Silver halide photographic material Number:6,828,087 from the United States Patent and Trademark Office (PTO) owispatent A silver halide photographic material comprising at least one methine dye of formula (I) and at least one coupler of formula (X): ##STR1##wherein X.sup.1 and X.sup.2 each represents O, S, Se, Te, N or C; Y.sup.1 represents a furan, pyrrole or thiophene ring which may be condensed and substituted with the specific ring; Y.sup.2 represents an atomic group necessary for forming a benzene ring or a 5- or 6-membered unsaturated heterocycle; R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, aryl or heterocyclic group; L.sup.1, L.sup.2 and L.sup.3 each represents a methine group; n.sup.1 represents 0 or 1; M.sup.1 represents a counter ion; and m.sup.1 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR2##wherein Z.sup.1 and Z.sup.2 each represents --C(Q3).dbd. or --N.dbd.; Q.sup.1 and Q.sup.3 each represents a hydrogen atom or a monovalent substituent group; Q.sup.2 represents a hydrogen atom or a coupling release group.<H photographic, material, Silver, halide, p, 6828087.html, Patent, pto, 6828087

Title: Silver halide photographic material

Abstract: A silver halide photographic material comprising at least one methine dye of formula (I) and at least one coupler of formula (X): ##STR1##wherein X.sup.1 and X.sup.2 each represents O, S, Se, Te, N or C; Y.sup.1 represents a furan, pyrrole or thiophene ring which may be condensed and substituted with the specific ring; Y.sup.2 represents an atomic group necessary for forming a benzene ring or a 5- or 6-membered unsaturated heterocycle; R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, aryl or heterocyclic group; L.sup.1, L.sup.2 and L.sup.3 each represents a methine group; n.sup.1 represents 0 or 1; M.sup.1 represents a counter ion; and m.sup.1 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR2##wherein Z.sup.1 and Z.sup.2 each represents --C(Q3).dbd. or --N.dbd.; Q.sup.1 and Q.sup.3 each represents a hydrogen atom or a monovalent substituent group; Q.sup.2 represents a hydrogen atom or a coupling release group.

Patent Number: 6,828,087 Issued on 12/07/2004 to Nakamura

Inventors: Nakamura; Tetsuo (Kanagawa, JP)
Assignee: Fuji Photo Film Co., Ltd. (Kanagawa, JP)

Appl. No.: 251841

Filed: September 23, 2002

Foreign Application Priority Data


Sep 26, 2001 [JP]			P.2001-293949

Current U.S. Class: 430/558 ; 430/552; 430/553; 430/570; 430/577; 430/578; 430/579; 430/581; 430/582; 430/583; 430/584; 430/585; 430/586; 430/587; 430/588; 430/589; 430/590

Current International Class: G03C 7/30 (20060101)

Field of Search: 430/550,552-3,570,577-579,581-590,558

References Cited [Referenced By]

U.S. Patent Documents


5057406	October 1991	Usagawa et al.
5061618	October 1991	Parton et al.
5457022	October 1995	Hioki et al.
2002/0058216	May 2002	Nakamura et al.

Foreign Patent Documents


2000-63690	Feb., 2000	JP

Primary Examiner: Letscher; Geraldine
Attorney, Agent or Firm: Sughrue Mion, PLLC

Claims

What is claimed is:

1. A silver halide photographic material comprising at least one methine dye represented by the following general formula (I) and at least one coupler represented by the following general formula (XII): ##STR139##

wherein X.sup.1 and X.sup.2 each represents an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a nitrogen atom or a carbon atom; Y.sup.1 represents a furan, pyrrole or thiophene ring which may be condense with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group; Y.sup.2 represents an atomic group necessary for forming a benzene ring or a 5- or 6-membered unsaturated heterocycle, which may be further condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group; a bond between two carbon atoms by which Y.sup.1 and Y.sup.2 are each condensed with the carbon ring or the heterocycle may be a single bond or a double bond; R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, aryl or heterocyclic group; L.sup.1, L.sup.2 and L.sup.3 each represents a methine group; n.sup.1 represents 0 or 1; M.sup.1 represents a counter ion; and m.sup.1 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR140##

wherein Q.sup.21 represents an alkyl group, Q.sup.22 represents a hydrogen atom or a halogen atom, and Q.sup.23 represents a substituent group containing --SO.sub.2 --.

2. The silver halide photographic material of claim 1, comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains said at least one methine dye represented by general formula (I) and at least one coupler represented by the following general formula (XX): ##STR141##

wherein Q.sup.5 represents a substituted or unsubstituted aryl group; Q.sup.6 represents a substituted or unsubstituted a group; Q.sup.7 represents a hydrogen atom, a halogen atom, an alkoxyl group or an alkyl group; an X represents a hydrogen atom or a group to be released by a reaction with an oxidant of a developing agent.

3. The silver halide photographic material as claimed in claim 1, wherein the methine dye represented by general formula (I) is represented by the following general formula (II), (III), (IV) or (V): ##STR142##

wherein Y.sup.11 represents an oxygen atom, a sulfur atom or N--R.sup.13, wherein R.sup.13 represents a hydrogen atom or alkyl group; V.sup.15 and V.sup.16 each represents a hydrogen atom or a monovalent substituent group; X.sup.11 and X.sup.12 each represents an oxygen atom or a sulfur atom; R.sup.11 and R.sup.12 each represents alkyl group substituted by an acid group; V.sup.11, V.sup.12, V.sup.13 and V.sup.14 each represents a hydrogen atom or a monovalent substituent group; M.sup.11 represents a counter ion; and m.sup.11 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR143##

wherein Y.sup.21 represents an oxygen atom, a sulfur atom or N--R.sup.23, wherein R.sup.23 represents a hydrogen atom or alkyl group; V.sup.25 and V.sup.26 each represents a hydrogen atom or a monovalent substituent group; X.sup.21 and X.sup.22 each represents an oxygen atom or a sulfur atom; R.sup.21 and R.sup.22 each represents alkyl group substituted by an acid group; V.sup.21, V.sup.22, V.sup.23 and V.sup.24 each represents a hydrogen atom or a monovalent substituent group; M.sup.21 represents a counter ion; and m.sup.21 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR144##

wherein Y.sup.31 represents an oxygen atom, a sulfur atom or N--R.sup.33, wherein R.sup.33 represents a hydrogen atom or alkyl group; V.sup.35 and V.sup.36 each represents a hydrogen atom or a monovalent substituent group; X.sup.31 and X.sup.32 each represents an oxygen atom or a sulfur atom; R.sup.31 and R.sup.32 each represents an alkyl group substituted by an acid group; A.sup.31 represents a methyl group, an ethyl group or a propyl group; V.sup.31, V.sup.32, V.sup.33 and V.sup.34 each represents a hydrogen atom or a monovalent substituent group; M.sup.31 represents a counter ion; and m.sup.31 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR145##

wherein Y.sup.41 represents an oxygen atom, a sulfur atom or N--R.sup.43, wherein R.sup.43 represents a hydrogen atom or alkyl group; V.sup.45 and V.sup.46 each represents a hydrogen atom or a monovalent substituent group; X.sup.41 and X.sup.42 each represents an oxygen atom or a sulfur atom; R.sup.41 and R.sup.42 each represents an alkyl group substituted by an acid group; A.sup.41 represents a methyl group, an ethyl group or a propyl group; V.sup.41, V.sup.42, V.sup.43 and V.sup.44 each represents a hydrogen atom or a monovalent substituent group; M.sup.41 represents a counter ion, and m.sup.41 represents a number of 0 or more necessary for neutralizing a charge in a molecule.

