Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Wash or aftertreat
Reexamination Certificate
1995-04-05
2001-01-30
Bell, Mark L. (Department: 1755)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Wash or aftertreat
C430S372000, C430S379000, C430S407000, C430S427000, C430S428000, C430S429000, C430S432000
Reexamination Certificate
active
06180327
ABSTRACT:
FIELD OF THE INVENTION
This invention relates in general to color photography and in particular to methods and compositions useful in the processing of color photographic materials, especially color reversal photographic elements. More particularly, this invention relates to an improved pre-bleach stabilizing solution, and its use in the processing of the noted materials.
BACKGROUND OF THE INVENTION
Multicolor, multilayer photographic elements are well known in the art. Such materials generally have three different selectively sensitized silver halide emulsion layers coated on one side of a single support. Each layer has components useful for forming a particular color in an image. Typically, they utilize color forming couplers that form yellow, magenta and cyan dyes in the sensitized layers during processing.
After color development, it is necessary to remove the silver image that is formed coincident with the dye image. This can be done by oxidizing the silver using a suitable oxidizing agent, commonly referred to as a bleaching agent, in the presence of a halide, followed by dissolving the silver halide so formed using what is known as a fixing agent. In some instances, the bleaching and fixing steps are combined into a single bleach-fixing step.
One commercially important process intended for use with color reversal photographic elements that contain color couplers in the emulsion layers, or layers contiguous thereto, uses the following sequence of processing steps: first developing, washing, reversal bath, color developing, bleaching, fixing, washing and stabilizing. Another useful process has the same steps, but stabilizing is carried out between color developing and bleaching.
In such photographic processes, a bleach-accelerator bath is often used between the color developing and bleaching steps. The bleach-accelerator bath is also known as a “conditioning” bath or solution. It is used to “condition” the metallic silver developed in the two developing steps, for complete oxidation to silver halide and to help preserve the acidity of the bleaching solution by reducing carryover of color developer into the bleaching solution. The conditioning solution contains, as an essential component, an effective amount of a bleach accelerating agent. This agent is imbibed into the emulsion layers of the photographic element during treatment with the conditioning bath, and is accordingly present to exert its intended effect when the element is put into the bleaching solution.
Magenta dye instability is a particularly undesirable problem in color photography, as the magenta dye image may fade more rapidly than either the cyan or yellow dye images. This is particularly evident when arylpyrazolone type magenta dye forming color couplers are used. Thus, considerable effort has been exerted to find solutions to this problem, including the use of dye stabilizers in stabilization baths at the end of the processing method, as described in U.S. Pat. No. 4,786,583 (Schwartz).
It is also known from U.S. Pat. No.4,921,779 (Cullinan et al), U.S. Pat. No. 4,975,356 (Cullinan et al) and U.S. Pat. No. 5,037,725 (Cullinan et al) that formaldehyde precursors can be incorporated into conditioning solutions to further improve magenta dye stability. These patents describe a number of formaldehyde precursors for this purpose including sodium formaldehyde bisulfite, hexamethylenetetramine and various methylol compounds.
Copending and commonly assigned U.S. Ser. No. 08/393,293 , filed Feb. 23, 1995, by Darmon et al and entitled “Photographic Conditioning Solution Containing Bleach Accelerator, Formaldehyde Precursor and Secondary Amine and Method of Use”, describes the use of a secondary amine in conditioning solutions to enable the amount of formaldehyde precursor to be reduced without compromising the effect of the solution to stabilize magenta dyes in color reversal materials.
There is a need to prevent biogrowth (bacteria, yeast and fungi) in the conditioning solution. When the various components of known conditioning solutions are adjusted to change effects or the pH is changed, the concern about biogrowth increases because conventional solutions tend to be free of biogrowth. Excessive biogrowth may have an undesirable odor, or leave a residue on processed film that affects the image. Thus, there is a need for an effective means for preventing such biogrowth at an acceptable cost and without sacrificing other desirable properties such as biodegradability and stabilization of the magenta coupler in the processed elements.
SUMMARY OF THE INVENTION
The problems noted above have been overcome using a conditioning solution having a pH of from about 4.5 to about 8, and comprising a bleach accelerating agent, a formaldehyde precursor, and an antimicrobial composition consisting essentially of a polyaminocarboxylic acid or salt thereof as the sole antimicrobial agent, the antimicrobial agent being present in the conditioning solution in an amount of less than about 3 g/l.
This invention also provides a method for processing a color reversal photographic element comprising:
A) treating an imagewise exposed and developed color reversal photographic element with the conditioning solution as described above, and
B) bleaching the treated element.
The present invention effectively provides a conditioning solution for the processing of color reversal materials that both stabilizes the magenta dye and provides bleach acceleration. In addition, this solution is suitably protected against biogrowth using a very small amount (≦3 g/l) of a polyaminocarboxylic acid (or salt thereof) as the sole antimicrobial agent. The antimicrobial agent is relatively inexpensive and because a limited amount is used, the conditioning solution is more suitable for the environment.
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Russell et al,Principles&Practice of Disinfection, Preservation&Sterilization, 1st Ed., 1982, p. 67.
Block,Disinfection, Sterilization&Perservation, 4th Ed., 1991, p. 39.
Badger John Stuart
Craver Mary Ellen
McGuckin Hugh Gerald
Bell Mark L.
Eastman Kodak Company
Pasterczyk J.
Tucker J. Lanny
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