Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
2001-08-16
2003-02-11
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
Reexamination Certificate
active
06518003
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a three-part photographic color developing kit having three separate concentrated solutions that can be mixed together prior to or during use to form a homogeneous working strength color developing composition. This invention also relates to a method of using these three solutions to provide color photographic images. 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 a 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 (typically alkaline) used in a photographic processing bath must lie 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.
While multi-part color developing compositions are widely used in the photoprocessing industry (including in what are known as “minilabs”), they are sometimes supplied in containers that are not completely emptied during use. The residual solutions must therefore be discarded into the environment. In some countries, any of these solutions having extremely low or high pH are considered hazardous wastes and require more costly and tedious disposal procedures.
To the unskilled person in the art, a simple solution to the problems would be to adjust pH so the solutions are no longer considered hazardous or corrosive. However, as pointed out above, this is not a simple matter and requires expert and complicated balancing of various components and pH to maintain stability and photochemical activity. As the number of “parts” and components in each increase, the number of possible modifications increases correspondingly, making it even harder to find the truly viable (that is commercial) options that will solve all of the problems simultaneously.
U.S. Pat. No. 6,136,518 (Buongiome et al.) describes two- and three-part color developing kits that solve the problems noted above. These kits are designed to be safely handled and disposed of because they are less hazardous than conventional solutions. The resulting color developing composition can be readily prepared by mixing the multiple solutions in a safe manner. In addition, the various “parts” are less corrosive to low-carbon steels they may contact during use.
Formulating various solutions of the kit in a certain manner, especially to provide concentrates, is critical in order to prevent the formation of precipitates either in those solutions or in the eventual color developing composition formed when all solutions are mixed.
There continues to be a need for concentrated three-part color developing compositions that can be used in various processing equipment and methods without concern for precipitation and loss in sensitometric properties.
SUMMARY OF THE INVENTION
This invention provides an advance in the art with a three-part color developing kit comprising:
(I) a first concentrated aqueous solution having a pH of from about 11 to about 13.5 and comprising:
(a) at least 0.25 mol/l of sulfite ions,
(b) at least 2.5×10
−5
mol/l of iodide ions,
(c) at least 0.05 mol/l of bromide ions, and
(d) at least 0.5 mol/l of a buffer having a pKa of from about 11 to about 13.5,
(II) a second concentrated aqueous solution having a pH of from about 3 to about 6 and comprising:
(a) at least 1 g/l of a vinyl pyrrolidone polymer, and
(b) at least 0.05 mol/l of an organic antioxidant, and
(III) a third concentrated aqueous solution having a pH of from about 1 to about 3 and comprising:
(a) at least 0.05 mol/l of a color developing agent, and
(b) at least 0.005 mol/l of sulfite ions.
This invention also provides a method of making a working strength color developing composition from the three concentrated aqueous solutions noted above comprising:
(A) combining the first, second, and third concentrated aqueous solutions noted above in such a manner that the volume ratio of the first concentrated aqueous solution to the second concentrated aqueous solution is from about 1:1 to about 1.5:1, the volume ratio of the first concentrated aqueous solution to the third concentrated aqueous solution is from about 1:1 to about 1.5:1, and the volume ratio of the second concentrated aqueous solution to the third concentrated aqueous solution is from about 1:1 to about 1.5:1, and,
B) simultaneously or subsequently, diluting the first, second, and third concentrated aqueous solutions with water in such a manner as to dilute the first concentrated aqueous solution at least 8 times, the second concentrated aqueous solution at least 10 times, and the third concentrated aqueous solution at least 10 times.
Further, this invention includes a method for forming a color image comprising contacting an imagewise exposed color photographic silver halide material with the working strength color developing composition noted above.
In preferred embodiments, the color developed color photographic silver halide material can be desilvered using one or more desilvering processing compositions without removing the material from the working strength color developing composition.
The three-part color developing kit of this invention can also be provided as part of a larger photographic processing chemical kit that includes one or more other photographic processing single-part or multi-part photochemical processing compositions. Such photochemical processing compositions can include, but are not limited to, a photographic bleaching composition, a photographic bleach/fixing composition, a photographic fixing composition, and a photographic stabilizing or final rinsing composition.
The color developing kit of
Haye Shirleyanne E.
Huston Janet M.
No associations
LandOfFree
Three-part concentrated photographic color developing kit... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Three-part concentrated photographic color developing kit..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-part concentrated photographic color developing kit... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3158200