US3620744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dyestuff-bleaching preparation for the photographic silver dyestuff-bleaching process
Assignee: BASF Schweiz AG
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Filing: 1969-06-18
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Granted: 1971-11-16
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Expires: 1989-06-18
Abstract
Abstract In a photographic silver dyestuff-bleaching process a dyestuffbleaching preparation is used which contains an acid, a watersoluble iodide, optionally a dyestuff-bleaching catalyst and in addition a reductone such as ascorbic acid. These preparations, preferably in the form of baths, are distinguished by their stability and effectiveness even after prolonged storage in open containers.
Inventors
- 👤 Matthias Schellenberg
- 👤 Max Marthaler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:34
CPC Classifications
G; G03; G03C; G03C7/00; G03C7/28
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
14 words
A preparation according to claim 1 being in the form of a dyestuff-bleaching bath.
Claim 2
Dependent Claim
32 words
A preparation according to claim 1 containing as acid a member selected from the group consisting of an organic sulfonic acid, sodium bisulfate, hydrochloric acid, sulfuric acid, acetic acid and citric acid.
Claim 3
Dependent Claim
19 words
A preparation according to claim 1 containing as water-soluble iodide hydriodic acid, ammonium iodide, sodium iodide and potassium iodide.
Claim 4
Dependent Claim
14 words
A preparation according to claim 1 containing sulfuric acid, potassium iodide and ascorbic acid.
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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |