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EP0588408A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

An ascorbic acid type developer with a particular composition

Assignee: Agfa Gevaert NV
•
Filing: 1993-08-31
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Granted: —
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Expires: 2013-08-31
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Abstract

Abstract A developer solution for the development of photographic silver halide materials is disclosed comprising (1) an ascorbic acid type developing agent, and (2) a mixture of at least two 3-pyrazolidone type developing agents chosen from (a) 1-phenyl-3-pyrazolidone, (b) 1-phenyl-4-methyl-3-pyrazolidone), (c) 1-phenyl-4-methyl-4'-hydroxymethyl-3-pyrazolidone, (d) 1-phenyl-4,4'-dimethyl-3-pyrazolidone. In a preferred embodiment the ascorbic acid type developing agent is l-ascorbic acid or iso-ascorbic acid or a salt thereof, and the mixture of the 3-pyrazolidones consists of a mixture of 1-phenyl-3-pyrazolidone and 1-phenyl-4-methyl-3-pyrazolidone. The developer composition of the invention shows improved sensitometric stability against a pH decrease caused by exhaustive continuous processing without developer replenishment.

Inventors

  • 👤 Andriessen C/O Agfa-Gevaert N.V. Hieronymus
  • 👤 Lingier c/o Agfa-Gevaert N.V. Stefaan

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-06 15:00
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 95 words
Photographic developing solution comprising : (1) an ascorbic acid type developing agent corresponding to general formula (I), or a salt of it : wherein X represents an oxygen atom or an imino group, and n represents a positive integer from 1 to 4, and R represents a hydroxy group when n is 1, and R represents a hydroxy group or a hydrogen atom when n is 2 to 4. (2) a mixture of at least two 3-pyrazolidone type developing agents chosen from the group consisting of : (a) 1-phenyl-3-pyrazolidone, (b) 1-phenyl-4-methyl-3-pyrazolidone, (c) 1-phenyl-4-methyl-4'-hydroxymethyl-3-pyrazolidone, (d) 1-phenyl-4,4'-dimethyl-3-pyrazolidone.
Claim 2
Dependent Claim 23 words
Developing solution according to claim 1 wherein said ascorbic acid type developing agent is l-ascorbic acid or iso-ascorbic acid or a salt thereof.
Claim 3
Dependent Claim 25 words
Developing solution according to claim 1 or 2 wherein said ascorbic acid type developing agent is present in a concentration between 0.1 and 0.6 mole/l.
Claim 4
Dependent Claim 29 words
Developing solution according to any of claims 1 to 3 wherin said mixture of at least two 3-pyrazolidone type developing agents is a mixture of 1-phenyl-3-pyrazolidone and of 1-phenyl-4-methyl-3-pyrazolidone.
Claim 5
Dependent Claim 32 words
Developing solution according to claim 4 wherein said 1-phenyl-3-pyrazolidone is present in a concentration between 0.1 and 2.0 g/l, and said 1-phenyl-4-methyl-3-pyrazolidone is present in a concentration between 0.1 and 5.5 g/l.
Claim 6
Dependent Claim 31 words
Method for developing an image-wise exposed photographic material, comprising a support and a silver halide emulsion layer, by means of a developer solution according to any of claims 1 to 5.
Claim 7
Dependent Claim 14 words
Method according to claim 6 wherein there is no replenisher for said developing solution.
Claim 8
Dependent Claim 26 words
Method according to claim 6 or 7 wherein the silver halide emulsion, present in said silver halide layer, contains at least 70 mole % of bromide.

References Cited (Backward Citations)

FR1108865A Cited
GB2011103A Cited
US5041363A Cited
US5098819A Cited

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