Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
2002-12-18
2004-02-10
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C552S553000, C552S304000, C552S304000
Reexamination Certificate
active
06689551
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a silver halide photographic element containing a phenolic coupler with a carbonamido group in the 2-position and a carbonamido group in the 5-position the latter bearing a strong electron withdrawing group(s), said phenolic coupler capable of forming a magenta dye when reacted with oxidized photographic color developer.
BACKGROUND OF THE INVENTION
In silver halide based color photography, a typical photographic element contains multiple layers of light-sensitive photographic silver halide emulsions coated on a support with one or more of these layers being spectrally sensitized to each of blue light, green light and red light. The blue, green, and red light-sensitive layers typically contain yellow, magenta, and cyan dye-forming couplers, respectively. After exposure to light, color development is accomplished by immersing the exposed material in an aqueous alkali solution containing an aromatic primary amine color-developing agent. The dye-forming couplers are selected so as to react with the oxidized color developing agent to provide yellow, magenta and cyan dyes in the so called subtractive color process to reproduce their complementary colors, blue, green and red as in the original image.
The important features for selecting the dye-forming coupler include, efficient reaction with oxidized color developing agent, thus minimizing the necessary amounts of coupler and silver halide in the photographic element; the formation of dyes with hues appropriate for the photographic use of interest, for color photographic paper applications this requires that dyes have low unwanted side absorption leading to good color reproduction in the photographic print; minimization of image dye loss contributing to improved image permanence under both ambient illumination and conventional storage conditions; and in addition the selected dye-forming coupler must exhibit good solubility in coupler solvents, provide good dispersibility in gelatin and remain stable during handling and manipulation for maximum efficiency in manufacturing processes.
In recent years, a great deal of study has been conducted to improve dye-forming couplers for silver halide photosensitive materials in terms of expanded coupler types, improved color reproducibility and image dye stability. However, further coupler types and improvements are needed. In general, cyan dyes are formed from naphthols and phenols as described, for example, in U.S. Pat. Nos. 2,367,351, 2,423,730, 2,474,293, 2,772,161, 2,772,162, 2,895,826, 2,920,961, 3,002,836, 3,466,622, 3,476,563, 3,552,962, 3,758,308, 3,779,763, 3,839,044, 3,880,661, 3,998,642, 4,333,999, 4,990,436, 4,960,685, and 5,476,757; in French patents 1,478,188 and 1,479,043; and in British patent 2,070,000. More recently, cyan couplers based on 2,5-diacylaminophenols in Lau et al., in U.S. Pat. No. 5,686,235, and Begley et al., in U.S. Pat. Nos. 6,387,606, 6,251,575, 6,207,363, 6,201,125, 6,197,492, 6,197,491, 6,197,490, 6,197,489, 6,194,132, 6,190,850, 6,180,331, 6,180,328, and 6,132,947 form highly desirable cyan narrow bandwidth dyes with improved light and dark stabilities, and less unwanted green absorption. On the other hand, magenta couplers are generally formed from pyrazolones and pyrazolotriazoles as described, for example in U.S. Pat. Nos. 5,262,292, 5,925,503, 5,972,587, 5,985,533 and 4,540,654. Both the cyan and magenta types of couplers can be used either by being incorporated in the photographic silver halide emulsion layers or externally in the processing baths. In the former case the couplers must have ballast substituents built into the molecule to prevent the couplers from migrating from one layer into another. Although these couplers have been used extensively in color photographic film and paper products, the dyes derived from them still suffer from poor stability to heat, humidity or light, low coupling efficiency or optical density, and in particular from undesirable blue and green absorptions which cause considerable reduction in color reproduction and color saturation.
The hue of a dye is a function of both the shape and the position of its spectral absorption band. Traditionally, the magenta dyes used in color photographic papers have had nearly symmetrical absorption bands centered in the region of 530 to 560 nm, more typically in the region of 540 to 555 nm. Such dyes have rather large amounts of unwanted absorption in the blue and red regions of the spectrum.
More desirable would be a dye whose absorption band could be adjusted so as to tune the slope of the curve on both the short and long wavelength sides of the absorption curve. The half-bandwidth on the short side of the curve, also called the left half-bandwidth or LBW, and the half-bandwidth on the long side of the curve, also called the right half-bandwidth or RBW are both desirably narrowed. Such a dye would suitably peak at 550 nm, but the exact position of the desired peak depends on several factors including the degree of asymmetry and the shapes and positions of the absorption bands of the cyan and yellow dyes with which it is associated.
Phenolic couplers invariably react with oxidized color developer to form cyan dyes exhibiting a range of absorption maxima, bandwidths and general curve shapes. The &lgr;
max
, or wavelength of maximum absorption, for phenolic couplers usually lies in the red region of the visible spectrum in the range of 590 nm to 680 nm, but more usually between 620 nm and 650 nm. These couplers are highly desirable in the photographic industry because the starting materials needed to prepare them are readily available, they are inexpensive, and they provide dyes with such a wide range of features to choose from.
The introduction of changes to the phenolic coupler, which would provide dyes other than cyan when reacted with oxidized color developer, would be highly desirable. In particular, shifting the absorption curve of the dye or its &lgr;
max
from the red region of the visible spectrum 590-680 nm, into the green region of the spectrum, 530-585 nm, to provide a magenta dye would be very advantageous. Readily available and inexpensive phenols would then provide a common source of two of the dyes used in the photographic industry with a significant cost savings, thus eliminating the need for the more expensive and more difficult to manufacture magenta dye yielding pyrazolone and pyrazolotriazole based couplers.
One way to shift the &lgr;
max
of a dye is through the careful selection and location of substituents on the dye's chromophore. Although individual electron-withdrawing or electron-donating substituents directly attached to the chromophore of a dye is known to affect the dye hue, by shifting the &lgr;
max
to either shorter or longer wavelength, such shifts are usually small. Shifts induced by electron-withdrawing or electron-donating substituents rarely move the dye absorption from one region of the visible spectrum to another. However, the effect of introducing a group of carefully selected electron-withdrawing or electron-donating substituents at specific locations on the dye is unknown.
Begley et al., in co-pending application Ser. No. 10/060,691 filed Jan. 30, 2002, Infrared Couplers for Incorporating and Recovering Metadata, discloses couplers with a 5-carbonamido group, specifically a substituted 5-benzoamido group containing 1 to 4 fluoro substituents. Begley et al., teaches infrared couplers with no reference to phenolic magenta couplers.
Ishii et al., U.S. Pat. No. 5,585,227 suggests certain phenolic couplers having electron withdrawing groups and teaches the use of such couplers as cyan couplers for use in a red-sensitive layer for reducing stains upon processing. There is no indication that said couplers are useful as magenta dye forming couplers in the green-sensitive layer.
Iwasaki et al., U.S. Pat. No. 6,156,489 suggests certain phenolic couplers having an electron withdrawing group with a branched &agr;-alkyl substituent on the 2-carbonamido group and teaches the use of such couplers as cyan
Begley William J.
Russo Gary M.
Triguel Mathilde R.
Eastman Kodak Company
Kluegel Arthur E.
Letscher Geraldine
LandOfFree
Photographic element, compound, and process does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photographic element, compound, and process, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photographic element, compound, and process will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3298189