US4088494A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sulfur-sensitized AgX emulsion containing cubic AgX grains and a mercaptan sensitizer
Assignee: Fujifilm Holdings Corp
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Filing: 1977-09-01
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Granted: 1978-05-09
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Expires: 1997-09-01
Abstract
Abstract A chemically sulfur-sensitized silver halide photographic emulsion which contains: (1) at least 80 mol% silver bromide or silver chloride; wherein substantially are of the silver halide particles present are of the cubic crystal form; and (2) a sensitizing amount of an organic compound having at least one mercapto group and capable of reacting with a silver ion to form a water-insoluble silver salt. A method of sensitizing such an emulsion and a process of forming such an emulsion are also disclosed.
Inventors
- 👤 Tadaaki Tani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:11
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/06; G03C1/08; G03C1/09; G03C1/035; G03C2001/03511; G03C2001/03558; G03C2200/00; G03C2200/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
104 words
A chemically sulfur-sensitized silver halide photographic emulsion which contains: (1) at least 80 mol% silver bromide or silver chloride; wherein at least 80% by weight of all of the silver halide particles present are of the cubic crystal form; and in addition to said sulfur sensitizer (2) a sensitizing amount of an organic compound having at least one mercapto group and capable of reacting with a silver ion to form a water-insoluble silver salt, said organic compound having a 1,3,4-thiadiazole ring and a pKa of not more than 7.6, said pKa is measured in water at 25° C at an ionic strength of 0.1.
Claim 2
Dependent Claim
104 words
A chemically sulfur-sensitized silver halide photographic emulsion which contains: (1) at least 80 mol% silver bromide or silver chloride; wherein at least 80% by weight of all of the silver halide particles present are of the cubic crystal form; and in addition to said sulfur sensitizer (2) a sensitizing amount of an organic compound having at least one mercapto group and capable of reacting with a silver ion to form a water-insoluble silver salt, said organic compound having a 1,3,4-thiadiazole ring and a pKa of not more than 7.6, said pKa is measured in water at 25° C at an ionic strength of 0.1.
Claim 3
Dependent Claim
30 words
The silver halide photographic emulsion as claimed in claim 1 wherein 90% or more of the silver halide particles in the emulsion by weight are in the cubic crystal form.
Claim 4
Dependent Claim
64 words
The silver halide photographic emulsion as claimed in claim 1 wherein said silver halide is selected from the group consisting of silver bromide, silver iodobromide containing not more than 3 mol% of silver iodide, silver chloroiodobromide containing not more than 3 mol% of silver iodide and at least 80 mol% of silver bromide or silver chlorobromide containing at least 80 mol% of silver bromide.
Claim 5
Dependent Claim
35 words
The silver halide photographic emulsion as claimed in claim 1 wherein said silver halide is selected from the group consisting of silver bromide or silver iodobromide containing not more than 3 mol% of silver iodide.
Claim 6
Dependent Claim
51 words
The silver halide photographic emulsion as claimed in claim 1 wherein said silver halide is selected from the group consisting of silver chlorobromide containing at least 80 mol% of silver bromide or silver chloroiodobromide containing at least 80 mol% of silver bromide and not more than 3 mol% of silver iodide.
Claim 7
Dependent Claim
17 words
The silver halide photographic emulsion as claimed in claim 1 wherein said silver halide is silver bromide.
Claim 8
Independent Claim
97 words
A method for increasing a sensitivity of sulfur-sensitized silver halide photographic emulsion which comprises adding a sensitizing amount of an organic compound having at least one mercapto group and capable of reacting with a silver ion to form a water-insoluble silver salt to a sulfur-sensitized photographic emulsion containing at least 80 mol% of a member selected from the group consisting of silver bromide or silver chloride, wherein said pKa is measured in water at 25° C at an ionic strength of 0.1, said organic compound having a 1,3,4-thiadiazole ring and a pKa of not more than 7.6.
Claim 9
Independent Claim
97 words
A method for increasing a sensitivity of sulfur-sensitized silver halide photographic emulsion which comprises adding a sensitizing amount of an organic compound having at least one mercapto group and capable of reacting with a silver ion to form a water-insoluble silver salt to a sulfur-sensitized photographic emulsion containing at least 80 mol% of a member selected from the group consisting of silver bromide or silver chloride, wherein said pKa is measured in water at 25° C at an ionic strength of 0.1, said organic compound having a 1,3,4-thiadiazole ring and a pKa of not more than 7.6.
Claim 10
Independent Claim
26 words
The method as claimed in 7 wherein 90% or more of the silver halide particles in the emulsion by weight are in the cubic crystal form.
Claim 11
Dependent Claim
61 words
The method as claimed in claim 7 wherein said silver halide is selected from the group consisting of silver bromide, silver iodobromide containing not more than 3 mol% of silver iodide, silver chloroiodobromide containing not more than 3 mol% of silver iodide and at least 80 mol% of silver bromide or silver chlorobromide containing at least 80 mol% of silver bromide.
Claim 12
Dependent Claim
32 words
The method as claimed in claim 7 wherein said silver halide is selected from the group consisting of silver bromide or silver iodobromide containing not more than 3 mol% of silver iodide.
Claim 13
Dependent Claim
48 words
The method as claimed in claim 7 wherein said silver halide is selected from the group consisting of silver chlorobromide containing at least 80 mol% of silver bromide or silver chloroiodobromide containing at least 80 mol% of silver bromide and not more than 3 mol% of silver iodide.
Claim 14
Dependent Claim
14 words
The silver halide photographic emulsion of claim 1, wherein said organic compound is: ##STR3##
Claim 15
Dependent Claim
11 words
The process of claim 7, wherein said organic compound is: ##STR4##
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) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |