Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Process of preparing composition from plural preformed...
Reexamination Certificate
2001-05-21
2002-08-20
Le, Hao Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Process of preparing composition from plural preformed...
C430S467000
Reexamination Certificate
active
06436618
ABSTRACT:
COPENDING APPLICATION
Copending and commonly assigned U.S. Ser. No. 09/132,200 filed on Aug. 11, 1998 by Darmon et al.
Copending and commonly assigned U.S. Ser. No. 09/438,121 filed on Nov. 10, 1999 by Haye et al.
FIELD OF THE INVENTION
The present invention relates to a multi-part photographic color developing composition having two or three separate solutions that can be mixed together prior to or during use. This invention also relates to a method of manufacturing this multi-part photographic color developing composition, and to a method for its use. 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 (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.
In addition, multi-part color developing compositions may also be corrosive to low carbon steel that may be present in photoprocessing equipment. This corrosivity may also be a result of extremely high or low pH.
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.
SUMMARY OF THE INVENTION
This invention provides an advance in the art by solving the problems noted above. In particular, the present invention provides a multi-part color developing kit comprising:
(I) a first solution having a pH of from about 7 to about 12.5 and comprising:
(a) water,
(b) a color developing agent in free base form, the color developing agent being present in the first solution in an amount of at least 0.05 mol/l,
(c) at least 0.005 mol/l of an antioxidant for the color developing agent,
(d) water-miscible or water-soluble hydroxy-containing, straight-chain organic solvent for the color developing agent in free base form, the organic solvent having a molecular weight of from about 50 to about 200,
(e) at least 0.001 mol/l of a triazinylstilbene optical brightening agent, and
(f) a first chemical base,
(II) a second solution having a pH of from about 7 to about 12.5, and comprising:
(a) water,
(b) a buffering agent,
(c) a second chemical base, and
(d) at least 0.001 mol/l of a first phosphonic acid metal ion sequestering agent.
A method of making a multi-part color developing kit comprises:
(A) making a first solution to have a pH of from about 7 to about 12.5 by mixing in water, a color developing agent present as a sulfate salt, an antioxidant for the color developing agent, alkali metal ions in at least stoichiometric proportion to the sulfate salt, and a water-miscible or water-soluble hydroxy-containing, straight-chain organic solvent for the color developing agent in free base form, the organic solvent having a molecular weight of from about 50 to about 200, to form an alkali metal sulfate in the first solution,
B) removing the alkali metal sulfate from the first solution,
C) adding to the first solution a triazinylstilbene optical brightening agent, and
(D) making an aqueous second solution to have a pH of from about 7 to about 12.5 of a buffering agent, a second chemical base, and at least one phosphonic acid metal ion sequestering agent.
This invention also provides a color developing composition obtained by mixing the first and second solutions described above in an approximate 1:1 volume ratio.
Further, this invention includes a method for providing a color image in a color silver halide photographic element comprising contacting the element with the color developing composition described above that is prepared from the multi-part color developing kit. This color developing step in a photographic processing method can be followed by desilvering the color photographic silver halide element, as well as any other useful photoprocessing steps known in the art.
The color developing kit of this invention can also be provided as part of a photographic processing chemical kit that includes one or more other photographic processing single-part or multi-part photochemical processing compositions. Such compositions can include, but 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 and composition of this invention have a number of advantages. In particular, the various solutions can 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 a
Buongiorne Jean M.
Christ, Jr. Charles S.
Darmon Charles M.
Haight Michael J.
Kocher Barry C.
Eastman Kodak Company
Le Hao Van
Tucker J. Lanny
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