US3632340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cored direct positive silver halide emulsion developed with polyhydroxybenzene
Assignee: Eastman Kodak Co
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Filing: 1968-09-09
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Granted: 1972-01-04
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Expires: 1988-09-09
Abstract
Abstract Processing exposed, direct-positive, high-contrast photographic elements with a polyhydroxybenzene developing agent wherein the silver halide emulsion of the element contains silver halide grains comprising internal centers which promote the deposition of photolytic silver and an outer region comprising a fogged silver halide that develops to silver without exposure. Certain halogen-conducting compounds and electron-accepting compounds can also be added to the element to increase speed.
Inventors
- 👤 Bernard D Illingsworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:16
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48515
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
49 words
A process according to claim 1 wherein said direct-positive silver halide emulsion comprises silver halide grains comprising a central core of silver halide containing centers which promote the deposition of photolytic silver and an outer shell covering said core comprising fogged silver halide that develops to silver without exposure.
Claim 2
Dependent Claim
26 words
A process according to claim 2 wherein said centers which promote the deposition of photolytic silver are formed by a chemical treatment of the central core.
Claim 3
Dependent Claim
21 words
The process of claim 1 wherein said centers which promote the deposition of photolytic silver are obtained from an iridium salt.
Claim 4
Dependent Claim
14 words
The proceSs of claim 1 wherein said halide comprises at least 70-mole percent chloride.
Claim 5
Dependent Claim
39 words
The process of claim 1 wherein said direct-positive emulsion has adsorbed to said fogged grains a halogen-accepting compound having an anodic polarographic halfwave potential less than 0.85 and a cathodic polarographic halfwave potential which is more negative than -1.0.
Claim 6
Dependent Claim
13 words
The process of claim 6 wherein said halogen-accepting compound is a merocyanine dye.
Claim 7
Dependent Claim
30 words
The process of claim 6 wherein said direct-positive emulsion also contains a sulfonated compound having the following formula: R-SO3M wherein R represents a polynuclear group and M represents a cation.
Claim 8
Dependent Claim
11 words
The process of claim 1 wherein said polyhydroxy-benzene compound is hydroquinone.
Claim 9
Dependent Claim
15 words
The process of claim 9 wherein said developer also contains a carbonyl bisulfite-amine condensation product.
Claim 10
Dependent Claim
12 words
The process of claim 9 wherein said developer contains excess free amine.
Claim 11
Dependent Claim
12 words
The process of claim 1 wherein said element also contains a 3-pyrazolidone.
Claim 12
Dependent Claim
26 words
The process of claim 1 wherein said direct-positive silver halide emulsion comprises an electron-accepting compound having an anodic and polarographic halfwave potential sum which is positive.
Claim 13
Dependent Claim
31 words
A process as in claim 1 wherein said developer also contains a carbonyl bisulfite-amine condensation product and contains at least 0.075 mole of excess free amine per liter of said developer.
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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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |