Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2001-12-11
2003-02-11
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S551000, C430S567000, C430S569000, C430S607000, C430S610000, C430S617000, C430S639000
Reexamination Certificate
active
06518007
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to silver halide elements containing solubilized antifoggants. More specifically it relates to silver halide elements containing solubilized antifoggants and a high bromide emulsion containing low fogging tabular silver halide grains. In one embodiment the silver halide grains are precipitated in a low pH environment.
BACKGROUND OF THE INVENTION
Problems with fogging have plagued the photographic industry from its inception. Fog is a deposit of silver or dye that is not directly related to the image-forming exposure, i.e., when a developer acts upon an emulsion layer, some reduced silver is formed in areas that have not been exposed to light. Fog can be defined as a developed density that is not associated with the action of the image-forming exposure, and is usually expressed as “D-min”, the density obtained in the unexposed portions of the emulsion. Density, as normally measured, includes both that produced by fog and that produced as a function of exposure to light. It is known in the art that the appearance of photographic fog related to intentional or unintentional reduction of silver ion (reduction sensitization) can occur during many stages of preparation of the photographic element including silver halide emulsion preparation, spectral/chemical sensitization of the silver halide emulsion, melting and holding of the liquid silver halide emulsion melts, subsequent coating of silver halide emulsions, and prolonged natural and artificial aging of coated silver halide emulsions. The chemicals used for preventing fog growth as a result of aging or storage are generally known as emulsion stabilizers.
The control of fog, whether occurring during the formation of the light-sensitive silver halide emulsion, during the spectral/chemical sensitization of those emulsions, during the preparation of silver halide compositions prior to coating on an appropriate support, or during the aging of such coated silver halide compositions, has been attempted by a variety of means. Mercury-containing compounds such as those described in U.S. Pat. Nos. 2,728,663; 2,728,664; and 2,728,665 have been used as additives to control fog. Thiosulfonates and thiosulfonate esters such as those described in U.S. Pat. Nos. 2,440,206; 2,934,198, 3,047,393, and 4,960,689 have also been employed. Organic dichalcogenides, for example, the disulfide compounds described in U.S. Pat. Nos. 1,962,133; 2,465,149; 2,756,145, 2,935,404; 3,184,313; 3,318,701; 3,409,437; 3,447,925; 4,243,748; 4,463,082, and 4,788,132 have been used not only to prevent formation of fog, but also as desensitizers and as agents in processing baths and as additives in diffusion transfer systems
Recently there has appeared in the patent literature art that describes the precipitation of silver halide photographic emulsions in a peptizer, cationic waxy starch , which departs substantially from the traditionally used medium, gelatin. These starch precipitated emulsions may be unique in their ability to tolerate the use of powerful oxidants such as elemental bromine or else very low pH used during the precipitation (U.S. application Ser. No. 09/731,454 “PREPARATION OF HIGH CHLORIDE PHOTOGRAPHIC EMULSIONS WITH STARCH PEPTIZER”, Ser. No. 09/731,454 “PREPARATION OF HIGH BROMIDE PHOTOGRAPHIC EMULSIONS WITH STARCH PEPTIZER AND OXIDIZING AGENT”, and Ser. No. 09/731,446 “PREPARATION OF HIGH BROMIDE PHOTOGRAPHIC EMULSIONS WITH STARCH PEPTIZER” of Maskasky, all filed Dec. 7, 2000). Oxidized cationic starches are advantageous in exhibiting lower levels of viscosity than gelatino-peptizers. This facilitates mixing. Under comparable levels of chemical sensitization higher photographic speeds can be realized using cationic starch peptizers. Alternatively, speeds equal to those obtained using gelatino-peptizers can be achieved at lower precipitation and/or sensitization temperatures, thereby avoiding unwanted grain ripening. The starch peptized emulsions, when precipitated under certain conditions, also exhibit low Dmins, presumably as a consequence of either the removal of or the prevention of metallic silver center formation which gives rise to primitive emulsion fog. The use of cationic starch as a peptizer for the precipitation of high bromide {111} tabular grain emulsions is taught by Maskasky in U.S. Pat. Nos. 5,604,085; 5,620,840; 5,667,955, 5,691,131; and 5,733,718.
