US2815284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developers for photographic silver halide papers
Assignee: Photographica Gesellschaft fuer Photographische Industrie mbH
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Filing: 1953-04-08
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Granted: 1957-12-03
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Expires: 1973-04-08
Abstract
No abstract record available.
Inventors
- 👤 Tausch Ernst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:19
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/305; Y; Y10; Y10S; Y10S430/00; Y10S430/134
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
67 words
IN THE PROCESS OF PRODUCING PHOTOGRAPHIC IMAGES WITH IMPROVED WHITENESS, THE STEP OF PROCESSING EXPOSED LIGHT-SENSITIVE SILVER HALIDE-COATED PAPERS WITH A SILVER HALIDE DEVELOPER HAVING DISSOLVED THEREIN A SUBSTANTIALLY COLORLESS DERIVATIVE OF 4,4''-DIAMINO-STILBENE-2,2''-DISULPHONIC ACID, SAID DERIVATIVE ABSORBING ULTRAVIOLET RADIATION OF BETWEEN ABOUT 3,000 ANGSTROM UNITS AND 4,000 ANGSTROM UNITS AND EMITTING FLUORESCENT LIGHT OF BETWEEN ABOUT 4,000 ANGSTROM UNITS AND 5,500 ANGSTROM UNITS AND HAVING THE FORMULA:
Claim 2
Dependent Claim
67 words
IN THE PROCESS OF PRODUCING PHOTOGRAPHIC IMAGES WITH IMPROVED WHITENESS, THE STEP OF PROCESSING EXPOSED LIGHT-SENSITIVE SILVER HALIDE-COATED PAPERS WITH A SILVER HALIDE DEVELOPER HAVING DISSOLVED THEREIN A SUBSTANTIALLY COLORLESS DERIVATIVE OF 4,4''-DIAMINO-STILBENE-2,2''-DISULPHONIC ACID, SAID DERIVATIVE ABSORBING ULTRAVIOLET RADIATION OF BETWEEN ABOUT 3,000 ANGSTROM UNITS AND 4,000 ANGSTROM UNITS AND EMITTING FLUORESCENT LIGHT OF BETWEEN ABOUT 4,000 ANGSTROM UNITS AND 5,500 ANGSTROM UNITS AND HAVING THE FORMULA:
References Cited (Backward Citations)
BE498125A
Cited
US2316595A
Cited
FR878823A
Cited
US2303917A
Cited
US2639900A
Cited
GB672803A
Cited
BE502230A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-12-02 | 1961-06-03 | 1961-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-12-02 | 1965-06-03 | 1965-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-12-02 | 1969-06-03 | 1969-12-03 | $7700.00 | Window Closed / Lapsed |