EP0107112B1

EP0107112B1 - Silver halide color photographic light-sensitive materials

Info

Publication number: EP0107112B1
Application number: EP83109820A
Authority: EP
Inventors: Noboru Sasaki; Seiji Ichijima; Kozo Aoki
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1982-09-30
Filing date: 1983-09-30
Publication date: 1988-01-07
Also published as: EP0107112A3; DE3375228D1; JPH0375852B2; EP0107112A2; JPS5960437A

Description

Field of the Invention

This invention relates to a silver halide color photographic light-sensitive material and more particularly to a color photographic light-sensitive material for photographing having simultaneously improved graininess and sharpness, comprising a support base having positioned thereon a red-sensitive silver halide emulsion layer; a green-sensitive silver halide emulsion layer; and a blue-sensitive silver halide emulsion layer; wherein at least one of the emulsion layers comprises a plurality of silver halide emulsion sublayers, the highest-sensitive sublayer containing a fast coupling coupler and a low-sensitive sublayer containing a slow coupling coupler and a DIR coupler or DIR compound.

Background of the Invention

Recently, the picture size of a photographic film have been reduced to miniaturize cameras and increase their portability. However, it is well known that reduction of the picture size cause deterioration of the image print quality. In other words, if the picture size of a color photographic light-sensitive material is reduced, the enlarging magnification for obtaining a print of the same size must be increased, whereby the graininess and sharpness of the printed image are deteriorated to that extent. Accordingly, there is a need to improve the graininess, resolving power, and sharpness of photographic films in order to obtain a good print even when using a miniaturized camera.
A technique for improving graininess is described in U.S. Patent No. 3,726,681 wherein the graininess of a high-sensitive color photographic material is improved by using a coupler having a fast coupling reaction rate in a high-sensitive silver halide emulsion layer and a coupler having a slow coupling reaction rate in a low-sensitive silver halide emulsion layer. A technique for improving sharpness involves using either a compound which forms a dye and also releases a development inhibitor by coupling with the oxidation product of a color developing agent as described in U.S. Patent Nos. 3,148,062 and 3,227,554; or a compound which releases a development inhibitor but does not form a dye by coupling with the oxidation product of a color developing agent as described in U.S. Patent No. 3,632,345 (hereinafter, both compounds are referred to as DIR compounds).
However, it was found that even by combining the aforesaid two techniques, the improvement of the graininess and the improvement of the sharpness conflict with each other and hence the good image that was expected could not be obtained. The reason is as follows. That is, when a high reaction rate coupler is used in a high-sensitive silver halide emulsion layer, the graininess of high density portions is improved but the development of the high-sensitive silver halide emulsion layer is accelerated owing to the high reaction rate of the coupler. Therefore, when DIR compound is added to a low-sensitive silver halide emulsion layer adjacent to the high-sensitive silver halide emulsion layer, an interlayer effect from the low-sensitive silver halide emulsion layer to the high-sensitive silver halide emulsion iayer does not occur, whereby an edge effect scarecely occurs in the images formed in the high-sensitive silver halide emulsion layer. This phenomenon is based on the difference in coupling activities of the high reaction rate coupler used in the high-sensitive silver halide emulsion layer, the low reaction rate coupler used in the low-sensitive silver halide emulsion layer, and the DIR compounds balanced with them.
On the other hand, when the method described in British Patent No. 923,045 for improving the graininess of high density portions by increasing the coated amount of silver without using the high reaction rate coupler in a high-sensitive silver halide emulsion layer so as to increase the ratio of silver halide to a coupler is used together with DIR compounds, the graininess and the adjacency effect may be improved. However, irradiation is increased by scattering of light based on the increased silver halide grains, whereby the sharpness is not improved to the extent expected.
In a color photographic material of which graininess is improved by using a low reaction rate coupler in one layer of photographic silver halide emulsion layers being sensitive for the same color and a high reaction rate coupler in another layer of the photographic silver halide emulsion layers being sensitive for the same color, it is necessary for improving the sharpness that the development inhibiting property of all the emulsion layers is increased by either increasing the addition amount of the DIR compound or using a DIR compound having a high development inhibiting degree. However, when the inhibiting property is increased, the sensitivity and coupling property are reduced and in order to correct for the reduction in sensitivity and coupling property, the amounts of silver halide and coupler are increased. This results in reduction of the resolving power in a high spatial frequency region.
In order to use the high reaction rate coupler: without such a side reaction, it is necessary to increase an MTF value (a value at a certain spatial frequency point on an MTF (modulation transfer function) curve) at a low spatial frequency region, that is to increase a so-called edge effect, without reducing the sensitivity or without increasing the development inhibiting property. (In addition, an MTF curve is described in, for example, Mees, The Theory of the Photographic Process, 3rd edition, page 536 and followings, published by Macmillan Co.). DE-A-2 600 524 and US-A-3 726 681 describe that the layer having higher sensitivity simultaneously contains fast and slow coupling couplers whereas the other layer having a low sensitivity contains slow coupling coupler and DIR coupler and/or DIR compound.
The object of DE-A-2 600 524 and US-A-3 726 681 is to provide photographic material of less fog by incorporating a slow coupling coupler into a high-sensitive layer.
However, these publications do not suggest the present invention to simultaneously improve the granularity and the sharpness of a color photographic material by selecting a reactivity of each couplers contained in high-sensitive and low-sensitive layer, as well as DIR coupler or DIR compound capable of releasing a development inhibitor having a high diffusibility due to a coupling reaction. Furthermore, both publications also do not say anything about diffusibility of released group of DIR coupler.
This also applies to JA-A-57 155 536 which describes silver halide color photographic materials comprising high and low sensitivity silver halide emulsion layers in the same color. However, this prior art is characterized by interposing non-photosensitive intermediate layer containing a coupler less reactive than the coupler in the high sensitive layer.
Although the intermediate layer of this prior art contains a color coupler, the layer is non-photosensitive as clearly recited in claim thereof. Experiments have been carried out to determine whether the technical advantage of the present invention may be obtained even when the non-photosensitive layer of JPA-A-57 155 536 will be interposed as taught therein. However, these experiments showed that this is not the case.
It was found that the above purpose can be attained by using a DIR coupler or a DIR compound capable of releasing a development inhibitor having a high diffusibility (the diffusibility being defined hereinafter) due to a coupling reaction (hereinafter, the DIR coupler or DIR compound releasing a development inhibitor having a high diffusibility is referred to simply as "a diffusible DIR compound").

Summary of the Invention

The main object of this invention is to simultaneously improve the granularity and the sharpness of a color photographic material.
According to the invention this object can be attained by a silver halide color photographic light-sensitive material comprising a support base having positioned thereon a red-sensitive silver halide emulsion layer; a green-sensitive silver halide emulsion layer; and a blue-sensitive silver halide emulsion layer; wherein at least one of the emulsion layers comprises a plurality of silver halide emulsion sublayers, the highest-sensitive sublayer containing a fast coupling coupler and a low-sensitive sublayer containing a slow coupling coupler and a DIR coupler or DIR compound, which is characterized in that the highest-sensitive sublayer only contains one or more fast coupling couplers and that the low-sensitive sublayer contains a slow coupling coupler having a coupling rate in a range of 1/1,3 to 1/15 of that of the fast coupling coupler contained in the highest-sensitive sublayer in combination with 0,0001 to 0,05 mole per mole of silver halide of the low-sensitive sublayer of a DIR coupler represented by the general formula:
wherein A represents a coupler component, m represents 1 or 2, and Y represents a group which is attached to the coupler component A at the coupling position thereof and can be eliminated from the coupler by reaction with an oxidation product of a color developing agent to produce a development inhibitor or a precursor thereof, the development inhibitor having a diffusibility of 0,4 to 1,0 as defined in the description.
According to the present invention it is possible to simultaneously improve the granularity and the sharpness of a color photographic material.

Brief Description of the Drawings

Fig. 1 is a graph showing MTF curves when the diffusibility of released development inhibitors is changed from 0.1 to 0.8 with the same inhibiting property (wherein a shows a case of diffusibility of 0.1; b shows a case of diffusibility of 0.2; c shows a case of diffusibility of 0.4; and d shows a case of diffusibility of 0.8), and
Fig. 2 is a graph showing C-MTF (chemical MTF) curves when the diffusibility is changed and O-MTF (optical MTF) curve.

In Figs. 1 and 2, the ordinate is the MTF value, M(u); and the abscissa is spatial frequency u(c/mm).

Description of the Preferred Embodiments

Changes in MTF curves caused by using diffusible DIR compounds are theoretically explained below.
In the high spatial frequency region, MTF curves are controlled by light scattering, whereas in the low spatial frequency region they are controlled by the edge effect arising from development inhibition. In the former region, MTF curves change depending on the thicknesses of layers present, e.g., silver halide emulsion layers, from which light is scattered. Thus, the thicker the layers, the greater the influence of light scattering becomes. Consequently, MTF curves are greatly lowered in the high spatial frequency region. On the other hand, in the latter region, if the development inhibiting material used has high diffusibility, the edge effect extends to a great distance. Consequently, MTF curves are raised even in the low spatial frequency region.
The C-MTF curves of Figure 2 are those obtained by heightening the diffusibility from a to d under the condition that the light scattering does not occur at all and the development inhibiting materials used have the same inhibiting degree. As can be seen therefrom, the higher the diffusibility, the higher the MTF value in the low spatial frequency region. On the other hand, the 0-MTF values represent the MTF curve under the condition that there is no edge effect, but a certain level of light scattering is observed. The actual MTF value is that which is obtained by multiplying the value on the C-MTF curve at each point, M_c(u), by the value on the O-MTF curve at the corresponding point, M_o(u). Therefore, the resultant MTF curves corresponding to the case that development inhibiting materials which have the same inhibiting degree, but differ only in diffusibility, are employed are as shown in Figure 1.
From the above explanation, it is understood that the purpose of increasing the edge effect can be attained by increasing the diffusibility of the development inhibitor released even though the inhibitive property of the development inhibitor is same.
The foregoing theory leads to a method of improving the reduction of the edge effect by using a diffusible DIR compound without deteriorating the sensitivity and coupling property, said edge effect reduction occurring at a side reaction in the case of improving the graininess by using a fast coupling coupler in a high-sensitive silver halide emulsion layer and using a coupler coupling slower than the aforesaid fast coupling coupler in a low-sensitive silver halide emulsion layer being sensitive to the same color as that of the high-sensitive silver halide emulsion layer.
That is, the present invention is a silver halide color photographic light-sensitive material comprising a support having formed thereon at least one red-sensitive silver halide emulsion layer, at least one green-sensitive silver halide emulsion layer, and at least one blue-sensitive silver halide emulsion layer; and at least one of said color-sensitive emulsion layers being composed of plural silver halide emulsion sublayers (i.e., plural silver halide emulsion sublayers being sensitive to the same color), the highest-sensitive emulsion sublayer of said plural emulsion sublayers containing one or more fast coupling couplers, and the low-sensitive sublayer containing a slow coupling coupler having a coupling rate in a range of 1/1.3 to 1/15, preferably 1/1.5 to 1/10 of that of the fast-coupling coupler contained in the highest-sensitive sublayer in combination with a specific DIR-coupler.
In the photographic material of this invention, the low-sensitive silver halide emulsion layer may be a low sensitive emulsion layer of a double sublayer type silver halide emulsion sublayers being sensitive to the same color, or may be an intermediate-sensitive emulsion layer or a low sensitive emulsion layer of a triple sublayer type silver halide emulsion sublayers being sensitive to the same color. Also, fast-coupling couplers used in the high-sensitive silver halide emulsion sublayer may be used solely or as a mixture of them.
The amount of the diffusible DIR compound used in the low-sensitive silver halide emulsion sublayer is 0.0001 mole to 0.05 mole, preferable 0.0003 to 0,01 mole, per mole of silver halide used in the low-sensitive silver halide emulsion sublayer.
The addition amounts of the fast-coupling coupler and the slow-coupling coupler are 0.001 to 0.5 g/m² and 0,2 to 2 g/m², preferable 0.005 to 0.5 g/m² and 0.5 to 2 g/m², respectively.
The coupling reactivity (i.e., coupling reaction rate) of the fast-coupling coupler and the slow-coupling coupler are determined as relative value with using a different dye forming coupler as a standard (i.e., coupler N used herebelow). That is, a coupler M (of which coupling reaction rate should be determined) is mixed with a standard coupler N wherein the coupler M and the coupler N provide different dyes which can be clearly separated from each other. The mixture of the couplers M and N is added to a silver halide emulsion layer followed by color development to form a color image. The amounts of each dye formed in the color image are measured and, therefrom, the coupling reactivity of the coupler M is determined as a relative value in the following manner.
When the maximum color density of coupler M is shown by (DM)max, the color density of coupler M in an intermediate step is shown by DM, the maximum color density of coupler N is shown by (DN)max, and the color density of coupler N in an intermediate step is shown by DN, the ratio of the reactivities of both couplers, RM/RN is shown by the following equation;
That is, the silver halide emulsion containing a mixture of the couplers M and N is step-wise exposed and followed by color development to obtain several sets of DM and DN. The combinations of DM and DN obtained are plotted as
onto a graph of two axis perpendicularly intersecting each other to obtain a straight line. The coupling activity ratio RM/RN is obtained from the inclination of the straight line.
Thus, by measuring RM/RN values of various couplers M using a definite coupler N in the manner as described above, coupling reactivities are relatively obtained.
In this invention, the following couplers were used as the foregoing definite coupler N.
For measuring the coupling reactivity of cyan couplers, the following magenta coupler was used as the coupler N.
For measuring the coupling reactivity of magenta couplers and yellow couplers, the following cyan coupler was used as the coupler N.
Preferred combinations of fast-coupling couplers and slow-coupling couplers are illustrated below. In these couplers, the right side number is the relative reaction rate measured by the foregoing method.

1. Combination of Cyan couplers:

1-1. Combination example (1):

Examples of fast-coupling couplers:
Examples of slow-coupling couplers to be combined with the foregoing fast-coupling couplers:

1-2. Combination example (2):

Example of fast-coupling coupler:
Examples of slow-coupling couplers to be combined with the foregoing fast-coupling coupler:

1-3. Combination example (3):

Example of fast-coupling coupler:
Example of slow-coupling coupler to be combined with the foregoing fast-coupling coupler:

2. Combination of Magenta couplers:

2-1. Combination example (1):

2-2. Combination example (2):

Example of fast coupling coupler:
Example of slow-coupling coupler to be combined with the foregoing fast-coupling coupler:

2-3. Combination example (3):

2-4. Combination example (4):

Example of fast coupling coupler:
Examples of slow-coupling couplers to be combined with the foregoing fast-coupling coupler:

3. Combination of Yellow couplers:

3-1. Combination example (1):

3-2. Combination example (2):

Examples of fast-coupling couplers:
Examples of slow-coupling couplers to be combined with the foregoing fast-coupling couplers:
The magnitude of the diffusibility of a development inhibitor can be measured in the following manner.
On a transparent support there were coated the layers described below in this order to prepare a multilayer color light-sensitive material (Sample B).

(1) A red-sensitive silver halide emulsion layer formed by coating at a coverage of 1.8 g silver per square meter (a thickness of 2 pm) a gelatin solution containing a silver iodobromide emulsion (containing 5 mol% of silver iodide, and having a mean grain size of 0.4 micron), to which red sensitivity had been imparted by using Sensitizing Dye I employed in the Example 1 described hereinafter in an amount of 6 x 10-⁵ mol per 1 mol silver, and 0.0015 mol/mol of silver of Coupler F. Coupler F
(2) A gelatin layer containing the same silver iodobromide emulsion as used in the first layer (1) except that red sensitivity had not been imparted thereto, and polymethyl methacrylate particles (diameter of about 1.5 pm) (having a coverage of 2 g silver per square meter and a thickness of 1.5 um).

In each of these layers, a conventional gelatin hardener and surface active agent were incorporated in addition to the above-described composition.
The other sensitive material (Sample A) was prepared in the same manner as Sample B except that the silver iodobromide emulsion which was incorporated in the second layer of Sample B was not present in the second layer of Sample A.
Sample A and Sample B each was subjected to wedgewise exposure and to development processing in the same manner as in the Example 1 except that the development time was changed to 2 minutes and 10 seconds. On the other hand, different kinds of development inhibitors were added to the same developing solution as used in the Example 1 independently in such amounts that the image density of Sample A was reduced to one-half that obtained in the former experiment. Under the same conditions, Sample B was examined for magnitudes of reduction of image densities. Degrees of reduction of image densities in Sample B are used as a measure of the diffusibility of the development inhibitor in the silver halide emulsion layer. The thus obtained results are set forth in Table 1.
When a ratio of the coupling rate of the slow-coupling coupler to that of the fast-coupling coupler is in a range of 1/1.3 to 1/15, it is preferred to use a DIR compound capable of releasing, as a splitting-off group, a development inhibitor having a diffusibility of 0.4 or more.
DIR couplers having diffusibilities of 0.4 to 1.0 used according to the invention are DIR couplers represented by the following general formula (I):
wherein A represents a coupler component, m represents 1 or 2, and Y represents a group which is attached to the coupler component A at the coupling position thereof and can be eliminated from the coupler by reaction with the oxidation product of a color developing agent to produce a highly diffusible development inhibitor or a precursor capable of releasing a highly diffusible development inhibitor.
Any A will do so long as it functions as a coupler, and it is not always an essential property that A produce a dye by the coupling reaction.
In general formula (I), the moiety Y may be specifically illustrated by the following general formulae (II) to (V):
In general formulae (Ila), (IIb) and (III), R, represents an alkyl group, an alkoxy group, an acylamino group, a halogen atom, an alkoxycarbonyl group, a thiazolylideneamino group, an aryloxycarbonyl group, an acyloxy group, a carbamoyl group, an N-alkylcarbamoyl group, an N,N-dialkylcarbamoyl group, a nitro group, an amino group, an N-arylcarbamoyloxy group, a sulfamoyl group, an N-alkylcarbamoyloxy group, a hydroxy group, an alkoxycarbonylamino group, an alkylthio group, an arylthio group, an aryl group, a heterocyclic group, a cyano group, an alkylsulfonyl group or an aryloxycarbonylamino group. In general formulae (Ila), (Ilb) and (III), n represents 1 or 2. When n is 2, two R_l's may be the same or different, and the number of carbon atoms contained in n R_l's is 0 to 10 in total. [When n R,'s contain no carbon atoms (for example, R, is a nitro group), the number of carbon atoms is 0 in total.]
In general formula (IV), R₂ represents an alkyl group, an aryl group or a heterocyclic group.
In general formula (V), R₃ represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group; and R₄ represents a hydrogen atom, an alkyl group, an aryl group, a halogen atom, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, an alkanesulfonamido group, a cyano group, a heterocyclic group, an alkylthio group or an amino group.
Examples of alkyl groups represented by R₁, R₂, R₃ or R₄ include both substituted and non-substituted ones. They may have a chain form or a cyclic form. Substituents for such alkyl groups include a halogen atom, a nitro group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfamoyl group, a carbamoyl group, a hydroxy group, an alkanesulfonyl group, an arylsulfonyl group, an alkylthio group and an arylthio group.
Aryl groups represented by R₁, R₂, R₃ or R₄ may also have substituents. Suitable examples of such substituents include an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, a halogen atom, a nitro group, an amino group, a sulfamoyl group, a hydroxy group, a carbamoyl group, an aryloxycarbonylamino group, an alkoxycarbonylamino group, an acylamino group, a cyano group and a ureido group.
If R₁, R₂, R₃ or R₄ represents a heterocyclic group, a hetero atom of such a group may be a nitrogen atom, an oxygen atom or a sulfur atom. A heterocyclic ring of such a group may be a 5-membered ring, 6- membered ring, or a condensed ring containing such a ring. Specific examples of such heterocyclic groups include a pyridyl group, a quinolyl group, a furyl group, a benzothiazolyl group, an oxazolyl group, an imidazolyl group, a thiazolyl group, a triazolyl group, a benzotriazolyl group, an imido group and an oxazinyl group. These groups may be further substituted with substituents set forth as examples of those for the above-described aryl groups.
In general formula (IV), R₂ can contain 1 to 15 carbon atoms.
In general formula (V), the total number of carbon atoms which may be contained in R₃ and R₄ is 1 to 15.
Further, Y in general formula (I) may be represented by the following general formula (VI):
wherein the TIME moiety is attached to the coupler moiety at the coupling position thereof, can split off by reaction with a color developing agent, and after elimination from the coupler moiety, it can release the INHIBIT group with controlling the releasing time properly; and the INHIBIT moiety released becomes a development restrainer.
A-TIME-INHIBIT group in general formula (VI) can be specifically illustrated by the following general formulae (VII) to (XIII):
In the general formulae (VII) to (XIII), R₅ represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkoxycarbonyl group, an anilino group, an acylamino group, a ureido group, a cyano group, a nitro group, a sulfonamido group, a sulfamoyl group, a carbamoyl group, an aryl group, a carboxy group, a sulfo group, a hydroxy group, or an alkanesulfonyl group; in general formulae (VII), (VIII), (IX), (XI) and (XIII), I represents 1 or 2; in general formulae (VII), (Xl), (XII) and (XIII), k represents 0, 1 or 2; in general formulae (VII), (X) and (XI), R₆ represents an alkyl group, an alkenyl group, an aralkyl group, a cycloalkyl group or an aryl group; and in general formulae (XII) and (XIII), B represents an oxygen atom or
(wherein R₆ has the same meaning as defined above). The number of carbon atoms contained in I R_s's per one molecule of general formula (VII), (VIII), (IX), (X), (XI), (XII) or (XIII) is 0 to 15 in total. The number of carbon atoms contained in R₆ is 1 to 15.
The INHIBIT moiety is represented by general formulae (Ila), (Ilb), (III), (IV) and (V) except for changing the number of carbon atoms contained in individual general formulae as shown below.
As for the number of carbon atoms contained in the INHIBIT moiety, the number of carbon atoms contained in n R_l's per one molecule of general formula (Ila), (IIb) or (III) is 1 to 32 in total; the number of carbon atoms contained in R₂ of general formula (IV) is 1 to 32; and the number of carbon atoms contained in R₃ and R₄ of general formula (V) is 1 to 32 in total.
When R₅ and R₆ represent alkyl groups, those alkyl groups may be substituted or unsubstituted, chain or cyclic. Substituents therefor include those which are set forth in the case that R₁ to R₄ represent an alkyl group.
When R₅ and R₆ represent aryl groups, those aryl groups may have substituents. Suitable examples of such substituents include those which are set forth in the case that R, to R₄ represent an aryl group.
Among the above-described diffusible DIR compounds, those having splitting-off groups represented by general formula (Ila), (IIb) or (V) are especially effective.
Suitable examples of the yellow color image forming coupler residue represented by A include those of pivaloyl acetanilide type, benzoyl acetanilide type, malonic diester type, malondiamide type, dibenzoyl- methane type, benzothiazolyl acetamide type, malonic ester monoamide type, benzothiazolyl acetate type, benzoxazolyl acetamide type, benzoxazolyl acetate type, benzimidazolyl acetamide type and benzimidazolyl acetate type; the coupler residues derived from hetero ring-substituted acetamides or hetero ring-substituted acetates involved in U.S. Patent 3,841,880; the coupler residues derived from the acyl acetamides described in U.S. Patent 3,770,446, British Patent 1,459,171, West German Patent Application (OLS) No. 2,503,099, Japanese Patent Application (OPI) No. 139738/75 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") and Research Disclosure, No. 15737; and the hetero ring type coupler residues described in U.S. Patent 4,046,574.
Preferable examples of the magenta color image forming coupler residue represented by A include coupler residues having 5-oxo-2-pyrazoline nuclei, pyrazolo[1,5-a]benzimidazole nuclei or cyanoaceto- phenone type coupler residues.
Preferable examples of cyan color image forming coupler residue represented by A include the coupler residues having a phenol nucleus or an a-naphthol nucleus.
In addition, even if couplers cannot produce dyes substantially after they couple with an oxidation product of a developing agent and release development inhibitors, they can exhibit their effects as DIR couplers to the same extent as the above-described color compound forming couplers. Examples of the above-described type of coupler residue represented by A include those which are described in U.S. Patents 4,052,213, 4,088,491, 3,632,345, 3,958,993 and 3,961,959.
More specifically, A in the general formula (I) may represent a residue having the following general formula (IA), (IIA), (IIIA), (IVA), (VA), (VIA), (VIIA) or (VIIIA):
. In the above-illustrated formulae, R₁₁ represents an aliphatic group, an aromatic group, an alkoxy group or a heterocyclic group; and R₁₂ and R₁₃ each represents an aromatic group or a heterocyclic group.
Aliphatic groups represented by R₁₁ are preferably those containing 1 to 22 carbon atoms, and may have substituents or not, and further, may have a chain form or a cyclic form. Preferable substituents therefor include an alkoxy group, an aryloxy group, an amino group, an acylamino group and a halogen atom, which each may further have a substituent(s). Specific examples of aliphatic groups useful as R₁₁ include an isopropyl group, an isobutyl group, a tert-butyl group, an isoamyl group, a tert-amyl group, a 1,1-dimethylbutyl group, a 1,1-dimethylhexyl group, a 1,1-diethylhexyl group, a dodecyl group, a hexadecyl group, an octadecyl group, a cyclohexyl group, a 2-methoxyisopropyl group, a 2-phenoxyisopropyl group, a 2-p-tert-butylphenoxyisopropyl group, an a-aminoisopropyl group, an a-(diethylamino)isopropyl group, an a-(succinimido)isopropyl group, an a-(phthalimido)isopropyl group, an a-(benzenesulfonamido)-isopropyl group.
In the case that R₁₁, R₁₂ or R₁₃ represents an aromatic group (especially a phenyl group), it may have a substituent. Such an aryl group as phenyl may be substituted with a 32 or less carbon atoms containing alkyl, alkenyl, alkoxy, alkoxycarbonyl, alkoxycarbonylamino, aliphatic amido, alkylsulfamoyl, alkylsulfonamido, alkylureido or alkyl-substituted succinimido group. The alkyl group therein may include one which contains an aromatic group such as phenylene in its main chain. Further, a phenyl group represented by R₁₁, R₁₂ or R₁₃ may be substituted with an aryloxy group, an aryloxycarbonyl group, an arylcarbamoyl group, an arylamido group, an arylsulfamoyl group, an arylsulfonamido group or an arylureido group, the aryl moiety of which groups each may be substituted with one or more alkyl groups wherein the number of carbon atoms is 1 to 22 in total.
Furthermore, a phenyl group represented by R₁₁, R₁₂ or R₁₃ may be substituted with an amino group which includes one containing a lower (C, to C₆) alkyl group as a substituent, a hydroxy group, a carboxy group, a sulfo group, a nitro group, a cyano group, a thiocyano group or a halogen atom.
In addition, R₁₁, R,₂ or R,₃ may represent a substituent formed by condensing a phenyl group and another ring, such as naphthyl, quinolyl, isoquinolyl, chromanyl, coumaranyl or tetrahydronaphthyl. These substituents may further have substituents in themselves.
In the case that R₁₁ represents an alkoxy group, the alkyl moiety thereof represents a C₁ to C₄₀. preferably C₁ to C₂₂, straight chain or branched chain alkyl, alkenyl, cycloalkyl or cycloalkenyl group, which each may be substituted with a halogen atom, an aryl group or an alkoxy group.
In the case that R₁₁, R₁₂ or R₁₃ represents a heterocyclic group, the heterocyclic group is bonded to the carbon atom of the acyl moiety or the nitrogen atom of the amido moiety of an a-acylacetamido group through one of the carbon atoms forming the ring. As examples of such a heterocyclic ring, mention may be made of thiophene, furan, pyran, pyrrole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, imidazole, thiazole, oxazole, triazine, thiadiazine or oxazine. These rings may further have substituents on the individual rings.
R,₅ in the general formula (IVA) represents a C, to C₄₀, preferably C, to C₂₂, straight chain or branched chain alkyl (e.g., methyl, isopropyl, tert-butyl, hexyl, dodecyl), alkenyl (e.g., allyl), cyclic alkyl (e.g., cyclopentyl, cyclohexyl, norbornyl), aralkyl (e.g., benzyl, β-phenylethyll, or cyclic alkenyl (e.g., cyclopentenyl, cyclohexenyl) group, which groups each may be substituted with a halogen atom, a nitro group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, a carboxy group, an alkylthiocarbonyl group, an arylthiocarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfo group, a sulfamoyl group, a carbamoyl group, an acylamino group, a diacylamino group, a ureido group, a urethane group, a thiourethane group, a sulfonamido group, a heterocyclic group, an arylsulfonyl group, an alkylsulfonyl group, an arylthio group, an alkylthio group, an alkylamino group, a dialkylamino group, an anilino group, an N-arylanilino group, an N-alkylanilino group, an N-acylanilino group, a hydroxy group or a mercapto group.
R₁₅ in general formula (IVA) may further represent an aryl group (e.g., phenyl, a or β-naphthyl). The aryl group may have one or more substituents. Specific examples of such a substituent include an alkyl group, an alkenyl group, a cyclic alkyl group, an aralkyl group, a cyclic alkenyl group, a halogen atom, a nitro group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, a carboxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfo group, a sulfamoyl group, a carbamoyl group, an acylamino group, a diacylamino group, a ureido group, a urethane group, a sulfonamido group, a heterocyclic group, an arylsulfonyl group, an alkylsulfonyl group, an arylthio group, an alkylthio group, an alkylamino group, a dialkylamino group, an anilino group, an N-alkylanilino group, an N-arylanilino group, an N-acylanilino group, a hydroxy group and a mercapto group. Among the above-described substituents, more preferable ones for R₁₅ are phenyl groups which are substituted by an alkyl group, an alkoxy group or a halogen atom at at least one of the o-positions, because they can contribute to reduction of photo- coloration or thermocoloration of couplers remaining in film layers.
Further, R,₅ may represent a heterocyclic ring residue (e.g., a 5- or 6-membered heterocyclic one containing as a hetero atom a nitrogen atom, an oxygen atom or a sulfur atom, or the condensed ring residues thereof, with specific examples including pyridyl, quinolyl, furyl, benzothiazolyl, oxazolyl, imidazolyl, or naphthoxazolyl), a heterocyclic ring residue substituted with one of substituents set forth as examples for the above-described aryl group, an aliphatic or an aromatic acyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylcarbamoyl group, an arylcarbamoyl group, an alkylthiocarbamoyl group, or an arylthiocarbamoyl group.
R₁₄ in formula (IVA) or (VA) represents a hydrogen atom, a C, to C₄₀, preferably C, to C₂₂, straight chain or branched chain alkyl, alkenyl, cyclic alkyl, aralkyl or cyclic alkenyl group (which each may have one of the substituents set forth as examples for the above-described substituent R₁₅), an aryl group or a heterocyclic ring residue (which each also may have one of the substituents set forth as examples for the above-described substituent (R₁₅), an alkoxycarbonyl group (e.g., methoxycarbonyl, ethoxycarbonyl, stearyloxy- carbonyl), an aryloxycarbonyl group (e.g., phenoxycarbonyl, naphthoxycarbonyl), an aralkyloxycarbonyl group (e.g., benzyloxycarbonyl), an alkoxy group (e.g., methoxy, ethoxy, heptadecyloxy), an aryloxy group (e.g., phenoxy, tolyloxy), an alkylthio group (e.g., ethylthio, dodecylthio), an arylthio group (e.g., phenylthio, a-naphthylthio), a carboxy group, an acylamino group (e.g., acetylamino, 3-[(2,4-di-tert-amyl- phenoxy)acetamido]benzamido), a diacylamino group, an N-alkylacylamino group (e.g., N-methylpropion- amido), an N-arylacylamino group (e.g., N-phenylacetamido), a ureido group (e.g., ureido, N-arylureido, N-alkylureido), a urethane group, a thiourethane group, an arylamino group (e.g., phenylamino, N-methylanilino, diphenylamino, N-acetylanilino, 2-chloro-5-tetradecanamidoanilino), an alkylamino group (e.g., n-butylamino, methylamino, cyclohexylamino), a cycloamino group (e.g., piperidino, pyrrolidino), a heterocyclic amino group (e.g., 4-pyridylamino, 2-benzoxazolylamino), an alkylcarbonyl group (e.g., methylcarbonyl), an arylcarbonyl group (e.g., phenylcarbonyl), a sulfonamido group (e.g., alkylsulfonamido, arylsulfonamido), a carbamoyl group (e.g., ethylcarbamoyl, dimethylcarbamoyl, N-methylphenylcarbamoyl, N-phenylcarbamoyl), a sulfamoyl group (e.g., N-alkylsulfamoyl, N,N-dialkylsulfamoyl, N-arylsulfamoyl, N-alkyl-N-arylsulfamoyl, N,N-diarylsulfamoyl), a cyano group, a hydroxy group, a mercapto group, a halogen atom or a sulfo group.
R₁₇ in general formula (VA) represents a hydrogen atom, or a C, to C₃₂, preferably C, to C₂₂, straight chain or branched chain alkyl, alkenyl, cycloalkyl, aralkyl or cyclic alkenyl group, which each may have one of the substituents set forth as an example for the above-described substituent R₁₅.
Further, R₁₇ may represent an aryl group or a heterocyclic residue, which each may have one of the substituents set forth as examples for the above-described substituent R₁₅.
Furthermore, R₁₇ may represent a cyano group, an alkoxy group, an aryloxy group, a halogen atom, a carboxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, a sulfo group, a sulfamoyl group, a carbamoyl group, an acylamino group, a diacylamino group, a ureido group, a urethane group, a sulfonamido group, an arylsulfonyl group, an alkylsulfonyl group, an arylthio group, an alkylthio group, an alkylamino group, a dialkylamino group, an anilino group, an N-arylanilino group, an N-alkylanilino group, an N-acylanilino group, a hydroxy group or a mercapto group.
Substituents R₁₈, R₁₉ and R₂₀ include groups which have been employed in conventional 4-equivalent type phenol or a-naphthol couplers. Specifically, substituent R₁₈ represents a hydrogen atom, a halogen atom, an aliphatic hydrocarbon residue, an acylamino group, an ―O―R₂₁ group or an ―S―R₂₁ group (wherein R₂₁ is an aliphatic hydrocarbon residue). When two or more of R₁₈'s are present in one molecule, they may be different from each other. The above-described aliphatic hydrocarbon residues include those having substituents. Substituents R₁₉ and R₂₀ include aliphatic hydrocarbon residues, aryl groups and heterocyclic ring residues. Either of them may be a hydrogen atom. The above-described substituents may further have certain substituents. Furthermore, R₁₉ and R₂₀ may combine with each other and form a nitrogen-containing heterocyclic nucleus. I represents an integer of 1 to 4, m represents an integer of 1 to 3, and n represents an integer of 1 to 5. More specifically, the above-described aliphatic hydrocarbon residues include both saturated and unsaturated ones, which each may have a straight chain form, a branched chain form or a cyclic form, with preferable examples including an alkyl group (e.g., methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, dodecyl, octadecyl, cyclobutyl, cyclohexyl) and an alkenyl group (e.g., allyl, octenyl). The above-described aryl group is a phenyl group or a naphthyl group. Representatives of the above-described heterocyclic ring residues are pyridinyl, quinolyl, thienyl, piperidyl and imidazolyl. These aliphatic hydrocarbon residues, aryl groups and hetero ring residues each may be substituted by a halogen atom, a nitro group, a hydroxy group, a carboxy group, an amino group, a substituted amino group, a sulfo group, an alkyl group, an alkenyl group an aryl group, a hetero ring residue, an alkoxy group, an aryloxy group, an arylthio group, an arylazo group, an acylamino group, a carbamoyl group, an ester residue, an acyl group, an acyloxy group, a sulfonamido group, a sulfamoyl group, a sulfonyl group or a morpholino group.
Substituents R₁₁, R₁₂, R,₃, R₁₄, R₁₅, R₁₇, R₁₈, R₁₉ and R₂₀ in the couplers represented by general formulae (IA) to (VIIIA) may combine with their respective corresponding substituents, or one of them may become a divalent group to form a symmetric or an asymmetric complex coupler.
Specific examples of the DIR couplers which can be effectively used in the present invention are illustrated below.
These compounds employed in the present invention can be easily synthesized using the methods described in, e.g., U.S. Patents 4,234,678, 3,227,554, 3,617,291, 3,958,993, 4,149,886 and 3,933,500, Japanese Patent Application (OPI) Nos. 56837/82 and 13239/76, British Patents 2,072,363 and 2,070,266, Research Disclosure, No. 21228, Dec., 1981, and so on.
The diffusibilities of the DIR couplers employed in the present invention are 0.4 to 1.0. More preferably, the diffusibilities are not higher than about 1.0. When the diffusibilities are extremely heightened, the visual sharpness tends to decrease.
For incorporating the coupler in a silver halide emulsion layer, a known method such as the method as described in U.S. Patent 2,322,027 may be used. For example, after dissolving the coupler in a high-boiling organic solvent such as a phthalic acid alkyl ester (e.g., dibutyl phthalate, dioctyl phthalate), a phosphoric acid ester (e.g., diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, dioctylbutyl phosphate), a citric acid ester (e.g., tributyl acetylcitrate), a benzoic acid ester (e.g., octyl benzoate;, an alkylamide (e.g., diethyllaurylamide), a fatty acid ester (e.g., dibutoxyethyl succinate, dioctyl azelate), a trimesic acid ester (e.g., tributyl trimesate) or an organic solvent having a boiling point of about 30°C to 150°C, such as lower alkyl acetate (e.g., ethyl acetate, butyl acetate), ethyl propionate, sec-butyl alcohol, methyl isobutyl ketone, (3-ethoxyethyl acetate or methyl cellosolve acetate, the solution is dispersed in a hydrophilic colloid. In this case, a mixture of the aforesaid high-boiling organic solvent and the low-boiling organic solvent may be used.
Also, a dispersion method by a polymer as described in Japanese Patent Publication No. 39,853/'76 and Japanese Patent Application (OPI) No. 59,943/'76 can be used for the incorporation of the coupler.
When the coupler has an acid group such as a carboxylic acid and sulfonic acid, the coupler is introduced into a hydrophilic colloid as an alkaline aqueous solution thereof.
Binders or protective colloids which can be used to advantage in preparing photographic emulsions include conventional gelatins. However, other conventional hydrophilic colloids can be also used herein.
Examples of suitable hydrophilic colloids include proteins such as gelatin derivatives, graft polymers obtained by grafting other high polymers onto gelatin, albumin or casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose or cellulose sulfates; sugar derivatives such as sodium alginate or starch derivatives; and synthetic hydrophilic high molecular weight polymers such as polyvinyl alcohol, partially acetylated polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole or copolymers containing repeating units which constitute the above-described polymers.
Examples of the gelatins which can be used are not only lime-processed gelatin, but also acid- processed gelatin, enzyme-processed gelatin as described in Bull. Soc. Sci. Phot. Japan, No. 16, p. 30 (1966) and, further-hydrolysis products and enzymatically decomposed products of gelatins.
Gelatin derivatives which can be used include those obtained by reacting gelatin with various kinds of compounds such as acid halides, acid anhydrides, isocyanates, bromoacetic acid, alkane, sulfones, vinylsulfonamides, maleinimide compounds, polyalkylene oxides or epoxy compounds. Specific examples thereof are disclosed in U.S. Patents 2,614,928, 3,132,945, 3,186,846 and 3,312,553, British Patents 861,414, 1,033,189 and 1,005,784 and Japanese Patent Publication No. 26845/67.
The foregoing gelatin graft polymers include the graft polymers formed by grafting home- or copolymer of a vinyl monomer or monomers such as acrylic acid, methacrylic acid, or the derivatives thereof such as the esters or the amides, acrylonitrile or styrene to gelatin. In particular, the graft polymers formed by grafting a polymer having a compatibility with gelatin to some extent, such as the polymer of acrylic acid, methacrylic acid, acrylamide, methacrylamide and hydroxyalkyl methacrylate to gelatin are preferred. Examples of these graft polymers are described in U.S. Patent Nos. 2,763,625, 2,831,767 and 2,956,884.
Typical examples of synthetic hydrophilic high polymers which can be used are those described in West German Patent Application (OLS) No. 2,312,708, U.S. Patents 3,620,751 and 3,879,205, and Japanese Patent Publication No. 7561/68.
Silver halides which can be present in photographic emulsion layers of photographic materials employed in the present invention are conventional and include silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide and silver chloride. Preferable silver halides are silver iodobromides containing 15 mol% or less of iodide. Especially preferred ones ar silver iodobromides containing 2 to 12 mol% of silver iodide.
Silver halide grains in the photographic emulsion may have any conventional mean grain size (the grain size being defined as grain diameter if the grain has a spherical or a nearly spherical form and as a length of the edge if the grain has a cubic form, and being averaged based on projected areas of the grains). However, very good results are obtained when the mean grain size is 3 pm or less.
Grain size distribution may be either narrow or broad.
Silver halide grains in the photographic emulsion may have a regular crystal form such as that of a cube or an octahedron, an irregular crystal form such as that of a sphere or a plate or a composite form thereof. Also, silver halide grains may be a mixture of grains having various kinds of crystal forms.
The individual silver halide grains may comprise a core and an outer shell or may be homogeneous. In addition, they may have a surface where a latent image has been formed to an appreciable extent, or may be grains where a latent image is predominantly formed in the interior thereof.
Photographic emulsions employed in the present invention can be prepared using conventional methods as described in P. Glafkides, Chimie et Physique Photographique, Paul Montel, Paris (1967), G. F. Duffin, Photographic Emulsion Chemistry, The Focal Press, London (1966) or V. L. Zelikman, et al., Making and Coating Photograhic Emulsion, The Focal Press, London (1964). That is, photographic emulsions can be prepared using the acid process, the neutral process or the ammonia process. Suitable methods for reacting a water-soluble silver salt with a water-soluble halide include a single jet method, a double jet method and a combination thereof.
Also, a method in which silver halide grains are produced in the presence of excess silver ions (the so-called reverse mixing method) can be employed. Further, the so-called controlled double jet method, in which the pAg of the liquid phase wherein silver halide grains are to be precipitated is maintained constant, may be employed.
According to this method, silver halide emulsions in which grains have a regular crystal form and almost uniform size can be obtained.
Two or more silver halide emulsions prepared separately may also be employed in the form of mixture.
In a process of producing silver halide grains or allowing the produced silver halide grains to ripen physically, cadmium salts, zinc salts, lead salts, thallium salts, iridium salts or complexes, rhodium salts or complexes and/or iron salts or complexes may be present.
Silver halide emulsions having any grain size distribution may be employed in this invention. However, for low-sensitive color negative silver halide emulsion layers requiring a long exposure latitude, a silver halide emulsion having a wide grain size distribution (called as "poly-dispersed emulsion) may be used or several kinds of mono-dispersed silver halide emulsion having a narrow grain size distribution (the mono-dispersed silver halide emulsion in this specification is a silver halide emulsion wherein more than 90% of the weight or number of total silver halide grains is included in the size range within ±40% of the mean grain size) may be used as a mixture of them. Futhermore, a mixture of the mono-dispersed emulsion and the poly-dispersed emulsion may be used. Also, it is preferred to use a mono-dispersed emulsion for a high sensitive silver halide emulsion layer. The mono-dispersed silver halide emulsion may have a uniform composition and property throughout the inside and the surface thereof or may be a co-called core-shell structure having different composition and property between the inside and surface thereof. A silver halide emulsion layer may be a double layer type silver halide emulsion layer composed of a high-sensitive emulsion layer and a low-sensitive emulsion, or may be a triple layer type silver halide emulsion layer composed of a high-sensitive emulsion layer, an intermediate-sensitive emulsion layer and a low-sensitive emulsion layer.
Removal of the soluble salts from the silver halide emulsion after the formation of silver halide grains or after physical ripening can be effected using the noodle washing method (which comprises gelling the gelatin), or using a sedimentation process (thereby causing flocculation in the emulsion) using an inorganic salt, an anionic surface active agent, an anionic polymer, (e.g., polystyrenesulfonic acid), or a gelatin derivative (e.g., acylated gelatin or carbamoylated gelatin).
It is usual for the silver halide emulsion to be chemically sensitized. Chemical sensitization can be carried out using processes as described in, e.g., H. Frieser, Die Griindlagen der Photographischen Prozesse mit Silberhalogeniden, pp. 675-734, Akademische Verlagsgesellschaft (1968).
More specifically, sulfur sensitization using compounds containing sulfur capable of reacting with active gelatin or silver ions, (e.g., thiosulfates, thioureas, mercapto compounds, rhodanines), reduction sensitization using reducing materials (e.g., stannous salts, amines, hydrazine derivatives, formamidinesulfinic acid, silane compounds) or noble metal sensitization using noble metal compounds (e.g., gold complexes, and complexes of Periodic Table Group VIII metals such as Pt, Ir or Pd) can be employed individually or as a combination thereof.
Specific examples of sulfur sensitization are described in U.S. Patents 1,574,944, 2,410,689, 2,278,947, 2,728,668 and 3,656,955. Specific examples of reduction sensitization are described in U.S. Patents 2,983,609, 2,419,974 and 4,054,458. Specific examples of noble metal sensitization are described in U.S. Patents 2,399,083 and 2,448,060, and British Patent 618,061.
Photographic emulsions employed in the present invention can contain various conventional compounds for the purpose of preventing fog in preparation, storage or photographic processing, or for stabilizing photographic properties. Specific examples of such compounds include azoles such as benzothiazolium salts, nitroindazoles, triazoles, benzotriazoles and benzimidazoles (especially nitro- or halogen-substituted ones); heterocyclic mercapto compounds such as mercaptobenzimazoles, mercaptothiadiazoles, mercaptoetrazoles (especially 1-phenyl-5-mercaptotetrazole) and mercaptopyrimidines; the above-described heterocyclic mrcapto compounds having water-soluble groups such as a carboxyl group or a sulfonyl group; thioketo compounds such as oxazolinethione; azaindenes such as tetraazaindenes (especially 4-hydroxy-substituted (1,3,3a,7)tetraazaindenes); benzenethiosulfonic acids; benzenesulfinic acids; and other various compounds known as anti-foggants or stabilizers.
For details of specific examples and usages of such compounds disclosure is given in, e.g., U.S. Patents 3,954,474, 3,982,947 and 4,021,248, or Japanese Patent Publication No. 28660/77 can be referred to.
Photographic emulsions or other hydrophilic colloidal layers of the light-sensitive materials of the present invention may contain various kinds of surface active agents for a wide variety of conventional purposes, for example, as a coating aid, prevention of static charges, improvement in a slipping property, emulsifying dispersions, prevention of adhesion, or improvement in photographic characteristics (e.g., development acceleration, increase in contrast and sensitization).
Specific examples of surface active agents which can be used include nonionic surface active agents such as saponin (steroid type), alkylene oxide derivatives (e.g., polyethylene glycol, polyethylene glycol/ polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol sorbitol esters, polyalkylene glycol alkylamines or polyalkylene glycol alkylamides and polyethylene oxide adducts of silicone), glycidol derivatives (e.g., alkenyl- succinic polyglycerides and alkylphenyl polyglycerides), fatty acid esters of polyhydric alcohols or alkyl esters of sugars, anionic surface active agents containing acidic groups such as carboxyl, sulfo, phospho, sulfate and phosphate groups, e.g., alkylcarboxylates, alkylsulfonates, alkylbenzenesulfonates, alkyl- naphthalenesulfonates, alkylsulfates, alkylphosphates, N-acyl-N-alkyltaurines, sulfosuccinates, sulfoalkyl- polyoxyethylene alkyl phenyl ethers and polyoxyethylene alkylphosphates; amphoteric surface active agents such as amino acids, aminoalkylsulfonic acids, aminoalkyl sulfates or phosphates, alkylbetaines and amine oxides; and cationic surface active agents such as alkylamine salts, aliphatic or aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts, e.g., pyridinium or imidazolium, aliphatic or heterocyclic phosphonium or sulfonium salts.
The photographic emulsions may contain, for example, polyalkylene oxides and derivatives thereof such as the ethers, esters and amines thereof, thioether compounds, thiomorpholines, quaternary ammonium salt compounds, urethane derivatives, urea derivatives, imidazole derivatives or 3-pyrazolidones, in order to increase the sensitivity and the contrast thereof, or in order to accelerate the developing rate thereof. Examples of such compounds are disclosed in, e.g., U.S. Patents 2,400,532, 2,423,549, 2,716,062, 3,617,280, 3,772,021, 3,808,003 and British Patent 1,488,991.
The photographic emulsions or other hydrophilic colloidal layers of photographic materials used in the practice of the present invention can contain dispersions of water-insoluble or slightly soluble synthetic polymers for the purpose of improving dimensional stability. Specific examples of such polymers include those having as monomer components alkyl(meth)acrylate, alkoxyalkyl(meth)acrylate, glycidyl-(meth)acrylate, (meth)acrylamide, vinyl ester (e.g., vinyl acetate), acrylonitrile, olefin and styrene, individually or as combinations of two or more thereof, or a combination of one of the above-described monomers and acrylic acid, methacrylic acid, an a,j3-unsaturated dicarboxylic acid, a hydroxyalkyl-(meth)acylate, a sulfoalkyl(meth)acrylate or styrenesulfonic acid. More specifically, such polymers are disclosed in U.S. Patents 2,376,005, 2,739,137, 2,853,547, 3,062,674, 3,411,911, 3,488,708, 3,525,620, 3,607,290, 3,635,715 and 3,645,740, British Patents 1,186,699 and 1,307,373.
Conventional methods and processing solutions, as described in, e.g., Research Disclosure, No. 176, pp. 28-30 (RD-17643), can be applied to photographic processing of photographic emulsions prepared in accordance with the present invention. Any photographic processing, whether for the formation of dye images (for color photographic processings) or not can be used depending on the end use of the light-sensitive material. Processing temperatures ar generally selected from the range of 18°C to 50°C. However, temperatures lower than 18°C and temperatures higher than 50°C may also be used.
In development processing, a method where a developing agent is contained in the light-sensitive material, e.g., in an emulsion layer, and the sensitive material is treated in an aqueous alkaline solution to effect development may be employed. Developing agents which are hydrophobic can be incorporated in emulsion layers using various methods as described in, e.g., Research Disclosure, No. 169 (RD-16928), U.S. Patent 2,739,890, British Patent 813,253 and West German Patent 1,547,763. Such development processing may be carried out in combination with silver salt stabilizing processing using a thiocyanate.
A conventional fixing solution can be used. Examples of fixing agents which can be used include not only thiosulfates and thiocyanates, but also organic sulfur compounds which are known to have a fixing effect. The fixing solution may contain water-soluble aluminum salts as a hardener.
Dye images can be formed using conventional methods, for examples, the negative-positive method as described in Journal of the Society of Motion Picture and Television Engineers, Vol. 61, pp. 667-701 (1953).
The color developing solution is conventional and generally comprises an alkaline aqueous solution containing a color developing agent. Specific examples of color developing agents include aromatic primary amine developers such as phenylenediamines (e.g., 4-amino-N,N-diethylaniline, 3-methyl-4-amino-N,N-diethylaniline, 4-amino-N-ethyl-N-(3-hydroxyethylaniline, 3-methy!-4-amino-N-ethyt-N-(3-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfonamidoethylaniline and 4-amino-3-methyl-N-ethyl-N-β-methoxyethylaniline).
In addition to the above-described color developing agents, those described in L. F. A. Mason, Photographic Processing Chemistry, pp. 226-229, Focal Press, London (1966), U.S. Patents 2,193,015 and 2,592,364 and Japanese Patent Application (OPI) No. 64933/73 may be employed as a color developing agent.
The color developing solution can additionally contain a pH buffer, a development inhibitor and an anti-foggant. Optionally, it may contain a water softener, a preservative, an organic solvent, a development accelerator, dye forming couplers, competing couplers, a fogging agent, an assistant developer, a viscosity imparting agent, a polycarboxylic acid series chelating agent or an antioxidant.
Specific examples of these additives are disclosed in Research Disclosure (RD-17643), U.S. Patent 4,083,723 and West German Patent Application (OLS) No. 2,622,950.
After color development, the photographic emulsion is generally subjected to a conventional bleaching. Bleaching may be carried out simultaneously with conventional fixing, or these two processes may be carried separately. Examples of bleaching agents which can be used include compounds of polyvalent metals, such as Fe (III), Co (III), Cr (VI) and Cu (II); peroxy acxids, quinones and nitroso compounds.
More specifically, bleaching agents which can be used include ferricyanides; bichromates; complex salts formed by Fe (III) or Co (III) and aminopolycarboxylic acids, such as ethylenediaminetetraacetic acid, nitrilotriacetate and 1,3-diamino-2-propanol tetraacetic acid, or organic acids such as citric acid, tartaric acid and malic acid; persulfates and permanganates; and nitrosophenol. Among these agents potassium ferricyanide, sodium (ethylenediaminetetraacetato)ferrate (III) and ammonium (ethylenediaminotetra- acetato)ferrate (III) are especially useful. The (ethylenediaminetetraacetato)iron (III) complexes are useful in both an independent bleaching solution and a combined bleach-fix bath.
The bleaching or the bleach-fix bath can contain a bleach accelerating agent as described in U.S. Patents 3,042,520 and 3,241,966, Japanese Patent Publication Nos. 8506/70 and 8836/70, thiol compounds described in Japanese Patent Application (OPI) No. 65732/78, and other various kinds of additives.
Photographic emulsions employed in the present invention may be spectrally sensitized with methine dyes and others.
Examples of useful sensitizing dyes are described in German Patent 929,080, U.S. Patents 2,493,748, 2,503,776, 2,519,001, 2,912,329, 3,656,959, 3,672,897 and 4,025,349, British Patent 1,242,588, and Japanese Patent Publication No. 14030/69.
These sensitizing dyes may be employed solely or as a combination of two or more thereof. Combinations of sensitizing dyes are frequently employed for the purpose of supersensitization. Typical examples of supersensitizing combinations are described in U.S. Patents 2,688,545, 2,977,229, 3,397,060, 3,522,052, 3,527,641, 3,617,293, 32,628,964, 3,666,480, 3,672,898, 3,679,428, 3,814,609 and 4,026,707, British Patent 1,344,281, Japanese Patent Publication Nos. 4936/68 and 12375/83, Japanese Patent Application (OPI) Nos. 110618/77 and 109925/77.
In the photographic materials prepared in accordance with the present invention, photographic emulsion layers and other layers are coated on a conventional flexible support such as a plastic film, paper or cloth or a rigid support such as glass, ceramic or metal. Examples of flexible support which can be used to advantage include films made from semi-synthetic or synthetic high molecular weight polymers such as cellulose nitrate, cellulose acetate, cellulose acetate butyrate, polystyrene, polyvinyl chloride, polyethylene, terephthalate and polycarbonate; and paper coated or laminated with a baryta layer or an a-olefin polymer (e.g., polyethylene, polypropylene, an ethylene-butene copolymer).
Supports may be colored with dyes or pigments. Further, they may be rendered black for the purpose' of shielding light. The surfaces of these supports are, in general, subjected to a subbing treatment to increase adhesiveness to photographic emulsion layers. Before or after receiving the subbing treatment, the surfaces of the support may be subjected to a corona discharge treatment, an ultraviolet irradiation treatment or a flame treatment.
In the photographic materials prepared in accordance with the present invention, photographic emulsion layers and other layers can be coated on a support or other layers using conventional coating methods. Examples of such coating methods include dip coating, roller coating, curtain coating and extrusion coating. The methods disclosed in U.S. Patents 2,681,294, 2,761,791 and 3,526,528 can be used to advantage in coating such layers.
The present invention can be applied to a multilayer multicolor photographic material having layers of at least two different spectral sensitivities on the support. A multilayer color photographic material usually has at least one red-sensitive emulsion layer, at least one green-sensitive emulsion layer and at least one blue-sensitive emulsion layer on a support. The order of these layers can be arbitrarily selected. It is general, however, to incorporate a cyan forming coupler in a red-sensitive emulsion layer, a magenta forming coupler in a green-sensitive emulsion layer, and a yellow forming coupler in a blue-sensitive emulsion layer. However, different combinations may be used.
The exposure for obtaining a photographic image is carried out in a conventional manner. Any known light sources including natural light (sunlight), a tungsten lamp, a fluorescent lamp, a mercury lamp, a xenon arc lamp, a carbon arc lamp, a xenon flash lamp, or a CRT spot can be employed for exposure.
Suitable exposure times whch can be used include not only exposure times commonly used in cameras ranging from about 1/1,000 to about 1 sec., but also exposure times shorter than 1/1,000 sec., for example, about 1/10⁴ to about 1/10⁶ sec. as with xenon flash lamps and cathode ray tubes. Exposure times longer than 1 second can also be used. The spectral distribution of the light employed for the exposure can be controlled using color filters, if desired. Laser beams can also be employed for exposure. Moreover, the emulsions used in the present invention may also be exposed to light emitted from phosphors excited by electron beams, X-rays, y-rays or a-rays.
In the photographic emulsions layers of photographic materials prepared in accordance with the present invention, conventional color forming couplers, that is, compounds capable of forming colors by oxidative coupling with aromatic primary amine developers (e.g., phenylenediamine derivatives or aminophenol derivatives) in color development processing may be used in combination with the fast-coupling or slow-coupling coupler, or may be used independently of the fast-coupling or slow-coupling coupler by addition to a layer not containing the fast-coupling or slow-coupling coupler. Examples of conventional magenta couplers which can be used include 5-pyrazolone couplers, pyrazolobenzimidazole couplers, cyanoacetylcumarone couplers and open-chain acylacetonitrile couplers. Examples of conventional yellow couplers which can be used include acylacetamide couplers (e.g., benzoyl acetanilides and pivaloyl acetanilides). Examples of conventional cyan couplers which can be used include naphthol couplers and phenol couplers. These couplers can provide desirable results when they have hydrophobic groups (ballast groups) in their molecules and are thereby rendered non-diffusible. These couplers may be 4-equivalent or 2-equivalent. Moreover, they may be colored couplers having a color correcting effect, or couplers capable of releasing development restrainers with the progress of development (conventional DIR couplers). In addition to conventional DIR couplers, conventional colorless DIR coupling compounds which yield colorless products upon coupling and release development restrainers may be used.
Specific examples of conventional magenta color forming couplers which can be used are disclosed in U.S. Patents 2,600,788, 2,983,608, 3,062,653, 32,127,269, 3,311,476, 3,419,391, 3,519,429, 3,558,319, 3,582,322, 3,615,506, 3,834,908 and 3,891,445, West German Patent 1,810,464, West German Patent Application (OLS) Nos. 2,408,665, 2,417,945, 2,418,959 and 2,424,467, Japanese Patent Publication No. 6031/65, Japanese Patent Application (OPI) Nos. 20826/76, 58922/77, 129538/74, 74027/74, 159336/75, 42121/77, 74028/74, 60233, 26541/76 and 55122/78.
Specific examples of conventional yellow color forming couplers which can be used are disclosed in U.S. Patents 2,875,057, 3,265,506, 3,408,194, 3,551,155, 3,582,322, 3,725,072 and 3,891,445, West German Patent 1,547,868, West German Patent Application (OLS) Nos. 2,219,917, 2,261,361 and 2,414,006, British Patent 1,425,020, Japanese Patent Publication No. 10783/76, Japanese Patent Appliction (OPI) Nos. 26133/ 72, 73147/73, 102636/76, 6341/75, 123342/75, 130442/75, 21827/76, 87650/75, 82424/77 and 115219/77.
Specific examples of conventional cyan couples which can be used are described in U.S. Patents 2,369,929, 2,434,272, 2,474,293, 2,521,908, 2,895,826, 3,034,892, 3,311,476, ,458,315, 3,476,563, 3,583,971, 3,591,383, 3,767,411 and 4,004,929, West German Patent Application (OLS) Nos. 2,414,830 and 2,454,329, Japanese Patent Application (OPI) Nos. 59838/73, 26034/76, 5055/73, 146828/76, 69624/77 and 90932.77.
Specific examples of colored couplers which can be used in the present invention are described in, e.g., U.S. Patents 3,476,560, 2,521,908 and 3,034,892, Japanese Patent Publication Nos. 2016,22335/63, 11304/67 and 32461/69, Japanese Patent Application (OPI) Nos. 26034/76 and 42121/77, and West German Patent Application (OLS) No. 2,418,959.
Specific examples of conventional DIR couplers which can be used in the present invention are described in, e.g., U.S. Patents 3,227,554, 3,617,291, 3,701,783, 3,790,384 and 3,632,345, West German Patent Application (OLS) Nos. 2,414,007, 2,454,301 and 2,454,329, British Patent 953,454, Japanese Patent Application (OPI) Nos. 69624/77 and 122335/74, and Japanese Patent Publication No. 16141/76.
Besides conventional DIR couplers, conventional compounds capable of releasing development restrainers with the progress of development may be incorporated in the light-sensitive materials. Specific examples thereof are described in, e.g., U.S. Patents 3,297,445 and 3,379,529, West German Patent Application (OLS) No. 2,417,914, and Japanese Patent Application (OPI) Nos. 15271/77 and 9116/78.
In the photographic materials of the present invention, photographic emulsion layers and other hydrophilic colloidal layers may contain inorganic or organic hardeners. Specific examples thereof include chromium salts (e.g., chromium alum, chromium acetate), aldehydes (e.g., formaldehyde, glyoxal, glutaraldehyde), N-methylol compounds (e.g., dimethylolurea, methyloldimethylhydantoin), dioxane derivatives (e.g., 2,3-dihydroxydioxane), active vinyl compounds (e.g., 1,3,5-triacryloyl-hexahydro-s-triazine, 1,3-vinylsulfonyl-2-propanol), active halogen compounds (e.g., 2,4-dichloro-6-hydroxy-s-triazine) and mucohalogenides (e.g., mucochloric acid, mucophenoxychloric acid). Such hardners may be used individually or as a combination of two or more thereof.
In case that the hydrophilic colloidal layers of the photographic materials of the present invention contain dyes and ultraviolet absorbents, they may be mordanted by cationic polymers. Specific examples of such polymers are described in, e.g., British Patent 685,475, U.S. Patents 2,675,316, 2,839,401, 2,882,156, 3,048,487, 3,184,309 and 3,445,231, West German Patent Application (OLS) No. 1,914,362, Japanese Patent Application (OPI) Nos. 47624/75 and 71332/75.
The photographic materials prepared in accordance with the present invention may contain a color fog preventing agent, such as a hydroquinone derivative, aminophenol derivative, gallic acid derivative and ascorbic acid derivative.
The hydrophilic colloidal layers of the photographic materials prepared in accordance with the present invention may contain ultraviolet absorbents. Specific examples thereof include benzotriazole compounds substituted with aryl groups, 4-thiazolidone compounds, benzophenone compounds,"einnamic acid esters, butadiene compounds, benzoxazole compounds, and, further, ultraviolet absorbing polymers. A polymer ultraviolet absorbent in a latex form is preferably used. These ultraviolet absorbents may be fixed in the foregoing hydrophilic colloidal layers.
More specifically, such ultraviolet absorbents are described in U.S. Patents 3,533,794, 3,314,794 and 3,352,681, Japanese Patent Application (OPI) No. 2784/71, U.S. Patents 3,705,805, 3,707,375, 4,045,229, 3,700,455 and 3,499,762 and West German Patent Publication 1,547,863.
Hydrophilic colloidal layers of the photographic materials prepared in accordance with the present invention may contain water-soluble dyes for various purposes, e.g., as filter dyes or prevention of irradiation. Examples of such dyes include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes and azo dyes. Among these dyes, oxonol dyes, hemioxonol dyes and merocyanine dyes are used to greater advantage.
Known discoloration inhibitors can be used in practice of the present invention and, further, color image stabilizing agents can also be used individually or as a combination of two or more thereof. Examples of known discoloration inhibitors include hydroquinone derivatives, gallic acid derivatives, p-alkylphenols, p-oxyphenol derivatives and bisphenols.
Specific examples of hydroquinone derivatives which can be used for the above-described purpose are disclosed in U.S. Patents 2,360,290, 2,418,613, 2,675,314, 2,701,197, 2,704,713, 2,728,659, 2,732,300, 2,735,765, 2,710,801 and 2,816,028 and British Patent 1,363,921.
Specific examples of gallic acid derivatives which can be used for the above-described purpose are described in U.S. Patents 3,457,079 and 3,069,262; p-alkoxyphenols are disclosed in U.S. Patents 2,735,765 and 3,698,909, Japanese Patent Publication Nos. 20977/74 and 6623/77; p-oxyphenol derivatives are disclosed in U.S. Patent 3,432,300, 3,573,050, 3,574,627 and 3,764,337, Japanese Patent Application (OPI) Nos. 35633/77, 147434/77 and 152225/77; and bisphenols are disclosed in U.S. Patent 3,700,455.

Example 1

Multilayer color photographic material sample 101 was prepared by coating the layers having the following compositions on a polyethylene terephthalate film support.

Sample 101:

The 1st layer: Antihalation layer (AHL):

A gelatin layer containing black colloid silver.

The 2nd layer: Interlayer (ML):

A gelatin layer containing an emulsified dispersion of 2,5-di-t-octylhydroquinone.

The 3rd layer: 1st red-sensitive emulsion layer (RL₁):

Silver iodobromide emulsion (silver iodide: 5 mol%, a poly-dispersed emulsion having a mean grain size of 0.3 pm) - silver coverage of 0.8 g/m².
Silver iodobromide emulsion (silver iodide: 7 mol%, a mono-dispersed emulsion having a mean grain size of 0.5 µm) ― silver coverage of 0.8 g/m².
Sensitizing dye I ― 6 x 10-⁵ mol per mol of silver.
Sensitizing dye II - 1.5 x 10-⁵ mol per mol of silver.
Coupler C-4 - 0.04 mol per mol of Ag.
Coupler EX-1 - 0.003 mol per mol of Ag.
Coupler D-3 - 0.0006 mol per mol of Ag.

The 4th layer: 2nd red-sensitive emulsion layer (RL₂):

Silver iodobromide emulsion (silver iodide: 7 mol%, a mono-dispersed emulsion having a mean grain size of 0.65 µ,) - silver coverage of 1.4 g/m^2.
Sensitizing dye I ― 3 x 10-⁵ mol per mol of Ag.
Sensitizing dye II - 1.2 x 10-⁵ mol per mol of Ag.
Coupler C-1 - 0.017 mol per mol of Ag.
Coupler C-4 - 0.003 mol per mol of Ag.
Coupler EX-1 - 0.0016 mol per mol of Ag.

The 5th layer: Interlayer (ML):

Same as the 2nd layer.

The 6th layer: 1st green-sensitive emulsion layer (GL,):

Silver iodobromide emulsion (silver iodide: 4 mol%, a poly-dispersed emulsion having a mean grain size of 0.35 pm) - silver coverage of 1.5 g/m².
Sensitizing dye III ― 3 x 10-⁵ mol per mol of Ag.
Sensitizing dye IV - 1 x 10-⁵ mol per mol of Ag.
Coupler M-4 - 0.05 mol per mol of Ag.
Coupler EX-3 - 0.008 mol per mol of Ag.
Coupler EX-2 - 0.0015 mol per mol of Ag.

The 7th layer: 2nd green-sensitive emulsion layer (GL₂):

Silver iodobromide emulsion (silver iodide; 9 mol%, a mono-dispersed emulsion having a mean grain size of 0.60 µm) ― silver coverage of 1.6 g/m².
Sensitizing dye III - 2.5 x 10-⁵ mol per mol of Ag.
Sensitizing dye IV - 0.8 x 10-⁵ mol per mol of Ag.
Coupler M―4 ― 0.02 mol per mol of Ag.
Coupler EX-3 - 0.003 mol per mol of Ag.

The 8th layer: Yellow filter layer (YFL):

A gelatin layer containing an emulsified dispersion of yellow colloid silver an 2,5-di-t-octylhydroquinone in an aqueous gelatin solution.

The 9th layer: 1st blue-sensitive emulsion layer (BL₁):

Silver iodobromide emulsion (silver iodide: 6 mol%, mean grain size: 0.3 µm)― silver coverage of 1.5 g/m².
Coupler Y-1 - 0.25 mol per mol of Ag.
Coupler EX-2 - 0.015 mol per mol of Ag.

The 10th layer: 2nd blue-sensitive emulsion layer (BL₂):

Silver iodobromide emulsion (silver iodide: 6 mol%, mean grain size: 0.7 pm; - 1.1 g/m².
Coupler Y-1 - 0.06 mol per mol of Ag.

The 11th layer: 1st protective layer (PL,):

A gelatin layer containing silver iodobromide (silver iodide: 1 mol%, mean grain size: 0.7 µm) in a silver coverage of 0.5 g/m² and ultraviolet absorbent UV-1.

The 12th layer: 2nd protective layer (PL₂):

A gelatin layer containing trimethyl methacrylate particles (diameter of about 1.5 µm).
To each of the foregoing layers were further added a gelatin hardening agent H-1 and a surface active agent in addition to the above components.

Compounds employed for preparing Sample 101 are described below.
Sensitizing Dye I:

Pyridinium salt of anhydro-5,5'-dichloro-3,3'-di(γ-sulfopropyl)-9-ethyl-thiacarbocyaninehydroxide Sensitizing Dye II:
Triethylamine salt of anhyrdro-9-ethyl-3,3'-di(y-sulfopropyl)-dibenzo[4,5,4',5']thiacarbocyanine hydroxide

Sensitizing Dye III:

Sodium salt of anhydro-9-ethyl-5,5'-dichloro-3,3'-di(y-sulfopropyl)oxacarbocyanine Sensitizing Dye IC:
Sodium salt of anhydro-5,6,5',6'-tetrachloro-1,1'-diethyl-3,3'-di-{β-[β(γ-sulfopropoxy)ethoxy]-ethyl}imidazolocarbocyanine hydroxide

Sample 102:

This sample was prepared in the same manner as Sample 101 except that an equivalent mole of Coupler EX-2 was used in place of Coupler D-3 in RL₁.

Sample 103:

This sample was prepared in the same manner as Sample 101 except that an equivalent mole of Coupler C-4 was used in place of Coupler C-1 in RL₂ and the reduction in sensitivity was compensated by increasing the mean grain size of the silver halide emulsion to 0.70 pm without changing the structure of the mono-dispersed silver iodobromide emulsion.

Sample 104:

This sample was prepared in the same manner as Sample 101 except that an equivalent mole of Coupler EX-2 was used in place of Coupler D-3 in RL₁, and an equivalent mole of Coupler C-4 was used in place of Coupler C-1 in RL₂, and the reduction in sensitivity was compensated by increasing the mean grain size of the silver halide emulsion to 0.70 pm without changing the structure of the mono-dispersed silver iodobromide emulsion.
When each of Samples 101 to 104 was wedge-exposed to white light and processed, the samples showed almost the same sensitivity and gradation.
The granularity of the cyan color image of each sample was measured by a conventional RMS (Root Mean Square) method. The determination of granularity by the RMS method is well known in the art and is described in Photographic Science and Engineering, Vol. 19, No. 4 pages 235-238 (1975) as a title of "RMS Granularity: Determination of Just Noticeable Difference".
The aperture for measurement was 48 µm. Furthermore, the MTF value of each cyan image at a spatial frequency of 7 cycles per mm was measured.
The development processing for the photographic material was performed as follows at 38°C.
The compositions of the processing solution used in the above process were as follows.

Color developer:

Bleach solution:

Fix solution:

Stabilization solution:

The results obtained are shown in Table 2.
In Table 2, the smaller the RMS value is, the better the granularity is; and the larger the MTF value is, the better the sharpness is.
As is clear from the above results, Sample 104 having a combination of the slow-coupling coupler and the slow-coupling coupler shows a poor granularity at high-density portions. Sample 102 having the slow-coupling coupler and the fast-coupling coupler for improving the granularity shows good granularity but shows a reduced MTF value, that is, sharpness is reduced. On the other hand, when the diffusible DIR coupler is used in place of the DIR coupler in Sample 102, the MTF value can be improved (Sample 101) without being accompanied by reduction in sensitivity, that is, the granularity and sharpness can be improved at once.

Example 2

Sample 201:

This sample was prepared in the same manner as Sample 101 except that an equimolar mole of Coupler D-3 was used in place of Coupler EX-2 in GL₁ of the 6th layer.

Sample 202:

This sample was prepared in the same manner as Sample 101 except that an equimolar mole of Coupler M-1 was used in place of Coupler M-4 in GL₂ of the 7th layer and the increase in sensitivity was corrected by reducing the mean grain size of the silver halide emulsion from 0.60 pm to 0.50 µm without changing the structure of the silver halide grains.

Sample 203:

This sample was prepared in the same manner as Sample 101 except that an equimolar mole of Coupler D-3 was used in place of Coupler EX-2 in GL, of the 6th layer, an equimolar mole of Coupler M-1 was used in place of Coupler M-4 in GL₂ of the 7th layer, and the increase in sensitivity was corrected by reducing the mean grain size of the silver halide emulsion in GL₂of the 7th layer from 0.60 pm to 0.50 µm without changing the structure of the silver halide grains.
When each of Samples 201 to 203 was wedge-exposed to white light and processed, Samples 201 and 203 caused a density reduction to some extent on the cyan image and the yellow image but showed almost the same sensitivity and gradation on the aimed magenta color image.
About these samples, the granularity and the MTF value of each magenta image were measured, the results being shown in Table 3.
As is clear from the results shown in Table 3, the magenta image of Sample 203 has excellent granularity from a low density portion to a high density portion and also shows a good MTF value, which shows the superior effects of this invention.

Example 3

Samples 301-304 were prepared in the same manner as Sample 203 except that an equimolar amount of DIR Coupler set forth in Table 3 was used in place of Coupler D-3 in GL, of the 6th layer of Sample 203 prepared in Example 2.
The RMS value and the MTF value of each magenta image of these samples were measured. The results are shown in Table 3 below.
As is clear from the results shown in Table 3, each of the samples of this invention has excellent granularity and sharpness.

Claims

1. A silver halide color photographic material, comprising: a support base having positioned thereon a red-sensitive silver halide emulsion layer; a green-sensitive silver halide emulsion layer; and a blue-sensitive silver halide emulsion layer wherein at least one of the emulsion layers comprises a plurality of silver halide emulsion sublayers, the highest-sensitive sublayer containing a fast coupling coupler and a low-sensitive sublayer containing a slow coupling coupler and a DIR coupler or DIR compound, characterized in that the highest-sensitive sublayer only contains one or more fast coupling couplers and that the low-sensitive sublayer contains a slow coupling coupler having a coupling rate in a range of 1/1,3 to 1/15 of that of the fast coupling coupler contained in the highest-sensitive sublayer in combination with 0,0001 to 0,05 mole per mole of silver halide of the low-sensitive sublayer of a DIR coupler represented by the general formula:

wherein A represents a coupler component, m represents 1 or 2, and Y represents a group which is attached to the coupler component A at the coupling position thereof and can be eliminated from the coupler by reaction with an oxidation product of a color developing agent to produce a development inhibitor or a precursor thereof, the development inhibitor having a diffusibility of 0,4 to 1,0 as defined in the description.

2. A silver halide color photographic material as claimed in Claim 1, wherein the DIR coupler or DIR compound is present in an amount in a range of 0,0003 to 0,01 mole per mole of silver halide of low-sensitive sublayer.

3. A silver halide color photographic material as claimed in Claim 1, wherein the ratio of coupling rates of the slow coupling coupler to that of the fast coupling coupler is 1/1,5 to 1/10.

4. A silver halide color photographic material as claimed in Claim 1, wherein the DIR coupler or DIR compound is present in an amount of 0,001 to 0,3 mole per mole of the slow coupling coupler.

5. A silver halide color photographic material as claimed in Claim 4, wherein the DIR coupler or DIR compound is present in an amount in a range of 0,005 to 0,1 mole per mole of the slow coupling coupler.

6. A silver halide color photographic material as claimed in Claim 1, wherein the fast coupling coupler is present in the highest-sensitive sublayer in an amount in a range of 0,001 to 0,5 g/_M ².

7. A silver halide color photographic material as claimed in Claim 1, wherein the slow coupling coupler is present in the low-sensitive sublayer in an amount in a range of 0,2 to 2 g/m^2.

8. A silver halide color photographic material as claimed in Claim 1, wherein at least one of the red-sensitive, green-sensitive and blue-sensitive silver halide emulsion layers is a double sublayer type silver halide emulsion layer comprising a highest-sensitive emulsion layer and a low-sensitive emulsion sublayer.

9. A silver halide color photographic material as claimed in Claim 1, wherein at least one of the red-sensitive, green-sensitive and blue-sensitive silver halide emulsion layers is a triple sublayer type silver halide emulsion layer comprising a highest-sensitive emulsion layer an intermediate-sensitive emulsion sublayer and a low-sensitive emulsion sublayer.

10. A silver halide color photographic material as claimed in Claim 9, wherein the intermediate-sensitive emulsion sublayer contains the slow coupling coupler and the DIR coupler or DIR compound.

11. A silver halide color photographic material as claimed in Claim 9, wherein the low-sensitive emulsion sublayer contains the slow coupling coupler and the DIR coupler or DIR coupler.