Ferrous photographic bleach-fixing precursor compositions and methods for their use
AssigneeEastman Kodak Company
InventorsSheridan E. Vincent, Valerie L. Kuykendall, Jean M. Buongiorne
Life of this patent
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Abstract
Stable, single-part photographic bleach-fixing “precursor” compositions comprise one or more iron-ligand complexes, one or more thiosulfates as the sole fixing agents, and optionally, a sulfite preservative. At least 50 mol % of the iron in the composition is in the form of Fe(II). This composition can be used directly in photoprocessing, or used as a regenerator when mixed with bleach-fixing overflow to provide a replenishing solution. Because the Fe(II) compounds are precursor bleaching agents, they must be oxidized to Fe(III) for active bleaching prior to or during the photographic processing operations.
Claims24
A single-part photographic bleach-fixing precursor composition having a pH of from about 4 to about 10 and comprising
- at least 0.05 mol/l of one or more iron-ligand complexes,
- at least 0.15 mol/l of one or more thiosulfates as the sole photographic fixing agents, and
- optionally one or more sulfites,
- provided that over 50 mol % of the iron present in said precursor composition is in the form of Fe(II).
A single-part, concentrated photographic bleach-fixing precursor composition having a pH of from about 4.5 to about 8 and comprising:
- from about 0.15 to about 0.75 mol/l of one or more iron-ligand complexes, said iron complexes comprising a ligand selected from the group consisting of ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, ethylenediaminedisuccinic acid, methyliminodiacetic acid, alaninediacetic acid, nitrilotriacetic acid, ethylenediaminemonosuccinic acid, 2,6-pyridinedicarboxylic acid, and salts thereof,
- from about 0.75 to about 3 mol/l of potassium thiosulfate, sodium thiosulfate, or ammonium thiosulfate as the sole photographic fixing agent,
- from about 0.05 to about 2 mol/l of one or more sulfites, and
- from about 0.1 to about 1 mol/l of acetic acid, succinic acid, glycolic acid, maleic acid, propionic acid, malic acid, benzoic acid, or any mixture of these acids,
- provided from about 70 to 100 mol % of the iron present in said composition is in the form of Fe(II).
A method of providing a color photographic image comprising:
- A) color developing an imagewise exposed color photographic silver halide material,
- B) contacting said color developed color photographic silver halide material with a bleach-fixing solution for sufficient time to remove at least 95% of the silver in said color developed color photographic silver halide material, and
- C) replenishing said bleach-fixing solution by adding to it a bleach-fixing replenisher solution prepared by mixing:
- overflow from said bleach-fixing solution or water, and
- a single-part photographic bleach-fixing precursor composition having a pH of from about 4 to about 10 and comprising
- at least 0.05 mol/l of one or more iron-ligand complexes,
- at least 0.15 mol/l of one or more thiosulfates as the sole photographic fixing agents, and
- optionally one or more sulfites,
- provided more than 50 mol % of the iron present in said precursor composition is in the form of Fe(II),
- wherein the mixed volume ratio of said overflow or water to said single-part bleach-fixing precursor composition is from about 50:1 to about 1:1.
A method of regenerating a spent bleach-fixing solution comprising mixing:
- a spent bleach-fixing solution, and
- a single-part photographic bleach-fixing precursor composition having a pH of from about 4 to about 10 and comprising
- at least 0.05 mol/l of one or more iron-ligand complexes,
- at least 0.15 mol/I of one or more thiosulfates as the sole photographic fixing agents, and
- optionally one or more sulfites,
- provided more than 50 mol % of the iron present in said single-part, concentrated photographic bleach-fixing precursor composition is in the form of Fe(II),
- wherein the mixed volume ratio of said spent bleach-fixing solution to said single-part photographic bleach-fixing precursor composition is from about 50:1 to about 1:1.
A photographic processing kit comprising:
- a) a single-part photographic bleach-fixing precursor composition having a pH of from about 4 to about 10 and comprising:
- at least 0.05 mol/l of one or more iron-ligand complexes,
- at least 0.15 mol/l of one or more thiosulfates as the sole photographic fixing agents, and
- optionally one or more sulfites,
- provided more than 50 mol % of the iron present in said single-part photographic bleach-fixing precursor composition is in the form of Fe(II), and
- b) either a composition comprising a Fe(III)-ligand complex, a composition comprising a ferrous ion oxidant, or both compositions.
A photographic processing kit comprising:
- a) a single-part photographic bleach-fixing precursor composition having a pH of from about 4 to about 10 and comprising:
- at least 0.05 mol/l of one or more iron-ligand complexes,
- at least 0.15 mol/l of one or more thiosulfates as the sole photographic fixing agents, and
- optionally mol/l of one or more sulfites as the sole preservatives for said thiosulfate(s),
- provided more than 50 mol % of the iron present in said single-part, concentrated bleach-fixing precursor composition is in the form of Fe(II), and
- b) one or more additional photographic processing compositions.
A single-use processing kit that comprises at least the following multiple photographic photoprocessing liquid concentrates, each concentrate having a volume designed for dilution to the same predetermined volume of working strength photographic processing solution:
- a) a single-part, concentrated photographic bleach-fixing precursor composition having a pH of from about 4 to about 10 and comprising:
- at least 0.05 mol/l of one or more iron-ligand complexes,
- at least 0.15 mol/l of one or more thiosulfates as the sole photographic fixing agents, and
- optionally, one or more sulfites,
- provided more than 50 mol % of the iron present in said single-part, concentrated bleach-fixing precursor composition is in the form of Fe(II),
- b) single-part or two-part photographic color developing concentrate compositions,
- c) a single-part photographic final rinsing or stabilizing concentrate composition, and optionally,
- d) a single-part composition comprising a Fe(III)-ligand complex, a composition comprising a ferrous ion oxidant, or both compositions.
Dependencies are inferred from the claim text.