Radiation imagery chemistry: process – composition – or product th – Color imaging process – Using identified radiation sensitive composition in the...
Reexamination Certificate
2003-05-30
2004-08-24
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Using identified radiation sensitive composition in the...
C430S385000, C430S387000, C430S389000, C430S543000, C430S544000, C430S505000, C430S955000, C430S553000, C430S555000, C430S558000
Reexamination Certificate
active
06780573
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a silver halide color photographic element containing a coupler moiety that does not form a permanent dye and that releases a photographically useful group (PUG) upon reaction with oxidized developer through an improved amino acid timing group. The coupler moiety may be contained in a light-sensitive silver halide emulsion layer or in an adjacent light-insensitive layer.
BACKGROUND OF THE INVENTION
It is well known in the photographic art to use coupling species to release photographically useful groups or PUG in an imagewise fashion upon reaction with oxidized developer. It is also well known in the art to use a so-called “timing group” (also sometimes referred to as a “linking group” or “switch”) as an intermediate fragment chemically bound between the coupling site and the PUG. Upon reaction with oxidized developer, the entire “timing group-PUG” fragment is released and subsequently decomposes to release the free PUG. A timing group can serve one or more of three purposes: it can delay the presence of the free PUG if the decomposition is slow; it can serve as a convenient way to attach the PUG to the coupling moiety; or it can serve to modify the overall performance or physical properties of the entire molecule.
Timing groups are particularly useful when the PUG is an inhibitor of silver development (INH). Couplers which release development inhibitors, either directly or through the use of an intermediate timing group, are typically referred to as development inhibitor releasers or DIRs. For DIRs that release an inhibitor directly without a timing group, the inhibitor fragment will reduce the silver development in the layer in which it is released, thereby reducing the speed and light sensitivity of that record. Any interimage effect (decreased development in other layers as a function of development in one layer) will be due to the inherent diffusibility of the inhibitor molecule.
When the DIR employs a timing group, diffusion of the ‘timing group-INH’ fragment away from the initial site of release and slow decomposition to free INH is useful for increasing the sharpness and degree of interimage of the film. The diffusion of the INH fragment improves sharpness by increasing the amount of chemical adjacency effects. Interimage, which is a change in the development of different color record as a function of exposure of one record, arises from diffusion of the INH generated by development in one color record into another. For both acutance and interimage, the greater the degree of diffusion away from the site of release, the greater are the improvements. In order to accomplish these purposes, it is generally assumed that neither the timing group nor the INH can contain a ballast group that would restrict diffusion. If the timing group is ballasted, then it will not diffuse far from the initial site of coupling and free INH will only be generated in the same vicinity. This leads to speed losses in the layer that contains the DIR. Ballasting of the INH fragment is also undesirable since the ballast group prevents diffusion of the INH into other layers, increases the inhibitor strength, and leads to silver retention after processing due to the formation of insoluble silver salts. It is necessary, however, that a DIR contain a ballast somewhere in the molecule prior to processing so that the entire molecule does not wander between layers in a film element. Thus, unballasted ‘timing group-INH’ fragments are typically used in combination with coupler moieties that are ballasted and form permanent dyes after coupling.
DIRs that form permanent dyes that contribute density to the color record after processing are commonly used in the appropriate color record for the color generated. For example, cyan DIRs are typically used in red sensitive layers with cyan image couplers, magenta DIRs are used in green sensitive layers with magenta image couplers, and yellow DIRs are used in blue sensitive layers with yellow image couplers. Although they can be used in any color record to create acutance and interimage effects, location in the wrong color record is inefficient due to color contamination from the parent coupler.
In some cases, it is desirable to release a PUG or an inhibitor in a particular color record from a coupler moiety that does not form a permanent dye in order to prevent color contamination. Coupler moieties that do not form a permanent dye and leave no or little residual color in the film after processing are generally known as ‘universal’ couplers because they may be used in any color record. There are two types of universal couplers—those that form a dye that is unstable under the processing conditions and that forms a colorless residue that remains in the film, or those that form a stable dye that is subsequently washed out or removed during processing. Universal couplers based on 2-carbamoyl-1-naphthol compounds with small or water-solubilizing groups substituents on the carbamoyl group are well known in the art, for example, see U.S. Pat. No. 5,932,407 and U.S. Pat. No. 6,083,675. Such 2-carbamoyl-1-naphthol-based universal couplers have been used as DIRs, for example, see U.S. Pat. No. 4,482,629 and U.S. Pat. No. 5,272,043. In such DIRs, however, it is necessary to locate the ballast group on the timing group since it is undesirable to ballast either the parent or the INH fragment. Thus, the timing group has limited mobility, and the benefits of diffusing the ‘timing group-INH’ fragment are not fully realized. For practical use, such ballasted timing groups are generally designed to release the INH fragment very quickly and without delay on the photographic timescale; thus, the ballasted timing group serves only as a temporary linking group, and the material performs as if there was direct release of INH. Any acutance and interimage improvements are the result of the inherent diffusivity of the INH fragment alone.
It should be noted that although such 2-carbamoyl-1-naphthols are often referred to as ‘wash-out’ type couplers, the mechanism is likely to be one of reaction of the initial formed cyan dye by sulfite ion present in the process to form colorless addition products which may or may not wash of the film depending on the nature of the film element. A discussion of the decolorization mechanism can be found in L. K. J Tong and R. L. Reeves, JACS, 84, 2050-7 (1962).
Timing groups based on amino acids are known. U.S. Pat. No. 4,857,440 describes the use of acyclic amino acid derivatives, including those derived from N-alkyl-alanines and 2-(methyl or ethyl)-N-phenyl-alanines, as timing groups. This reference teaches that having a “bulky” substituent in the amino acid next to the carbonyl provides increased resistance towards hydrolysis during long-term storage. U.S. Pat. No. 5,021,322 describes similar acyclic amino acid groups as part of a double timing group fragment. This reference solves the problem of ballast location on universal DIRs by using two linked timing groups, one which is ballasted together with an amino acid based timing group that is not. Such double-switched DIRs, however, are complicated and difficult to manufacture in an economical manner. U.S. Pat. No. 4,847,185 describes the use of cyclic amino acid derivatives as timing groups.
Japanese Kokai 6-175310 shows an example of a universal DIR that utilizes a ballasted 2,2-dimethyl-3-anilino-propionic acid based timing group (see p. 14, compound (8)). However, amino acid derivatives with alpha-dimethyl substitution such as 2,2-dimethyl-3-aminoproprionic acid or 2-alkyl-alanines are exceedingly difficult to esterify, presumably due to their steric hindrance. Therefore, the preparation of DIRs with this type of timing group is low yielding, leading to high cost and an undesirable manufacturing position.
A problem to be solved is to provide color photographic elements that exhibit improved photographic speed, acutance and interimage at low cost, and methods for processing such elements. In particular, it is desirable to provide color photographic elements
Grote Christopher W.
Poslusny Jerrold N.
Singer Stephen P.
Stewart Robert C.
Younathan Janet N.
Eastman Kodak Company
Letscher Geraldine
Meeks Roberts Sarah
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