and irregular and have a grain size distribution so that at least 10% by weight of the silver halide grains have a diameter, which deviates for at least 40% from the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 2
Dependent Claim
92 words
Photographic material comprising at least one layer of a direct-positive radiation-sensitive emulsion containing fogged silver halide grains, wherein the silver halide grains are heterodisperse and irregular and have a grain size distribution so that at least 10% by weight of the silver halide grains have a diameter, which deviates for at least 40% from the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 3
Dependent Claim
31 words
Photographic material according to claim 1, wherein at least 20% by weight of the silver halide grains have a diameter, which deviates for at least 40% from the mean grain diameter.
Claim 4
Dependent Claim
22 words
A photographic material according to claim 1, wherein the silver iodide content is comprised between about 12 and about 20 mole %.
Claim 5
Dependent Claim
48 words
Photographic material according to claim 1, wherein the silver halide grains are free from interior ripening nuclei and have adsorbed to their surface an electron-accepting or desensitizing compound having an anodic polarographic half-wave potential and a cathodic polarographic half-wave potential that when added together give a positive sum.
Claim 6
Dependent Claim
18 words
Photographic material according to claim 1, wherein the said silver halide grains have been fogged by reduction sensitisation.
Claim 7
Dependent Claim
26 words
Photographic material according to claim 5, wherein the said silver halide grains have been fogged by treatment of the silver halide grains with a reducing agent.
Claim 8
Dependent Claim
16 words
Photographic material according to claim 6, wherein said reducing agent is thiourea dioxide or tin(II) chloride.
Claim 9
Dependent Claim
26 words
Photographic material according to claim 5, wherein the silver halide grains have been fogged by low pAg and/or high pH silver halide precipitating or digestion conditions.
Claim 10
Dependent Claim
23 words
Photographic material according to claim 5, wherein fogging also occurs in the presence of a compound of a metal more electropositive than silver.
Claim 11
Dependent Claim
14 words
Photographic material according to claim 9, wherein said metal compound is a gold compound.
Claim 12
Dependent Claim
13 words
Photographic material according to claim 1, wherein the emulsion has been spectrally sensitized.
Claim 13
Dependent Claim
96 words
Method of producing direct-positive images, which comprises image-wise exposing and subsequently surface developing a direct-positive material containing fogged silver halide grains wherein the silver halide grains are heterodisperse and irregular and have a grain size distribution so that at least 10% by weight of the silver halide grains have a diameter, which deviates for at least 40% from the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 14
Dependent Claim
96 words
Method of producing direct-positive images, which comprises image-wise exposing and subsequently surface developing a direct-positive material containing fogged silver halide grains wherein the silver halide grains are heterodisperse and irregular and have a grain size distribution so that at least 10% by weight of the silver halide grains have a diameter, which deviates for at least 40% from the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 15
Dependent Claim
21 words
Method according to claim 12, wherein development occurs by means of a viscous processing liquid comprising an alkalisoluble polymeric thickening agent.
Claim 16
Dependent Claim
11 words
Method according to claim 13, wherein said thicknening agent is carboxymethylcellulose.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |