JPH045372B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a silver halide color photographic light-sensitive material, and more particularly to a silver halide color photographic light-sensitive material with improved color reproducibility. [Prior Art] A method for forming a dye image using a silver halide color photographic light-sensitive material includes a method in which a dye is formed by a reaction between a photographic coupler and an oxidized form of a color developing agent. Magenta, yellow and cyan couplers are used as photographic couplers for reproduction, and aromatic primary amine color developing agents are used as color developing agents. A dye such as an azomethine dye is formed by the reaction between the coupler and an oxidized form of an aromatic primary amine color developing agent, and a reaction between the cyan coupler and an oxidized form of an aromatic primary amine color developing agent forms a dye such as an azomethine dye.
Pigments such as indoaniline dyes are formed. Among these, in order to form a magenta image, 5-pyrazolone, cyanoacetophenone,
Indazolone, pyrazolobenzimidazole, pyrazolotriazole couplers, etc. are used. Most of the conventional magenta color image forming couplers that have been put to practical use have been 5-pyrazolone couplers. Color images formed from 5-pyrazolone couplers have excellent fastness to light and heat, but the color tone of this dye is not sufficient;
Unnecessary absorption with a yellow component exists near 430 nm, and the visible light absorption spectrum near 550 nm is also broad, causing color turbidity and resulting in photographic images lacking in vividness. U.S. patent for coupler without unnecessary absorption
3725067, JP 59-162548, JP 59-171956
1H-pyrazolo[3,2-
c]-s-triazole type coupler, 1H-imidazo[1,2-b]-pyrazole type coupler, 1H-
pyrazolo[1,5-b]-pyrazole coupler,
Alternatively, 1H-pyrazolo[1,5-d]tetrazole type couplers are particularly excellent. However, the light fastness of dye images formed from these couplers is significantly lower. When these couplers are used in photosensitive materials, especially photosensitive materials suitable for direct viewing, they impair the essential requirement of photographic materials, which is to record and preserve images. Therefore, it was difficult to put it into practical use. Therefore, as a method of improving light resistance, the use of phenol-based or phenyl ether-based antioxidants is described in JP-A-59-125732. However, this method did not provide a sufficient effect of improving light resistance. On the other hand, the compounds represented by the general formulas [XI] and [XII] have a remarkable effect of improving light resistance. However, this method has the drawback of increasing color staining due to long-term storage (or heating) of photographic images. Furthermore, photographic performance (gradation) was not fully satisfactory. In particular, the low density portion (leg portion) had a drawback of being soft in tone. Therefore, there has been a desire for a photographic light-sensitive material that is free from any of these drawbacks and is capable of forming magenta images with good light resistance. [Object of the Invention] The object of the present invention is to provide a silver halide that has good color reproducibility of magenta images, good light fastness of magenta images, no increase in color contamination due to heat, and good photographic performance (gradation). Our objective is to provide photographic materials. [Structure of the Invention] The object of the present invention is to at least one of the couplers represented by the following general formula [] and at least one of the compounds represented by the following general formula [XI] and [XII]. This was achieved using a silver halide photographic material characterized by containing . General formula [] In the formula, R ₁ represents a substituent whose root atom directly connected to the ring is a carbon atom and there is only one hydrogen atom bonded to the carbon atom, and R ₂ represents a substituent different from R ₁ . represent. Further, X represents a hydrogen atom or a substituent that can be separated by reaction with an oxidized product of a color developing agent. General formula [XI] General formula [XII] In the formula, X ¹ , X ² and X ⁴ each represent an oxygen atom. X ³ represents a hydroxyl group, Y represents a sulfur atom, and R ¹ , R ² and R ³ each represent a hydrogen atom or an alkyl group. However, at least two of R ¹ , R ² and R ³ represent an alkyl group. ^R4 to ^R9 are
Represents an alkyl group, aryl group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, acyl group, acylamino group, alkylamino group, carbamoyl group, sulfamoyl group, sulfonamide group, sulfonyl group or cycloalkyl group . Alternatively, they may be connected to each other to form a 5- or 6-membered ring. M
represents a metal atom. a, b, c, d, e and f
each represents an integer from 0 to 4. Next, the present invention will be specifically explained. The above general formula according to the present invention [] General formula [] In the magenta coupler represented by R ₁
Examples of substituents represented by include alkyl groups, cycloalkyl groups, alkenyl groups, and cycloalkenyl groups in which the root atom directly connected to the ring is a carbon atom, and only one hydrogen atom is bonded to the carbon atom. , an alkynyl group, a heterocyclic group, a spiro compound residue, and a bridged hydrocarbon compound residue. The alkyl group represented by R ₁ has 1 carbon number
~32, alkenyl groups, alkynyl groups with 2 to 32 carbon atoms, cycloalkyl groups, cycloalkenyl groups with 3 to 12 carbon atoms, especially 5 to 32 carbon atoms.
7 is preferred. In addition, these alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, and cycloalkenyl groups are substituents (e.g., aryl, cyano, halogen atom, heterocycle, cycloalkyl, cycloalkenyl, spirocyclic compound residue, bridged hydrocarbon In addition to compound residues, those substituted via a carbonyl group such as acyl, carboxyl, carbamoyl, and alkoxycarbonyl, and those substituted via a hetero atom, specifically oxygen atoms such as hydroxyl, alkoxy, and aryloxy. Those substituted through a nitrogen atom such as nitro, amino (including dialkylamino, etc.), sulfamoylamino, alkoxycarbonylamino, aryloxycarbonylamino, acylamino, sulfonamide, imide, ureido, etc. , alkylthio, arylthio, heterocyclic thio, sulfonyl, sulfinyl, sulfamoyl, etc., which are substituted through a sulfur atom, and phosphonyl, which is substituted through a phosphorus atom.Specifically, for example, Isopropyl group, sec-butyl group, sec-amyl group, 1-ethylpropyl group,
1-ethylpentyl group, 1-hexylnonyl group,
1-heptyldecyl group, difluoromethyl group, 1
-Ethoxytridecyl group, 1-methoxyisopropyl group, 1-phenylisopropyl group, 2-
[4′-(4″-dodecyloxybenzenesulfonamido)phenyl] Examples include isopropyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc. The heterocyclic group represented by R ₁ is a 5- to 7-membered one. is preferable, and may be substituted or fused. Examples of the spiro compound residue represented by R ₁ include spiro[3.3]heptan-1-yl. Examples of substituents that can be removed by reaction with the oxidized product of the color developing agent include halogen atoms (chlorine, bromine, fluorine, etc.), as well as substituents via carbon, oxygen, sulfur, or nitrogen atoms. Examples of groups substituted via a carbon atom include carboxyl groups, as well as groups of the general formula (R ₁ and R ₂ have the same meanings as R ₁ and R ₂ above, and R ₃ and R ₄ represent a hydrogen atom, an aryl group, an alkyl group, or a heterocyclic group.) Enylmethyl group is mentioned. Examples of groups substituted via an oxygen atom include alkoxy groups, aryloxy groups, heterocyclic oxy groups, acyloxy groups, sulfonyloxy groups, alkoxycarbonyloxy groups, aryloxycarbonyl groups, alkyloxalyloxy groups, and alkoxyoxalicyloxy groups. Examples include groups. The alkoxy group may further have a substituent,
For example, ethoxy group, 2-phenoxyethoxy group,
2-cyanoethoxy group, phenethyloxy group, p
-chlorobenzyloxy group and the like. The aryloxy group is preferably a phenoxy group, and the aryl group may further have a substituent. Specifically, phenoxy group, 3-methylphenoxy group, 3-dodecylphenoxy group, 4-methanesulfonamidophenoxy group, 4-[α-
(3′-pentadecylphenoxy)butanamide]
Phenoxy group, hexadecylcarbamoylmethoxy group, 4-cyanophenoxy group, 4-methanesulfonylphenoxy group, 1-naphthyloxy group, p
-methoxyphenoxy group and the like. The heterocyclic oxy group is preferably a 5- to 7-membered heterocyclic oxy group, and may be a fused ring,
Moreover, it may have a substituent. Specifically, 1
-phenyltetrazolyloxy group, 2-benzothiazolyloxy group and the like. Examples of the acyloxy group include acetoxy groups, alkylcarbonyloxy groups such as butanoyloxy groups, alkenylcarbonyloxy groups such as cinnamoyloxy groups, and arylcarbonyloxy groups such as benzoyloxy groups. Examples of the sulfonyloxy include a butanesulfonyloxy group and a methanesulfonyloxy group. Examples of the alkoxycarbonyloxy group include an ethoxycarbonyloxy group and a benzyloxycarbonyloxy group. Examples of the aryloxycarbonyl group include a phenoxycarbonyloxy group. Examples of the alkyloxalyloxy group include methyloxysalyloxy group. Examples of the alkoxyoxalyloxy group include an ethoxyoxalyloxy group. Examples of the group substituted via a sulfur atom include an alkylthio group, an arylthio group, a heterocyclic thio group, and an alkoxycarbonylthio group. As the alkylthio group, butylthio group, 2
-cyanoethylthio group, phenethylthio group, benzylthio group, etc. As the arylthio group, phenylthio group,
4-methanesulfonamidophenylthio group, 4-
Examples include dodecylphenethylthio group, 4-nonafluoropentanamidephenethylthio group, 4-carboxyphenylthio group, and 2-ethoxy-5-t-butylphenylthio group. Examples of the heterocyclic thio group include 1-phenyl-1,2,3,4-tetrazolyl-5-thio group and 2-benzothiazolylthio group. Examples of the group substituting via the nitrogen atom include the general formula

〔Example〕

The present invention will be explained in more detail with reference to specific examples below, but the embodiments of the present invention are not limited thereto. Example 1 40 g of the above exemplary magenta coupler 11 was dissolved in a mixed solvent of 40 ml of dioctyl phthalate and 100 ml of ethyl acetate, and this solution was dissolved in 300 ml of a 5% aqueous gelatin solution containing sodium dodecylbenzenesulfonate.
The resulting dispersion was dispersed using a homogenizer, and the resulting dispersion was mixed with 500 g of green-sensitive silver chlorobromide emulsion (Ag amount: 30 g).
(containing), and a coating aid was added thereto to prepare a coating solution. Next, this coating solution was coated on a polyethylene-coated paper support, and further on this coated layer,
A coating solution containing 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzotriazole, gelatin, a spreading agent, and a hardening agent was applied to form a protective film. At this time, 2-(2'-hydroxy-3',5'-di-t
-amyl phenyl) benzotriazole is 5
mg/dm ² , and gelatin was applied in an amount of 15 mg/dm ² to prepare a silver halide photographic material, which was designated as Sample 1 (comparison). Next, Sample 2, which was the same as Comparative Sample 1, was prepared, except that Metal Complex B-4 according to the present invention was added to the emulsion layer of Comparative Sample 1 at a molar ratio of 0.4 to the coupler. Further, Samples 3 to 7 were prepared which were the same as Sample 2 except that the magenta coupler in Sample 2 was replaced with magenta couplers 19, 40, and 7 according to the present invention, comparative magenta coupler 1, and comparative magenta coupler 2. A sensitometer (manufactured by Konishiroku Photo Industry Co., Ltd.,
After performing optical wedge exposure for sensitometry using a KS-7 model, the following processing was performed. Processing process Processing temperature Processing time Color development 32.8°C 3 minutes 30 seconds Bleach-fixing 32.8°C 1 minute 30 seconds Water washing 32.8°C 3 minutes 30 seconds The composition of the processing solution used in the above processing step is as follows. (Color developer composition) 4-amino-3-methyl-N-ethyl-N-(β
-methanesulfonamidoethyl)aniline sulfate
5g Benzyl alcohol 15ml Sodium hexametaphosphate 2.5g Anhydrous sodium sulfite 18.5g Sodium bromide 0.7g Potassium bromide 0.5g Borax 39.1g Add water to make 1, and adjust the pH to 10.3 using sodium hydroxide. (Bleach-fix solution composition) Iron ammonium ethylenediaminetetraacetate 61.0g Ethylenediaminetetraacetic acid diammonium dihydrate 5.0g Ammonium thiosulfate 124.5g Sodium metabisulfite 13.5g Anhydrous sodium sulfite 2.7g Add water to make 1. After treatment, the light resistance of the obtained sample, the degree of increase in color staining (hereinafter referred to as yellow stain) due to storage,
and leg gradation were measured as follows. [Lightfastness test (fading rate measurement)] Fading rate (D ₀ − D / D ₀ ×100, _D0 initial density (1.0), D density after fading) were measured. These results are shown in Table 1. [Yellow stain test] Each sample was stored at 77°C in a constant temperature bath without humidification for 20 days. The difference in blue light reflection density (increase in density) of the white part of each sample before and after storage was measured. [Measurement of leg gradation (gamma value)] The slope (gamma value) between density 0.3 and density 0.8 of each wedge-exposed sample was measured. γ=0.5/logE _0.8 −logE _0.3 E _0.8 : Exposure amount that gives a density of 0.8 E _0.3 : Exposure amount that gives a density of 0.3 These test results are shown in Table 1.

[Table] The smaller the fading rate value, the better the light resistance. Table 1 shows that the samples using the metal complex according to the present invention have good light resistance. Further, in Comparative Samples 6 and 7 using comparative couplers, an increase in yellow stain or a softening of the leg gradation appears. By combining the magenta coupler of the present invention and the metal complex, photographic images with good light fastness, yellow stain, and leg gradation can be obtained. Example 2 A multicolor silver halide photographic material was prepared by sequentially coating the following layers on a support made of polyethylene-coated paper from the support side. 1st layer: blue-sensitive silver halide emulsion layer α-pivalyl-α- as a yellow coupler
(1-benzyl-2,4-dioxoimidazolidin-3-yl)-2-chloro-5-[γ-(2,
4-di-t-amylphenoxy)butyramide] acetonilide at 8 mg/dm ² , blue-sensitive silver halide emulsion at 3 mg/dm ² in terms of silver, 2,4
-di-t-butylphenol-3',5'-di-t
-amyl-4'-hydroxybenzoate 3
mg/dm ² , dioctyl phthalate 3 mg/dm ²
And gelatin was coated at a coating amount of 16 mg/dm ² . 2nd layer: Intermediate layer Gelatin was coated at a coating amount of 4 mg/dm ² . Third layer: green-sensitive silver halide emulsion layer: 4 mg/dm ² of the above-mentioned exemplary magenta coupler 20,
2 mg/d of green-sensitive silver chlorobromide emulsion converted to silver
m ² , 4 mg/dm ² of dioctyl phthalate and 16 mg/dm ² of gelatin were coated. 4th layer: Intermediate layer UV absorber 2-(2'-hydroxy-3',5'-
3 mg/dm ² of di-t-amyl phenyl)benzotriazole, 2-(2'-hydroxy-3',5'-
3 mg/dm ² of di-t-butylphenyl)benzotriazole and 4 mg/dm of dioctyl phthalate.
dm ² and gelatin were coated at a coating amount of 14 mg/dm ² . 5th layer: red-sensitive silver halide emulsion layer 2,4-dichloro-3 as cyan coupler
-Methyl-6-[α-(2,4-di-t-amylphenoxy)butyramide]phenol
mg/dm ² , 2-(2,3,4,5,6-pentafluorophenyl)acylamino-4-chloro-5-[α-(2,4-di-t-amylphenoxy)pentylamide]phenol 3mg/d
m ² , 2 mg/dm ² of dioctyl phthalate and 3 mg/dm ² of red-sensitive silver chlorobromide emulsion in terms of silver.
The coating was applied so that the coating amount was as follows. 6th layer: Intermediate layer 2-(2'-hydroxy-
2 mg/dm ² of 3',5'-di-t-amylphenyl)benzotriazole, 2 mg/dm2 of 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, and ² mg/dm2 of dioctyl phthalate. and gelatin were coated at a coating amount of 2 mg/dm ² and 6 mg/dm ² . 7th layer: Protective layer Gelatin was coated at a coating amount of 9 mg/dm ² . The sample thus prepared is designated as sample 8. Next, Samples 9 to 25 were prepared which were the same as Sample 8 except that the combinations of magenta coupler and metal complex in the third layer of Sample 8 were as shown in Table 2. The sample thus prepared was subjected to the same exposure treatment as in Example 1. However, in order to obtain a magenta monochromatic sample, light wedge exposure was performed using green light. For each sample obtained after the treatment, light resistance,
Yellow stain and leg gradation were measured. The results are shown in Table 2.

【table】

As is clear from Table 2, when a comparative metal complex or a comparative coupler is used, an increase in yellow stain or a decrease in leg gradation occurs. However, the samples of the present invention do not have any of these drawbacks. This effect was exhibited for the first time by the combination of the coupler according to the present invention and the metal complex according to the present invention, and was unexpected. In addition, the sample of the present invention had good light resistance and a clear magenta image with good color reproducibility was obtained. Example 3 The following layers were coated in order on a transparent support made of subbed cellulose triacetate film and having an antihalation layer (containing 0.40 g of black colloidal silver and 3.0 g of gelatin). , Sample 26 was prepared. 1st layer: Low-speed layer of red-sensitive silver halide emulsion layer 1.8 g of an emulsion (emulsion) made of AgBrI sensitized to red sensitivity and 0.8 g of 1-hydroxy-4-(β-methoxyethylamino carbonylmethoxy)-N-[δ-(2,4-di-t-amylphenoxy)butyl]-2-naphthamide (referred to as C-1), 0.075 g of 1-hydroxy-
4-[4-(1-hydroxy-8-acetamido-3,6-disulfo-2-naphthylazo)phenoxy]-N-[δ-(2,4-di-t-amylphenoxy)butyl]-2-naphthamide disodium (referred to as CC-1), 0.015 g of 1-hydroxy-2-[δ-(2,4-di-t-amylphenoxy)-n-butyl]naphthamide,
0.07g of 4-octadecylsuccinimide-2
-(1-phenyl-5-tetrazolylthio)-1
- A red-sensitive silver halide containing a dispersion of indanone (referred to as D-1) dissolved in 0.65 g of tricresyl phosphate (referred to as TCP) and emulsified and dispersed in an aqueous solution containing 1.85 g of gelatin. A low-speed layer of the emulsion layer. 2nd layer: High-sensitivity layer of red-sensitive silver halide emulsion layer 1.2 g of a red-sensitized emulsion (emulsion) consisting of AgBrI, 0.21 g of cyan coupler (C-1), and 0.02 g High sensitivity of red-sensitive silver halide emulsion layer containing a dispersion of colored cyan coupler (CC-1) dissolved in 0.23 g of TCP and emulsified in an aqueous solution containing 1.2 g of gelatin. layer. 3rd layer: middle layer 0.8g gelatin and 0.07g 2,5-di-
An intermediate layer containing 0.04 g of dibutyl phthalate (referred to as DBP) in which t-octylhydroquinone (referred to as HQ-1) was dissolved. 4th layer: 0.80 g of the low-speed layer emulsion of the green-sensitive silver halide emulsion layer color-sensitized to green sensitivity;
0.80g of Exemplified Compound 20, 0.01g of Compound (D-
A low-sensitivity layer of a green-sensitive silver halide emulsion layer containing a dispersion obtained by emulsifying and dispersing 0.95 g of diethyl lauryl amide dissolved in 1) in an aqueous solution containing 2.2 g of gelatin. 5th layer: 1.8 g of an emulsion obtained by color-sensitizing the high-sensitivity layer emulsion of the green-sensitive silver halide emulsion layer to green sensitivity;
A high-sensitivity layer of a green-sensitive silver halide emulsion layer containing a dispersion obtained by emulsifying and dispersing 0.25 g of diethyl lauryl amide in which 0.20 g of Exemplified Compound 20 is dissolved in an aqueous solution containing 1.9 g of gelatin. 6th layer: Yellow filter 0.15g yellow colloidal silver and 0.11g DBP dissolved in 0.2g color stain inhibitor (HQ-1)
and a yellow filter layer containing 1.5g of gelatin. 7th layer: 0.2g of the low-speed layer emulsion of the blue-sensitive silver halide emulsion layer color-sensitized to blue sensitivity, and 1.5g of the blue-sensitive silver halide emulsion layer.
g of α-pivaloyl-α-(1-benzyl-5
-Phenyl-2,4-dioxoimidazolidin-3-yl)-2-chloro-5-[α-dodecyloxycarbonyl)ethoxycarbonyl]acetanilide (referred to as Y-1) was dissolved in 0.6
A low-sensitivity layer of a blue-sensitive silver halide emulsion layer containing a dispersion in which 1.9 g of TCP is emulsified and dispersed in an aqueous solution containing 1.9 g of gelatin. 8th layer: High-sensitivity layer of blue-sensitive silver halide emulsion layer 0.9 g of a blue-sensitized emulsion of AgBrI containing 2 mol% of AgI and 1.30 g of yellow coupler (Y-1) are dissolved. 0.65g
A high-sensitivity blue-sensitive silver halide emulsion layer containing a dispersion of TCP emulsified in an aqueous solution containing 1.5 g of gelatin. 9th layer: Protective layer 0.23g gelatin protective layer. Samples 27 to 30 were prepared with the exception of sample 26 prepared in this manner, except that 40 mol % of the metal complex shown in Table 3 was added to the coupler in the green-sensitive emulsion layer. Furthermore, Samples 31 and 32 were prepared by replacing diethyl lauryl amide as the high-boiling organic solvent in the fourth and fifth layers of Sample 29 with trioctyl phosphate and dioctyl phthalate. After each of the samples 26 to 32 thus prepared was wedge exposed using green light, the following development treatment was performed. Development processing process Color development 38℃ 3 minutes 15 seconds Bleaching 38℃ 6 minutes 30 seconds Washing with water 38℃ 3 minutes 15 seconds Stabilization 38℃ 1 minute 30 seconds Drying The processing solution composition used in each processing step is as follows. It is. [Color developer] 4-amino-3-methyl-N-ethyl-N-(β
-hydroxylethyl)aniline sulfate 4.75g Anhydrous sodium sulfite 4.25g Hydroxylamine 1/2 sulfate 2.0g Anhydrous potassium carbonate 37.5g Sodium bromide 1.3g Nitrilotriacetic acid trisodium salt (monohydrate)
2.5g Potassium hydroxide 1.0g Add water to make 1 and adjust the pH to 10.02. [Bleach solution] Ethylenediaminetetraacetic acid iron ammonium salt 100g Ethylenediaminetetraacetic acid diammonium salt 10g Ammonium bromide 150g Glacial acetic acid 10ml Add water to make 1, and adjust the pH using ammonia water.
= 6.0. [Fixer] Ammonium thiosulfate 175g Anhydrous sodium sulfite 8.5g Sodium metabisulfite 2.3g Add water to make 1, and adjust to PH=6.0 using acetic acid. [Stabilizer] Formalin (37% aqueous solution) 1.5ml Konidax (manufactured by Konishiroku Photo Industry Co., Ltd.) 7.5ml Add water to make 1. The light resistance, yellow stain, and gradation of each sample thus obtained were measured in the same manner as in Example 1. The results are shown in Table 3.

[Table] As is clear from Table 3, the samples of the present invention have good light resistance and can provide good magenta images with little increase in yellow stain and little deterioration in gamma value. In addition, clear images with good color reproduction were obtained.

Claims (1)

[Scope of Claims] 1 Contains at least one coupler represented by the following general formula [] and at least one of the compounds represented by the following general formula [XI] and [XII] A silver halide photographic material characterized by: General formula [] [In the formula, R ₁ represents a substituent whose root atom directly connected to the ring is a carbon atom and there is only one hydrogen atom bonded to the carbon atom, and R ₂ represents a substituent different from R ₁ represents. Further, X represents a hydrogen atom or a substituent that can be separated by reaction with an oxidized product of a color developing agent. ] General formula [XI] General formula [XII] [In the formula, X ¹ , X ² and X ⁴ each represent an oxygen atom. X ³ represents a hydroxyl group, Y represents a sulfur atom, and R ¹ , R ² and R ³ each represent a hydrogen atom or an alkyl group. However, at least two of R ¹ , R ² and R ³ represent an alkyl group. ^R4 to ^R9 are
Represents an alkyl group, aryl group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, acyl group, acylamino group, alkylamino group, carbamoyl group, sulfamoyl group, sulfonamide group, sulfonyl group or cycloalkyl group . Alternatively, they may be connected to each other to form a 5- or 6-membered ring. M
represents a metal atom. a, b, c, d, e and f
each represents an integer from 0 to 4. ]