US3749576A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic light-sensitive silver halide material containing azo dyes
Assignee: Ilford Imaging Switzerland GmbH
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Filing: 1971-05-04
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Granted: 1973-07-31
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Expires: 1991-05-04
Abstract
Abstract PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL, ESPECIALLY FOR THE SILVER DYESTUFF BLEACHING PROCESS, CONTAINING AN AZO DYESTUFF DERIVED (A) FROM A TETRAZO COMPOUND OF A DIAMINE THE AMINO GROUPS OF WHICH ARE BOUND TO BENZENE RADICALS WHICH ARE LINKED TOGETHER IN AMIDE-LIKE MANNER BY AN ORGANIC BRIDGE MEMBER AND (B) 2-PHENYLAMINO-8HYDROXY-MONO- OR -DISULPHONIC ACIDS, THE PHENYL REDISUES CONTAINING AT LEAST ONE FURTHER SUBSTITUENT, BUT BEING UNSUBSTITUTED IN AT LEAST ONE POSITION ORTHO TO THE -NHGROUP. THESE MAGENTA DYESTUFFS ARE FAST TO DIFFUSION, EASILY SOLUBLE IN WATER, INSENSITIVE TO CALCIUM IONS AND COMPLETELY BLEACHABLE TO WHITE.
Inventors
- 👤 B Piller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:56
CPC Classifications
C; C09; C09B; C09B43/00; C09B43/32; B; B01; B01J; B01J37/00; B01J37/20; C09B43/12; C09B43/136
Claims Analysis
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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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |