US3785822A
Expired / Lapsed
US
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Photographic emulsions and developers containing 2-mercapto heterocyclic compounds
Assignee: WITT OVERMAN J DE
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Filing: 1971-06-30
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Granted: 1974-01-15
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Expires: 1991-06-30
Abstract
Abstract This invention relates to photographic materials designed for processing in developing agents which have a long induction period and to which fog-reducing adjuvants have been added. The induction period can be considerably shortened and the restraining action of any antifoggant overcome by the addition of certain heterocyclic nitrogen compounds which contain a mercapto substituent adjacent to the nitrogen atom and which exhibit a pKa not less than 7.7.
Inventors
- 👤 Witt Overman J De
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:25
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/06; G03C1/34; G03C1/346; G03C5/00; G03C5/26; G03C5/29; G03C5/305
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
26 words
An emulsion according to claim 1 wherein said compound is present in an amount of 10 2 to 2.5 millimoles per 1.5 moles of silver halide.
Claim 2
Dependent Claim
12 words
An emulsion according to claim 2 which is a gelatino-silver chlorobromide emulsion.
Claim 3
Dependent Claim
12 words
An emulsion according to claim 3 wherein said nitrogen compound is 2-mercaptopyridine.
Claim 4
Dependent Claim
12 words
An emulsion according to claim 3 wherein said nitrogen compound is 2-mercaptoquinoline.
Claim 5
Dependent Claim
12 words
An emulsion according to claim 3 wherein said nitrogen compound is 2-mercaptobenzimidazole.
Claim 6
Dependent Claim
29 words
An emulsion according to claim 2 wherein said compound is selected from the group consisting of 2-mercaptopyridine, 2-mercaptoquinoline, 2-mercaptobenzimidazole, 2-mercapto-4-phenylthiazole, 2-mercaptopyrimidine, 2-mercapto-1-methylimidazole, 2-mercaptoimidazoline, 3,4,5,6-tetrahydro-2-pyrimidinethiol, 2-mercaptoimidazole, epsilon -thiocaprolactam, and 2-mercaptothiazoline.
Claim 7
Dependent Claim
38 words
An emulsion according to claim 2 wherein at least one antifoggant selected from the group consisting of 5-nitroindazole, 5-nitrobenzimidazole, 1,2-naphthotriazole and benzotriazole is present in an amount of 0.05 - 20 millimoles per 1.5 moles of silver halide.
Claim 8
Dependent Claim
99 words
In a photographic developer solution comprising an aqueous alkaline solution containing: a silver halide developing agent with a long induction period consisting essentially of hydroquinone or a hydroquinone derivative, and an alkali metal sulphite in a concentration of about 1.0 to about 100 grams per liter of solution; the improvement wherein said solution further comprises 0.0005 to 1.0 gram per liter of at least one 2-mercapto substituted heterocyclic compound having: intracyclic nitrogen and carbon atoms, a mercapto group attached to the intracyclic carbon atom in the alpha-position to the intracyclic nitrogen atom, and a pKa not less than 7.7.
Claim 9
Dependent Claim
13 words
A developer solution according to claim 9 wherein the nitrogen compound is 2-mercaptopyridine.
Claim 10
Dependent Claim
13 words
A developer solution according to claim 9 wherein the nitrogen compound is 2-mercaptoquinoline.
Claim 11
Dependent Claim
13 words
A developer solution according to claim 9 wherein the nitrogen compound is 2-mercaptobenzimidazole.
Claim 12
Dependent Claim
44 words
A developer solution according to claim 9 wherein the developing agent is a hydroquinone, and an anti-foggant selected from the group consisting of 5-nitroindazole, 5-nitrobenzimidazole, 1,2-naphthotriazole, and a benzotriazole is present in an amount of 0.01 gram to 2.0 grams per liter of solution.
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |