Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
2002-02-15
2003-06-03
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
Reexamination Certificate
active
06573035
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to multi-part photographic color developing kits that have improved stability, and to methods for their use in color photographic processing. This invention is useful in the field of photography to provide color photographic images.
BACKGROUND OF THE INVENTION
The basic processes for obtaining useful color images from exposed color photographic silver halide materials include several steps of photochemical processing such as color development, silver bleaching, silver halide fixing and water washing or dye image stabilizing using appropriate photochemical compositions.
Photographic color developing compositions are used to process color photographic materials such as color photographic films and papers to provide the desired dye images early in the photoprocessing method. Such compositions generally contain color developing agents, for example 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline, as reducing agents to react with suitable color forming couplers to form the desired dyes. U.S. Pat. No. 4,892,804 (Vincent et al.) describes conventional color developing compositions that have found considerable commercial success in the photographic industry. Other known color developing compositions are described in U.S. Pat. No. 4,876,174 (Ishikawa et al.), U.S. Pat. No. 5,354,646 (Kobayashi et al.), and U.S. Pat. No. 5,660,974 (Marrese et al.).
It is common practice to add a “replenishing” solution to the color developing composition in the processing machine in order to replace photochemicals that are depleted during reaction or carried away by the processed materials. Such replenishment insures uniform development and maximum stability of the color developing agent.
Color developing compositions are commonly supplied in three or more “parts” (or solutions) that are mixed immediately before use. Multiple parts are often required in order to separate and preserve the chemical activity and solubility of components that may otherwise deteriorate or react with each other when they are stored together for long periods of time under alkaline conditions. For example, one part might include a color developing agent. Another part might contain agents to preserve the alkalinity of the mixed color developing composition. Still another part may include an optical brightener. Upon combination of all parts and additional water, a color developing composition can usually be obtained for use in the photographic processing machine.
It is generally known that the concentrations of various photochemicals and pH used in a photographic processing bath must be within certain narrow limits in order to provide optimal performance. A relatively small change in any of the component concentrations or pH can diminish desired photochemical activity, storage stability, solution homogeneity, or any combination of these. Thus, each “part” or solution used to make a working strength solution must be formulated to provide a desired balance of all desired properties.
There is a trend in the photographic industry to provide photoprocessing compositions (including color developing compositions) in concentrated form so that the manufacturer and user need not pay for use, transport or storage of large volumes of water, and to enable use of smaller containers. Moreover, there has been a desire in the industry to provide compositions that can be used right out of their containers without the need for mixing various components (thereby reducing mixing errors), such as in what are known as “automatic replenishing” processors.
Both single-part and multi-part solutions can be provided in concentrated form.
One concentrated form known in the art is a chemical paste or slurry, as described for example in EP-A-0 204,372 (Chemco) and EP-A-0 800,11 1 (Fuji Photo). These formulations have still other disadvantages, namely lack of homogeneity and slow dissolution rate of solid components.
Additional small volume, ready to use color developing compositions are described in U.S. Pat. No. 5,273,865 (Loiacono et al.). These compositions are said to be free of bromides, hydroxylamines and benzyl alcohol, to include a polyol compound having 4 to 8 hydroxy groups, and to be useful for rapid access processing of photographic elements having high silver bromide emulsions only.
A very useful single-part color developing composition that is homogeneous, concentrated, and stable is described and claimed in U.S. Pat. No. 6,077,651 (Darmon et al.). Such compositions are stable from the presence of the free base form of the color developing agent and a particular amount of water-soluble organic solvent.
Advantageous concentrated multi-part solutions for color development are described in U.S. Pat. No. 6,136,518 (Buongiorne et al.) and in copending and commonly assigned U.S. Ser. No. 09/931,315 (filed Aug. 16, 2001 by Haye and Huston).
Stability of the color developing agents in such compositions is generally achieved using sulfite ions or any of the many conventional organic antioxidants (or preservatives) that reduce aerial oxidation rates. For example, U.S. Pat. No. 4,892,804, U.S. Pat. No. 4,876,174, U.S. Pat. No. 5,354,646, and U.S. Pat. No. 5,660,974 (all noted above) describe hundreds of possible derivatives of hydroxylamines that can be used as antioxidants in color developing compositions.
However, there is a desire in the photoprocessing industry to find additional means of stabilizing multi-part compositions or kits used to formulate color developing compositions.
SUMMARY OF THE INVENTION
This invention addresses the problems noted above with a two-part color developing kit comprising:
(I) a first aqueous solution having a pH of from about 7 to about 13, and
(II) a second aqueous solution having a pH of from about 1 to about 6 and comprising:
(a) at least 0.005 mol/l of a color developing agent, and
(b) at least 0.001 mol/l of sulfite ions,
further comprising at least 0.01 mol/l of &agr;-ketocarboxylic acid or salt thereof in the first or second solutions, or both.
This two-part color developing kit can be used to prepare a color developing composition by:
(A) combining the first and second aqueous solutions (I) and (II) noted above in such a manner that the volume ratio of the first aqueous solution to the second aqueous solution is from about 2:1 to about 1:2.
This invention also provides a three-part color developing kit comprising:
(I) a first aqueous solution having a pH of from about 8 to about 12 and comprising:
(a) at least 0.005 mol/l of an organic antioxidant,
(II) a second aqueous solution having a pH of from about 1 to about 3 and comprising:
(a) at least 0.005 mol/l of a color developing agent, and
(b) at least 0.001 mol/l of sulfite ions, and
(III) a third aqueous solution having a pH of at least 7 and comprising:
(a) a buffering agent, and
(b) at least 0.001 mol/l of halide ions
wherein at least one of the first, second, and third aqueous solutions further comprises at least 0.01 mol/l of an &agr;-ketocarboxylic acid or a salt thereof.
This invention further provides a photographic processing chemical kit comprising:
a) the two- or three-part color developing kit described above, and
b) one or more of the following compositions:
a photographic bleaching composition,
a photographic bleach-fixing composition,
a photographic fixing composition, and
a photographic stabilizing or rinsing composition.
A color developing composition can be obtained by mixing the following three aqueous solutions:
(I) a first aqueous solution having a pH of from about 8 to about 13 and comprising:
(a) at least 0.005 mol/l of an organic antioxidant,
(II) a second aqueous solution having a pH of from about 1 to about 3 and comprising:
(a) at least 0.005 mol/l of a color developing agent, and
(b) at least 0.001 mol/l of sulfite ions, and
(III) a third aqueous solution having a pH of at least 7 and comprising:
(a) a buffering agent, and
(b) at least 0.001 mol/l of halide ions
wherein at least one of the first, second, and third aqueous solutions further comprises at least 0.01 mol/l of an &ag
Haye Shirleyanne E.
Huston Janet M.
Eastman Kodak Company
Le Hoa Van
Tucker J. Lanny
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