4. The silver halide photographic material as claimed in claim 1, wherein one of R.sup.1 and R.sup.2 of the methine dye represented by general formula (I) is an alkyl group substituted by a carboxyl group, a --CONHSO.sup.2 -- group, an --SO.sup.2 NHCO-- group, a --CONHCO-- group or an --SO.sup.2 NHSO.sup.2 -group, and the other is an alkyl group substituted by a sulfo group.

5. The silver halide photographic material as claimed in claim 1, wherein Y.sup.1 represents a thiophene ring.

Description

FIELD OF THE INVENTION

The present invention relates to a silver halide photographic material, and particularly to a silver halide photographic material having high sensitivity, decreased residual colors after processing and minor fluctuations in photographic characteristics after continuous processing.

BACKGROUND OF THE INVENTION

Much effort has hitherto been made to enhance sensitivity of silver halide photographic materials and to decrease residual colors after processing. It has been known that sensitizing dyes used for spectral sensitization greatly affect properties of the silver halide photographic materials. In the sensitizing dyes, the slight difference in structure greatly affects the photographic properties such as sensitivity, fog, storage stability and residual coloration (residual colors), and the use of two or more of the sensitizing dyes in combination also greatly affects the photographic properties. However, it is difficult to predict its effect beforehand. Accordingly, many researchers have hitherto made effort to synthesize many sensitizing dyes and to study the use of many sensitizing dyes in combination, thereby examining their photographic properties. However, it is still impossible to predict the photographic properties in the present circumstances. For the above-mentioned reason, a technique for spectrally sensitizing the silver halide photographic materials at high sensitivity without adverse effects such as fog and residual colors has been desired.

When it is desired that the absorption maximum of the sensitizing dye is shifted to the long wavelength side, a naphthazole nucleus has hitherto been widely used in which a benzene ring is further condensed with a benzazole nucleus. However, a recent strong demand toward enhancement in sensitivity increases the amount of the dye added, while a reduction in a processing waste solution for complying with rapid photographic processing and environmental problems must be complied with. A highly hydrophobic dye such as the naphthazole nucleus-containing dye becomes difficult to meet such demands.

In Japanese Patent Application No. 124612/2000 (corresponding to U.S. Patent Application Publication No. 2002/0058216A1), the present inventors have disclosed that a sensitizing dye in which an azole nucleus having a specific heterocycle condensed is used in place of a naphthazole nucleus is higher in sensitivity and more decreased in residual colors than a naphthazole dye. However, such a dye is much accumulated in a processing solution after processing in principle, so that the problem has become clear that a fatigued processing solution is liable to fluctuate the photographic properties.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a silver halide photographic material having high sensitivity, decreased residual colors after processing and minor fluctuations in photographic characteristics after continuous processing.

As a result of intensive investigation, the object of the present invention has been able to be attained by the following: (1) A silver halide photographic material comprising at least one methine dye represented by the following general formula (I) and at least one coupler represented by the following general formula (X): ##STR3## wherein X.sup.1 and X.sup.2 each represents an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a nitrogen atom or a carbon atom; Y.sup.1 represents a furan, pyrrole or thiophene ring which may be condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group; Y.sup.2 represents an atomic group necessary for forming a benzene ring or a 5- or 6-membered unsaturated heterocycle, which may be further condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group; a bond between two carbon atoms by which Y.sup.1 and Y.sup.2 are each condensed with the carbon ring or the heterocycle may be a single bond or a double bond; R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, aryl or heterocyclic group; L.sup.1, L.sup.2 and L.sup.3 each represents a methine group; n.sup.1 represents 0 or 1; M.sup.1 represents a counter ion; and m.sup.1 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR4## wherein Z.sup.1 and Z.sup.2 each represents --C(Q3).dbd. or --N.dbd.; Q.sup.1 and Q.sup.3 each represents a hydrogen atom or a monovalent substituent group; Q.sup.2 represents a hydrogen atom or a coupling release group; and Q.sup.1, Q.sup.2 or Q.sup.3 may be a divalent group, and combine with a multimer, a dimer or more, or a polymer chain to form a homopolymer or a copolymer; (2) A silver halide photographic material comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains at least one methine dye represented by the above-mentioned general formula (I) and at least one coupler represented by the following general formula (XX): ##STR5## wherein Q.sup.5 represents a substituted or unsubstituted aryl group; Q.sup.6 represents a substituted or unsubstituted alkyl group; Q.sup.7 represents a hydrogen atom, a halogen atom, an alkoxyl group or an alkyl group; and X represents a hydrogen atom or a group to be released by a reaction with an oxidant of a developing agent; (3) The silver halide photographic material described in the above (1) or (2), wherein the methine dye represented by the above-mentioned general formula (I) in (1) or (2) is represented by the following general formula (II), (III), (IV) or (V): ##STR6## wherein Y.sup.11 represents an oxygen atom, a sulfur atom or N--R.sup.13, wherein R.sup.13 represents a hydrogen atom or an alkyl group; V.sup.15 and V.sup.16 each represents a hydrogen atom or a monovalent substituent group; X.sup.11 and X.sup.12 each represents an oxygen atom or a sulfur atom; R.sup.11 and R.sup.12 each represents an alkyl group substituted by an acid group; V.sup.11, V.sup.12, V.sup.13 and V.sup.14 each represents a hydrogen atom or a monovalent substituent group; M.sup.11 represents a counter ion; and m.sup.11 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR7## wherein Y.sup.21 represents an oxygen atom, a sulfur atom or N--R.sup.23 wherein R.sup.23 represents a hydrogen atom or an alkyl group; V.sup.25 and V.sup.26 each represents a hydrogen atom or a monovalent substituent group; X.sup.21 and X.sup.22 each represents an oxygen atom or a sulfur atom; R.sup.21 and R.sup.22 each represents an alkyl group substituted by an acid group; V.sup.21, V.sup.22, V.sup.23 and V.sup.24 each represents a hydrogen atom or a monovalent substituent group; M.sup.21 represents a counter ion; and m.sup.21 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR8## wherein Y.sup.31 represents an oxygen atom, a sulfur atom or N--R.sup.33, wherein R.sup.33 represents a hydrogen atom or an alkyl group; V.sup.35 and V.sup.36 each represents a hydrogen atom or a monovalent substituent group; X.sup.31 and X.sup.32 each represents an oxygen atom or a sulfur atom; R.sup.31 and R.sup.32 each represents an alkyl group substituted by an acid group; A.sup.31 represents a methyl group, an ethyl group or a propyl group; V.sup.31, V.sup.32, V.sup.33 and V.sup.34 each represents a hydrogen atom or a monovalent substituent group; M.sup.31 represents a counter ion; and m.sup.31 represents a number of 0 or more necessary for neutralizing a charge in a molecule; ##STR9## wherein Y.sup.41 represents an oxygen atom, a sulfur atom or N--R.sup.43, wherein R.sup.43 represents a hydrogen atom or an alkyl group; V.sup.45 and V.sup.46 each represents a hydrogen atom or a monovalent substituent group; X.sup.41 and X.sup.42 each represents an oxygen atom or a sulfur atom; R.sup.41 and R.sup.42 each represents an alkyl group substituted by an acid group; A.sup.41 represents a methyl group, an ethyl group or a propyl group; V.sup.41, V.sup.42, V.sup.43 and V.sup.44 each represents a hydrogen atom or a monovalent substituent group; M.sup.41 represents a counter ion; and m.sup.41 represents a number of 0 or more necessary for neutralizing a charge in a molecule; (4) The silver halide photographic material described in the above (3), wherein one of R.sup.11 and R.sup.12 of the methine dye represented by the above-mentioned general formula (II) in (3) is an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and the other is an alkyl group substituted by a sulfo group; (5) The silver halide photographic material described in the above (4), wherein Y.sup.11 of the methine dye represented by the above-mentioned general formula (II) in (4) is a sulfur atom, V.sup.15 is a halogen atom, and V.sup.16 is a hydrogen atom; (6) The silver halide photographic material described in the above (3), wherein one of R.sup.21 and R.sup.22 of the methine dye represented by the above-mentioned general formula (III) in (3) is an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and the other is an alkyl group substituted by a sulfo group; (7) The silver halide photographic material described in the above (6), wherein Y.sup.21 of the methine dye represented by the above-mentioned general formula (III) in (6) is a sulfur atom, V.sup.25 is a halogen atom, and V.sup.26 is a hydrogen atom; (8) The silver halide photographic material described in the above (3), wherein one of R.sup.31 and R.sup.32 of the methine dye represented by the above-mentioned general formula (IV) in (3) is an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and the other is an alkyl group substituted by a sulfo group; (9) The silver halide photographic material described in the above (8), wherein Y.sup.31 of the methine dye represented by the above-mentioned general formula (IV) in (8) is a sulfur atom, V.sup.35 is a halogen atom, and V.sup.36 is a hydrogen atom; (10) The silver halide photographic material described in the above (3), wherein one of R.sup.41 and R.sup.42 of the methine dye represented by the above-mentioned general formula (V) in (3) is an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and the other is an alkyl group substituted by a sulfo group; (11) The silver halide photographic material described in the above (10), wherein Y.sup.41 of the methine dye represented by the above-mentioned general formula (V) in (10) is a sulfur atom, V.sup.45 is a halogen atom, and V.sup.46 is a hydrogen atom; (12) The silver halide photographic material described in the above (1), wherein the coupler represented by the above-mentioned general formula (X) in (1) is represented by the following general formula (XI) or (XII): ##STR10## wherein Q.sup.11 represents an alkyl group, Q.sup.12 represents a hydrogen atom or a halogen atom, and Q.sup.13 represents a substituent group containing --SO.sub.2 --; ##STR11## wherein Q.sup.21 represents an alkyl group, Q.sup.22 represents a hydrogen atom or a halogen atom, and Q.sup.23 represents a substituent group containing --SO.sub.2 --; (13) The silver halide photographic material described in the above (1) comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains at least one methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) and at least one coupler represented by the above-mentioned general formula (XII); (14) The silver halide photographic material described in the above (13), wherein one of (R.sup.11, R.sup.21, R.sup.31 or R.sup.41) and (R.sup.12, R.sup.22, R.sup.32 or R.sup.42) of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and the other is an alkyl group substituted by a sulfo group; (15) The silver halide photographic material described in the above (14), wherein (Y.sup.11, Y.sup.21, Y.sup.31 or Y.sup.41) of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is a sulfur atom, (V.sup.15, V.sup.25, V.sup.35 or V.sup.45) is a halogen atom, and (V.sup.16, V.sup.26, V.sup.36 or V.sup.46) is a hydrogen atom; (16) The silver halide photographic material described in the above (2) comprising a support having provided thereon at least one silver halide photographic emulsion layer, which contains at least one methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) and at least one coupler represented by the above-mentioned general formula (XX); (17) The silver halide photographic material described in the above (16), wherein one of (R.sup.11, R.sup.21 R.sup.31 or R.sup.41) and (R.sup.12, R.sup.22, R.sup.32 or R.sup.42)of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and the other is an alkyl group substituted by a sulfo group; and (18) The silver halide photographic material described in the above (17), wherein (Y.sup.11, Y.sup.21, Y.sup.31 or Y.sup.41) of the methine dye represented by the above-mentioned general formula (II), (III), (IV) or (V) is a sulfur atom, (V.sup.15, V.sup.25, V.sup.35 or V.sup.45) is a halogen atom, and (V.sup.16, V.sup.26, V.sup.36 or V.sup.46) is a hydrogen atom.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in detail below.

First, the groups used in the present invention will be described in detail.

In the present invention, when a specific moiety is referred to as a "group", it means that the moiety itself may not be substituted, or may be substituted by at least one substituent group (to the greatest number as possible). For example, an "alkyl group" means a substituted or unsubstituted alkyl group. The substituent group available in the present invention includes any substituent group, irrespective of the presence or absence of substitution.

Taking such a substituent group as W, the substituent group indicated by W may be any, and there is no particular limitation thereon. Examples thereof include a halogen atom, an alkyl group (including a cyclic alkyl group) also including an alkenyl group (including a cyclic alkenyl group) and an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxyl group, an aryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino group (including an anilino group), an ammonio group, an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an alkylsulfonylamino or arylsulfonylamino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfamoyl group, a sulfo group, an alkylsulfinyl or arylsulfinyl group, an alkylsulfonyl or arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an arylazo or heterocyclic azo group, an imido group, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, a phospho group (also called a phosphono group), a silyl group, a hydrazino group, a ureido group, a boronic acid group, a phosphato group, a sulfato group and other known substituent groups.

More particularly, W represents a halogen atom (for example, fluorine, chlorine, bromine or iodine) or an alkyl group (a straight chain, branched or cyclic, substituted or unsubstituted alkyl group). The alkyl group includes an alkyl group (preferably an alkyl group having from 1 to 30 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl or2-ethylhexyl), a cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having from 3 to 30 carbon atoms, for example, cyclohexyl, cyclopentyl or 4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having from 5 to 30 carbon atoms, that is to say, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having from 5 to 30 carbon atoms, for example, bicyclo[1,2,2]heptane-2-yl or bicyclo-[2,2,2]octane-3-yl), and a tricyclo structure having more ring structures. An alkyl group in the substituent group described below (e.g., the alkyl group of alkylthio group) indicates an alkyl group having such a concept, and further includes an alkenyl group and an alkynyl group. The alkenyl group indicates a straight chain, branched or cyclic, substituted or unsubstituted alkenyl group, and include an alkenyl group (preferably a substituted or unsubstituted alkenyl group having from 2 to 30 carbon atoms, for example, vinyl, allyl, prenyl, geranyl or oleyl), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having from 3 to 30 carbon atoms, that is to say, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having from 3 to 30 carbon atoms, for example, 2-cyclopentene-1-yl or 2-cyclohexene-1-yl), a bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having from 5 to 30 carbon atoms, that is to say, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond, for example, bicyclo[2,2,1]hepto-2-ene-1-yl or bicyclo[2,2,2]octo-2-ene-4-yl). The alkynyl group is preferably a substituted or unsubstituted alkynyl group having from 2 to 30 carbon atoms (for example, ethynyl, propargyl or trimethylsilylethynyl). W further represents an aryl group (preferably a substituted or unsubstituted aryl group having from 6 to 30 carbon atoms, for example, phenyl, p-tolyl, naphthyl, m-chlorophenyl or o-hexadecanoylaminophenyl), a heterocyclic group (preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered, substituted or unsubstituted, aromatic or nonaromatic heterocyclic compound, and more preferably a 5- or 6-membered aromatic heterocyclic group having from 3 to 30 carbon atoms, for example, 2-furyl, 2-thienyl, 2-pyrimidinyl or 2-benzothiazolyl, allowing a cationic heterocyclic group such as 1-methyl-2-pyridinio or 1-methyl-2-quinolinio), a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxyl group (preferably a substituted or unsubstituted alkoxyl group having from 1 to 30 carbon atoms, for example, methoxy, ethoxy, isopropoxy, t-butoxy, n-octyloxy or 2-methoxyethoxy), an aryloxy group (preferably a substituted or unsubstituted aryloxy group having from 6 to 30 carbon atoms, for example, phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy or 2-tetradecanoylaminophenoxy), a silyloxy group (preferably a silyloxy group having from 3 to 20 carbon atoms, for example, trimethylsilyloxy or t-butyldimethylsilyloxy), a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having from 2 to 30 carbon atoms, for example, 1-phenyltetrazole-5-oxy or 2-tetrahydropyranyloxy), an acyloxy group (preferably a formyloxy, an a substituted or unsubstituted alkylcarbonyloxy group having from 2 to 30 carbon atoms, or a substituted or unsubstituted arylcarbonyloxy group having from 6 to 30 carbon atoms, for example, formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy or p-methoxyphenylcarbonyloxy), a carbamoyloxy (preferably a substituted or unsubstituted carbamoyloxy group having from 1 to 30 carbon atoms, for example, N,N-dimethylcarbamoyloxy, N,N-diethylcarbamoyloxy, morpholinocarbonyloxy, N,N-di-n-octylaminocarbonyloxy or N-n-octylcarbamoyloxy), an alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxylcarbonyloxy group having from 2 to 30 carbon atoms, for example, methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy or n-octylcarbonyloxy), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having from 7 to 30 carbon atoms, for example, phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy or p-n-hexadecyloxyphenoxycarbonyloxy), an amino group (preferably an amino group, a substituted or unsubstituted alkylamino group having from 1 to 30 carbon atoms or a substituted or unsubstituted anilino group having from 6 to 30 carbon atoms, for example, amino, methylamino, dimethylamino, anilino, N-methylanilino or diphenylamino), an ammonio group (preferably an ammonio group or an ammonio group substituted by a substituted or unsubstituted alkyl having from 1 to 30 carbon atoms, aryl or a heterocycle, for example, a trimethylammonio, triethylammonio or diphenylmethylammonio), an acylamino group (preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having from 1 to 30 or a substituted or unsubstituted arylcarbonylamino group having from 6 to 30, for example, formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino or 3,4-5-tri-n-octyloxyphenylcarbonylamino), an aminocarbonylamino group (preferably a substituted or unsubstituted aminocarbonylamino group having from 1 to 30 carbon atoms, for example, carbamoylamino, N,N-dimethylaminocarbonylamino, N,N-diethylaminocarbonylamino or morpholinocarbonylamino), an alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having from 2 to 30 carbon atoms, for example, methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino or N-methylmethoxycarbonylamino), an aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having from 7 to 30 carbon atoms, for example, phenoxycarbonylamino, p-chlorophenoxycarbonylamio or m-(n-octyloxy)phenoxycarbonylamino), a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having from 0 to 30 carbon atoms, for example, sulfamoylamino, N,N-dimethylaminosulfonylamino or N-n-octylaminosulfonylamino), an alkylsulfonylamino or arylsulfonylamino group (preferably a substituted or unsubstituted alkanesulfonylamino group having from 1 to 30 carbon atoms or a substituted or unsubstituted arylsulfonylamino group having from 6 to 30 carbon atoms, for example, methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino or p-methylphenylsulfonylamino), a mercapto group, an alkylthio group (preferably a substituted or unsubstituted alkylthio group having from 1 to 30 carbon atoms, for example, methylthio, ethylthio or n-hexadecylthio), an arylthio group (preferably a substituted or unsubstituted arylthio group having from 6 to 30 carbon atoms, for example, phenylthio, p-chlorophenylthio or m-methoxyphenylthio), a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having from 2 to 30 carbon atoms, for example, 2-benzothiazolylthio or 1-phenyltetrazole-5-ylthio), a sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having from 0 to 30 carbon atoms, for example, N-ethylsulfamoyl, N-(3-dodecyloxypropyl)sulfamoyl, N,N-dimethylsulfamoyl, N-acetylsulfamoyl, N-benzoylsulfamoyl or N-(N'-phenylcarbamoyl)sulfamoyl), a sulfo group, an alkylsulfinyl or arylsulfinyl group (preferably a substituted or unsubstituted alkylsulfinyl group having from 1 to 30 carbon atoms or an arylsulfinyl group having from 6 to 30 carbon atoms, for example, methylsulfinyl, ethylsulfinyl, phenylsulfinyl or p-methylphenylsulfinyl, an alkylsulfonyl or arylsulfonyl group (preferably a substituted or unsubstituted alkanesulfonyl group having from 1 to 30 carbon atoms or a substituted or unsubstituted arylsulfonyl group having from 6 to 30 carbon atoms, for example, methylsulfonyl, ethylsulfonyl, phenylsulfonyl or p-methylphenylsulfonyl), an acyl group (preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having from 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having from 7 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic carbonyl group having from 4 to 30 carbon atoms which is linked by a carbon atom to a carbonyl group, for example, acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, p-n-octyloxyphenylcarbonyl, 2-pyridylcarbonyl or 2-furylcarbonyl), an aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having from 7 to 30 carbon atoms, for example, phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl or p-t-butylphenoxycarbonyl), an alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having from 2 to 30 carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl or n-octadecyloxycarbonyl), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having from 1 to 30 carbon atoms, for example, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N,N-di-n-octylcarbamoyl or N-(methylsulfonyl)carbamoyl), an arylazo or heterocyclic azo group (preferably a substituted or unsubstituted arylazo group having from 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic azo group having from 3 to 30 carbon atoms, for example, phenylazo, p-chlorophenylazo or 5-ethylthio-1,3,4-thiadiazole-2-ylazo), an imido group (preferably N-succinimido or N-phthalimido), a phosphino group (preferably a substituted or unsubstituted phosphino group having from2 to 30 carbon atoms,for example, dimethylphosphino, diphenylphosphino or methylphenoxyphosphino), a phosphinyl group (preferably a substituted or unsubstituted phosphinyl group having from 2 to 30 carbon atoms, for example, phosphinyl, dioctyloxyphosphinyl or diethoxyphosphinyl), a phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having from 2 to 30 carbon atoms, for example, diphenoxyphosphinyloxy or dioctyloxyphosphinyloxy), a phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having from 2 to 30 carbon atoms, for example, dimethoxyphosphinylamino or dimethylaminophosphinylamino), a phospho group, a silyl group (preferably a substituted or unsubstituted silyl group having from 3 to 30 carbon atoms, for example, trimethylsilyl, t-butyldimethylsilyl or phenyldimethylsilyl), a hydrazino group (preferably a substituted or unsubstituted hydrazino group having from 0 to 30 carbon atoms, for example, trimethylhydrazino), or a ureido group (preferably a substituted or unsubstituted ureido group having from 0 to 30 carbon atoms, for example, N,N-dimethylureido).

Two W's can also cooperatively form a ring-condensed structure. The rings are aromatic or nonaromatic hydrocarbon rings or heterocycles, which can be further combined to form a polycyclic condensed ring. Examples of the rings include a benzene ring, a naphthalene ring, an anthracene ring, a quinoline ring, a phenanthrene ring, a fluorene ring, a triphenylene ring, a naphthacene ring, a biphenyl ring, a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyridine ring, a pyradine ring, a pyrimidine ring, a pyridazine ring, an indolizine ring, an indole ring, a benzofuran ring, a benzothiophene ring, an isobenzofuran ring, a quinolizine ring, an isoquinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinoxazoline ring, a carbazole ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a thianthrene ring, a chromene ring, a xanthene ring, a phenoxathiin ring, a phenothiazine ring and a phenazine ring.

As for a hydrogen atom-containing substituent group of the above-mentioned substituent groups W, the hydrogen atom may be removed and further substituted by the above-mentioned substituent group. Examples of such substituent groups include a --CONHSO.sub.2 -- group (a sulfonylcarbamoyl or carbonylsulfamoyl group), a --CONHCO-- group (a carbonylcarbamoyl group) and an --SO.sub.2 NHSO.sub.2 -- group (a sulfonylsulfamoyl group). More specifically, the substituent groups include an alkylcarbonylaminosulfonyl group (for example, acetylaminosulfonyl), an arylcarbonylaminosulfonyl group (for example, benzoylaminosulfonyl), an alkanesulfonylaminocarbonyl group (for example, methylsulfonylaminocarbonyl) and an arylsulfonylaminocarbonyl group (for example, p-methylphenylsulfonylaminocarbonyl).

The methine dye represented by general formula (I) of the present invention will be described below.

X.sup.1 and X.sup.2 each represents an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, a nitrogen atom or a carbon atom. The nitrogen atom can be preferably represented by --N(Rx)--, and the carbon atom can be preferably represented by --C(Ry)(Rz)--. Rx, Ry and Rz are each a hydrogen atom or a monovalent substituent group (for example, W described above) preferably an alkyl group, an aryl group or a heterocyclic group, similar to the group represented by R, and more preferably an alkyl group. X.sup.1 and X.sup.2 are each preferably an oxygen atom, a sulfur atom or a nitrogen atom, and more preferably an oxygen atom or a sulfur atom.

Y.sup.1 represents a furan, pyrrole or thiophene ring which may be condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group. Although a bond between two carbon atoms by which Y.sup.1 is condensed may be a single bond or a double bond, it is preferably a double bond. Y.sup.1 can further form a condensed ring together with another 5- or 6-membered carbon ring or heterocycle. However, it is preferred that the third condensed ring does not exist. Y.sup.1 is preferably a thiophene ring. The substituent group for Y.sup.1 may be any, and includes W described above. The substituent group is preferably an alkyl group (for example, methyl), an aryl group (for example, phenyl), an aromatic heterocyclic group (for example, 1-pyrrolyl), an alkoxyl group (for example, methoxy), an alkylthio group (for example, methylthio),a cyano, an acyl group (for example, acetyl), an alkoxycarbonyl group (for example, methoxycarbonyl) or a halogen atom (for example, fluorine, chlorine, bromine or iodine), more preferably methyl, methoxy, cyano or a halogen atom, still more preferably a halogen atom, particularly preferably fluorine, chlorine or bromine, and most preferably chlorine. In particular, when Y.sup.1 is a thiophene ring, it preferably has a halogen substituent group. The substituent group is preferably chlorine or bromine, and most preferably chlorine.

Y.sup.2 represents an atomic group necessary for forming a benzene ring or a 5- or 6-membered unsaturated heterocycle, which may be further condensed with another 5- or 6-membered carbon ring or heterocycle or may have a substituent group. Although a bond between two carbon atoms by which Y.sup.2 is condensed may be a single bond or a double bond, it is preferably a double bond. The 5-membered unsaturated heterocycles include a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, a furan ring, an oxazole ring, an isoxazole ring, a thiophene ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, a selenophene ring, a selenazole ring, an isoselenazole ring, a tellurophene ring, a tellurazole ring and an isotellurazole ring, and the 6-membered unsaturated heterocycles include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyradine ring, a pyran ring and a thiopyran ring. Y.sup.2 can be further condensed with another 5- or 6-membered carbon ring or heterocycle to form, for example, an indole ring, a benzofuran ring, a benzothiophene ring or a thienothiophene ring. However, it is preferred that the third condensed ring does not exist. Y.sup.2 is preferably a benzene ring, a pyrrole ring, a furan ring or a thiophene ring, particularly preferably a benzene ring, a furan ring or a pyrrole ring, and most preferably a benzene ring. The substituent group for Y.sup.2 may be any, and includes W described above. The substituent group is preferably an alkyl group (for example, methyl), an aryl group (for example, phenyl), an aromatic heterocyclic group (for example, 1-pyrrolyl), an alkoxyl group (for example, methoxy), an alkylthio group (for example, methylthio), a cyano, an acyl group (for example, acetyl), an alkoxycarbonyl group (for example, methoxycarbonyl) or a halogen atom (for example, fluorine, chlorine, bromine or iodine), more preferably methyl, methoxy, cyano or a halogen atom, still more preferably a halogen atom, particularly preferably fluorine, chlorine or bromine, and most preferably chlorine.

R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, aryl or heterocyclic group. At least one of R.sup.1 and R.sup.2 is preferably an alkyl group substituted by an acid group. More preferably, both of R.sup.1 and R.sup.2 are alkyl groups each substituted by an acid group.

The acid group will be described herein. The term "acid group" means a group having a dissociative proton. Specific examples thereof include a group that dissociates a proton depending on the pKa and the surrounding pH, such as a sulfo group, a carboxyl group, a sulfato group, a --CONHSO.sub.2 -- group (a sulfonylcarbamoyl or carbonylsulfamoyl group), a --CONHCO-- group (a carbonylcarbamoyl group), an --SO.sub.2 NHSO.sub.2 -- group (a sulfonylsulfamoyl group), a sulfonamido group, a sulfamoyl group, a phosphato group, a phosphono group, a boronic acid group or a phenolic hydroxyl group. For example, a proton-dissociative acidic group in which 90% or more dissociates between pH 5 and pH 11 is preferred.

Preferred one of the "alkyl group substituted by an acid group" represented by R.sup.1 or R.sup.2 in the methine dye represented by general formula (I) can be expressed in the form of a formula as follows:

T.sup.1 =--SO.sub.3.sup.-

--COOH

--CONHSO.sub.2 Ra

--SO.sub.2 NHCORb

--CONHCORc

--SO.sub.2 NHSO.sub.2 Rd

Qa represents a connecting group necessary for forming an alkyl group (preferably a divalent connecting group). Ra, Rb, Rc and Rd each represents an alkyl group, an aryl group, a heterocyclic group, an alkoxyl group, an aryloxy group, a heterocyclyloxy group or an amino group.

Qa may be any connecting group, as long as it meets the above-mentioned requirements. It is preferably an atom or an atomic group containing at least one of a carbon atom, a nitrogen atom, a sulfur atom and an oxygen atom. It preferably represents a connecting group having from 0 to 10 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 1 to 5 carbon atoms which is constituted by a combination of one or more of an alkylene group (for example, methylene, ethylene, trimethylene, tetramethylene, pentamethylene or methyltrimethylene), an alkenylene group (for example, ethenylene or propenylene), an alkynylene group (for example, ethynylene or propynylene), an amido group, an ester group, a sulfoamido group, a sulfonic ester group, a ureido group, a sulfonyl group, a sulfinyl group, a thioether group, an ether group, a carbonyl group or an --N(Wa)-- group (wherein Wa represents a hydrogen atom or a monovalent substituent group, and the monovalent substituent group includes W described above.

The above-mentioned connecting group may further have the substituent group represented by W described above, and may have a ring (an aromatic or nonaromatic hydrocarbon ring or a heterocycle).

However, it is more preferred that the connecting group contains no heteroatom. It is still more preferred that the connecting group is not substituted by the substituent group represented by W described above.

More preferably, Qa is a divalent connecting group having from 1 to 5 carbon atoms which is constituted by a combination of one or more of an alkylene group having from 1 to 5 carbon atoms (for example, methylene, ethylene, trimethylene, tetramethylene, pentamethylene or methyltrimethylene), an alkenylene group having from 2 to 5 carbon atoms (for example, ethenylene or propenylene) and an alkynylene group having from 2 to 5 carbon atoms (for example, ethynylene or propynylene). Particularly preferred is an alkylene group having from 1 to 5 carbon atoms (preferably methylene, ethylene, trimethylene or tetrametylene).

When T.sup.1 is a sulfo group, Qa is more preferably ethylene, trimethylene, tetramethylene or methyltrimethylene, and particularly preferably trimethylene. When Xa is a carboxyl group, Qa is more preferably methylene, ethylene or trimethylene, and particularly preferably methylene. When T.sup.1 is --CONHSO.sub.2 Ra, --SO.sub.2 NHCORb, --CONHCORc or SO.sub.2 NHSO.sub.2 Rd, Qa is more preferably methylene, ethylene or trimethylene, and particularly preferably methylene.

Ra, Rb, Rc and Rd each represents an alkyl group, an aryl group, a heterocyclic group, an alkoxyl group, an aryloxy group, a heterocyclyloxy group or an amino group.

Preferred examples thereof include an unsubstituted alkyl group having from 1 to 18 carbon atoms, preferably from 1 to 10 carbon atoms, more preferably from 1 to 5 carbon atoms (for example, methyl, ethyl, propyl or butyl), a substituted alkyl group having from 1 to 18 carbon atoms, preferably from 1 to 10 carbon atoms, more preferably from 1 to 5 carbon atoms (for example, hydroxymethyl, trifluoromethyl, benzyl, carboxyethyl, ethoxycarbonylmethyl or acetylaminomethyl, it shall be considered to include an unsaturated hydrocarbon group having preferably from 2 to 18,- more preferably from 3 to 10 carbon atoms, particularly preferably from 3 to 5 (for example, a vinyl group, an ethynyl group, a 1-cyclohexenyl group, a benzylidyne group or a benzylidene group)), a substituted or unsubstituted aryl group having from 6 to 20 carbon atoms, preferably from 6 to 15 carbon atoms, more preferably from 6 to 10 carbon atoms (for example, phenyl, naphthyl, p-carboxyphenyl, p-nitrophenyl, 3,5-dichlorophenyl, p-cyanophenyl, m-fluorophenyl or p-tolyl), a heterocyclic group, which may be substituted, having from 1 to 20 carbon atoms, preferably from 2 to 10 carbon atoms, more preferably from 4 to 6 carbon atoms (for example, pyridyl, 5-methylpyridyl, thienyl, furyl, morpholino or tetrahydrofurfuryl, an alkoxyl group having from 1 to 10 carbon atoms, preferably from 1 to 8 carbon atoms (for example, methoxy, ethoxy, 2-methoxyethoxy, 2-hydroxyethoxy or 2-phenylethoxy), an aryloxy group having from 6 to 20 carbon atoms, preferably from 6 to 12 carbon atoms, more preferably from 6 to 10 carbon atoms (for example, phenoxy, p-methylphenoxy, p-chlorophenoxy or naphthoxy), a heterocyclyloxy group (which means an oxy group substituted by a heterocyclic group) having from 1 to 20 carbon atoms, preferably from 3 to 12 carbon atoms, more preferably from 3 to 10 carbon atoms (for example, 2-thienyloxy or 2-morpholinoxy) and an amino group having from 0 to 20 carbon atoms, preferably from 0 to 12 carbon atoms, more preferably from 0 to 8 carbon atoms (for example, amino, methylamino, dimethylamino, ethylamino, diethylamino,-hydroxyethylamino, benzylamino, anilino, diphenylamino, ring-formed morpholino or pyrrolidino). These may be further substituted by W described above.

More preferred are methyl, ethyl and hydroxyethyl, and particularly preferred is methyl.

The acid group, for example, a carboxyl group or a dissociative nitrogen atom, may be showed either in the non-dissociated form (COOH or NH) or in the dissociated form (COO.sup.- or N.sup.-). Actually, the acid group becomes either a dissociated state or a non-dissociated state, depending on the circumstances such as the pH under which a dye is placed.

When an anion exists as a counter ion, for example, it may be written as (COO.sup.- Na.sup.+) or (N.sup.- Na.sup.+). In the non-dissociated state, it is written as (COOH) or (NH). However, considering a cationic compound of the counter ion as a proton, it is also possible to write it as (COO.sup.- H.sup.+) or (N.sup.- H.sup.+).

In the methine dye represented by general formula (I), it is particularly preferred that at least one of R.sup.1 and R.sup.2 is an alkyl group substituted by an acid group other than a sulfo group. Most preferably, one of R.sup.1 and R.sup.2 is an alkyl group substituted by an acid group other than a sulfo group and the other is an alkyl group substituted by a sulfo group. In the above, the sulfo group-containing alkyl group is preferably a 3-sulfopropyl group, a 4-sulfobutyl group, a 3-sulfobutyl group or a 2-sulfoethyl group, and more preferably a 3-sulfopropyl group.

The alkyl group substituted by an acid group other than a sulfo group is preferably an alkyl group substituted by a carboxyl group, a --CONHSO.sub.2 -- group, an --SO.sub.2 NHCO-- group, a --CONHCO-- group or an --SO.sub.2 NHSO.sub.2 -- group, and particularly preferably a carboxymethyl group or a methane sulfonyl carbamoyl methyl group.

The combination of R.sup.1 and R.sup.2 is preferably a combination of a carboxymethyl group or a methanesulfonylcarbamoylmethyl group and a 3-sulfopropyl group, a 4-sulfobutyl group, a 3-sulfobutyl group or a 2-sulfoethyl group, and more preferably a combination of a carboxymethyl group or a methanesulfonylcarbamoylmethyl group and a 3-sulfopropyl group.

L.sup.1, L.sup.2 and L.sup.3 each represents a methine group, and may be unsubstituted or substituted by a substituent group (for example, W described above). preferred examples of the substituent groups include an aryl group, an unsaturated hydrocarbon group, a carboxyl group, a sulfo group, a sulfato group, a cyano group, a halogen atom (for example, fluorine, chlorine, bromine or iodine), a hydroxyl group, a mercapto group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a carbamoyl group, a sulfamoyl group, a heterocyclic group, an alkanesulfonylcarbamoyl group, an acylcarbamoyl group, an acylsulfamoyl group and an alkanesulfonylsulfamoyl group. n.sup.1 represents 0 or 1. When n.sup.1 is 0, L.sup.1 is preferably an unsubstituted methine group. When n.sup.1 is 1, L.sup.1 and L.sup.3 are each preferably an unsubstituted methine group, and L.sup.2 is preferably a methine group substituted by an unsubstituted alkyl group (for example, methyl, ethyl or propyl), more preferably a methine group substituted by ethyl.

M.sup.1 represents a counter ion. When necessary for neutralizing an ionic charge of a dye, M.sup.1 is contained in the formula for indicating the presence of a cation or an anion. It depends on the substituent group and the circumstances in a solution (such as the pH) whether a certain dye is a cation or an anion, or whether it has a net ionic charge or not. Typical examples of the cations include inorganic cations such as a hydrogen ion (H.sup.+), an alkali metal ion (for example, a sodium ion, a potassium ion or a lithium ion) and an alkali earth metal ion (for example, a calcium ion), and organic cations such as an ammonium ion (for example, an ammonium ion, a tetraalkylammonium ion, a triethylammonium ion, a pyridinium ion, an ethylpyridinium ion or a 1,8-diazabicyclo[5.4.0]-7-undecenium ion). The anions, which may be either inorganic anions or organic anions, include a halide anion (for example, a fluoride ion, a chloride ion, a bromide ion or an iodide ion), a substituted arylsulfonate ion (for example, a p-toluenesulfonate ion or a p-chlorobenzenesulfonate ion), an aryldisulfonate ion (for example, a 1,3-benzenedisulfonate ion, a 1,5-naphthalenedisulfonate ion or a 2,6-naphthalenedisulfonate ion) an alkylsulfate ion (for example, methylsulfate ion), a sulfate ion, a thiocyanate ion, a perchlorate ion, a tetrafluoroborate ion, a picrate ion, an acetate ion and a trifluoromethanesulfonate ion. Further, an ionic polymer or another dye having the charge reverse to that of the dye may also be used. The cation is preferably a sodium ion, a potassium ion, a triethylammonium ion, a tetraethylammonium ion, a pyridinium ion, an ethylpyridinium ion or a methylpyridinium ion. The anion is preferably a perchlorate ion, an iodide ion, a bromide ion or a substituted arylsulfonate ion (for example, p-toluenesulfonate ion).

m.sup.1 represents a number of 0 or more necessary for balancing a charge, and when an internal salt is formed, it is 0. It is preferably a number of from 0 to 4.

The methine dye represented by the above-mentioned general formula (I) is more preferably represented by general formula (II), (III), (IV) or (V).

In general formula (II), Y.sup.11 represents an oxygen atom, a sulfur atom or N--R.sup.13, wherein R.sup.13 represents a hydrogen atom, an unsubstituted alkyl group or a substituted alkyl group (for example, an alkyl group substituted by W described above). The substituent group of the substituted alkyl group is preferably a substituent group higher in hydrophilicity than an iodine atom, more preferably a substituent group having hydrophilicity equal to or higher than that of a chlorine atom, and particularly preferably a substituent group having hydrophilicity equal to or higher than that of a fluorine atom. R.sup.13 is more preferably a hydrogen atom or an unsubstituted alkyl group, and particularly preferably a hydrogen atom or a methyl group. It is particularly preferred that Y.sup.11 is a sulfur atom.

X.sup.11 and X.sup.12 each represents an oxygen atom or a sulfur atom. At least one thereof is preferably a sulfur atom, and both are preferably sulfur atoms.

V.sup.11, V.sup.12, V.sup.13, V.sup.14, V.sup.15 and V.sup.16 each represents a hydrogen atom or a monovalent substituent group. Two adjacent substituent groups of V.sup.11, V.sup.12, V.sup.13 and V.sup.14, or V.sup.15 and V.sup.16 may combine with each other to form a saturated or unsaturated condensed ring. However, it is better that no condensed ring is formed. Although the monovalent substituent groups include W described above, preferred is an alkyl group (for example, methyl), an aryl group (for example, phenyl), an aromatic heterocyclic group (for example, 1-pyrrolyl), an alkoxyl group (for example, methoxy), an alkylthio group (for example, methylthio), a cyano group, an acyl group (for example, acetyl), an alkoxycarbonyl group (for example, methoxycarbonyl) or a halogen atom (for example, fluorine, chlorine, bromine or iodine), more preferred is a methyl group, a methoxy group, a cyano group or a halogen atom, still more preferred is a halogen atom, particularly preferred is fluorine, chlorine or bromine, and most preferred is chlorine. V.sup.11, V.sup.12 and V.sup.14 are each preferably a hydrogen atom.

When Y.sup.11 is a sulfur atom, at least one of V.sup.15 and V.sup.16 is preferably a halogen atom (for example, fluorine, chlorine, bromine or iodine). More preferably, V.sup.16 is a hydrogen atom, and V.sup.15 is fluorine, chlorine or bromine, particularly preferably chlorine.

Although R.sup.11 and R.sup.12 each represents an alkyl group substituted by an acid group, at least one of R.sup.11 and R.sup.12, which are alkyl groups each substituted by an acid group as with R.sup.1 described above, is preferably an alkyl group substituted by an acid group other than a sulfo group. More preferably, one of R.sup.11 and R.sup.12 is an alkyl group substituted by an acid group other than a sulfo group (preferably a carboxyl group or an alkanesulfonylcarbamoyl group) and the other is an alkyl group substituted by a sulfo group. Specific examples and preferred combinations of these alkyl groups each substituted by an acid group are the same as with R.sup.1 described above. Still more preferably, one of R.sup.11 and R.sup.12 is a carboxymethyl group or a methanesulfonylcarbamoylmethyl group. Particularly preferably, R.sup.11 is a carboxymethyl group or a methanesulfonylcarbamoylmethyl group, and R.sup.12 is a 3-sulfopropyl group.

M.sup.11 represents a counter ion, and m.sup.11 represents a number of 0 or more necessary for neutralizing a charge in a molecule. M.sup.11 and m.sup.11 are the same as with M.sup.1 and m.sup.1 described above. M.sup.11 is particularly preferably a cation, and preferred examples of the cations include sodium, potassium, triethylammonium, pyridinium and N-ethylpyridinium.

In general formula (III), Y.sup.21 represents an oxygen atom, a sulfur atom or N--R.sup.23, wherein R.sup.23 represents a hydrogen atom, an unsubstituted alkyl group or a substituted alkyl group (for example, an alkyl group substituted by W described above). The substituent group of the substituted alkyl group is preferably a substituent group higher in hydrophilicity than an iodine atom, more preferably a substituent group having hydrophilicity equal to or higher than that of a chlorine atom, and particularly preferably a substituent group having hydrophilicity equal to or higher than that of a fluorine atom. R.sup.23 is more preferably a hydrogen atom or an unsubstituted alkyl group, and particularly preferably a hydrogen atom or a methyl group. It is particularly preferred that Y.sup.21 is a sulfur atom.

X.sup.21 and X.sup.22 each represents an oxygen atom or a sulfur atom. At least one thereof is preferably a sulfur atom, and both are preferably sulfur atoms.

V.sup.21, V.sup.22, V.sup.23, V.sup.24, V.sup.25 and V.sup.26 each represents a hydrogen atom or a monovalent substituent group. Two adjacent substituent groups of V.sup.21, V.sup.22, V.sup.23 and V.sup.24, or V.sup.25 and V.sup.26 may combine with each other to form a saturated or unsaturated condensed ring. However, it is better that no condensed ring is formed. Although the monovalent substituent groups include W described above, preferred is an alkyl group (for example, methyl), an aryl group (for example, phenyl), an aromatic heterocyclic group (for example, 1-pyrrolyl), an alkoxyl group (for example, methoxy), an alkylthio group (for example, methylthio), a cyano group, an acyl group (for example, acetyl), an alkoxycarbonyl group (for example, methoxycarbonyl) or a halogen atom (for example, fluorine, chlorine, bromine or iodine), more preferred is a methyl group, a methoxy group, a cyano group or a halogen atom, still more preferred is a halogen atom, particularly preferred is fluorine, chlorine or bromine, and most preferred is chlorine. V.sup.21, V.sup.22 and V.sup.24 are each preferably a hydrogen atom.

When Y.sup.21 is a sulfur atom, at least one of V.sup.25 and V.sup.26 is preferably a halogen atom (for example, fluorine, chlorine, bromine or iodine). More preferably, V.sup.26 is a hydrogen atom, and V.sup.25 is fluorine, chlorine or bromine, particularly preferably chlorine.

Although R.sup.21 and R.sup.22 each represents an alkyl group substituted by an acid group, at least one of R.sup.21 and R.sup.22, which are alkyl groups each substituted by an acid group as with R.sup.1 described above, is preferably an alkyl group substituted by an acid group other than a sulfo group. More preferably, one of R.sup.21 and R.sup.22 is an alkyl group substituted by an acid group other than a sulfo group (preferably a carboxyl group or an alkanesulfonylcarbamoyl group) and the other is an alkyl group substituted by a sulfo group. Specific examples and preferred combinations of these alkyl groups each substituted by an acid group are the same as with R.sup.1 described above. Still more preferably, one of R.sup.21 and R.sup.22 is a carboxymethyl group or a methanesulfonylcarbamoylmethyl group. Particularly preferably, R.sup.21 is a carboxymethyl group or a methanesulfonylcarbamoylmethyl group, and R.sup.22 is a 3-sulfopropyl group.

M.sup.21 represents a counter ion, and m.sup.21 represents a number of 0 or more necessary for neutralizing a charge in a molecule. M.sup.21 and m.sup.21 are the same as with M.sup.1 and m.sup.1 described above. M.sup.21 is particularly preferably a cation, and preferred examples of the cations include sodium, potassium, triethylammonium, pyridinium and N-ethylpyridinium.

In general formula (IV), Y.sup.31 represents an oxygen atom, a sulfur atom or N--R.sup.33, wherein R.sup.33 represents a hydrogen atom, an unsubstituted alkyl group or a substituted alkyl group (for example, an alkyl group substituted by W described above). The substituent group of the substituted alkyl group is preferably a substituent group higher in hydrophilicity than an iodine atom, more preferably a substituent group having hydrophilicity equal to or higher than that of a chlorine atom, and particularly preferably a substituent group having hydrophilicity equal to or higher than that of a fluorine atom. R.sup.33 is more preferably a hydrogen atom or an unsubstituted alkyl group, and particularly preferably a hydrogen atom or a methyl group. It is particularly preferred that Y.sup.31 is a sulfur atom.

X.sup.31 and X.sup.32 each represents an oxygen atom or a sulfur atom. At least one thereof is preferably a sulfur atom, and both are preferably sulfur atoms.

V.sup.31, V.sup.32, V.sup.33, V.sup.34, V.sup.35 and V.sup.36 each represents a hydrogen atom or a monovalent substituent group. Two adjacent substituent groups of V.sup.31, V.sup.32, V.sup.33 and V.sup.34, or V.sup.35 and V.sup.36 may combine with each other to form a saturated or unsaturated condensed ring. However, it is better that no condensed ring is formed. A