US3655394A
Expired / Lapsed
US
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Preparation of silver halide grains
Assignee: Eastman Kodak Co
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Filing: 1969-08-25
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Granted: 1972-04-11
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Expires: 1989-08-25
Abstract
Abstract Photographic emulsions comprising cubic-regular grains free of reduction sensitization are prepared by running an aqueous solution of silver nitrate and an aqueous solution of a silver halide simultaneously into an agitated aqueous solution of a peptizer in a double-run precipitation procedure while maintaining the pH at no more than 4.0 and the pAg at a value within the range of 8.6 to 9.1. In one aspect of this invention, emulsions prepared by the above procedure are chemically sensitized with a compound containing a labile atom selected from the group consisting of sulfur, selenium and tellurium and spectrally sensitized with a cyanine dye having an anodic halfwave potential less than 1.0 volt and a cathodic half-wave potential less than -0.8 volt.
Inventors
- 👤 Bernard D Illingsworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:23
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/015; G03C1/035; G03C2001/03541; G03C2200/00; G03C2200/06; G03C2200/44
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
13 words
A method according to claim 1 wherein said silver halide is silver bromoiodide.
Claim 2
Dependent Claim
32 words
A method according to claim 1 wherein said silver halide grains are chemically sensitized with a compound containing a labile atom selected from the group consisting of sulfur, selenium and tellurium atoms.
Claim 3
Dependent Claim
15 words
A method according to claim 1 including the step of gold-sensitizing said silver halide grains.
Claim 4
Dependent Claim
63 words
A cubic-regular grain silver halide emulsion, said grains being substantially free of reduction sensitization upon formation, said silver halide being thereafter chemically sensitized with a compound containing a labile atom selected from the group consisting of sulfur, selenium and tellurium and spectrally sensitized with a dye having anodic half-wave potential less than 1.0 volt and a cathodic half-wave potential less than -0.8 volt.
Claim 5
Dependent Claim
71 words
A cubic-regular grain silver halide emulsion in which the halide is predominately bromide, said grains being substantially free of reduction sensitization upon formation, said silver halide being chemically sensitized with a compound containing a labile atom selected from the group consisting of sulfur, selenium and tellurium, and spectrally sensitized with a cyanine dye having an anodic half-wave potential less than 1.0 volt and a cathodic half-wave potential less than -0.8 volt.
Claim 6
Dependent Claim
23 words
The emulsion of claim 6 in which the silver halide is silver bromoiodide having an average grain diameter of less than 0.5 micron.
Claim 7
Dependent Claim
8 words
The emulsion of claim 6 additionally being gold-sensitized.
Claim 8
Dependent Claim
32 words
The emulsion of claim 6 wherein it is spectrally sensitized with a cyanine dye containing at least one heterocyclic ring selected from the class consisting of thiazole, benzimidazole, oxazole, selenazole and quinoline.
Claim 9
Dependent Claim
14 words
A silver halide emulsion according to claim 6 which has been sulfur- and gold-sensitized.
Claim 10
Dependent Claim
12 words
A silver halide emulsion according to claim 6 comprising an infrared-sensitizing dye.
Claim 11
Dependent Claim
20 words
An emulsion according to claim 6 wherein the average grain diameter of said silver halide is less than 0.5 micron.
Claim 12
Dependent Claim
17 words
An emulsion according to claim 6 wherein said grains are made at a pH of about 2.
Claim 13
Dependent Claim
28 words
An emulsion according to claim 6 wherein at least 80 percent, by weight or by number, of said silver halide grains are free of twin plane stacking faults.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |