US3825426A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Development of exposed photographic silver halide elements
Assignee: Agfa Gevaert NV
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Filing: 1972-11-03
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Granted: 1974-07-23
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Expires: 1992-11-03
Abstract
Abstract A PHOTOGRAPHIC SILVER HALIDE EMULSION IS DESCRIBED WHICH COMPRISES A COMPOUND OF THE FORMULA: 1,2-DI(RO-),(R2-S-),R1-BENZENE WHEREIN: R IS HYDROGEN, ACYL, HALOACYL OR ACYL CARRYING A QUARTERNARY AMMONIUM GROUP, R1 IS HYDROGEN, ALKYL, ARYL, HALOGEN OR ALKOXY, AND R2 IS AN ALIPHATIC, AROMATIC OR HETERCYCLIC GROUP. THE COMPOUNDS ARE ESPECIALLY USEFUL IN LIPPMANNEMULSIONS TO REDUCE DISTORTIONS OF IMAGE DETAILS, TO ENHANCE IMAGE SHARPNESS AND TO REDUCE YELLOW STAINING UPON REVERSAL DEVELOPMENT.
Inventors
- 👤 R Pollett
- 👤 H Philippaerts
- 👤 A Vandenberghe
- 👤 J Willems
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:33
CPC Classifications
C; C07; C07D; C07D257/00; C07D257/02; C07D257/04; C07D249/00; C07D249/02; C07D249/08; C07D249/10; C07D249/12; C07D277/00; C07D277/60; C07D277/62; C07D277/68; C07D277/70; C07D277/74; G; G03; G03C; G03C1/00; G03C1/005; G03C1/06; G03C1/08; G03C1/09; G03C1/34; G03C1/346; G03C7/00; G03C7/30; G03C7/305; G03C7/30511; G03C1/035; G03C2001/03511; G03C2200/00; G03C2200/38; G03C2200/45
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |