Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2000-06-08
2003-02-18
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S547000
Reexamination Certificate
active
06521400
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to silver halide photographic elements. In particular, it relates to color reversal photographic elements containing release compounds which provide a non-imagewise distribution of an image-modifying compound.
BACKGROUND OF THE INVENTION
Conventional color photographic images are formed via a chromogenic development process comprising reaction of oxidized silver halide developing agent and dye precursors known as color couplers. After exposure of a color photographic element, the object scene is typically stored as a composite of red, green and blue latent silver halide images. During processing, these images or related reversal silver halide images are reductively developed in presence of a phenylenediamine color developer. Oxidized developer produced under these conditions reacts with the conjugate base of cyan, magenta or yellow dye-forming couplers to give their respective dyes. The composite dye image is then formed by the superpositioning of the cyan, magenta and yellow dye images to afford a reproduction of the original scene.
Color reproduction and image sharpness are important features of photographic reproductions. The color reproduction of conventional photographic system is primarily controlled by the hues of the cyan, magenta and yellow dyes that comprise the color image. Such image dyes, while generally reproducing a wide range of colors accurately, are never ideal; imperfections in the spectral characteristics of these dyes lead to degraded color reproduction. Thus, a yellow dye that absorbs too much green light appears orange and cannot effectively reproduce bright yellows, e.g. lemons. This yellow dye in combination with an effective magenta dye affords desaturated red colors, e.g. flowers or textiles.
In forming photographic images, it has become relatively common practice in the art to incorporate image-modifying compounds into either the developing solutions or the photographic materials themselves. These image-modifying compounds can impact such photographic properties as sharpness, granularity, contrast and color reproduction. Major changes in color reproduction can be obtained via alterations in the chemical nature of the image dye couplers, but a more subtle color correction mechanism is often employed: interlayer interimage effects (IIE). IIE occurs when the development process of one color record changes that of one or more of the other records. The most typical application of IIE for color correction is to inhibit the formation of one dye in response to the formation of another. In the case of the de-saturated red colors mentioned above, the imperfect yellow dye absorbs some green light, thus, less than a theoretical amount of magenta dye is needed for adequate red color reproduction. During the design of modern films, mechanisms for such IIE's have been perfected. Most typically a development inhibitor, perhaps iodide from the emulsion or an organic development inhibitor derived from a development. inhibitor releasing (DIR) coupler, are produced in one layer (the causing layer); this inhibitor, upon migration to another imaging layer (the receiver layer), suppresses development to eventually yield the desired color reproduction effect.
Negative materials are processed, after image exposure, directly with a chromogenic developer which color-develops the negative exposed areas. Positive dye image-forming reversal photographic materials, on the other hand, after imagewise exposure, are first processed with a black-and-white developer which develops a silver image in the negative exposed areas. This is followed by a reversal fogging step (e.g., a second overall exposure or a chemical fogging step) and then development with a chromogenic developer to form a positive color image. In negative dye image-forming photographic materials, interimage effects are always obtained during chromogenic development. In positive dye image-forming reversal photographic materials, interimage effects are generally obtained during processing by the release in the first black-and-white developer of a development inhibitor as a function of the silver development of the image-forming layers. The most generally used development inhibitor consists of iodide ions released as a result of the development of silver haloiodide, for example, silver bromoiodide emulsions.
In some color reversal films IIE's derived from inhibition in the black-and-white development step can be amplified via the inclusion of certain chemical addenda; often 4-carboxymethyl-2-mercaptothiazole (CMMT, CAS #36365-79-4) or related compounds are employed in this manner.
Frequently the beneficial effects of the presence of silver development inhibitors comes with a loss in photographic speed, due to losses incurred during the inhibition of emulsion development or via the interaction of the coated inhibitor with the photographic emulsion. The inclusion of CMMT or similar development inhibitors in color reversal films improves the color reproduction and sharpness of the image but with a substantial speed penalty. Direct incorporation of image-modifying compounds into photographic materials also often leads to unacceptable image reproduction as such compounds can prematurely interact with other components of the photographic elements, or can decompose during shelf keeping. Thus, methods for the incorporation of development inhibitors into photographic films that circumvent these disadvantage are of particular interest.
It has become accepted to attach image-modifying compounds to coupler moieties and to have them released in an imagewise manner during development of the photographic material. This, however, has the dual disadvantage of requiring image formation (as the coupler moiety reacts with oxidized developer) whenever the presence of an image-modifying compound is desired, and of providing only an imagewise release of the image-modifying compound. Materials that afford imagewise delivery of inhibitors during reversal black and white development, often termed inhibitor releasing developers (IRD's), have also been described previously (e.g. U.S. Pat. Nos. 4,636,456, 5,210,012, 5,310,638, 5,541,044,5,578,441, and 5,756,274; JP Kokai 11-327102). While potentially providing valuable photographic improvements, the useful embodiments of this technology are disadvantageous in two regards. Firstly, these compounds are oxidatively unstable, shortening product shelf life. Aerial oxidation of IRD's, during film storage, can initiate a chain of reactions leading to the premature release of development inhibitor that degrades photographic behavior. This is similar to the disadvantage of direct incorporation of development inhibitors describe above. Secondly, the imagewise delivery of the inhibitor by oxidative consumption of the IRD during development, by its very mechanism, necessitates the presence of residual IRD in the film after development. This residue when carried into the color developer can itself afford two disadvantages. First, the IRD can reductively consumed oxidized color developer leading to reduced image dye formation. In the second place, the residual IRD now provides delivery of a development inhibitor during the color development step; this release can limit or slow chromogenic development perhaps leading to reduced image dye formation or to an increased sensitivity of the film to processing solution variability.
There are known alternative means for incorporating image-modifying compounds into various types of photographic materials. Image modifying compounds have been inactivated by blocking as disclosed in, for example, U.S. Pat Nos. 3,674,478, 4,350,752, 4,478,929, 4,684,604, 5,019,492, 5,116,717, and 5,567,577; EP 0 255 085; and JP Kokai 7-311437. Although some of the blocked or timed inhibitors known in the art are capable of impacting photographic properties primarily during the initial black and white development step of reversal processing, at certain levels or in certain photographic elements, the may be inadequate for com
Dannhauser Thomas J.
Knight Phillip D.
Welter Thomas R.
Anderson Andrew J.
Le Hoa Van
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