US3773516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing silver halide emulsions
Assignee: Polaroid Corp
•
Filing: 1971-12-29
•
Granted: 1973-11-20
•
Expires: 1991-12-29
Abstract
Abstract Poly-disperse photographic silver halide emulsions comprising silver halide grains of uniform habit are produced by utilizing a continuous precipitation technique.
Inventors
- 👤 E Gutoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:48
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/015; G03C1/035; G03C2001/03564; G03C2001/03588
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
11 words
The invention of claim 1 wherein said protective colloid is gelatin.
Claim 2
Dependent Claim
92 words
A process for preparing a photosensitive poly-disperse silver halide emulsion comprising cubic silver halide grains of at least 80 percent silver bromide constituency which comprises the continuous precipitation in a reaction vessel of said silver halide grains in the presence of a protective colloid, with constant agitation, under ammoniacal conditions which promote formation of a cubic grain habit, at a pBr above 1.6, and with the continuous removal of the resultant silver halide emulsion in order to provide a predetermined average grain residence time in said vessel of less than 8 minutes.
Claim 3
Dependent Claim
11 words
The invention of claim 3 wherein said protective colloid is gelatin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |