Patent US4609620A successfully refreshed from Google Patents.
US4609620A
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Pyrazolone compounds and a process for their manufacture
Assignee: Ilford Imaging UK Ltd
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Filing: 1985-04-09
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Granted: 1986-09-02
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Expires: 2005-04-09
Abstract
Abstract Compounds of the formula ##STR1## where Y is a tertiary group, X is hydrogen or a leaving group, and Q is hydrogen, amidino, alkyl or aryl, there being present in Y or Q a ballasting group which comprises 10 to 30 carbon atoms, exhibit a high secondary absorption in the blue region of the visible spectrum and are useful couplers in chromogenic monochrome negative material.
Inventors
- 👤 Stephen R. Postle
- 👤 William E. Long
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:17
CPC Classifications
C; C07; C07D; C07D231/00; C07D231/02; C07D231/10; C07D231/14; C07D231/18; C07D231/20; C07D231/22; G; G03; G03C; G03C7/00; G03C7/30; G03C7/32; G03C7/36; G03C7/38; G03C7/384
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
48 words
Chromogenic, monochrome negative photographic material which comprises in at least one silver halide emulsion layer a pyrazolone compound having a high secondary absorption in the blue region of the visible spectrum, which is at least 54% of the primary absorption, said pyrazolone dye being of the formula ##STR17##
Claim 2
Dependent Claim
48 words
Chromogenic, monochrome negative photographic material which comprises in at least one silver halide emulsion layer a pyrazolone compound having a high secondary absorption in the blue region of the visible spectrum, which is at least 54% of the primary absorption, said pyrazolone dye being of the formula ##STR17##
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) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |