US4210450A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming photosensitive silver halide emulsion
Assignee: Polaroid Corp
•
Filing: 1978-11-20
•
Granted: 1980-07-01
•
Expires: 1998-11-20
Abstract
Abstract Photosensitive silver halide emulsions are prepared by alternating precipitation of silver halide and the addition of a water-soluble iodide salt which replaces a portion of the less soluble halide.
Inventors
- 👤 Leo D. Corben
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:43
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/015; G03C1/035; G03C2001/03523
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
60 words
The method for forming photosensitive silver halide grains which comprises the following steps, in sequence: (a) precipitating silver chloroiodobromide grains; (b) adding a water-soluble iodide salt to said chloroiodobromide grains; (c) precipitating additional silver chloroiodobromide; (d) adding a water-soluble iodide salt to said chloroiodobromide grains; (e) precipitating additional silver chloroiodobromide; (f) adding a water-soluble iodide salt to said chloroiodobromide grains.
Claim 2
Independent Claim
60 words
The method for forming photosensitive silver halide grains which comprises the following steps, in sequence: (a) precipitating silver chloroiodobromide grains; (b) adding a water-soluble iodide salt to said chloroiodobromide grains; (c) precipitating additional silver chloroiodobromide; (d) adding a water-soluble iodide salt to said chloroiodobromide grains; (e) precipitating additional silver chloroiodobromide; (f) adding a water-soluble iodide salt to said chloroiodobromide grains.
Claim 3
Dependent Claim
18 words
The method as defined in claim 1 wherein said precipitation is carried out in an aqeous gelatin solution.
Claim 4
Dependent Claim
28 words
The method as defined in claim 1 wherein said silver halide grains are precipitated by the reaction of silver nitrate and water-soluble salts of chlorine, bromine and iodine.
Claim 5
Dependent Claim
18 words
The method as defined in claim 3 wherein said salts of chlorine, bromine and iodine comprise ammonium salts.
Claim 6
Dependent Claim
15 words
The method as defined in claim 1 wherein said water-soluble iodide salt is ammonium iodide.
Claim 7
Dependent Claim
27 words
The method as defined in claim 3 wherein said grains comprise about 0.3 to 10 mole percent iodide, 1 to 5 percent chloride and the remainder bromide.
Claim 8
Dependent Claim
25 words
The method as defined in claim 6 wherein said grains comprise about 7 mole percent iodide, about 1 mole percent chloride and the remainder bromide.
Claim 9
Dependent Claim
20 words
The method as defined in claim 1 wherein the grain size ranges from about 0.1 to 4 microns average diameter.
Claim 10
Dependent Claim
16 words
The method as defined in claim 8 wherein said grain size is 0.9 microns average diameter.
Claim 11
Dependent Claim
19 words
The method as defined in claim 1 wherein said silver halide grains are formed in the presence of ammonia.
References Cited (Backward Citations)
US3477852A
Cited
US3561971A
Cited
US3597209A
Cited
US3960557A
Cited
US3917485A
Cited
US4075020A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-07-01 | 1983-12-31 | 1984-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-01 | 1987-12-31 | 1988-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-01 | 1991-12-31 | 1992-07-01 | $7700.00 | Window Closed / Lapsed |