Patent US2648604A successfully refreshed from Google Patents.
US2648604A
Expired / Lapsed
US
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Photographic developer containing a pyridinium salt and process of development
Assignee: GAF Chemicals Corp
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Filing: 1951-12-28
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Granted: 1953-08-11
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Expires: 1971-12-28
Abstract
No abstract record available.
Inventors
- 👤 Lawrence G Welliver
- 👤 Carl E Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:23
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/305
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
32 words
AN ALKALINE PHOTOGRAPHIC DEVELOPER FOR SILVER HALIDE EMULSIONS COMPRISING AN AROMATIC SILVER HALIDE DEVELOPING AGENT AND A PYRIDINUM SALT SELECTED FROM THE CLASS CONSISTING OF THOSE CORRESPONDING TO THE FOLLOWING GENERAL FORMULA:
Claim 2
Dependent Claim
32 words
AN ALKALINE PHOTOGRAPHIC DEVELOPER FOR SILVER HALIDE EMULSIONS COMPRISING AN AROMATIC SILVER HALIDE DEVELOPING AGENT AND A PYRIDINUM SALT SELECTED FROM THE CLASS CONSISTING OF THOSE CORRESPONDING TO THE FOLLOWING GENERAL FORMULA:
References Cited (Backward Citations)
US2419975A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-08-10 | 1957-02-09 | 1957-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-08-10 | 1961-02-09 | 1961-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-08-10 | 1965-02-09 | 1965-08-11 | $7700.00 | Window Closed / Lapsed |