US3748136A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic silver bleaching solution
Assignee: Agfa Gevaert NV
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Filing: 1971-07-14
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Granted: 1973-07-24
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Expires: 1991-07-14
Abstract
Abstract A METHOD OF BLEACHING SILVER IMAGES IN PHOTOGRAPHIC ELEMENTS BY MEANS OF NEGATIVELY CHARGED OXIDIZING AGENTS IS DESCRIBED WHEREIN SAID BLEACHING IS ACCLELERATED BY THIS USE OF ONIUM COMPOUNDS IN THE BLEACHING SOLUTION OR IN A SOLUTION USED PRIOR TO THE BLEACHING SOLUTION. THE METHOD MAKES POSSIBLE TO USE AS OXIDIZING AGENTS THE INEXPENSIVE AND COLOURLESS PERSULPHATES WHICH ARE OTHERWISE TOO SLOW FOR SILVER BLEACHING.
Inventors
- 👤 J Willems
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:16
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/40; G03C5/44
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |