JPH04153646A - Novel photographic coupler - Google Patents

Abstract

PURPOSE:To provide the novel color photographic coupler capable of forming a cyan dye image excellent in fastness to heat, humidity, and light by using a specified material. CONSTITUTION:The material to be used is represented by formula I in which each of R1 - R3 and Y is H or a substituent; and X is H or a group to be released by coupling with the oxidation product of a color developing agent, thus permitting the obtained cyan dye coupler to be used as a color photographic material and to form a dye image to be fast to heat, humidity, and light and to form the cyan dye image not changing tone against heat, humidity, and light.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a novel photographic coupler used as a color photographic material, and more particularly, to a novel photographic coupler that forms a dye image with excellent fastness to heat, humidity, and light. Regarding photographic couplers.

[Background of the Invention] After a silver halide photographic material is exposed to light and then subjected to color development processing, the oxidized aromatic primary amine color developing agent and the dye-forming coupler react in the exposed area. Pigments are produced and a color image is formed.

Generally, this photographic method uses a subtractive color reproduction method to form yellow-magenta and yellow-colored images.

Examples of photographic couplers used to form the above-mentioned yellow image include acylacetanilide couplers, and examples of couplers used to form magenta images include pyrazolone, pyrazolobenzimidazole, and pyrazolone. Triazole or indacylon couplers are known, and as couplers for forming cyan images, for example, phenol or naphthol couplers are generally used.

It is desired that the dye image obtained in this way does not change color or fade even if it is exposed to light for a long time or stored under high temperature and high humidity.

However, phenolic couplers and naphthol couplers, which have been studied as couplers for forming cyan dyes, have poor spectral absorption characteristics, heat resistance, moisture resistance, light resistance, etc. of the formed cyan dye images. This is still unsatisfactory, and various proposals have been made to improve this, including devising substituents, but a compound that satisfies all of these has so far not been obtained.

Therefore, the present inventors conducted further research regarding the above points, and as a result, discovered a photographic coupler that can form a cyan dye image that does not change in hue due to heat, humidity, or light.
The present invention has now been completed.

[Object of the Invention] A first object of the present invention is to provide a novel photographic coupler that can be used as a color photographic material.

A second object of the present invention is to provide a photographic coupler that forms a cyan dye image that does not change in hue due to heat, humidity, or light.

[Structure of the Invention] The above object of the present invention is achieved by a photographic coupler represented by the general formula [I] (hereinafter referred to as the coupler of the present invention).

General formula [I1 [In the formula, R, R, , R, and Y represent hydrogen atoms or substituents, and R2 and R3 may be combined to form a ring.

Alternatively, it represents a hydrogen atom or a substituent that is eliminated by reaction with an oxidized product of a color developing agent. ] Hereinafter, the present invention will be explained in more detail.

R, R,, R, and Y in general formula [I] represent a hydrogen atom or a substituent, and the substituents represented by R, R, and R1 are not particularly limited, or are typically , alkyl, aryl, anilino, anruamino, sulfonamide, alkylthio, arylthio, alkenyl, cycloalkyl, etc. In addition, halogen atoms, cycloalkenyl, alkynyl, heterocycle, sulfonyl, sulfinyl, phosphonyl, acyl , carbamoyl, sulfamoyl, cyan, alkoxy/, sulfonyloxy, aryloxy, heterocyclicoxy, siloquine, acyloxy, carbamoyloxy, amino, alkylamino, imide, ureido, sulfamoylamino, alkoxycarbonylamino, aryloxycarbonylamino, alkoxycarbonyl, aryloxycarbonyl, heterocyclic thio, thioureido, carboxy,
Also included are six groups such as hydroquine, mercapto, nitro, and sulfo, as well as spiro compound residues, bridged hydrocarbon compound residues, and the like.

Among the substituents represented by R, R, and R1, the alkyl group preferably has 1 to 32 carbon atoms, and may be linear or branched.

As the aryl group, a phenyl group is preferred.

Examples of the acylamino group include an alkylcarbonylamino group and an arylcarbonylamino group.

Examples of the sulfonamide group include an alkylsulfonylamino group and an arylsulfonylamino group.

Examples of the alkyl component and aryl component in the alkylthio group and arylthio group include the aforementioned alkyl groups and aryl groups.

The alkenyl group preferably has 2 to 32 carbon atoms, and the cycloalkyl group preferably has 3 to 2 carbon atoms, particularly 5 to 7 carbon atoms, and the alkenyl group may be linear or branched.

The cycloalkenyl group has 3 to I2 carbon atoms, especially 5
-7 is preferred.

Sulfonyl groups include alkylsulfonyl groups, arylsulfonyl groups, etc. Sulfinyl groups include alkylsulfinyl groups, arylsulfinyl groups, etc. Phosphonyl groups include alkylphosphonyl groups, alkoxyphosphonyl groups, aryloxyphosphonyl groups, arylphosphonyl groups, etc. Niacyl groups include alkylcarbonyl groups, arylcarbonyl groups, etc.; carbamoyl groups include alkylcarbamoyl groups, arylcarbamoyl groups, etc.; sulfamoyl groups include alkylsulfamoyl groups,
Arylsulfamoyl groups, etc.; Acyloxy groups include alkylcarbonyloxy groups, arylcarbonyloxy groups, etc.; carbamoyloxy groups include alkylcarbamoyloxy groups, arylcarbamoyloxy groups, etc.; ureido groups include alkylureido groups, arylureido groups, etc. ; As the sulfamoylamino group, an alkylsulfamoylamino group, an arylsulfamoylamino group, etc.; as a heterocyclic group, a 5- to 7-membered one is preferable, and specifically, a 2-furyl group, a 2-thienyl group , 2-pyrimidinyl group, 2-benzothiazolyl group, 1-pyrrolyl group, 1-tetrazolyl group, etc.: The heterocyclic oxy group preferably has a 5- to 7-membered heterocycle, for example, 3.4-, 5.6- Tetrahydrobilanyl-2-oxy group, 1-phenyltetrazole-5-
Oxy group, etc.; The heterocyclic thio group is preferably a 5- to 7-membered heterocyclic thio group, such as 2-pyridylthio group, 2-benzothiazolylthio group, 2,4-diphenoxy1.3.5-triazole-6 Monothio group, etc.: Siloxy group includes trimethylsiloxy group, triethylsiloxy group, dimethylbutylsiloxy group, etc.; imide group includes succinimide group, 3-heptadecylsuccinimide group, phthalimide group, glutarimide group, etc.; The compound residue is spiro[3,3]hebutane-
1-yl, etc.; As a bridged hydrocarbon compound residue, bicyclo[2°2.1
]Heptan-1-yl, trisyphnia [3°3.1
．． 137] decane-1-yl, 77-dimethyl-bicyclo[2,2,1]hebutan-1-yl, and the like.

can be mentioned.

Among the above substituents, R2 and R3 include, for example, an alkyl group, an aryl group, a carboxyl group, an oxycarbonyl group, a cyano group, a hydroxy group, an alkoxy group, an aryloxy group, an amino group, an amide group, and a sulfonamide group. , hydrogen atoms, halogen atoms, etc. are preferred.

R2 and R1 may be combined to form a ring, and the chain ring is preferably a saturated or unsaturated 5-membered ring, 7-membered ring, 8-membered ring, etc., and specifically, benzene, pyridine ring, and quinoline ring. Examples include rings.

The above group may further have a substituent such as a long-chain hydrocarbon group or a diffusion-resistant group such as a polymer residue.

Examples of the group that is released by reaction with the oxidized product of the color developing agent represented by quin, alkoxycarbonyloxy, aryloxycarbonyl, alkyloxaryluoquine, alkoxyoxalyloxy, alkylthio, arylthio, heterocyclic thio, alkyloxythiocarbonylthiosulfonamide, nitrogen-containing heterocycle bonded via N atom, alkyl oxalyloxy carponylamino, aryloxycarbonylamino Y' Rb (RI R2 , R3' and Y' are the above R, R2
Each has the same meaning as H and Y, and Ra and Rb represent a hydrogen atom, an aryl group, an alkyl group, or a heterocyclic group. ) etc., preferably a halogen atom. Among these, particularly preferable ones represented by X are hydrogen atoms and chlorine atoms.

In the general formula [I], Y represents a hydrogen atom or a substituent, and preferable examples of the substituent represented by Y include those that are separated from the compound of the present invention after the compound of the present invention reacts with the oxidized form of the developing agent. However, for example, the substituent represented by Y is
Groups that can be separated under alkaline conditions, such as those described in JP-A-61-228444, and JP-A-56-1
Examples include substituents that are coupled off by reaction with oxidized developing agents as described in No. 33734 and the like.

Preferably Y is a hydrogen atom.

Therefore, the compound of the present invention represented by general formula [I] is more preferably represented by general formula [I1].

General formula [] [wherein R, R2, Ri and X have the same meanings as RI R2, R3 and X of the compound represented by general formula [I]. Next, typical examples of compounds of the present invention are shown below, but the present invention is not limited thereto.

Margin below The couplers of the invention described above are described in the Journal of.

Organic, Chemistry (J, Org, Che+
+, ).

1959, Vol. 24, No. 779-787, and can be easily synthesized according to the described synthesis method.

Incidentally, the above-mentioned cited document does not describe at all that the compound described in the document is useful as a coupler for color photography.

Synthesis Example (Synthesis of Exemplified Compound 1) 13.2 g of 2-aminoimidazole 1/2 sulfate (0,
1 mol) and 14.3 g (0.11 mol) of ethyl acetoacetate were added to 60 ml of acetic acid and reacted under boiling reflux for 5 hours. After the reaction is completed, 60 ml of water is added, and the precipitated crystals are collected by filtration and further recrystallized with water to obtain 1 g (yield: 72%) of the target exemplary compound 1. Melting point 239
The structure was confirmed by NMR, IR, and MASS.

The couplers of the invention typically have IX per mole of silver halide.
10-' mol-1 mol, preferably I x 10-2
It can be used in the range of mol to g x (0-' mol).

The couplers of the present invention can also be used in combination with other types of cyan couplers.

The methods and techniques used for conventional dye-forming couplers apply similarly to the couplers of the invention.

The coupler of the present invention can be used as a material for forming color photographs by any coloring method, and specific examples include external coloring method and internal coloring method. When used as an external coloring method, the coupler of the present invention can be dissolved in an alkaline aqueous solution or an organic solvent (eg, alcohol) and added to a developing solution.

When the coupler of the present invention is used as a material for forming a color photograph by an internal coloring method, the coupler of the present invention is incorporated into a photographic light-sensitive material.

Typically, a method is preferably used in which the coupler of the present invention is blended into a silver halide emulsion and this emulsion is coated on a support to form a color light-sensitive material. The coupler of the present invention is used, for example, in color photographic materials such as color negative and positive films and color photographic paper.

This color photographic paper and other light-sensitive materials using the coupler of the present invention may be monochromatic or multicolor. In a multicolor light-sensitive material, the coupler of the present invention may be contained in any layer, but it is usually contained in a red-sensitive silver halide emulsion layer.

Multicolor light-sensitive materials have dye image-forming constituent units that are sensitive to each of the three primary color regions of the spectrum. Each structural unit can consist of a single or multiple emulsion layer sensitive to a certain region of the spectrum. The constituent layers of the photosensitive material, including the layers of image-forming units, can be arranged in various orders as is known in the art. A typical multicolor light-sensitive material is a cyan dye image-forming unit consisting of at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler (at least one of the cyan couplers is the cyan coupler of the present invention). ), a magenta dye image-forming unit consisting of at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler, at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler. It consists of a yellow dye image-forming structural unit consisting of an emulsion layer supported on a support.

The photosensitive material may contain additional layers such as filter layers, interlayers,
It can have a protective layer, an undercoat layer, etc.

In order to incorporate the coupler of the present invention into an emulsion, a conventionally known method may be followed. For example, the present invention may be added to a high boiling point organic solvent having a boiling point of 175°C or higher such as tricresyl phosphate or dibutyl phthalate, or a low boiling point solvent such as butyl acetate or butyl propionate, or a mixture thereof as necessary. After the coupler is dissolved alone or in combination, it can be mixed with an aqueous gelatin solution containing a surfactant, then emulsified in a high-speed rotary mixer or colloid mill, and then added to and incorporated into the silver halide emulsion. .

Silver halide compositions preferably used in the light-sensitive material using the coupler of the present invention include silver chloride, silver chlorobromide, and silver chloroiobromide. Furthermore, a combination mixture such as a mixture of silver chloride and silver bromide may be used. That is, when a silver halide emulsion is used for color photographic paper, particularly fast developability is required, so it is preferable that the halogen composition of the silver halide contains chlorine atoms, and at least 1%.
It is particularly preferable to use silver chloride, silver chlorobromide or silver chloroiodobromide containing silver chloride.

The silver halide emulsion is chemically sensitized by conventional methods. Furthermore, it can be optically sensitized to a desired wavelength range.

Silver halide emulsions are used during the manufacturing process of photosensitive materials, during storage,
Alternatively, compounds known as antifoggants or stabilizers in the photographic industry may be added for the purpose of preventing fog during photographic processing and/or keeping photographic performance stable.

In the color photosensitive material using the coupler of the present invention, color antifoggants, dye image stabilizers, ultraviolet inhibitors, antistatic agents, matting agents, surfactants, etc., which are normally used in photosensitive materials, can be used. .

Regarding these, for example, Research Disclosure +
-(Research Disclosure)
176, pages 22-31 (December 1978) can be referred to.

An image can be formed on a color photographic material using the coupler of the present invention by subjecting it to a color development treatment known in the art.

A color photographic light-sensitive material using the coupler of the present invention may be impregnated with a color developing agent as the color developing agent itself or as a precursor thereof in the hydrophilic colloid layer, and then processed in an alkaline activating bath.

A color photographic material using the coupler of the present invention is subjected to a bleaching treatment and a fixing treatment after color development.

Bleaching treatment may be performed simultaneously with fixing treatment.

After the fixing process, a washing process is usually performed.

Further, a stabilization treatment may be performed as an alternative to the water washing treatment, or both may be used in combination.

[Example] Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 A red-sensitive color photosensitive material sample 1 was prepared by sequentially coating the following layers on a paper support laminated on both sides with polyethylene from the support side. Note that the amount of the compound added is per rrr unless otherwise specified (silver halide is a silver equivalent value).

1st layer: Emulsion layer 1.2 g of gelatin, 0.30 g of red-sensitive silver chlorobromide emulsion (containing 96 mol% silver chloride) and dioctyl phosphate)
Comparative cyan coupler a dissolved in 1.35 g 9.
Red-sensitive emulsion layer consisting of 10-' moles of IX.

2nd layer: protective layer gelatin 0.50. A protective layer containing. In addition, as a hardening agent, 2
, 4-dichloro-6-hydroxy-s-triazine sodium salt was added in an amount of 0.017 g per 1 g of gelatin.

Next, Samples 2 to 8 of the present invention were prepared in exactly the same manner as in Sample 1, except that comparative coupler a was replaced with the coupler shown in Table 1 (the amount added was the same molar amount as comparative coupler a).

An activator, anti-spill agent (a mixture of 2-methylisothiazol-3-one and 5-chloro-2-methylisothiazol-3-one) was added to each sample.

Samples 1 to 8 obtained above were each subjected to wedge exposure according to a conventional method, and then developed in the next step.

[Development processing process] Color development 38°C 3 minutes 30 seconds Bleach fixing 38°C 1 minute 30 seconds Stabilization processing 25°C ~ 3 (1'C 3 minutes drying)
Drying: 75°C to 80°C The composition of the treatment liquid used in the two-part treatment step is as follows.

[Color developer cobenzyl alcohol 15ml! Ethylene glycol 15 m 9 Potassium sulfite 2.0 g Potassium bromide
0.7g sodium chloride
0.2g potassium carbonate
30.0g hydroxylamine sulfate 3.
0 g polyphosphoric acid (TPPS) 2.5□
3-Methyl-4-amino-N-ethyl-N-(β-methanesulfonamidoethyl)aniline sulfate 55g optical brightener (
4,4'-diaminostilbendisulfonic acid derivative) 1.0 g potassium hydroxide 2.0 g water was added to bring the total amount to I.
g and pHl (adjust to 1.20).

[Bleach-fix solution Ferric ammonium coethylenediaminetetraacetic acid dihydrate 60 g Ethylenediaminetetraacetic acid 3 g Ammonium thiosulfate (70% solution) 100 mg Ammonium sulfite (
40% solution) Adjust the pH to 7.1 with 27.5 ml potassium carbonate or glacial acetic acid, and add water to bring the total volume to IR.

[Stabilizing liquid] 5-chloro-2-methyl-4-isothiazolin-3-one t,og ethylene glycol IOg Water is added to prepare IM.

The concentrations of Samples 1 to 8 treated above were measured using a densitometer (Model KD-7 manufactured by Konica Corporation), and each of the above-treated samples was measured at high temperature and high humidity (60°C, 80% RH).
) The dye image was left in an atmosphere for 14 days, and the heat resistance and moisture resistance of the dye image were examined.

Further, each sample was irradiated with a xenon fade meter for 10 days, and then the density was measured to examine light resistance. The results are shown in Table-1. However, the heat resistance, humidity resistance, and light resistance of the dye image are expressed as the percentage of dye remaining after the heat resistance, humidity resistance, and light resistance tests with respect to the initial density of 1.0.

Comparative coupler a Table 1 As is clear from the results in Table 1, the samples using the coupler of the present invention all had higher dye residual rates and better heat resistance and moisture resistance than the samples using the comparative coupler. It can be seen that it is excellent and robust. It can also be seen that the light resistance is the same or higher, indicating that it is excellent.

Example 2 A red-sensitive color photosensitive material (sample 9) was prepared by sequentially coating the following layers on a triacetate film as a base material from the support side. Incidentally, the amount of the compound added is per unit unless otherwise specified (silver halide is a silver equivalent value).

1st layer: Emulsion layer 1.4 g of gelatin, 15 g of red-sensitive silver iodobromide emulsion (containing 4 mol% silver iodide) and tricresyl phosphate 1.
Comparative cyan coupler b8, OXl0-' dissolved in 1 g
A red-sensitive emulsion layer consisting of moles.

2nd layer: Protective layer Protective layer containing 1.5 g of gelatin. In addition, as a hardening agent, 2,
0.017 g of 4-dichloro-6-hydroxy-5-) riazine sodium salt was added per 1 g of gelatin.

Next, for sample 9, the comparison cyan coupler b is shown in Table-2.
The coupler shown in (the amount added is the same molar amount as comparative coupler b)
Samples 10 to 10 of the present invention were prepared in exactly the same manner except that
1B was produced.

An activator, anti-spill agent (a mixture of 2-methylisothiazol-3-one and 5-chloro-2-methylisothiazol-3-one) was added to each sample.

The obtained film samples were wedge exposed in a conventional manner and color developed according to the color processing steps described below.

Comparative coupler b [Processing process] (Processing temperature 38°C) Processing time Color development 3 minutes 15 seconds Bleaching
Rinse with water for 6 minutes and 30 seconds, set for 3 minutes and 15 seconds
Arrive 6 minutes 30
Second wash
Stabilization for 3 minutes and 15 seconds Drying for 1 minute and 30 seconds The composition of the treatment liquid used in each treatment step is as follows.

[Color developer] 4-amino-3-methyl-N- Ethyl-N-(β-hydroxy ethyl)aniline sulfate anhydrous sodium sulfite Hydroxyamine 1/2 sulfate Anhydrous potassium carbonate sodium bromide Nitrilotriacetic acid trisodium (monohydrate salt) potassium hydroxide Add water to make 1g, and add hydroxide. Adjust the pH to 10.6.

[Bleach solution] Ethylenediaminetetraacetic acid iron ammonium salt Ethylenediaminetetraacetic acid diammonium chloroammonium bromide 2.5 g 1.0 g Using thorium 4.75° 4.25 g 2.0 g 37.5r 1.3 g too, ( 1g 10.0g 150.0r Glacial acetic acid 10.0g Add water to make 1g, and adjust the pH to 6.0 for aqueous ammonia.

[Fixer] Ammonium thiosulfate 175.0g Anhydrous sodium sulfite 8.62 Sodium metasulfite 2.3□ Add water to make 1g,
Adjust the pH to 8.0 using acetic acid.

[Stabilizing liquid] Formalin (37% by weight) 1.5 mN
Conidax (manufactured by Konica Corporation) Add 7.5 ml of water to make III.

For the samples 9 to 16 treated above, the transmission density was measured using a densitometer (model KD-7R, manufactured by Konica Corporation), and each of the above-treated samples was measured at high temperature and high humidity (60°C, 8°C).
The dye image was left for 14 days under an atmosphere (0% RH), and the heat resistance and moisture resistance of the dye image were examined.

In addition, each sample was irradiated with a xenon fade meter for 10 days to examine light resistance. The results are shown in Table-2. However, the heat resistance, moisture resistance and light resistance of the dye image are expressed as the percentage of dye remaining after the heat resistance, moisture resistance and light resistance tests with respect to the initial density of 1.0.

Table 2 As is clear from the results in Table 2, the samples using the coupler of the present invention all had higher dye residual rates and superior heat and moisture resistance than samples using the comparative coupler. It can be seen that it is robust. It can also be seen that the light resistance is the same or better, indicating that it is excellent.

Example 3 The following layers were sequentially coated on a triacetyl cellulose film support from the support side to prepare red-sensitive color reversal photographic materials 17 to 22 containing the couplers shown in Table 3.

1st layer: Emulsion layer Gelatin 1.4g, red-sensitive silver chlorobromide emulsion (silver chloride 96
mol%) 0.5g and dibutyl phthalate 1
．． Coupler 9,1×1O− shown in Table 3 dissolved in 5g
Red-sensitive emulsion layer consisting of 4 moles.

2nd layer: protective layer protective layer containing 0.5 g of gelatin. In addition, as a hardening agent, 2,
4-dichloro-6-hydroxy-s-triazine sodium salt was added in an amount of 0.017 g per 1 g of gelatin.

An activator, anti-spill agent (a mixture of 2-methylisothiazol-3-one and 5-chloro-2-methylisothiazol-3-one) was added to each sample.

The samples obtained above were each subjected to wedge exposure according to a conventional method, and then developed in the next step.

[Reversal process] Process time Temperature box - Current R 6 minutes 38℃ Water washing 2 minutes 3
8℃ inversion 2 minutes
38℃ color development @ 6 minutes 38℃ tone
Regular 2 minutes 38
℃ bleach 6 minutes
38℃ fixation 4 minutes
Wash with water at 38℃ for 4 minutes
Stable at 38℃ for 1 minute
Dry at 38℃
The following composition was used for the room temperature treatment solution.

[First developer Sodium cotetrapolyphosphate 2g Sodium sulfite 20g Hydroquinone
Monosulfonate 30, sodium carbonate (monohydrate) 3
0 □ 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone 2 g Potassium bromide 2.5 g Potassium thiocyanate 1.22 Potassium iodide (0.1% solution) 2 mg Add water
iooom (1 [Reversal solution] Nitrilotrimethylenephosphonic acid, hexasodium salt 3g stannous chloride (dihydrate) Igp-aminophenol 0.1g sodium hydroxide
5g glacial acetic acid
1000 m by adding 15 mN water
l) [Color developer] Sodium tetrapolyphosphate 2g Sodium sulfite 7g Sodium tertiary phosphate (dodecahydrate) Potassium bromide Potassium iodide (0.1% solution) Sodium hydroxide N-ethyl-N- citrazate Add (β-methanesulfonamidoethyl)-3-methyl-4-aminoaniline sulfate ethylenediamine water [Adjustment solution] Sodium sulfite ethylenediamine sodium tetraacetate (dihydrate) Add thioglycerin glacial acetic acid water [Bleach] Liquid] Sodium ethylenediaminetetraacetate (dihydrate) 0.4 i1 mfl Iron(III) ethylenediaminetetraacetate Ammonium (dihydrate) L20. Og potassium bromide LOo, add Og water
1000 mfl [Fixer] Ammonium thiosulfate go, o g Sodium sulfite 5.0 g Sodium bisulfite 5.0 g Add water
1000 ml [stabilizing liquid coformin (37% by weight) 5.0 mj Konidax (manufactured by Konica Corporation) 5. Add ornl water 1000 mj? For each sample treated above, the heat resistance, moisture resistance, and light resistance of the dye image were examined in the same manner as in Example 2. Table the results.
Shown in 3.

Margin Table 3 below As is clear from Table 3, the samples using the coupler of the present invention all have a higher dye residual rate, superior heat resistance and moisture resistance, and are more durable than samples using the comparative coupler. It can be seen that it is. Furthermore, it can be seen that the light resistance is also the same or higher, which indicates that the light resistance is excellent.

Effects of the Invention Dye images formed from couplers of the invention are robust to heat, humidity and light.

Claims (1)

[Claims] A photographic coupler represented by the general formula [I]. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [In the formula, R_1, R_2, R_3 and Y represent hydrogen atoms or substituents, and R_2 and R_3 may be combined to form a ring. X represents a hydrogen atom or a substituent that is eliminated by reaction with an oxidized product of a color developing agent. ]