Silver halide photographic material

Details Silver halide photographic material Silver halide photographic material

2002-12-04

2004-09-21

Letscher, Geraldine (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S576000, C430S577000, C430S581000, C430S583000, C430S584000, C430S588000, C430S567000, C430S599000, C430S603000

Reexamination Certificate

active

06794122

ABSTRACT:

FILED OF THE INVENTION
The present invention relates to a silver halide photographic emulsion and to a silver halide photographic material that contains the emulsion. More precisely, the invention relates to a silver halide photographic emulsion of good dissolution-storage stability, and to a silver halide photographic material that contains the emulsion, having the advantages that its sensitivity is high, its graininess is good, it is free from residual color even when processed rapidly, and its storage stability is good.
BACKGROUND OF THE INVENTION
It is known that sensitizing dyes for spectral sensitization of silver halide photographic materials have significant influences on the properties of the materials containing them. For example, some mere difference in the structure of sensitizing dyes may have significant influences on the photographic properties such as sensitivity, fog, storage stability, residual color after processed and graininess of photographic materials that contain any of such sensitizing dyes. Combining at least two different types of sensitizing dyes to be in photographic materials also has significant influences on the photographic properties of the materials. However, it is difficult to forecast the results of the sensitizing dyes used in photographic materials. Heretofore, accordingly, many scholars have produced many different types of sensitizing dyes and have tried many their combinations for investigating their influences on the photographic properties of photosensitive materials that contain any of them or their combinations. At present, however, it is still impossible to accurately forecast the influences of different types of sensitizing dyes on the photographic properties of photosensitive materials that contain any of them.
The recent tendency in the art is toward photographic materials of high sensitivity capable of forming high-quality images, while, on the other hand, it is much desired to rapidly process photographic materials and to reduce processing wastes so as not to cause environmental pollution. In particular, a technique of spectral sensitization of silver halide grains in photographic materials is being more and more important for making them have an increased sensitivity with no defects of fog and residual color in the processed photographic materials.
Tabular photographic grains are preferred for spectral sensitization, since they have a large surface area (specific surface area) relative to their volume and can therefore adsorb a larger amount of sensitizing dye molecules. Therefore, tabular grains are effective for improving the ratio of sensitivity/graininess of photographic materials containing them. After processed, however, color-sensitized tabular grains leave much residual color in the processed materials, and the problem of residual color from color-sensitized tabular grains is more serious than that from color-sensitized regular grains.
On the other hand, it is desired to shorten the time for processing photographic materials. However, when color-sensitized photographic materials are processed rapidly within a short period of time, then the amount of the sensitizing dye that remains in the processed emulsion increases and the problem of residual color in the rapidly processed photographic materials is more serious. Accordingly, a technique of reducing residual color in processed photographic materials is much desired in the art of photography.
Regarding the means of solving the problem of residual color in processed photographic materials, it is known that sensitizing dyes of increased hydrophilicity are effective for solving the problem. In general, however, sensitizing dyes of higher hydrophilicity are more poorly adsorbed by silver halide grains, and their negative influences on the photographic properties of the silver halide grains that have poorly adsorbed them are inevitable in that the sensitivity of the silver halide grains could not be increased so much. Accordingly, the ability of such sensitizing dyes of increased hydrophilicity to solve the problem of residual color in processed photographic materials is limited.
On the other hand, when a large amount of sensitizing dye is added to tabular silver halide grains, the grains adsorb many dye molecules and the dye molecules cover the grains to a great extent. Thus much covering the tabular grains, the sensitizing dye molecules detract from the protective colloidal property of gelatin around the tabular grains. Of the tabular grains, in particular, those having a higher aspect ratio readily contact with each other at their main face to aggregate into large aggregates. Accordingly, it has been clarified that, while the emulsion is dissolved in time, there occur various side effects of fog increase, sensitivity reduction and graininess reduction. To solve the problem, for example, there is known a method of adding an emulsion of substantially insoluble fine silver iodobromide grains to the tabular silver halide grain. emulsion while or after the tabular silver halide grain emulsion is chemically sensitized; as in JP-A 6-332091 (The term “JP-A” as used herein means an unexamined published Japanese Patent Application”). However, this method is not always applicable to any and every emulsion. For example, it could not be applied to a silver chloride-rich emulsion (i.e., a high silver chloride emulsion). Therefore, any other method substitutable for it is desired.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a silver halide photographic emulsion of good dissolution-storage stability, and to provide a silver halide photographic material that contains the emulsion, having the advantages that its sensitivity is high, its graininess is good, it is free from residual color even when processed rapidly, and its shelf life is good.
Having assiduously studied, the present inventors have found that the object matter of the present invention can be attained by the following:
(1) A silver halide photographic material comprising a support having thereon at least one silver halide photographic emulsion layer, wherein the emulsion layer contains at least one compound selected from the group consisting of compounds represented by formulae (Ia), (Ib) and (Ic) and at least one compound represented by formula (II):
In formulae (Ia) (Ib) and (Ic), Z
1
represents a sulfur, oxygen, selenium, tellurium, nitrogen or carbon atom; R represents an optionally-substituted alkyl, aryl or heterocyclic group; D represents a group necessary for forming the methine dye; V
1
, V
2
, V
3
and V
4
each represent a hydrogen atom or a monovalent substituent; M represents a charge-balancing counter ion; and m indicates a number of 0 or more necessary for neutralizing the charge of the molecule.
In formula (II), Z
31
and Z
32
each represent an atomic group necessary for forming the nitrogen-containing hetero-ring that may be optionally condensed with any other ring and may be optionally substituted; R
31
and R
32
each represent an alkyl, aryl or heterocyclic group; L
31
, L
32
, L
33
, L
34
, L
35
, L
36
and L
37
each represent a methine group; p
31
and p
32
each indicate 0 or 1; n
3
indicates 0, 1, 2, 3 or 4; M
3
represents a charge-balancing counter ion; m
3
indicates a number of 0 or more necessary for neutralizing the charge of the molecule; but the compound of formula (II) does not include the compounds of formulae (Ia), (Ib) and (Ic).
(2) The silver halide photographic material of above (1), wherein D in formulae (Ia), (Ib) and (Ic) is a group necessary for forming a merocyanine dye or a cyanine dye.
(3) The silver halide photographic material of above (1), wherein D in formulae (Ia), (Ib) and (Ic) is a group necessary for forming a cyanine dye.
(4) The silver halide photographic material of any of above (1) to (3), wherein D in formulae (Ia), (Ib) and (Ic) is D
1
represented by the following formula:
In D
1
, R
12
represents an alkyl, aryl or heterocyclic group; z
11
represents an atomic group necessary for forming the nitrogen-containing hetero-ring

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