Patent US4131467A successfully refreshed from Google Patents.
US4131467A
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US
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4,7-Dihydroxybenzimidazole hydrobromide as antifogger
Assignee: EIDP Inc
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Filing: 1977-11-23
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Granted: 1978-12-26
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Expires: 1997-11-23
Abstract
Abstract Compounds of the general formula ##STR1## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions and X - represents Br - , Cl - or I - are incorporated into light-sensitive silver halide emulsions to improve their sensitometric characteristics. In general, these compounds act as antifoggants by restraining fog growth but at the same time act as development accelerators by increasing gradient and Dmax, usually at some speed loss.
Inventors
- 👤 John H. Bigelow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:11
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30; G03C5/3021; G03C1/00; G03C1/005; G03C1/06; G03C1/34; G03C5/305
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
70 words
A photographic element comprising a support having thereon a light-sensitive silver halide emulsion layer, said layer containing a dihydroxybenzimidazole hydrohalide of the formula ##STR12## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions, and X - is Br - , Cl - or I - , the concentration of said hydrohalide being 5 × 10 -6 mole to 5 × 10 -2 mole/mole of silver halide.
Claim 2
Dependent Claim
70 words
A photographic element comprising a support having thereon a light-sensitive silver halide emulsion layer, said layer containing a dihydroxybenzimidazole hydrohalide of the formula ##STR12## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions, and X - is Br - , Cl - or I - , the concentration of said hydrohalide being 5 × 10 -6 mole to 5 × 10 -2 mole/mole of silver halide.
Claim 3
Dependent Claim
17 words
The photographic element of claim 1 wherein said dihydroxybenzimidazole hydrohalide is 4,7-dihydroxybenzimidazole hydrobromide having the formula ##STR13##
Claim 4
Dependent Claim
17 words
The photographic element of claim 1 wherein said dihydroxybenzimidazole hydrohalide is 4,7-dihydroxybenzimidazole hydrochloride having the formula ##STR14##
Claim 5
Dependent Claim
17 words
The photographic element of claim 1 wherein said dihydroxybenzimidazole hydrohalide is 4,7-dihydroxybenzimidazole hydroiodide having the formula ##STR15##
Claim 6
Dependent Claim
17 words
The photographic element of claim 1 wherein said dihydroxybenzimidazole hydrohalide is 5,6-dihydroxybenzimidazole hydrobromide having the formula ##STR16##
Claim 7
Dependent Claim
17 words
The photographic element of claim 1 wherein said dihydroxybenzimidazole hydrohalide is 5,6-dihydroxybenzimidazole hydrochloride having the formula ##STR17##
Claim 8
Dependent Claim
17 words
The photographic element of claim 1 wherein said dihydroxybenzimidazole hydrohalide is 5,6-dihydroxybenzimidazole hydroiodide having the formula ##STR18##
Claim 9
Dependent Claim
61 words
A photographic developer containing a silver halide developing agent and a dihydroxybenzimidazole hydrohalide of the formula ##STR19## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions and X - represents Br - , Cl - or I - ; said dihydroxybenzimidazole hydrohalide being present in an amount of 10 -6 to 10 -2 moles/liter of developing solution.
Claim 10
Dependent Claim
61 words
A photographic developer containing a silver halide developing agent and a dihydroxybenzimidazole hydrohalide of the formula ##STR19## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions and X - represents Br - , Cl - or I - ; said dihydroxybenzimidazole hydrohalide being present in an amount of 10 -6 to 10 -2 moles/liter of developing solution.
Claim 11
Dependent Claim
72 words
A photographic element comprising a support having thereon a light-sensitive silver halide emulsion layer and an auxiliary layer, said auxiliary layer containing a dihydroxybenzimidazole hydrohalide of the formula ##STR20## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions, and X - is Br - , Cl - or I - , the concentration of said hydrohalide being 10 -6 to 10 -2 mole per mole of silver halide.
Claim 12
Dependent Claim
72 words
A photographic element comprising a support having thereon a light-sensitive silver halide emulsion layer and an auxiliary layer, said auxiliary layer containing a dihydroxybenzimidazole hydrohalide of the formula ##STR20## wherein A and B are hydroxy radicals in the 4,7 or 5,6 positions, and X - is Br - , Cl - or I - , the concentration of said hydrohalide being 10 -6 to 10 -2 mole per mole of silver halide.
Claim 13
Dependent Claim
17 words
The photographic element of claim 9 wherein said dihydroxybenizimidazole hydrohalide is 4,7-dihydroxy-benzimidazole hydrobromide having the formula ##STR21##
Claim 14
Dependent Claim
17 words
The photographic element of claim 9 wherein said dihydroxybenzimidazole hydrohalide is 4,7-dihydroxybenzimidazole hydrochloride having the formula ##STR22##
Claim 15
Dependent Claim
17 words
The photographic element of claim 9 wherein said dihydroxybenzimidazole hydrohalide is 4,7-dihydroxybenzimidazole hydroiodide having the formula ##STR23##
Claim 16
Dependent Claim
17 words
The photographic element of claim 9 wherein said dihydroxybenzimidazole hydrohalide is 5,6-dihydroxybenzimidazole hydrobromide having the formula ##STR24##
Claim 17
Dependent Claim
17 words
The photographic element of claim 9 wherein said dihydroxybenzimidazole hydrohalide is 5,6-dihydroxybenzimidazole hydrochloride having the formula ##STR25##
Claim 18
Dependent Claim
17 words
The photographic element of claim 9 wherein said dihydroxybenzimidazole hydrohalide is 5,6-dihydroxybenzimidazole hydroiodide having the formula ##STR26##
References Cited (Backward Citations)
US2384593A
Cited
US2418613A
Cited
US2893865A
Cited
US3271154A
Cited
US3137578A
Cited
US3499761A
Cited
US3761278A
Cited
US3850638A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-12-25 | 1982-06-26 | 1982-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-25 | 1986-06-26 | 1986-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-25 | 1990-06-26 | 1990-12-26 | $7700.00 | Window Closed / Lapsed |