Radiation imagery chemistry: process – composition – or product th – Color imaging process – Intensifying
Reexamination Certificate
2002-11-01
2003-12-09
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Intensifying
C430S372000, C430S414000, C430S429000
Reexamination Certificate
active
06660461
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to stabilized photographic amplified color developing compositions, sometimes known as “redox” amplification compositions, and to a method for their use. This invention also relates to two- and three-part kits that provide these compositions. 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 been used with 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.).
Color development is generally followed with one or more desilvering steps, such as bleaching and fixing steps, or a combined bleach-fixing step. In such processes, color development can continue until the photographic material enters the bleaching or bleach-fixing solution.
Calcium or other metal ions in photographic processing compositions (such as color developing compositions) have been sequestered or complexed using a wide variety of organic complexing agents including various polyaminocarboxylic acids and polyphosphonic acids. Such innovations are described for example in U.S. Pat. No. 4,873,180 (Marchesano et al.), U.S. Pat. No. 6,416,940 (Haye et al.), and U.S. Pat. No. 6,159,670 (Buongiorne et al.).
In redox amplification (or RX) processes, imagewise exposed color photographic materials are developed to provide a silver image and then treated with a redox amplification composition (or a combined developer-amplifier composition) to form a dye image. Desilvering can then follow these steps. Such processes are well known in the art and described for example in U.S. Pat. No. 5,702,873 (Twist) and U.S. Pat. No. 5,723,268 (Fyson) and references cited therein.
A redox amplification composition (or as identified below as an amplified color developing composition) contains a reducing agent (usually a color developing agent) and a redox oxidizing agent (usually hydrogen peroxide) that is more powerful than silver halide and that will oxidize the reducing agent in the presence of the silver image that acts as a catalyst. The oxidized reducing agent (for example, the oxidized color developing agent) reacts with color forming couplers in the photographic material to form image dye. The redox amplification processes are particularly useful for processing color photographic papers that comprise relatively low amounts of silver chloride.
Since the amplified color developing compositions contain both an oxidizing agent and a reducing agent, they are inherently unstable and will decompose upon keeping. This instability is catalyzed during processing by various species in the processing environment that come from various sources.
U.S. Pat. 5,702,873 (noted above) describes the use of various metal ion sequestering agents such as polyaminocarboxylic, polyphosphonic or poly sulfonic acids that provide improved stability for various amplified color developing compositions.
Despite the continuing research by the industry to find ways to stabilize amplified color developing compositions, the industry has failed to provide sufficient stability so that such compositions could have general acceptance and use in commercial applications. Thus, there remains a need for means to increase the solution stability of redox amplification compositions. It is to this problem that the present invention is directed.
SUMMARY OF THE INVENTION
This invention provides an advance in the art with a stabilized photographic amplified color developing composition that comprises:
a) at least 0.001 mol/l of a color developing agent,
b) at least 0.005 mol/l of a redox oxidizing agent,
c) at least 0.001 mol/l of a hydroxylamine antioxidant, and
d) at least 0.0005 mol/l of a cyclicaminomethanediphosphonic acid or a salt thereof.
In preferred embodiments, the present provides an aqueous redox amplification composition having a pH of from about 10 to about 12 and comprising:
a) from about 0.001 to about 1 mol/l of a color developing agent that is 4-(N-ethyl-N-&bgr;-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4) or 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3),
b) from about 0.001 to about 1 mol/l of hydroxylamine sulfate as an antioxidant for the color developing agent,
c) from about 0.005 to about 5 mol/l of hydrogen peroxide or a compound that provides hydrogen peroxide, and
d) from about 0.0005 to about 0.5 mol/l of morpholinomethanediphosphonic acid or a salt thereof.
This invention also provides a method for providing a color image comprising contacting an imagewise exposed color photographic element with a stabilized amplified color developing composition that comprises:
a) at least 0.001 mol/l of a color developing agent,
b) at least 0.005 mol/l of a redox oxidizing agent,
c) at least 0.001 mol/l of a hydroxylamine antioxidant, and
d) at least 0.0005 mol/l of a cyclicaminomethanediphosphonic acid or a salt thereof.
In preferred embodiments, it provides a method for providing a color image comprising contacting an imagewise exposed color photographic element with a stabilized photographic redox amplification composition that has a pH of from about 10 to about 12 and comprises:
a) from about 0.001 to about 1 mol/l of a color developing agent that is 4-(N-ethyl-N-&bgr;-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4) or 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3),
b) from about 0.001 to about 1 mol/l of hydroxylamine sulfate as an antioxidant for the color developing agent,
c) from about 0.005 to about 5 mol/l of hydrogen peroxide or a compound that provides hydrogen peroxide, and
d) from about 0.0005 to about 0.5 mol/l of morpholinomethanediphosphonic acid or a salt thereof.
Still again, the present invention provides a method of photographic processing comprising the steps of:
A) contacting an imagewise exposed color photographic silver halide element with a stabilized amplified color developing composition that comprises:
a) at least 0.001 mol/l of a color developing agent,
b) at least 0.005 mol/l of a redox oxidizing agent,
c) at least 0.001 mol/l of a hydroxylamine antioxidant, and
d) at least 0.0005 mol/l of a cyclicaminomethanediphosphonic acid or a salt thereof, and
B) desilvering the color developed color photographic silver halide element.
A photographic processing kit of this invention comprises:
A) a first solution comprising a color developing agent, a cyclicaminomethanediphosphonic acid or salt thereof, and a hydroxylamine antioxidant, and
B) a second solution that comprises a redox oxidizing agent.
In other embodiments, a photographic processing kit comprises:
A) a first solution that comprises a color developing agent,
B) a second solution that comprises a cyclicaminomethanediphosphonic acid or salt thereof, and
C) a third solution that comprises a redox oxidizing agent, the first or second solution, or both, further comprising a hydroxylamine antioxidant.
The redox amplification composition of this i
Haye Shirleyanne E.
Horn Richard R.
Huston Janet M.
Jarkowski Anthony
Eastman Kodak Company
Le Hoa Van
Tucker J. Lanny
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