Starch peptized emulsions precipitated either at low pH or else in the presence of bromine or a bromine precursor appear particularly well suited for use with very active chemistries such as fragmental electron donors, FEDs (J. E. Maskasky et. al U.S. Pat. No. 6,090,536), one equivalent yellow couplers (J. E. Maskasky et. al U.S. Pat. No. 6,225,036), light scattering particles (J. E. Maskasky et. al U.S. Pat. No. 6,027,869), and combinations of these chemistries. These active chemistries, however, tend to amplify image and fog. While the use of the starch peptized emulsions may provide a good initial Dmin position, further fog reduction is necessary to in order to obtain the maximum imaging performance.
SUMMARY OF THE INVENTION
This invention provides a multicolor silver halide photographic element comprising a support and at least one high bromide silver halide emulsion layer comprising low fogging tabular silver halide grains, said element further comprising an antifoggant represented by the following Structure I:
R
1
—SO
2
—C(R
2
)R
3
—(CO)
m
—(L)
n
—SG I
wherein R
1
is an aliphatic or cyclic group, R
2
and R
3
are independently hydrogen or bromine as long as at least one of them is bromine, L is a divalent linking group, m and n are independently 0 or 1 and SG is a solubilizing group that has a pKa of 8 or less.
This invention further provides silver halide elements with an unexpected improvement in the fog position of already quite clean or low fog emulsions, particularly starch precipitated emulsions. These improvements translate to substantial imaging advances as measured by speed and image structure (granularity) metrics.
DETAILED DESCRIPTION OF THE INVENTION
The silver halide photographic elements of this invention include one or more water-soluble or water-dispersible antifoggants containing a solubilizing group with a pKa of 8 or less. These compounds are represented by the following Structure I.
R
1
—SO
2
—C(R
2
)R
3
—(CO)
m
—(L)
n
—SG I
wherein R
1
is a substituted or unsubstituted aliphatic or cyclic group of any size as long as the antifoggant remains soluble or readily dispersible in water. Substituted or unsubstituted aliphatic groups for R
1
include monovalent groups having 1 to 20 carbon, nitrogen, sulfur, and oxygen atoms in the chain including, but not limited to, chains that include one or more substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, substituted or unsubstituted alkenylene groups having 2 to 20 carbon atoms, substituted or unsubstituted alkylenearylene groups having 7 to 20 carbon atoms in the chain, and combinations of any of these groups, as well as combinations of these groups that are connected with one or more amino, amido, carbonyl, sulfonyl, carbonamido, sulfonamido, thio, oxy, oxycarbonyl, oxysulfonyl, and other connecting groups that would be readily apparent to one skilled in the art. The various types of useful aliphatic groups would be readily apparent to one skilled in the art. Preferred aliphatic groups for R
1
include substituted or unsubstituted t-butyl groups and trifluoromethyl groups.
R
1
can also be substituted or unsubstituted cyclic groups including substituted or unsubstituted carbocyclic aryl groups having 6 to 14 carbon atoms to form the cyclic ring, substituted or unsubstituted cycloalkylene groups (having 5 to 10 carbon atoms to form the cyclic ring), and heterocyclic groups (having 5 to 10 carbon, nitrogen, sulfur, or oxygen atoms to form the cyclic ring), both aromatic and non-aromatic. The various types of cyclic groups would be readily apparent to one skilled in the art.
Preferred cyclic groups for R
1
include substitute
Burgmaier George J.
Keevert John E.
Klaus Roger L.
Reed Kenneth J.
Eastman Kodak Company
Meeks Roberts Sarah
Schilling Richard L.
LandOfFree
Silver halide elements containing solubilized antifoggants... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver halide elements containing solubilized antifoggants..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver halide elements containing solubilized antifoggants... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3118111