Radiation imagery chemistry: process – composition – or product th – Post imaging processing – Developing
Reexamination Certificate
2000-11-03
2003-12-16
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Post imaging processing
Developing
C430S490000
Reexamination Certificate
active
06664035
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to photographic processing of color photographic elements. More specifically, this invention relates to the use of stabilized alkaline color developer compositions in the rapid processing of color negative film.
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 and automatic processing machines. Photographic color developing compositions are used 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
Traditionally, this service has required one or two days for providing the customer with the desired prints. In recent years, customers have wanted faster service, and in some locations known as “mini-labs”, it is desired to provide the customer with the desired prints within an hour. This requires the photoprocessing methods to be even faster, and reducing the processing time to within a few minutes is the ultimate desire in the industry. Much effort has been directed towards co-optimizing photographic film/paper and processes for very short processing times of two minutes or less.
Reduction in processing time of the “display” elements or color photographic papers has been facilitated by a number of recent innovations, including the use of predominantly silver chloride emulsions in the display elements. U.S. Pat. No. 4,892,804 (Vincent et al) describes conventional color developing compositions for use with high chloride photographic elements that have found considerable commercial success in the photographic industry.
Color negative films, however, generally comprise little or no silver chloride in their emulsions, and generally have silver bromide as the predominant silver halide. More typically, the emulsions are silver bromoiodide emulsions with silver iodide levels up to several mol percent. Such films require these types of emulsions because emulsions containing high silver chloride have not demonstrated sufficient light sensitivity to be used as camera speed materials although they have the advantage of being rapidly processed without major changes to the color developer solution.
To shorten the processing time, specifically the color development time, of films containing silver bromoiodide emulsions, more active color developer solutions are needed. While more active color developers may be obtained by either increasing the pH, the temperature or the color developing agent concentration of the color developer or by decreasing the halide ion concentration of the developer; these methods often compromise the stability of the developer solution and the photographic image quality. Photographic image quality may be corrected by scanning and digitally adjusting the image from a chemically processed color negative film. This technology, however, does not address the problem of maintaining the stability of processing solutions for extended periods of time at high temperatures.
For Black and White developers, high levels of sulfite or combinations of sulfite and borax are generally used to protect the developing agent against oxidation in many rapid access developers. In color systems, although sulfite is oftentimes used, other methods have been proposed to overcome problems encountered in rapid processing. For instance, novel antioxidants have been developed to stabilize developer solutions used with high chloride silver halide elements in U.S. Pat. No. 4,897,339 of Andoh et al, U.S. Pat. No. 4,906,554 of Ishikawa et al, and U.S. Pat. No. 5,094,937 of Morimoto. Also, specific hydroxylamine antioxidant, were suggested in U.S. Pat. No. 5,827,635 for rapid color development of silver bromoiodide films, and novel color developing agents have been proposed for rapid development in U.S. Pat. No. 5,278,034 (Ohki et al).
There is still a need, however, for a color developer which is active enough to rapidly process bromoiodide color negative films but is also stable under such rapid processing conditions.
SUMMARY OF THE INVENTION
This invention provides a method for providing a color image in an exposed color negative silver bromoiodide film element comprising contacting said element with an aqueous color developing composition having a pH of 9.0 to 12.0 and comprising a color developing agent, sulfite ion and an additional antioxidant wherein the color developing agent/sulfite ion molar ratio is less than 10:1 and greater than 0.55:1, and the sulfite ion/ antioxidant molar ratio is less than 4.35:1 and greater than 0.25:1.
The method of this invention allows for rapid color development of camera ready film elements containing a silver bromoiodide emulsion. The color developer solutions are remarkably stable against aerial oxidation even when maintained and/or used at relatively high temperatures, that is, above 45° C. for lengthy periods of time.
DETAILED DESCRIPTION OF THE INVENTION
The color developing compositions used in this invention include one or more color developing agents that are well known in the art that, in oxidized form, will react with dye forming color couplers in the processed materials. Such color developing agents include, but are not limited to, aminophenols, p-phenylenediamines (especially N,N-dialkyl-p-phenylenediamines) and others which are well known in the art, such as EP 0 434 097A1 (published Jun. 26, 1991) and EP 0 530 921A1 (published Mar. 10, 1993). It may be useful for the color developing agents to have one or more water-solubilizing groups as are known in the art. Further details of such materials are provided in Research Disclosure, publication 38957, pages 592-639 (September 1996).
Preferred color developing agents include, but are not limited to, N,N-diethyl p-phenylenediamine sulfate (KODAK Color Developing Agent CD-2), 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline sulfate, 4-(N-ethyl-N-p-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4), p-hydroxyethylethylaminoaniline sulfate, 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3), 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate, and others readily apparent to one skilled in the art. Particularly suitable for use in the current invention is 4-(N-ethyl-N-p-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4)
In order to protect the color developing agents from oxidation, one or more antioxidants are generally included in the color developing compositions. In the developer compositions used in the invention both a sulfite compound (such as sodium sulfite, potassium sulfite, sodium bisulfite and potassium metabisulfite) and an additional antioxidant are utilized. Either inorganic or organic antioxidants can be used as the additional antioxidant. Many classes of useful antioxidants are known, including but not limited to, hydroxylamine (and derivatives thereof), hydrazines, hydrazides, amino acids, ascorbic acid (and derivatives thereof), hydroxamic acids, aminoketones, mono- and polysaccharides, mono- and polyamines, quaternary ammonium salts, nitroxy radicals, alcohols, and oximes. Also useful as antioxidants are 1,4-cyclohexadiones as described in U.S. Pat. No. 6,077,653. Mixtures of compounds from the same or different classes of antioxidants can also be used if desired.
The most preferred antioxidant for use in this invention is hydroxylamine sulfate. Other useful antioxidants are hydroxylamine derivatives as described for example, in U.S. Pat. No. 4,892,804 (Vincent et al), 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
Arcus Robert A.
Haye Shirleyanne
Huston Janet M.
Le Hoa Van
Meeks Roberts Sarah
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