Patent US5536625A successfully refreshed from Google Patents.
US5536625A
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Photographic peracid bleaches with ferric 2-pyridinecarboxylate and 2,6-pyridinecarboxylate catalysts
Assignee: Eastman Kodak Co
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Filing: 1995-03-20
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Granted: 1996-07-16
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Expires: 2015-03-20
Abstract
Abstract This invention provides an accelerator for peracid bleaches used for bleaching silver halide photographic elements. The accelerator is a complex of ferric (Fe III) ion and a 2-pyridinecarboxylic acid or a 2,6-pyridinecarboxylic acid. The accelerator may be contained in the bleaching solution, a solution preceding the bleaching solution or in the photographic elements themselves.
Inventors
- 👤 John M. Buchanan
- 👤 Stuart T. Gordon
- 👤 Keith H. Stephen
- 👤 Richard P. Szajewski
- 👤 Sidney J. Bertucci
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:07
CPC Classifications
G; G03; G03C; G03C7/00; G03C7/30; G03C7/42; Y; Y10; Y10S; Y10S430/00; Y10S430/144
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
50 words
A method of processing an imagewise exposed and developed color silver halide photographic element having incorporated therein a complex of ferric ion and a 2-pyridinecarboxylic acid or a 2,6-pyridinedicarboxylic acid, said method comprising bleaching said photographic element with a peracid bleach solution comprising a peracid or peracid salt bleaching agent.
Claim 2
Independent Claim
50 words
A method of processing an imagewise exposed and developed color silver halide photographic element having incorporated therein a complex of ferric ion and a 2-pyridinecarboxylic acid or a 2,6-pyridinedicarboxylic acid, said method comprising bleaching said photographic element with a peracid bleach solution comprising a peracid or peracid salt bleaching agent.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said peracid bleaching agent is a persulfate salt.
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein said peracid bleaching agent is hydrogen peroxide or a hydrogen peroxide precursor.
Claim 5
Dependent Claim
18 words
The method of claim 1 wherein said peracid bleach solution has a pH of from 3 to 6.
Claim 6
Dependent Claim
21 words
The method of claim 1 wherein said peracid bleach solution further comprises halide ion at a concentration of 0.025 to 2.0M.
Claim 7
Dependent Claim
20 words
The method of claim 5 wherein said halide ion is chloride ion present at a concentration of 0.05 to 0.5M.
Claim 8
Dependent Claim
47 words
The method of claim 1 wherein said peracid bleach solution further comprises an aliphatic carboxylic acid buffer, an aromatic carboxylic acid buffer, a sulfo-substituted aliphatic carboxylic acid buffer or a sulfo-substituted aromatic carboxylic acid buffer such that the basic form of the buffer is less than 0.5M.
Claim 9
Dependent Claim
56 words
The method of claim 1 wherein said 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid is of formula I or II as follows: ##STR15## wherein X 1 , X 2 , X 3 and X 4 are independently H, OH, CO 2 M, SO 3 M, or PO 3 M, and M is H or an alkali metal cation.
Claim 10
Dependent Claim
19 words
The method of claim 8 wherein X 1 , X 2 , X 3 and X 4 are H.
Claim 11
Dependent Claim
55 words
The method of claim 1 wherein the amount of the ferric ion of said complex incorporated within said photographic element is 5 to 250 micromoles per ft 2 and the amount of the 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid of said complex incorporated within said photographic element is 5 to 500 micromoles per ft 2 .
Claim 12
Dependent Claim
15 words
The photographic element of claim 1 wherein said 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid is unsubstituted.
Claim 13
Dependent Claim
15 words
The method of claim 1 wherein said photographic element further contains a 2-equivalent magenta coupler.
Claim 14
Dependent Claim
14 words
The method of claim 12 wherein said 2-equivalent magenta coupler has the structure ##STR16##
Claim 15
Dependent Claim
20 words
The method of claim 1 wherein said ferric ion complex is incorporated within said photographic element in a non-imaging layer.
Claim 16
Dependent Claim
25 words
The method of claim 1 wherein said photographic element is contacted with a stop or stop-accelerator bath having a pH of ≦7 prior to bleaching.
Claim 17
Dependent Claim
26 words
The method of claim 2 wherein said persulfate ion bleaching agent is present in said peracid bleach solution in an amount of from 0.020 to 2.0M.
Claim 18
Dependent Claim
25 words
The method of claim 3 wherein said peroxide bleaching agent is present in said peracid bleach solution in an amount of from 0.1 to 2.0M.
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