Silver halide photographic material

Details Silver halide photographic material Silver halide photographic material

2001-02-22

2004-04-20

Baxter, Janet (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S567000, C430S569000

Reexamination Certificate

active

06723496

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a silver halide photographic material and, more particularly, to a highly sensitive silver halide photographic material utilizing a dopant art.
BACKGROUND OF THE INVENTION
There are known the arts of modifying silver halide grains so as to bring about improvements as intended in properties of a silver halide photographic material in its entirety. One of such arts is the art of incorporating a substance (a dopant) other than silver and halide ions into silver halide grains (the art of doping). In particular, many pieces of research have been done on the art of doping silver halide grains with transition metal ions. As a result, it is widely recognized that the photographic properties can be modified effectively by transition metal ions brought in silver halide grains as a dopant even if the ions are added in a very slight amount.
For increasing sensitivities of silver halide emulsions, it is known to utilize the arts of doping silver halide grains with not only transition metal ions but also transition metal complexes formed with cyanide ions as ligands. In particular, there are many disclosures regarding the emulsions increased in sensitivity by being doped with the group VIII metal complexes (in the periodic table) which each contain 6 cyanide ions as ligands. As dopants containing cyanide ions, for instance, JP-B-48-35373 (the term “JP-B” as used herein means an “examined Japanese patent publication”) discloses potassium ferrocyanide as a hexacyanoferrate(II) complex salt and potassium ferricyanide as a hexacyanoferrate(III) complex salt. In the reference described above, however, the sensitivity-increasing effect is confined to the cases using the iron ion-containing dopants, irrespective of the species of ligands. There are many other disclosures regarding emulsions acquiring high sensitivities by being doped with hexacyanoferrate(II) complex salts. For instance, such emulsions are disclosed in JP-A-5-66511 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) and U.S. Pat. No. 5,132,203. Further, highly sensitive emulsions doped with cyano-complexes besides iron complexes are known. For example, JP-A-2-20853 discloses that highly sensitive emulsions are obtained when silver iodochloride comprised therein are doped with cyano-rhenium complexes, cyano-ruthenium complexes, cyano-osmium complexes and cyano-iridium complexes respectively. Many of complexes formed by other metal ions are also used as dopants, and can produce not only the sensitivity increasing effect but also a wide variety of effects including improvement of reciprocity (law) failure and increasing contrast. U.S. Pat. No. 2,448,060 discloses that emulsions are sensitized when doped with platinum(II) or palladium(IV) complexes containing halogen ions as ligands. U.S. Pat. No. 3,790,390 describes the emulsions doped with cyano-cobalt(III) complex in addition to emulsions doped with cyano-iron(II) complexes and those doped with cyano-iron(III) complexes, and discloses silver halide emulsions containing spectral sensitizing dyes. The silver halide grains formed in the presence of a rhodium(III) complex having 3, 4, 5 or 6 cyano ligands are disclosed in U.S. Pat. No. 4,847,191. Those patents prove that the dopants can diminish high intensity reciprocity (law) failure. The silver halide emulsions doped with rhenium, ruthenium, osmium or iridium complexes having at least 4 cyano ligands are disclosed in European Patent 0,336,425, European Patent 0,336,426, and JP-A-2-20854. Therein, it is described that the doped emulsions are improved in storage stability of sensitivity and gradation, and improved in low intensity reciprocity (law) failure. European Patent 0,336,427 and JP-A-2-20852 disclose the silver halide emulsions doped respectively with six-coordinated vanadium, chromium, manganese, iron, ruthenium, osmium, rhenium and iridium complexes containing nitrosyl or thionitrosyl ligands. By the use of such complexes, those patents achieve improvement in low intensity reciprocity (law) failure without lowering medium illumination sensitivity. As to the dopants other than transition metal ions, the emulsions doped with bismuth or lead ions are disclosed in U.S. Pat. No. 3,690,888, and the emulsions containing the group XIII and XIV metal ions (in the periodic table) respectively are disclosed in JP-A-7-128778.
Among the ligands of complexes used as dopants, the most frequently used ligand is supposed to be cyanide ion, but halogen ions are also used frequently. As examples of dopant complexes having a [MCl
6
]
n−
structure, wherein M is an arbitrary metal, mention may be made of hexachlororuthenate, hexachloroiridate, hexachlororhodate and hexachlororhenate disclosed, e.g., in JP-A-63-184740, JP-A-1-285941, JP-A-2-20852 and JP-A-2-20855. Further, European Patent 0,336,689 and JP-A-2-20855 disclose as dopants the six-coordinated rhenium complexes formed with halogeno, nitrosyl, thionitrosyl, cyano, water or/and thiocyano ligands. Furthermore, as emulsions having useful photographic properties, the emulsion wherein is incorporated a six-coordinated transition metal complex having one carbonyl ligand and the emulsion wherein is incorporated a six-coordinated transition metal complex having two oxo ligands are disclosed in JP-A-3-118535 and JP-A-3-118536 respectively.
As described above, complexes used as dopants are various in their central metal ions and their ligands. In recent years have been disclosed the arts of reforming emulsions by doping the silver halide grains with complexes containing organic compounds as ligands. For instance, the use of various complexes containing organic compounds as ligands is disclosed in U.S. Pat. Nos. 5,360,712, 5,457,021 and 5,462,849, European Patent 0,709,724, JP-A-7-72569 and JP-A-8-179452. In these patents, it is described that sensitivity increasing effect becomes great in particular when [(NC)
5
Fe(&mgr;-4,4′-bipyridine)Fe(CN)
5
]
6−
is used for doping, while high intensity reciprocity (law) failure can be improved notably by using iridium complexes, such as [IrClr
5
(thiazole)]
2−
. JP-A-11-24194 makes the emulsions improved in both sensitivity and reciprocity (low) failure by using [Fe(CO)
4
(P(Ph)
3
)]
0
or [Fe(CO)
3
(P(Ph)
2
)]
0
for doping them. In addition, JP-A-11-102042 obtains highly sensitive emulsions when the complexes used as dopants are represented by formulae [M(CN)
5
L]
3−
(M=Fe
2+
, Ru
2+
, Ir
2+
), [Fe(CO)
4
L]
0
, [M′(CN)
3
L]
−
(M′=Pd
2+
, Pt
2+
) and [IrCl
5
L]
2−
respectively, and besides, the ligand L therein is 2-mercapto-benzimidazole, 5-methyl-s-triazolo(1,5-A)pyrimidine-7-ol or 2-mercapto-1,3,4-oxadiazole. Further, JP-A-10-293377 discloses emulsions doped with [RuCl
5
L′]
2−
(L′=imidazole, benzimidazole or a derivative thereof). Those emulsions have extremely increased contrast, and the sensitivities thereof are substantially increased, compared with those of the emulsions using dopants known to cause desensitization and increasing contrast. Almost all ligands present in the complexes used in the references described above form coordination bonds via their respective nitrogen atoms. On the other hand, there are few dopants forming coordination bonds via the oxygen atoms in their ligands, and no cases are known yet wherein the complexes forming coordination bonds via the oxygen atoms of ketone ligands are used as dopants.
When six-coordinated complexes having an octahedron structure are incorporated as dopants in silver halide grains, some units [AgX
6
]
−5
(X=halide ion) in the silver halide grains are replaced by the complex molecules as described in a large literature, including
J. Phys.: Condens. Matter,
9 (1997) 3227-2240, and many patents. In such replacement, it is supposed that the central metal ions occ

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