US3767413A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Emulsion containing internally fogged photosensitive silver halide grains formed with an aqueous silver salt solution containing alkali metal iodide in thioether
Assignee: Eastman Kodak Co
•
Filing: 1972-02-03
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Granted: 1973-10-23
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Expires: 1992-02-03
Abstract
Abstract A photosensitive emulsion containing internally fogged photosensitive silver halide grains having substantially no surface fog on the grains can be prepared by mixing a silver salt solution with a halide solution in a liquid reaction medium wherein the silver salt solution contains about 0.5 to about 7.0 mole percent iodide per mole of silver and mixing is carried out in the presence of at least 0.5 grams of a thioether silver halide solvent per mole of silver in the liquid reaction medium. Emulsions prepared can be employed in negative or direct-positive photographic materials. Such emulsions enable higher concentrations of sensitizing dyes to be employed on the photosensitive silver halide grains.
Inventors
- 👤 J Miller
- 👤 C Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:29
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/015; G03C1/485; G03C1/48515; G03C2200/00; G03C2200/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
27 words
The method of claim 1 wherein said silver salt solution is an aqueous silver nitrate solution and said liquid reaction medium is an aqueous gelatino peptizer solution.
Claim 2
Dependent Claim
13 words
The method of claim 1 wherein said thioether silver halide solvent is 1,8-di-hydroxy-3,6-dithiaoctane.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said thioether is silver halide solvent is 1,10-dithia-4,7,13,16-tetraoxacyclooctadecane.
Claim 4
Dependent Claim
29 words
The process of claim 1 wherein pH during mixing of said solutions is controlled at less than about 7 and pAg is controlled between about 7 and about 9.8.
Claim 5
Independent Claim
109 words
A method of preparing a photosensitive emulsion containing internally fogged, silver bromoiodide grains having substantially no surface fog on said grains comprising mixing an aqueous silver nitrate solution with an aqueous potassium bromide solution in an aqueous gelatino peptizer solution, said method being carried out in the absence of an intentional silver halide chemical sensitization step, the improvement wherein (a) said silver nitrate solution contains 0.5 to 7.0 mole percent potassium iodide per mole of silver in said silver nitrate solution, and said aqueous gelatino peptizer solution contains about 0.5 gram to about 10 grams of 1,8-dihydroxy-3,6-dithiaoctane or 1,10-dithia-4,7,13,16-tetraoxacyclooctadecane per mole of silver in said aqueous gelatino peptizer solution.
Claim 6
Dependent Claim
12 words
A photosensitive silver halide emulsion prepared by the process of claim 1.
Claim 7
Dependent Claim
12 words
A photosensitive silver halide emulsion prepared by the process of claim 6.
References Cited (Backward Citations)
US3531288A
Cited
US3574628A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |