EP0264954A2

EP0264954A2 - Silver halide photographic material having specific silver halide structure

Info

Publication number: EP0264954A2
Application number: EP87115593A
Authority: EP
Inventors: Shunichi Fuji Photo Film Co. Ltd. Aida; Hiroyuki Fuji Photo Film Co. Ltd. Yamagami; Shinpei Fuji Photo Film Co. Ltd. Ikenoue
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1986-10-24
Filing date: 1987-10-23
Publication date: 1988-04-27
Anticipated expiration: 2007-10-23
Also published as: DE3785291T2; EP0264954B1; JPS63106745A; EP0264954A3; DE3785291D1; JPH0575096B2

Abstract

A silver halide photographic material having excellent color sensitizability, which comprises a support having thereon at least one light-sensitive silver halide emulsion layer comprisingchemically sensitized silver halide grain having a silver halide core portion comprising about 10 to 40 mol % silver iodide, substantially surrounded by a silver halide shell portion containing less silver iodide than the core portion and the silver halide of the surface region of the shell portion contains at least about 5 mol % silver iodide.

Description

FIELD OF THE INVENTION

This invention relates to a silver halide photographic material and, more particularly, to a silver halide photographic material having an emulsion containing silver halide grains of novel structure.

BACKGROUND OF THE INVENTION

The basic properties required for photographic silver halide emulsions are high sensitivity, low fogging, fine graininess, and high development activity. Silver halides include silver fluoride, silver chloride, silver bromide, and silver iodide. Usually, however, silver fluoride is not used in photographic emulsions due to its high solubility in water, and combinations of the remaining three silver halides have been intensively studied for improving the basic properties of the emulsions. Light absorption increases in the order of silver chloride, silver bromide, and silver iodide, whereas development activity decreases in this order. Therefore, a high light absorption and a high development activity are difficult to achieve using a single silver halide. E. Klein and E. Moisar have disclosed that mixed silver halide emulsions containing silver halide cores covered by layers of different silver halides (specifically, a silver bromide core, a first layer composed of silver bromoiodide containing 1 mol % of silver iodide, and an outer layer composed of silver bromide) shows increased light sensitivity without reduced development activity (Japanese Patent Publication No. 13,162/68 corresponding to Brit. Pat. 1,027,146).
Koitabashi et al have disclosed that photographically desirable properties such as improved covering power can be obtained by forming a thin outer layer (hereinafter referred to as shell) of 0.01 to 0.1 u.m in thickness on core grains containing a comparatively low content of silver iodide (Japanese Patent Applicatio (OPI) No. 154,232/82 corresponding to U.S. Pat. 4,444,877 (the term "OPI" as used herein means an "unexamined published Japanese patent application)).
These formulations are useful with emulsions containing a small amount of silver iodide in the core portion of the grains, therefore containing a small total amount silver iodide. However, in order to obtain higher sensitivity and higher image quality, it has been necessary to increase the content of iodide in emulsions.
Techniques of enhancing sensitivity and image quality by increasing the iodide content in the core portion are disclosed in Japanese Patent Application (OPI) Nos. 138,538/85, 88,253/86 (corresponding to European Pat. 171,238A), 177,535/84 (corresponding to Brit. Pat. 2,138,963B), 112,142/86, 143,331/85, etc.
The common technical concept in these patents is to adjust development activity and light sensitivity by increasing the iodide content in the core portion as much as possible, while decreasing the iodide content in the shell portion.
However, double structure grains based on this technical concept still undergo serious intrinsic desensitization when sensitized with sensitizing dyes, and undergo desorption of sensitizing dyes when light-sensitive materials containing them. are stored under high humidity condition .

SUMMARY OF THE INVENTION

An object of the present invention is to provide a silver halide photographic material having excellent color sensitizability and, hence, an improved sensitivity/graininess ratio.
Another object of the present invention is to provide a silver halide photographic material having reduced deterioration of photographic properties, such as speed and spectral sensitivity, when stored under the conditions of high humidity.
As a result of intensive investigations, it has now been found that these objects of the present invention can be attained by a silver halide photographic material comprising a support having thereon at least one light-sensitive silver halide emulsion layer containing chemically sensitized silver halide grain having a silver halide core portion comprising about 10 to 40 mol % silver iodide, substantially surrounded by a silver halide shell portion containing less silver iodide than the core portion and the silver halide of the surface region of the shell portion contains at least about 5 mol % silver iodide.

DETAILED DESCRIPTION OF THE INVENTION

In the present invention "a silver halide surface portion" means "the portion between the surface of a silver halide grain and about 50 A in depth of the grain from the surface". Furthermore, the silver halide content of this portion is analyzed by XPS (X-ray photoelectron spectroscopy).
The mechanism by which the objects of the present invention can be attained by controlling the distribution of iodide ion in silver halide grains is not clear.
The XPS method used for analyzing the iodide content in the surface of silver halide grains is described in Junichi Aihara et al. Denshi no Bunko (Spectroscopy of Electrons , Kyoritsu Library 16 (Kyoritsu Shuppan, 1978).
A standard method of XPS is to use Mg-Ka as exciting X-rays and measure the intensity of photoelectrons of iodide (I) and silver (Ag) (usually 1-3d_5/2 and Ag-3d_5/2) released from silver halide grains of a suitable sample form.
The content of iodide can be determined by using a calibration curve of the intensity ratio of photoelectrons from iodide (I) to those from silver (Ag) (intensity (I)fintensity (Ag)), prepared by using several standard samples having known iodide contents. With silver halide emulsions, the XPS must be performed after decomposing gelatin adsorbed on the surface of silver halide grains with protease or the like to remove it.
The contents of silver iodide in the core portion and shell portion can be measured by X-ray diffractiometry. Examples of applying the X-ray diffractiometry to silver halide grains are described in H. Hirsch; Journal of Photographic Science, 10, p.129 et seq., etc. The lattice constant is determined by the halide composition, and a diffraction peak appears at a diffraction angle satisfying Bragg's formula (2d sine = nx:wherein d is lattice constant, 9 is incidence angle, X is wavelength and n is a positive integer).
A method for measuring X-ray diffraction is described in detail in Kiso Bunseki Kagaku Koza 24, X-sen Bunseki (Kyoritsu Shuppan), X-sen Kaisetsu no Tebiki (Rigaku Denki K.K.), etc.
A standard measuring method is to use Cu as a target and determine the diffraction curve of a (220) crystal face of silver halide using Kβ rays of Cu as a radiation source (tube voltage: 40 KV; tube current: 60 mA). In order to enhance the resolving power of the measuring apparatus, it is necessary to confirm the measuring accuracy by properly selecting the width of the slit (e.g., diverging slit, receiving slit, etc.), the time constant of the apparatus, the scanning speed of goniometer, and the recording speed using a standard sample such as silicon.
Curves of diffraction intensity versus diffraction angle obtained with (220) crystal face of silver halide using Kβ rays of Cu are grouped into two types: one type containing a diffraction peak corresponding to the higher iodide content layer containing 10 to 45 mol % of silver iodide and a diffraction peak corresponding to the lower iodide content layer distinctly separated from each other; and the other type containing two overlapping peaks not distinctly separated from each other.
The technique of analyzing a diffraction curve composed of two diffraction components is well known and is described, for example, in Jikken Butsurigaku Koza 11, "Koshi Kekkan (Lattice Defect)" (Kyoritsu Shuppan), etc.
It is preferable to analyze the curve by assuming it as a function of Gauss or Lorenz and using a curve analyzer manufactured by Du Pont Co.
The above-described lower iodide content layer and higher iodide content layer of the silver halide grains to be used in the present invention may or may not be distinctly separated from each other.
With emulsions containing two kinds of grains without a distinctly layered structure and having different silver halide formulations (e.g., grains having a high silver iodide content and a low silver iodide content), two peaks appear in X-ray diffractiometry.
However, such emulsions do not have the excellent photographic properties obtained by the present invention.
In addition to the above-described X-ray diffractiometry, the EPMA method (Electron-Probe Micro Analyzer method) can also be used to determine whether a particular silver halide emulsion is an emulsion in accordance with the present invention or an emulsion containing the above-described two kinds of silver halide grains.
In ths method, a sample is prepared having well-dispersed silver halide grains that do not to come into contact with each other, and it is irradiated with electron beams. X-ray analysis by electron beam excitation permits elemental analysis of an extremely small portion.
This method permits determination of the halide compositions of individual grains by determining the intensity of the characteristic X-rays emitted by silver and iodine.
Confirmation of the halide composition of at least 50 grains according to the EPMA method is generally sufficient to determine whether a particular emulsion is an invention emulsion, which is preferably as uniform as possible in iodide contents among grains.
As to the iodide content distribution among grains measured by the EPMA method, the relative standard deviation is preferably not more than about 50 %, more preferably not more than about 35 %, particularly preferably not more than about 20 %.
Preferred halide compositions of the silver halide grains of the present invention are described below.
The core portion contains a higher iodide content silver halide, with average iodide content being between about 10 mol % and 40 mol % which is the solid solution limit, preferably between about 15 and 40 mol %, more preferably between about 20 and 40 mol %. The optimum iodide content in core portion is between about 20 and 40 mol % or between 30 and 40 mol %, depending upon the process for preparing core grains.
In the core portion, the silver halide other than silver iodide may be at least one of silver bromide, silver chloride and silver chlorobromide, preferably with at least about 50 mol%, more preferably with at least about 60 mol% of silver bromide content.
The average iodide content of the shell portion is less than that of the core portion, and the shell portion contains silver halide containing preferably from 0 to about 10 mol%, more preferably up to about 5 mol%, of silver iodide. In the shell portion at least one of silver bromochloride, silver chloride and silver bromide is contained. The distributio of silver iodide in the shell portion may be uniform or non-uniform. The grains used in the present invention contain an average of about 5 mol % or more, preferably about 7 mol % to 15 mol %, of silver iodide in the grain surface portion measured according to the XPS method, and it may be more than or the same as the average silver iodide content in the shell portion. The distribution of silver iodide in the vicinity of the grain surface maybe uniform or non-uniform.
As silver halides other than silver iodide to be used in the surface portion, any of silver chloride, silver chlorobromide, and silver bromide may be used, with the content of silver bromide being preferably at least 40 mol %, more preferably at least 60 mol %.
As to the total halide composition, the effects of the present invention are remarkable when the total content of silver iodide is about 7 mol % or more. The total silver iodide content is more preferably about 9 mol % or more, particularly preferably about 12 mol % to 21 mol %.
The size of silver halide grains to be used in the present invention are not particularly limited, but are preferably about 0.4 u.m or more, more preferably about 0.6 u.m to 2.5 um.
The silver halide grains used in the present invention may have a regular form ("normal crystal grains") such as hexahedral, octahedral, dodecahedral, and tetradecahedral, or an irregular form, such as spherical, pebble-like shape or tabular.
With normal crystal grains, those which have about 50 % or more of a (111) face are particularly preferred. With irregular form grains, too, those which have about 50 % or more of (111) face are particularly preferable. The face ratio of (111) face can be determined by Kubelka-Munk's dye adsorption method. In this method, a dye is selected which preferentially adsorbs on either the (111) face or (100) face, and which associates on the (111) face in a spectrally differentiable state from that on (100) face. The thus selected dye is added to an emulsion to be measured, and the spectrum for an amount of the dye added is studied in detail to determine the face ratio of the (111) face.
With twin crystal grains, tabular grains are preferred. Grains having a thickness of not more than about 0.5 um, a diameter of about 0.6 u.m or more, and an aspect ratio of about 2 or more, preferably about 3 to 10, account for particularly preferably at least about 50 % of the total projected area of silver halide grains present in one and the same layer. The definition of average aspect ratio and a method for its measurement are specifically described in Japanese Patent Application (OPI) Nos. 113,926/83, 113,930/83, 113,934/83, etc.
The emulsions used in the present invention may have a broad grain size distribution, but emulsions with a narrow grain size distribution are preferred. Particularly in emulsions containing normal crystal grains, monodisperse emulsions in which about 90 % (by weight or number) of the total silver halide grains have grain sizes within ±40 %, more preferably ±30 %, of the average grain size are preferred.
The silver halide grains of the present invention may be prepared by combining proper processes selected from various conventional processes.
First, for the preparation of core grains, any of an acidic process, a neutral process, an ammoniacal process, etc. may be selected and, as for reacting a soluble silver salt with a soluble halide salt, any of a one sided-mixing process, a simultaneous mixing process, their combination, etc. can be used.
As one type of simultaneous mixing process, a process in which the pAg in the liquid phase in which silver halide is formed is kept constant, i.e., a controlled double jet process, may be employed. As another type ofthe simultaneous mixing process, a triple jet process in which soluble halide salts with different compositions (for example, soluble silver salt, soluble bromide salt, and soluble iodide salt) are independently added may also be used. For preparation of core grains, silver halide solvents such as ammonia, a rhodanate, a thiourea, a thioether, an amine, etc. may be properly selected for use. Core grains desirably have a narrow grain size distribution, and the monodisperse core emulsions described above are particularly preferred. Whether the halide composition of individual core grains is uniform or not can be determined by the technique of X-ray diffraction and the EPMA method described above. Grains with uniform halide composition give a narrow and sharp diffraction peak width in X-ray diffraction.
Japanese Patent Publication No. 21,657/74 (corresponding to Brit. Patent 1,350,619) discloses two processes for preparing core grains with uniform halide composition among grains.
One process is a double jet process in which a solution is prepared by dissolving 5 g of inert gelatin and 0.2 g of potassium bromide in 700 ml of distilled water and, while stirring the solution, simultaneously adding 1 liter of an aqueous solution containing dissolved therein 52.7 g of potassium bromide and 24.5 g of potassium iodide, and 1 liter of an aqueous solution containing dissolved therein 100 g of silver nitrate. These two solutions are simultaneously added to the stirred solution at an equal and constant rate in about 80 minutes, then water is added thereto to make the total amount 3 liters. By the process, silver bromoiodide grains containing 25 mol % of silver iodide are obtained. These silver bromoiodide grains have been found to have a comparatively sharp iodide distribution curve by X-ray diffractiometry. Another process is a rash addition process wherein an aqueous solution is prepared by dissolving 33 g of inert bone gelatin, 5.4 g of potassium bromide, and 4.9 g of potassium iodide in 500 ml of distilled water and, while stirring the aqueous solution at 70°C, 125 ml of an aqueous solution containing 12.5 g of silver nitrate is added at once to obtain comparatively uniform silver bromoiodide grains containing 40 mol % of silver iodide.
Japanese Patent Application (OPI) No. 16,124/81 (corresponding to U.S. Patent 4,349,622) discloses that uniform silver bromoiodide grains can be obtained by keeping the pAg of a protective colloid-containing solution with a silver bromoiodide emulsion containing silver bromoiodide having a silver iodide content of 15 to 40 mol % at 1 to 8.
After preparation of silver bromoiodide seed crystals containing a high content of silver iodide, uniform silver bromoiodide can also be prepared by a process of accelerating the rate of addition of an aqueous solution of a water soluble halide as disclosed in Japanese Patent Publication No. 36,890/73.(corresponding to U.S. Patent 3,650,757) by Iris and Suzuki, or by a process of increasing the concentrations of added solutions to develop silver bromoiodide grains as disclosed in U.S. Patent 4,242,445 to Saito. These processes give particularly preferable results. The process of Irie et al is a process of preparing photographic, slightly soluble inorganic crystals by double decomposition reaction through simultaneous addition of almost equal amounts of two or more aqueous solutions of inorganic salts in the presence of a protective colloid. The aqueous solutions of inorganic salts to be reacted are added at an addition rate not slower than a definite level and at a rate Q which is not more than the addition rate in proportion to the total surface area of the slightly soluble inorganic salt crystals under growing, i.e., not slower than Q = y and not faster than Q = at² + 6t + y (wherein a, (3 and y are constants which are experimentally determined, t represents the time of lapse after beginning of the reaction).
The Saito's process is a process of preparing silver halide crystals by simultaneously adding two or more aqueous solutions of inorganic salts in the presence of a protective colloid, in which the concentrations of the aqueous solutions of inorganic salts to be reacted are increased to such a degree that new crystal nuclei are scarcely produced during the crystal growth period.
In addition, those emulsion-preparing processes which are described in Japanese Patent Application (OPI) Nos. 138,538/85, 88,253/86 (corresponding to U.S. Patent 3,467,603), 177,535/84 (corresponding to Brit. Patent 2,138,963B), 112,142/86, 143,331/85, etc. maybe use to prepare the emulsion of the present invention.
There are many techniques for introducing silver iodide into the shell portion of the silver halide grains of the present invention. Silver iodide in the core portion may be transferred into the shell portion upon addition of an aqueous solution of a water-soluble bromide salt and an aqueous solution of a water-soluble silver salt according to the double jet process. In this case, the amount and distribution of silver iodide in the shell portion can be controlled by adjusting the pAg during the addition or using a silver halide solvent.
Alternatively, an aqueous solution of a mixture of a water-soluble bromide and a water-soluble iodide and an aqueous solution of a water-soluble silver salt may be added according to the double jet process, or an aqueous solution of a water-soluble bromide, an aqueous solution of water-soluble iodide, and a water-soluble silver salt may be added according to the triple jet process.
In order to introduce silver iodide into the grain surface or the portion of 50 to 100 A from he surface, an aqueous solution containing a water-soluble iodide'can be added, or 0.1 u.m or smaller silver iodide fine grains or silver halide fine grains having a high silver iodide content can be added after formation of the grians.
In preparing silver halide grains of the present invention; the shell may be formed around the core grains without further treatment after core formation, but it is preferred to form the shell after washing the core emulsion to desalt the core grains.
Shell formation may be conducted according to various processes known in the field of silver halide photographic materials, with a simultaneous mixing process being preferred. The above-described process of Irie et al and the Saito's process are preferred for preparing emulsions having grains with a distinct layered structure. The necesary shell thickness varies depending upon grain sizes. Large grains 1.0 _Ilm or larger are preferably covered by a shell of 0.1 µm or more in thickness, while small grains not larger than 1.0 u.m are preferably covered by a shell of 0.05 _Ilm or more in thickness.
The ratio of silver in the core portion to that in the shell portion is preferably in the range of from about 1:5 to 5:1, more preferably about 1:5 to 3:1, most preferably about 1:5 to 2:1.
In the present invention, cadmium salts, zinc salts, lead salts, thallium salts, iridium salts or the complex salts thereof, rhodium salts or the complex salts thereof, iron salts or the complex salts thereof, etc. may be present during the formation or physical ripening of silver halide grains.
The silver halide emulsion used in the present invention is chemically sensitized. Chemical sensitization can be conducted according to the processes described in, for example, H. Frieser, Die Grundlagen der Photographischen Prozesse mit Silberhalogeniden pp. 675 - 734 (Akademische Verlagsgesellschaft, 1968).
That is, sulfur sensitization using active gelatin or sulfur-containing compounds capable of reacting with silver (e.g., thiosulfates, thioureas, mercapto compounds, rhodanines, etc.); reduction sensitization using a reductive substance (e.g., stannous salts, amines, hydrazine derivatives, formamidinesulfinic acid, silane compounds, etc.); and noble metal sensitization using compounds of noble metals (e.g., complexes of group VIII metals of the periodic table such as Pt, lr, Pd, etc. as well as gold complex salts) may be employed alone or in combination.
Specific examples of the sulfur sensitization process are described in U.S. Pats. 1,574,944, 2,410,689, 2,278,947, 2,728,668, 3,656,955, specific examples of the reduction sensitization process are described in U.S. Pats. 2,983,609, 2,419,974, 4,054,458, and specific examples of the noble metal sensitization process are described in U.S. Pata. 2,399,083, 2,448,060, and British Pat. No. 618,061, etc.
As a protective colloid used in preparation of an emulsion of silver halide grains in accordance with the present invention, or as a binder for hydrophilic colloidal layers, gelatin is advantageously used. However, other hydrophilic colloids can be used as well. For example, proteins such as gelatin derivatives, graft polymers of gelatin and other high polymers, albumin, casein, etc.; cellulose derivatives such as hydroxyethyl cellulose, carboxymethylcellulose, cellulose sulfate, etc.; sugar derivatives such as sodium alginate, starch derivatives, etc.; and various synthetic hydrophilic macromolecular substances such as homopolymers or copolyemrs (e.g., polyvinyl alcohol, partially acetallized polyvinyl alcohol, poly-n-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinyl imidazole, polyvinyl pyrazole, etc.) can be used.
As gelatin, acid-processed gelatin or enzyme-processed gelatin as described in Bull. Soc. Sci. Phot. Japan , No. 16, p. 30 (1966) may be used, as well as lime-processed gelatin, a gelatin hydrolyzate or an enzyme-decomposed product.
Photographic emulsions used in the present invention may be spectrally sensitized with methine dyes or the like. Dyes to be used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Particularly useful dyes are those belonging to cyanine dyes, merocyanine dyes, and complex merocyanine dyes. In these dyes, any of the nuclei ordinarily used as basic hetero ring nuclei in cyanine dyes can be used. That is, a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus, a pyridine nucleus, etc.; those in which these nuclei are fused with an alicyclic hydrocarbon ring; and those in which these nuclei are fused with an aromatic ring, i.e., an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a benzoselenazole nucleus, a benzimidazole nucleus, a quinoline nucleus, etc. can be used. These nuclei may be substituted at their carbon atoms.
The merocyanine dyes or complex merocyanine dyes can contain a ketomethylenen nucleus, including 5-or 6-membered hereto ring nuclei such as a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thiooxazolidine-2,4-dione nucleus, a thiohydantoin nucleus, a 2-thiooxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus, a thiobarbituric acid nucleus, etc.
These sensitizing dyes may be used alone or in combination. A combination of sensitizing dyes is often employed, particularly for the purpose of supersensitization. Typical examples thereof are described in U.S. Pats. 2,688,545, 2,977,229, 3,397,060, 3,522,052, 3,527,641, 3,617,293, 3,628,964, 3,666,480, 3,672,898, 3,679,428, 3,703,377, 3,769,301, 3,814,609, 3,837,862, 4,026,707, British Pat. 1,344,281, 1,507,803, Japanese Patent Publication Nos. 4,936/68, 12,375/78, and Japanese Patent Application (OPI) Nos. 110,618/77, 109,925/77.
A dye which itself does not have a spectrally sensitizing effect or a substance which substantially does not absorb visible light and which shows a supersensitizing effect may be incorporated to an emulsion together with the sensitizing dye.
The silver halide grains used in the present invention are preferably spectrally sensitized with a sensitizing dye or dyes represented by the following general formula (I) or (II). These sensitizing dyes may be used alone or as a combination thereof.
General formula (I):
In the above general formula, Z, and Z₂ each represents atomic group necessary for forming the same or different, substituted or unsubstituted 5-or 6-membered, nitrogen-containing hetero rings, such as a thiazoline ring, a thiazole ring, a benzothiazole ring, a naphthothiazole ring, a selenazoline ring, a selenazole ring, a benzoselenazole ring, a naphthoselenazole ring, an oxazole ring, a benzoxazole ring, a naphthoxazole ring, a benzimidazole ring, a naphthoimidazole ring, a pyridine ring, a quinoline ring, an indolenine ring, an imidazo (4,5-b)quinoxaline ring, etc. These heterocyclic nuclei ,ay be substituted. Examples of the substituents include a lower alkyl group (containing preferably up to 6 carbon atoms and being optionally further substituted by a hydroxy group, a halogen atom, a phenyl group, a substituted phenyl group, a carboxy group, an alkoxycarbonyl group, an alkoxy gruop, etc.), a lower alkoxy group (containing preferably up to 6 carbon atoms), an acylamino group (containing preferably up to 8 carbon atoms), a monocyclic aryl group, a carboxy gruop, a lower alkoxycarbonyl group (containing preferably up to 6 carbon atoms), a hydroxy gruop, a cyano group, a halogen atom, etc.
Q₁ represents an atomic group necessary for forming a 5-or 6-membered, nitrogen-containing ketomethylene ring such as a thiazolidin-4-one ring, a selenazolidin-4-one ring, an oxazolidin-4-one ring, an imidazolidin-4-one ring, etc.
Ri, R₂, R₃, and R₄, which may be the same or different, each represents a hydrogen atom, a lower alkyl group (containing preferably up to 4 carbon atoms), a substituted or unsubstituted phenyl group, or aralkyl group; provided that when ℓ₁ represents 2 or 3 or when n represents 2 or 3, one R₁ and another Ri, one R₂ and another R₂, one R₃ and another R₃, or one R₄ and another R₄ may be linked to each other to form a 5-or 6-membered ring optionally containing an oxygen atom, a sulfur atom, a nitrogen atom, or the like.
R₅, R₆ and R₇, which may be the same or different, each represents a substituted or unsubstituted alkyl or alkenyl group containing up to 10 carbon atoms which may have an oxygen atom, a sulfur atom or a nitrogen atom in the carbon chain. The substituents include a sulfo group, a carboxy group, a hydroxy group, a halogen atom, an alkoxycarbonyl group, a carbamoyl group, a phenyl group, a substituted phenyl group, etc.
Where the hetero ring represented by Z₁ or Z₂ is a ring containing another substitutable nitrogen atom such as a benzimidazole ring, a naphthoimidazole ring, an imidazo[4,5-b]quinoxaline ring or the like, the other nitrogen atom in the hetero ring may be substituted by, for example, an alkyl or alkenyl group containing up to 6 carbon atoms, this substituent optionally substituted by a hydroxy group, an alkoxy group, an alkoxycarbonyl group, etc.
l₁ and n₁ each represents 0 or a positive integer of up to 3, with ℓ₁ + n₁ being up to 3. When ℓ₁ represents 1, 2 or 3, R₅ and R₁ may be connected to each other to form a 5-or 6-membered ring.
ji, ki, and m₁ each represents 0 or 1.
X₁ represents an acid anion such as Cℓ^-, Br-, I-, CH₃OSO₃- or
r₁ represents 0 or 1.
At least one of R₅, R₆, and R₇ more preferably represents a group substituted with a sulfo or carboxy group.
Of the sensitizing dyes represented by general formula (I), the following are preferred but the present invention is not to be construed as being limited thereto.
In the above general formula, Z11 represents an atomic group necessary for forming a nitrogen-containing, 5-or 6-membered hetero ring, including for example, hetero ring nuclei which are usually used for forming cyanines, such as thiazoline, thiazole, benzothiazole, naphthothiazole, selenazoline, selenazole, benzoselenazole, naphthoselenazole, oxazole, benzoxazole, naphthoxazole, benzimidazole, naphthoimidazole, pyridine, quinoline, pyrrolidine, indolenine, imidazo[4,5-b]quinoxalinetetrazole, etc. These hetero ring nuclei may optionally be substituted. Examples of such substituents include a lower alkyl group (containing preferably up to 10 carbon atoms and being optionally substituted by a hydroxy group, a halogen atom, a phenyl group, a substituted phenyl group, a carboxy group, an alkoxycarbonyl gruop, an alkoxy group or the like), a lower alkoxy group (containing preferably up to 7 carbon atoms), an acylamino group (containing preferably up to 8 carbon atoms), a monocyclic aryl group, a monocyclic aryloxy gruop, a carboxy group, a lower alkoxycarbonyl group (containing preferably up to 7 carbon atoms), a hydroxy group, a cyano group, a halogen atom SPECIFY.
Q₁₁ represents an atomic group necessary for forming a nitrogen-containing, 5-or 6-membered ketomethylene ring such as thiazolidin-4-one, selenazolidin-4-one, oxazolidin-4-one, imidazolidin-4-one or the like.
Q₁₂ represents an atomic group necessary for forming a nitrogen-containing, 5-or 6-membered ketomethylene ring, including for example, a hetero ring nucleus capable of forming an ordinary merocyanine dye, such as rhodanine, 2-thiohydantoin, 2-selenathiohydantoin, 2-thio-oxazolidine-2,4-dione, 2-selenaoxazolidine-2,4-dione, 2-thioselenazolidine-2,4-dione, 2-selenathiazolidine-2,4-dione, 2- selenazolidine-2,4-dione or the like.
Where the hetero rings represented by _z11, Q₁₁, and Q₁₂ are rings containing two or more nitrogen atoms as the hetero ring-forming atoms, such as benzimidazoles and thiohydantoins, the nitrogen atoms not bonded to R₁₃, R₁₅, and R₁₄, respectively, may be substituted. Examples of such substituents include alkyl or alkenyl groups containing up to 8 carbon atoms and in which a carbon atom or atoms may be substituted by an oxygen atom, a sulfur atom, a nitrogen atom, etc. and may further be substituted, or oprionally substituted monocyclic aryl groups, etc.
R₁₁ represents a hydrogen atom or an alkyl group containing up to 4 carbon atoms, R₁₂ represents a hydrogen atom, a phenyl group or a substituted phenyl group (examples of the substituents being an alkyl or alkoxy group containing up to 4 carbon atoms, a halogen atom, a carboxyl group, a hydroxyl group, etc.) or an alkyl group optionally substituted by a hydroxyl group, a carboxyl group, an alkoxy group, a halogen atom, etc. and, when m₂₁ represents 2 or 3, plural R₁₂ groups may be linked to form a 5-or 6-membered ring optionally containing an oxygen atom, a sulfur atom or a nitrogen atom.
R₁₃ represents substituted or unsubstitutes alkyl, alkenyl or hetero ring group containing up to 10 carbon atoms and optionally containing an oxygen atom, a sulfur atom or a nitrogen atom in the carbon chain or a hetero ring roup. Examples of the substituents include a sulfo group, a hydroxy group, a halogen atom, an alkoxycarbonyl group, a carbamoyl group, a phenyl group, a substituted phenyl group, and a monocyclic saturated hetero ring gruop.
R₁₄ and R₁₅ which may be the same or different, each has the same definition as R₁₃, or each represents a hydrogen atom or substituted or unsubstituted monocyclic aryl group (examples of the substituents being a sulfo group, a carboxy group, a hydroxy group, a halogen atom, an alkyl, acylamino or alkoxy group containing up to 5 carbon atoms, etc.).
m₂₁ represents 0 or a positive integer of up to 3, j₂₁ represents 0 or 1, and n21 represents 0 or 1; provided that when m₂₁ represents a positive integer of 1 to 3, R₁₁ and R₁₃ may be linked to form a 5-or 6- membered ring.
At least one of R₁₃, R₁₄,and R₁₅ preferably represents a group containing a sulfo or carboxy group.
Of the sensitizing dyes represented by general formula (II), the following compounds are particularly preferred, but the present invention is not be construed as being limited thereto.
In the present invention, it is preferable to conduct supersensitization using compounds represented by the following general formula and described in Japanese Patent Application (OPI) No. 89,952/87:
wherein R represents an aliphatic, aromatic or heterocyclic group substituted by at least one of -COOM or -S0₃M, and M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium group or a quaternary phosphonium group.
Preferred specific examples of the compounds represented by the general formula (III) used in the present invention are illustrated below, but the present invention is not to be construed as being limited thereto.
Silver halide emulsion used in the present invention preferably contain a sulfur-containing silver halide solvent. The sulfur containing silver halide solvent used in the present invention may be added in any step between formation of emulsion grains and coating of the emulsion. The amount of sulfur-containing silver halide solvent used in the present invention is usually from about 1.25 ^x 10^-4 mol to 5.0 ^x 10^-2 mol per mol of silver, and more specifically, an amount of 5.0 ^x10^-4 mol to 5.0 ^x10^-2 mol per mol of silver is preferred with respect to silver halide grains of from about 0.4 to 0.8 µm in grain size, about 2.5 ^x10^-4 to 2.5 ^x10^-2 mol per mol of silver is preferred with respect to silver halide grains of from about 0.8 to 1.6 µm in grain size, and about 1.25 ^x10^-4 to 1.25 ^x10-³ mol per mol of silver is preferred with respect to silver halide grains of from about 1.6 to 3.5 µm in grain size.
The term "sulfur-containing silver halide solvent" as used herein means a silver halide solvent capable of being coordinated with the silver ion through the sulfur atom.
More specifically, the silver halide solvent is a compound which, when it is added into water or water/organic solvent mixture (for example, water/methanol = 1/1 by volume) in a concentration of 0.02 mole at 60°C, can increase the solubility of silver chloride in an amount more than two times as much as the maximum amount of silver chloride soluble.
Specifically, such solvents include thiocyanates (potassium rhodanate, ammonium rhodanate, etc.), organic thioether compounds (for example, compounds described in US Pats. 3,574,628, 3,021,215, 3,057,724, 3,038,805, 4,276,374, 4,297,439, 3,704,130, Japanese Patent Application (OPI) No. 104,926/82, etc.), thione compounds (for example, tetra-substituted thioureas described in Japanese Patent Application (OPI) Nos. 82,408/78, 77,737/80, US Pat. 4,221,863, etc. and compounds described in Japanese Patent Application (OPI) No. 144,319/78), mercapto compounds capable of accelerating growth of silver halide grains described in Japanese Patent Application (OPI) No. 202,531/82, etc., with thiocyanates and organic thioether compounds being particularly preferred.
More specifically, compounds represented by the general formula (IV) are preferred as the organic thioethers:
In the above general formula, m represents 0 or an integer of 1 to 4.
R₁₆ and R₁₇, which may be the same or different, each represents a lower alkyl group (containing 1 to 5 carbon atoms) or a substituted alkyl group (containing a total of 1 to 30 carbon atoms), substituted for example, with -OH, -COOM, -SO₃M, -NHR₁₉, -NR₁₉R₁₉ (provided that the two R₁₉ groups may be the same or different), -OR₁₉, -CONHR₁₉, -COOR₁₉, a hetero ring, etc.
R₁₉ represents a hydrogen atom, or a lower alkyl group which may further be substituted by the above-described substituent or substituents.
Two or more substituents may be present in the alkyl group, which may be the same or different. M represents a hydrogen atom or a cation such as an alkali metal atom and an ammoniums ion.
R₁₈ represents an alkylene group (containing preferably 1 to 12 carbon atoms) provided that, when m is 2 or more, the plural R₁₈ groups may be the same or different.
The alkylene chain may contain one or more of -0-, -CONH-, -SO₂NH-, etc. and may be substituted by those substituents which have been described for R₁₆ and R₁₇.
Further, R₁₆ and R₁₇ may be linked to form a cyclic thioether.
As the thione compounds, compounds represented by the general formula (V) are preferred.
In the above general formula, Z represents
-OR₂₄ or -SR₂₅.
R₂₀, R₂₁, R₂₂, R₂₃, R₂₄, and R₂₅, which may be the same or different and may optionally be substituted, each represents an alkyl group, an alkenyl group, an aralkyl group, an aryl group or a hetero ring residue (each containing preferably a total of up to 30 carbon atoms).
Further, R₂₀ and R₂i, R₂₂ and R₂₃, R₂₀ and R₂₂, R₂₀ and R₂₄, or R₂₀ and R₂₅ may be linked to form a 5-or 6- membered hetero ring, which may be substituted.
As the mercapto compounds, compounds represented by the following general formula (VI) are preferred.
In the above general formula, A represents an alkylene group, R₂₆ represents -NH₂, -NHR₂₇,
-CONHR₃₀, -OR₃₀, -COOM, -COOR₂₇, -SO₂NHR₃₀, -NHCOR₂₇ or -SM₃M (containing preferably a total of up to 30 carbon atoms).
L represents -S ⊖ when R₂₆ represents
or represents -SM in other cases.
R₂₇, R₂₈, and R₂₉ each represents an alkyl group, R₃₀ represents a hydrogen atom or an alkyl group, and M represents a hydrogen atom or a cation (e.g., an alkali metal ion or an ammonium ion).
These compounds can be synthesized according to processes described in the aforesaid patents and cited literature, etc. Some of the compounds are commercially available.
Examples of the sulfur-containing silver halide solvent compounds used in the present invention are illustrated below, but the present invention is not to be construed as bneing limited thereto.
In the photographic emulsion in the present invention may be incorporated various compounds for the purpose of preventing formation of fog or stabilizing photographic properties during production, or during storage or processing of light-sensitive materials containing the emulsion. Any of azoles (e.g., benzothiazolium salts, nitroimidazoles,. nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mer- captothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriidiazoles, mercaptotetrazoles (particularly 1-phenyl-5-mercaptotetrazole), etc.); mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxazolinethione; azaindenes (such as, triazaindenes, tetrazaindenes (particularly 4-hydroxy-substituted (1,3,3a,7)tetrazaindenes), pentazaindenes, etc.; benzenethiosulfonic acid, benzenesulfinic acid, benzenesulfonic acid amide, etc. known as antifoggants or stabilizers can be added. For example, those described in US Pats. 3,954,474, 3,982,947, and Japanese Patent Publication No. 28>660/77 can be used.
The photographic light-sensitive material of the present invention may contain in its photographic emulsion layer or layers a polyalkylene oxide or its ether, ester or amine derivative, a thioether compound, a thiomorpholine, a quaternary ammonium salt compound, a urethane derivative, a urea derivative, an imidazole derivative, a 3-pyrazolidone; etc. for the purpose of enhancing sensitivity or contrast or for accelerating development. For example, those described in US Pats. 2,400,532, 2,423,549, 2,716,062, 3,617,280, 3,772,021, 3,808,003, and British Pat. 1,488,991 can be used.
The light-sensitive material prepared according to the present invention may contain in its hydrophilic layer a water-soluble dye as a filter dye or for various purposes such as prevention of irradiation. Such dye includes oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes, and azo dyes. Of these, oxonol dyes, hemioxonol dyes, and merocyanine dyes are particularly useful.
The light-sensitive material prepared according to the present invention may contain in its photographic emulsion layer or other hydrophilic colloidal layer a brightening agent such as a stilbene, a triazine, an oxazole, or a coumarin. These may be water-soluble, and water-insoluble brightening agents may be used in the form of a dispersion.
In the present invention, the following known antifading agents may be used in combination. In addition, color image stabilizers used in the present invention may be used alone or in combination of two or more. The known dye stabilizers include, for example, hydroquinone derivatives described in US Pats. 2,360,290, 2,418,613, 2,675,314, 2,702,197, 2,704,713, 7,728,659, 2,732,300, 2,735,765, 2,710,801, 2,816,028, British Pat. No. 1,363,921, etc., gallic acid derivatives described in US Pats. 3,457,079, 3,069,262, etc., p-alkoxyphenols described in US Pats. 2,735,765, 3,698,909, and Japanese Patent Publication Nos. 20,977/74, and 6,623/77, p-hydroxyphenol derivatives described in US Pats. 3,432,300, 3,573,050, 3,574,627, 3,764,337, Japanese Patent Application (OPI) Nos. 35,633/77, 147,434/77, and 152,225/77, bisphenols described in US Pat. No. 3,700,455, and the like.
The light-sensitive material prepared according to the present invention may contain hydroquinone derivatives, aminophenol derivatives, gallic acid derivatives, ascorbic acid derivatives, etc. as color fog- preventing agents.
The photographic light-sensitive materials of the present invention include both black-and-white light-sensitive materials and multi-layer multi-color light-sensitive materials. They are particularly preferably used as high-speed color light-sensitive materials for photographic use.
Multi-layer natural color photographic materials usually contain a support having thereon at least one red-sensitive emulsion layer, one green-sensitive emulsion layer, and one blue-sensitive emulsion layer. The order of these layers can be arbitrarily selected as the case demands. The red-sensitive emulsion layer usually contains a cyan-forming coupler, the green-sensitive emulsion layer a magenta-forming coupler, and the blue-sensitive emulsion layer a yellow-forming coupler. In some cases, however, different combinations may be employed.
As the yellow color-forming couplers, known open chain ketomethylene couplers may be used. Of these, benzoylacetanilide type and pivaloylacetanilide type compounds are advantageous. Specific examples of yellow color-forming couplers are those described in US Pats. 2,875,057, 3,265,506, 3,408,194, 3,551,155, 3,582,322, 3,725,072, 3,891,445, West German Pat. No. 1,547,868, West German Pat. Application (OLS) Nos. 2,219,917, 2,261,361, 2,414,006, British Pat. No. 1,425,020, Japanese Patent Publication No. 10,783/76, Japanese Patent Application (OPI) Nos. 26,133/72, 73,147/73, 102,636/76, 6,341/75, 123,342/75, 130,442/75, 21,827/76, 87,650/75, 82,424/77,115,219/77, etc.
As magenta color-forming couplers, pyrazolone compounds, indazolone compounds, cyanoacetyl compounds, etc. may be used, with pyrazolone compounds being particularly advantageous. Specific examples of useful magenta color-forming couplers are those described in US Pats. 2,600,788, 2,983,608, 3,062,653, 3,127,269, 3,311,476, 3,419,391, 3,519,429, 3,558,319, 3,582,322, 3,615,506, 3,834,908, 3,891,445, West German Pat. No. 1,810,464, West German Pat. Application (OLS) Nos. 2,408,665, 2,417,945, 2,418,959, 2,424,467, Japanese Patent Publication No. 6,031/65, Japanese Patent Application (OPI) Nos. 20,826/76, 58,922/77, 129,538/74, 74,027/74, 159,336/75, 42,121/77, 74,028/74, 60,233/75, 26,541/76, 55,122/78, etc.
As cyan color-forming couplers, phenolic compounds, naphtholic compounds, etc. may be used. Specific examples thereof are described in US Pats. 2,369,929, 2,434,272, 2,474,293, 2,521,908, 2,895,826, 3,034,892, 3,311,476, 3,458,315, 3,476,563, 3,583,971, 3,591,383, 3,767,411, 4,004,929, West German Pat. Application (OLS) Nos. 2,414,830, 2,454,329, Japanese Patent Application (OPI) Nos. 59,838/73, 26,034/76, 5,055/73, 146,828/76, 69,624/77, and 90,932/77.
As cyan couplers, couplers having a ureido group described in Japanese Patent Application (OPI) Nos. 204,545/82, 65,134/81, 33,252/73, 33,249/83 are may preferably used (corresponding to U.S. Pats. 4,451,559, 4,333,999, European Pat. 73, 145A and U.S. Pat. 4,444,872, respectively).
The couplers may be of either 4-equivalent type or 2-equivalent type based on silver ions. Since 2- equivalent couplers are capable of more effectively utilizing silver, they are more preferred. Particularly in silver halide emulsions containing grains containing silver iodide in an average content of not less than 7 mol %, it is more advantageous to employ 2-equivalent couplers in view of photographic properties.
Referred 2-equivalent couplers used in the present invention are represented by the following general formuale (Cp-1) to (Cp-9).
R₅₁ to R₅₉, Zi, Z₂, Z₃, Y, t, m, and p in the above general formulae (Cp-1) to (Cp-9) are described below.
In the general formulae, R₅₁ represents an aliphatic group, an aromatic group, an alkoxy group or a heterocyclic group, and R₅₂ and R₅₃, which may be the same or different each represents an aromatic group or a heterocyclic gruop.
The aliphatic group represented by R₅₁ contains preferably 1 to 22 carbon atoms, and may be substituted or unsubstituted, and may be in a chain form or cyclic form. Substituents for an alkyl group represented by R₅, include an alkoxy group, an aryloxy group, an amino group, an acylamino group, a halogen atom, etc., which themselves may further be substituted. Specific examples of the aliphatic group represented by R₅₁ include an isopropyl group, an isobutyl group, a tert-butyl group, an isoamyl group, a tert-amyl group, a 1,1-dimethylbutyl, 1,1-dimethylhexyl, 1,1-diethylhexyl gruop, a dodecyl group, a hexadecyl group, an octadecyl group, a cyclohexyl group, a 2-methoxyisopropyl group, a 2-phenoxyisopropyl group, 2-p-tert-butyl-phenoxy-isopropyl group, an a-aminoisopropyl group, an a-(diethylaminoisopropyl group, an a-(succinimido)isopropyl group, an α-(phthalimido)isopropyl group, an α-(benzenesulfonamido)-isopropyl group, etc.
When R₅₁, R₅₂ or R₅₃ represents an aromatic group (particularly a phenyl group), the aromatic group may be substituted, by an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonylamino group, an aliphatic amido group, an alkylsulfamoyl group, an alkylsulfonamido group, an alkyureido group, an alkyl-substituted succinimido group, etc., containing up to 32 carbon atoms. In such cases, the alkyl group may contain in its chain an aromatic group such as a phenylene group. The phenyl group in the aromatic group may also be substituted by an aryloxy group, an aryloxycarbonyl group, an arylcarbamoyl group, an arylamido group, an arylsulfamoyl group, an arylsulfonamido group, an arylureido group, etc., with the aryl moiety of these substituents being optionally substituted by one or more alkyl groups containing a total of 1 to 22 carbon atoms.
The phenyl group in the aromatic group represented by R₅₁, R₅₂ or R₅₃ may further be substituted by an amino group including those substituted by a lower alkyl group or groups containing 1 to 6 carbon atoms, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group, a cyano group, a thiocyano group or a halogen atom.
Further, R₅₁, R₅₂ or R₅₃ may represent a substituent in which a phenyl group is fused with an other ring, such as a naphthyl group, a quinolyl group, an isoquinolyl group, a chromanyl group, a coumaranyl group, a tetrahydronaphthyl group, etc. These substituents themselves may further have a substituent or substituents.
When R₅₁ represents an alkoxy group, the alkyl moiety includes a straight or branched alkyl, alkenyl, cyclic alkyl or cyclic alkenyl group containing 1 to 32, preferably 1 to 22, carbon atoms, which may further be substituted by a halogen atom, an aryl group, an alkoxy group, etc.
When R₅₁, R₅₂ or R₅₃ represents a heterocyclic group, the heterocyclic group is linked to the carbon atom of the carbonyl group in the acyl group of the a-acylacetamido group, or to the nitrogen atom of the amido group of the a-acylacetamido group through one carbon atom contained in the ring. Such hetero rings include thiophene, furan, pyran, pyrrole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, in- dolidine, imidazole, thiazole, oxazole, triazine, thiadiazine, oxazine, etc. These may further have a substituent or substituents in the ring.
In general formula (Cp-3), R₅₅ represents a straight or branched alkyl group containing 1 to 32, preferably 1 to 22, carbon atoms (e.g., a methyl group, an isopropyl group, a tert-butyl group, a hexyl group, a dodecyl group, etc.), an alkenyl group (e.g., an allyl group), a cyclic alkyl group (e.g., a cyclopentyl group, a cyclohexyl group, a norbornyl group, etc.), an aralkyl group (e.g., a benzyl group, a β-phenylethyl group, etc.), or a cyclic alkenyl group (e.g., a cyclopentenyl group, a cyclohexenyl group, etc.), which may further be substituted by a halogen atom, a nitro group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl 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, a mercapto group, etc.
Further, R₅₅ may represent an aryl group (e.g., a phenyl group, an a-or β-naphthyl group, etc.). The aryl group may have one or more substituents. Examples of the substituents 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 carboxyl 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, etc.
Still. further, R_E5 may represent a heterocyclic group (for example, a 5-or 6-membered heterocyclic group or fused heterocyclic group containing a sulfur atom, an oxygen atom or a nitrogen atom as a hetero atom, such as a pyridyl group, a quinolyl group, a furyl group, a benzothiazolyl group, an oxazolyl group, an imidazolyl group, a naphthoxazolyl group, etc.), a heterocyclic group substituted with a substituents for the aryl group represented by R₅₅, an aliphatic or aromatic acyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylcarbamoyl group, an arylcarbamoyl group, an alkylthiocarbamoyl group or an arylthiocar- bamoyl group.
In the general formulae, Red represents a hydrogen atom, a straight or branched alkyl or alkenyl group containing 1 to 32, preferably 1 to 22, carbon atoms, a cyclic alkyl group, an aralkyl group, a cyclic alkenyl group (these groups optionaly having substituents mentioned with respect to Ræ), an aryl group and a heterocyclic group (these optionally having substituents mentioned with respect to R_æ), an alkoxycarbonyl group (e.g., a methoxycarbonyl group an ethoxycarbonyl group, a stearyloxycarbonyl group, etc.), an aryloxycarbonyl group (e.g., a phenoxycarbonyl group, a naphthoxycarbonyl group, etc.), an aralkyloxycarbonyl group (e.g., a benzyloxycarbonyl group, etc.), an alkoxy group (e.g., a methoxy group, an ethoxy group, a heptadecyloxy group, etc.), an aryloxy group (e.g., a phenoxy group, a tolyloxy group, etc.), an alkylthio group (e.g., an ethylthio group, a dodecylthio group, etc.), an arylthio group (e.g., a phenylthio group, an a-naphthylthio group, etc.), a carboxyl group, an acylamino group (e.g., an acetylamino group, a 3-((2,4-di-tert-amylphenoxy)-acetamido]benzamido group, etc.), a diacylamino group, an N-alkylacylamino group (e.g., an N-methylpropionamido group, etc.), an N-arylacylamino group (e.g., an N-phenylacetamido group, etc.), a ureido group (e.g., a ureido group, an N-arylureido group, an N-alkylureido group, etc.), a urethane group, a thio-urethane group, an arylamino group (e.g., a phenylamino group, an N-methylanilino group, a diphenylamino group, an N-acetylanilino group, a 2-chloro-5-tetradecanamidoanilino group, etc.), an alkylamino group (e.g., an n-butylamino group, a methylamino group, a cyclohexylamino group, etc.), a cycloamino group (e.g, a piperidino group, a pyrrolidino group, etc.), a heterocyclic amino group (e.g., a 4-pyridyl-amino group, a 2-benzoxazolylamino group, etc.), an alkylcarbonyl group (e.g., a methylcarbonyl group, etc.), an arylcarbonyl group (e.g., a phenylcarbonyl group, a sulfonamido group (e.g., an alkylsulfonamido group, an arylsulfonamido group, etc.), a carbamoyl group (e.g., an ethylcarbamoyl group, a dimethylcarbamoyl group, an N-methylphenylcarbamoyl group, an N-phenylcarbamoyl group, etc.), a sulfamoyl group (e.g., an N-alkylsulfamoyl group, an N,N-dialkylsulfamoyl group, an N-arylsulfamoyl group, an N-alkyl-N-arylsulfamoyl group, an N,N-diarylsulfamoyl group, etc.), a cyano group, a hydroxyl group, and a sulfo group.
In the general formulae, R₅₆ represents a hydrogen atom or a straight or branched chain alkyl or alkenyl group containing 1 to 32, preferably 1 to 22, carbon atoms, a cyclic alkyl group, an aralkyl group or a cyclic alkenyl group, which may be substituted by the substituents for R₅₅.
Further, R₅₆ may represent an aryl group or a heterocyclic group, which may be substituted by the substituents for R₅₅.
Still further, Rss 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 or a hydroxyl group.
R₅₆ may be substituted at any position of the benzen ring. R₅₇, Rss, and R₅₉, which may be the same or different each represents a group present ordinary 4-equivalent phenolic or a-naphtholic couplers, specifically a hydrogen atom, a halogen atom, an alkoxycarbonylamino group, an aliphatic hydrocarbon group, an N-arylureido group, an acylamino group, -O-R₆₂ or -S-R₆₂ (provided that R₆₂ represents an aliphatic hydrocarbon group). Plural R₅₇ groups in the same molecule may be the same or different. The aliphatic hydrocarbon group includes those which have a substituent or substituents.
When these substituents include an aryl moiety, the aryl moiety may have one or more substituent for R₅₅.
R₅₈ and R₅₉ include aliphatic hydrocarbon groups, aryl groups, and hetero ring groups, or one of them may be a hydrogen atom. The groups may have a substituent or substituents. In addition, R₅₈ and R₅₉ may , be linked to form a nitrogen-containing hetero ring nucleus.
The aliphatic hydrocarbon residue represented by Rss and R₅₉ may be saturated or unsaturated, and may be in a straight chain form, a branched chain form or a cyclic form. Preferred examples thereof include an alkyl group (e.g., a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, an isobutyl group, a dodecyl group, an octadecyl group, a cyclobutyl group, a cyclohexyl group, etc.), and an alkenyl group (e.g., an allyl group, an octenyl group, etc.). The aryl group represented by R₅₈ and R₅₉ includes a phenyl group, a naphthyl group, etc., and the hetero ring group represented by R₅₈ and R₅₉ typically includes a pyridinyl group, a quinolyl group, a thienyl group, a piperidyl group, an imidazolyl group, etc. The substituents for these aliphatic hydrocarbon groups, aryl groups, and hetero ring groups include a halogen atom, a nitro group, a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, a sulfo group, an alkyl group, an alkenyl group, an aryl group a heterocyclic group, an alkoxy group, an aryloxy group, an arylthio group, an arylazo group, an acylamino group, a carbamoyl group, an ester group, an acyl group, an acyloxy group, a sulfonamido group, a sulfamoyl group, a sulfonyl group, a morpholino group, etc.
In the formulas, 1 represents an integer of 1 to 4, m represents an integer of 1 to 3, and p represents an integer of 1 to 5.
Of the above-described couplers preferred yellow couplers are those represented by general formula (Cp-1), in which R₅, represents a t-butyl group or a substituted or unsubstituted aryl group, and R_s2 represents a substituted or unsubstituted aryl group; and those represented by general formula (Cp-2), in which R₅₂ and R₅₃ each represents a substituted or unsubstituted aryl group.
Preferred magenta couplers are those represented by general formula (Cp-3), in which R₅₄ represents an acylamino group, a ureido group or an arylamino group and R₅₅ represents a substituted aryl group; those represented by general formula (Cp-4) in which R₅₄ represents an acylamino group, a ureido group or an arylamino group and R₅₆ represents a hydrogen atom; and those represented by general formulae (Cp 5) and (Cp-6) in which R₅₄ and R₅₆ each represents a straight or branched alkyl or alkenyl group, a cyclic alkyl or aralkyl group or a cyclic alkenyl group.
Preferred cyan couplers are those represented by general formula (Cp-7), in which R₅₇ represents a 2- position acylamino or ureido group, a 5-position acylamino or alkyl group, or a 6-position hydrogen or chlorine atom; and those represented by general formula (Cp-9) in which R₅₇ represents a 5-position hydrogen atom, acylamino group, sulfonamido group or alkoxycarbonyl group, R₅₈ represents a hydrogen atom, and R₅₉ represents a phenyl group, an alkyl group, an alkenyl group, a cyclic alkyl group, an aralkyl group or a cyclic alkenyl group.
In the general formulas, Z₁ represents a halogen atom, a sulfo group, an acyloxy group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group or a heterocyclic thio group, which may be further substituted by such substitutents as an aryl group (e.g., a phenyl group), a nitro group, a hydroxyl group, a cyano group, a sulfo group, an alkoxy group (e.g., a methoxy group), an aryloxy group (e.g., a phenoxy group), an acyloxy group (e.g., an acetoxy group), an acylamino group (e.g., an acetylamino group), a sulfonamido group (e.g., a methanesulfonamido group), a sulfamoyl group (e.g., a methlsulfamoyl group), a halogen atom (e.g., a fluorine atom, a chlorine atom, or a bromine atom), a carboxy group, a carbamoyl group (e.g., a methylcarbamoyl group), an alkoxycarbonyl group (e.g., a methoxycarbonyl group, etc.), a sulfonyl group (e.g., a methylsulfonyl group), etc.
In the formulae, Z₂ and Y, which may be the same or different each represents a coupling-off group bonded to the coupling site through an oxygen atom, a nitrogen atom or a sulfur atom. When Z₂ and Y are bonded to the coupling site through an oxygen atom, a nitrogen atom or a sulfur atom, these atoms are bound to an alkyl group, an aryl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylcarbonyl group, an arylcarbonyl group or a heterocyclic group. With respect to the nitrogen atom, Z₂ or Y represents a 5-or 6-membered ring containing the nitrogen atom to form a coupling-off group (e.g., an imidazolyl group, a pyrazolyl group, a triazolyl group, a tetrazolyl group, etc.).
The above-described alkyl, aryl, and hetorocyclic groups contained in Z₂ and Y may have substituents. Specific examples of the substituents include an alkyl group (e.g., a methyl group, an ethyl group, etc.), an alkoxy group (e.g., a methoxy group, an ethoxy group, etc.), an aryloxy group (e.g., a phenyloxy group, etc.), an alkoxycarbonyl group (e.g., a methoxycarbonyl group, etc.), an acylamino group (e.g., an acetylamino group, etc.), a carbamoyl group, an alkylcarbamoyl group (e.g., a methylcarbamoyl group, an ethylcarbamoyl group, etc.), a dialkylcarbamoyl group (e.g., a dimethlcarbamoyl group, etc.), an arylcarbamoyl group (e.g., a phenylcarbamoyl group, etc.), alkylsulfonyl group (e.g., a methylsulfonyl group, etc.), an arylsulfonyl group (e.g., a phenylsulfonyl group, etc.), an alkylsulfonamido group (e.g., a methanesulfonamido group, etc.), an arylsulfonamido group (e.g., a phenylsulfonamido group, etc.), a sulfamoyl group, an alkylsulfamoyl group (e.g., an ethylsulfamoyl group, etc.), a dialkylsulfamoyl group (e.g., a dimethylsulfamoyl group, etc.), an alkylthio group (e.g., a methylthio group, etc.), an arylthio group (e.g., a phenylthio group, etc.), a cyano group, a nitro group, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, etc.), etc. When two or more substituents are present, they may be the same or different.
Particularly preferred substituents include a halogen atom, an alkyl group, an alkoxy group, an alkoxycarbonyl group, and a cyano group.
Preferable examples of Z₂ are groups which are bonded to the coupling site through a nitrogen atom or a sulfur atom, and preferred examples of Y are a chlorine atom and groups which are bonded to the coupling site through an oxygen atom, a nitrogen atom or a sulfur atom.
In the formulae, Z₃ represents a hydrogen atom or a group represented by the following general formulae (R-I), (R-II), (R-III) or (R-IV):
wherein R₆₃ represents substituted or unsubstituted aryl or heterocyclic group;
wherein R₆₄ and R 65, which may be the same or different, each represents a hydrogen atom, a halogen atom, a carboxylic acid ester group, an amino group, an alkyl group, an alkylthio group, an alkoxy group, an alkylsufonyl group, an alkylsulfinyl group, a carboxylic acid group, a sulfonic acid group, an unsubstituted or substituted phenyl or hetero cyclic group;
wherein W₁ represents a non-metallic atomic group necessary for forming a 4-, 5-or 6-membered ring together with
therein.
Of groups represented by general formula (IV), those represented by the following formulae (R-V) to (R-VII) are preferable:

wherein R₆₆ and R₆₇, which may be the same or different each represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or a hydroxy group, R₆₈, R₆₉, and R₇₀, which may be the same or different, each represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or an acyl group, and W₂ represents an oxygen atom or a sulfur atom.
The couplers used in the present invention may be polymers derived from coupler monomers represented by the following general formula (CI) and having repeating units represented by the general fomula (CII) or copolymers of the coupler monomer and one or more non-color forming monomers incapable of oxidatively coupling with an aromatic primary amine developing agent, and containing at least one ethylene group. Two or more of the coupler monomers may be contained in the polymer.
In the above general formulae, R' represents a hydrogen atom, a lower alkyl group containing 1 to 4 carbon atoms or a chlorine atom, K₁ represents -CONR"-, -NR"CONR"-, -NR"COO-, -COO-, -SO₂-, -CO-, -NR"CO-, -S0₂NR"-, -NR"SO₂-, -OCO-, -OCONR"-, -NR"-, -S-, or -0-, K₂ represents -CONR"-or -COO-, R" represents a hydrogen atom, an aliphatic group or an aryl group and, when two or more R" groups are present in the same molecule, they may be the same or different.
K₃ represents an unsubstituted or substituted alkylene group containing 1 to 10 carbon atoms, an aralkylene group or an unsubstituted or substituted arylene group, with the alkylene group a straight chain or branched chain group.
The alkylene group includes a methylene group, a methylmethylene group, a dimethylmethylene group, a dimethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a decylmethylene group, etc.; the aralkylene group includes a benzylidene group; and the arylene group includes a phenylene group and naphthylene group.
Substituents for the alkylene, aralkylene, or arylene group represented by K₃ include an aryl group (e.g., a phenyl group, etc.), a nitro group, a hydroxyl group, a cyano group, a sulfo group, an alkoxy group (e.g., a methoxy group, etc.), an aryloxy group (e.g., a phenoxy group, etc.), an acyloxy group (e.g., an acetoxy group, etc.), an acylamino group (e.g., an acetylamino group, etc.), a sulfonamido group (e.g., a methanesulfonamido group, etc.), a sulfamoyl group (e.g., a methylsulfamoyl group, etc.), a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, etc.), a carboxyl group, a carbamoyl group (e.g., a methylcarbamoyl group, etc.), an alkoxycarbonyl group (e.g., a methoxycarbonyl group, etc.), a sulfonyl group (e.g., a methlsulfonyl group, etc.), etc. When two or more of these substituents are present, they may be the same or different.
i, j, and k, which may be the same or different, each represents 0 or 1..
Q is bonded to
-(K₂) _i-(K₃)_j-(K₁)_k in formula (CI) or (CII) through any of R₅₁ to R₅₉, 2₁ to Z₃, and Y of the foregoing general formulae (Cp-1) to (Cp-9).
The non-color forming ethylenic monomers incapable of coupling with an oxidation product of an aromatic primary amine developing agent include acrylic acid, a-chloroacrylic acid, a-alkylacrylic acid (e.g., acrylic acid, methacrylic acid, etc.), an ester or amide derived therefrom (e.g., acrylamide, methacrylamide, t-butylacrylamide, methyl acrylate, methyl methacrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, n-octylatrylate, lauryl acrylate, and methylenebisacrylamide), a vinyl ester (e.g., vinyl acetate, vinyl propionate, and vinyl laurate), acrylonitrile, methacrylonitrile, an aromatic vinyl compound (e.g., styrene and its derivatives, vinyltoluene, divinylbenzene, vinylacetophenone, etc.), vinylidene chloride, vinyl alkyl ether (e.g., vinyl ethyl ether, etc.), an maleic acid ester, N-vinyl-2-pyrrolidone, N-vinyl-pyridine, 2-or 4-vinylpyridine, etc., with acrylic esters, methacrylic acid esters, and maleic acid esters being particulary preferred.
These non-color forming ethylenically unsaturated monomers may be used as a combination of two or more. For example, a combination of n-butyl acrylate and divinylbenzene, a combination of styrene and methacrylic acid, a combination of n-butyl acrylate and methacrylic acid, or the like may be employed.
The polymer couplers used in the present invention may be water-soluble or water-insoluble, with a polymer coupler latex being particularly preferable.
The polymer coupler latex may be prepared by dissolving a hydrophilic polymer coupler obtained by polymerization of the coupler monomer in an organic solvent, and dispersing the solution to obtain a latex form or by directly dispersing the hydrophilic polymer coupler solution obtained by polymerization to obtain a latex. A_fternatively, a polymer coupler latex prepared by emulsion polymerization or layer-structure polymer coupler latex may directly be added to a gelatin-silver halide emulsion.
In the silver halide photographic material of the present invention, 2-equivalent magenta couplers or 2- equivalent cyan couplers are preferably used, and especially 2-equivalent magenta coupers are preferably used.
2-Equivalent yellow couplers include the following examples, but the present invention is not to be consumed as being limited thereto.

2-Equivalent magent couplers:
Cyan couplers:
Colored couplers can be used in the present invention, including those described in, for example, US Pats. 3,476,560, 2,521,908, 3,034,892, Japanese Patent Publication Nos. 2016/69, 22,335/63, 11,304/67, 32,461/69, Japanese Patent Application (OPI) Nos. 26,034/76, 42,121/77, and West German Patent Application (OLS) No. 2,418,959.
DIR couplers can be used in the present invention, including those described in, for example, US Pats. 3,227,554, 3,617,291, 3,701,783, 3,790,384, 3,632,345, West German Patent Application (OLS) Nos. 2,414,006, 2,454,301, 2,454,392, British Pat. No. 953,454, Japanese Patent Application (OPI) Nos. 69,624/77, 122,335/74, and Japanese Patent Publication No. 16,141/76.
In addition to DIR couplers, compounds which release a development inhibitor according to proceeding of development may be incorporated in light-sensitive materials according to the invention, including, for example, those described in US Pats. 3,297,445, 3,379,529, West German Patent Application (OLS) No. 2,417,914, Japanese Patent Application (OPI) Nos. 15,271/77 and 9,116/78.
Couplers capable of releasing a development accelerator or a fogging agent according to proceeding of development as described in Japanese Patent Application (OPI) No. 150,845/82 (corresponding to U.S. Pat. 4,390,618) are particularly preferably used.
Non-diffusible couplers capable of forming a slightly diffusible dye as described in British Pat. No. 2,083,640 are also preferably used.
These couplers are added to emulsion layers in an amount of about 2 x 10^-3 mol to 5 x 10^-1 mol, preferably about 1 ^x10-² mol to 5 ^x10-¹ mol.
The light-sensitive material prepared according to the present invention may contain in its hydrophilic colloidal layer an ultraviolet light absorbent, including, for example, aryl group-substituted benzotriazole compounds (e.g., those described in US Pat. 3,533,794), 4-thiazolidone compounds (e.g., those described in U.S. Pats. 3,314,794 and 3,352,681), benzophenone compounds (e.g., those described in Japanese Patent Application (OPI) No. 2784/71), cinnamic acid esters (e.g., those described in U.S. Pats. 3,705,805 and 3,707,375), butadiene compounds (e.g., those described in US Pat. 4,045,229) or benzoxazole compounds (e.g., those described in U.S. Pat. 3,700,455). In addition, those described in U.S. Pat. 3,499,762 and Japanese Patent Application (OPI) No. 48,535/79 may be used. Ultraviolet light absorbing couplers (e.g., a-naptholic cyan dye-forming couplers), ultraviolet ray-absorbing polymers, etc. may also be used. These ultraviolet light absorbent may be mordanted to a specific layer.
In the case of color light-sensitive materials according to the present invention, the layer containing the emulsion of the present invention is not particularly limited. Further, fine silver halide grains not more than 0.2 u.m in grain size are preferably present in at least one layer adjacent to the emulsion layer.
In the photographic processing of the light-sensitive material of the present invention, any of known processes and known processing solutions may be employed. The processing temperature is usually selected between 18 and 50°C. However, temperatures lower than 18°C or higher than 50°C may be employed. Any of silimer image-forming development (black-and white development) and color photographic processing (dye image-forming development) may be used depending upon purpose.
When applied to the light-sensitive material of the present invention, "parallel development" such as color development gives particularly preferred results with respect to sensitivity and graininess.
A color developer generally is an alkaline aqueous solution containing a color-developing agent. As the color-developing agent, there may be used known primary aromatic amine developers such as phenylenediamines (e.g., 4-amino-N,N-diethylaniline, 3-methyl-4-amino-N,N-diethyl-aniline, 4-amino-N-ethyl-N-p-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfoamido-ethyaniline, 4-amino-3-methyl-N-ethyl-N-β-methoxyethylaniline, etc.).
Color-developed photographic emulsion layers are usually bleached. Bleaching may be conducted separately or simultaneously with fixing. As bleaching agents, compounds of polyvalent metals such as iron (III), cobalt (III), chromium (VI), copper (II), etc., peracids, quinones, nitroso compounds, etc. are used, including, for example, ferricyanides, dichromates, organic complex salts of iron (III) or cobalt (III), complex salts of aminopolycarboxylic acids (e.g., ethylenediaminetetraacetic acid, nitrilotriacetic acid, 1, 3-diamino-2-propanol-tetraacetic acid, etc.) or organic acids (e.g., citric acid, tartaric acid, malic acid, etc.), persulfates, permanganates, nitrosophenols, etc. Of these, potassium ferricyanide, iron (III) sodium ethylenediaminetetraacetate, and iron (III) ammonium ethylenediaminetetraacetate are particularly useful. Iron (III) ethylenediaminetetraacetate complexes are useful in both a separate blanching solution and a monobath bleach-fixing solution.
The present invention is now illustrated in greater detail by reference to the following examples which, however, are not to be construed as limiting the present invention in any way. Unless otherwise indicated, all parts, percents and ratios are by weight.

Example 1

Emulsions A to G containing silver bromoiodide tabular were prepared according to the process described in Japanese Patent Application (OPZ) No. 209,445/87, as follows:

An aqueous solution of 30 g of inert gelatin and 6 g of potassium bromide in 1 liter of distilled water was stirred at 60°C, and 35 m of an aqueous solution containing 5.0 g of silver nitrate and 35 mt of an aqueous solution containing 3.2 g of potassium bromide and 0.98 g of potassium iodide were added thereto at a flow rate of 70 mt/min for 30 seconds, then the solution was ripened for 30 minutes by raising the pAg of the solution to 10 to prepare a seed emulsion.

Subsequently a predetermined amount of 1 liter of an aqueous solution of 145 g of silver nitrate and an equimolar amount of an aqueous solution of a mixture of potassium bromide and potassium iodide were added thereto at a predetermined temperature and a pAg and at an addition rate approximately equal to the critical growth rate to prepare a tabular core emulsion. Then the remaining silver nitrate aqueous solution and an aqueous solution of a mixture of potassium bromide and potassium iodide different in halide composition from the aqueous solution used for preparing the core emulsion were added thereto in equimolar amounts at an addition rate approximately equal to the critical growth rate to cover the cores thus core/shell type silver bromoiodide tabular emulsion A to G being prepared.
The aspect ratios of emulsions A to G were changed by adjusting the pAg.
The grain sizes of silver balide in emulsions A to G were controlled to be 0.75 u.m, in terms of the diameter of a sphere corresponding to the projected area of the grains. With reset to grain size distribution, emulsions A to G had a variation coefficient of diameter about 30%, thus being considered to have almost the same distribution.
Table 1 shows the size and iodide contents of silver halide grains in emulsions A to G.
XPS analysis was conducted using ESCA-750 made by Shimazu Seisakusho Ltd. As exciting X-rays, Mg-Ka (accelerating voltage: 8 kV; current: 30 mA) was used, and peak areas corresponding to I-3d_5/2 and Ag-3d _5/2 were determined. The average silver iodide content in the surface portion of the silver halide grains was determined from the intensity ratio.
The silver bromoiodide tabular emulsions A to G were chemically sensitized to have optimal sensitivity for 1/100" exposure. The amounts of chemically sensitizing agents (per mole of silver) used are shown in Table 2.
Samples 101 to 114 were prepared by changing the silver bromoiodide emulsions in the 4th, 7th, and 12th layers of the following coated stratum structure as shown in Table 3.
In addition to the above described ingredients an emulsion stabilizer (Cpd-3) and a surfactant (Cpd-4) as a coating aid were added to respective layers.
Further, the following compounds Cpd-5 and Cpd-6 were added.
These samples were kept for 14 hours under conditions of 40°C and 70% relative humidity, then subjected to exposure for sensitometry and to the following color development processing.
The densities of the processed samples were measured through a red filter, a green filter, and a blue filter.
results of the thus obtained photographic properties are shown in Table 4.
Color development processing was conducted according to the following processing steps at 38°C.
The formulations of the processing solutions used in the respective steps were as follows.

Color developer

Bleaching solution

Fixing solution

Stabilizing solution

The sensitivities of the red-sensitive layer, green-sensitive layer, and blue-sensitive layer are given below, relative to taking that of sample 101 taken as 100.
Comparative samples 108 to 111 were less sensitive than standard samples 101 and 112. Samples 102 to 107, 113, and 114 of the present invention were more sensitive than the standard samples 101 and 112 and had equal or better graininess. Of the samples of the present invention, samples 103, 104, 106, 107, and 114 using a sulfur-containing silver halide solvent showed particularly good results.
Furthermore, samples stored for 3 days under conditions of 45°C and 80% RH before exposure, and frosy samples not having been subjected to such conditions were simultaneously subjected to spectrum separation exposure and developed as above. standard samples 101 and 112 suffered serious changes in spectral sensitivity distribution due to the difference of storing conditions, whereas samples 102 to 107, 113, and 114 of the present invention were scarcely influenced by the change in storage conditions.

Example 2

Samples 201 to 204 were prepared by changing ExM-8 used in the 7th layer of samples 101 to 104 in Example 1 to an equimolar amount of following ExM-20.
These samples were subjected to exposure for sensitometry in the same manner as in Example 1. Sensitivities of the green-sensitive layer thus determined are shown in Table 5.
As is shown in Table 5, particularly remarkabe effects of the present invention can be obtained by using a 2-equivalent coupler.

Example 3

Octahedral monodisperse silver bromoiodide core grains containing 24 mol% of silver iodide were prepared according to the controlled double jet proces in the presence of ammonia, as follows. 500 mt of an aqueous solution containing 100 g of silver nitrate and 500 ml of an aqueous solution containing KBr and Kl were added to 1000 ml of an aqueous solution containing 3% of gelatin and 45 ml of 25% NH₃. The reaction temperature was 70°C, and the silver potential was controlled at 10 mV, and the flow rates were accelerated so that the final flow rates became 4 times as fast as the initial flow rates. After washing with water, a shell of pure silver bromide was formed till the silver amount in the shell portion became the same as that in the core portion according to the controlled double jet proces. 500 m of an aqueous solution containing 100 g of AgNÜ₃ and 500 m t of an aqueous solution containing KBr were simultaneously added to a reactor containing the above core grains. The reaction temperature was 75°C, and the silver potential was controlled at -20 mA. The flow rate was accelerated so that the final flow rate became 2 times as fast as the initial flow rate. The grains thus obtained were of octahedrons 1.9 µm in average diameter, and were confirmed by X-ray diffractiometry to be grains showing two peaks at diffraction angles corresponding to the lattice constant of about 22 mol% silver bromoiodide and the lattice constant of about 2 mol% silver bromoiodide and having a double structure of 12 mol % in total Agl content. This emulsion was designated emulsion K.
Emulsions L to P shown in Table 6 were also prepared in the same manner as emulsion K except for replacing KI by an equimolar amount of KBr.
Emulsions K to P were chemically senstized using sodium thiosulfate, potassium chloroaurate, sulfur-containing silver halide solvent SSS-1, so that they showed optimal sensitivity when subjected to 1/1000" exposure.
Samples 301 to 306 were prepared by coating 1.5 g/m² of each of emulsions K to P in place of the AgBrl emulsion used in the 12th layer of sample 101 in Example 1.
These samples were subjected to the same exposure for sensitometry as in Example 1. The sensitivities of the blue-sensitive layers thus determined are shown in Table 7, based on the sensitivity of sample 301 as 100.
As is seen from the results given in Table 7, samples 302 and 303 of the present invention were more sensitive than the standard samples 301 and 304, and showed the same or better graininess.
Results obtained in the case of samples 305 and 306 show when the silver iodide content in the core portion does not satisfy the definition of the present invention, satisfactory performances cannot be obtained even if the silver iodide content in the surface portion is higher than 5 mol%.
While the present invention has been described in detail and with reference to specific embodiments thereof, it is apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and the scope of the present invention.

Claims

1. A silver halide photographic material comprising a support having thereon at least one light-sensitive silver halide emulsion layer containing chemically sensitized silver halide grain having a silver halide core portion comprising about 10 to 40 mol % silver iodide, substantially surrounded by a silver halide shell portion containing less silver iodide than the core portion and the silver halide of the surface region of the shell portion contains at least about 5 mol % silver iodide.

2. A silver halide photographic material as in claim 1, wherein the relative standard deviation of the iodide content distribution among grains is not more than about 50%.

3. A silver halide photographic material as in claim 1, wherein the content of silver iodide in the core portion is from about 15 to 40 mol %.

4. A silver halide photographic material as in claim 1, wherein the content of silver bromide in the core portion is at least 50 mol %.

5. A silver halide photographic material as in claim 1, wherein the core portion further contains at least one of silver bromochloride and silver bromide.

6. A silver halide photographic material as in claim 1, wherein the shell portion contains from about 0 to 10 mol % of silver iodide.

7. A silver halide photographic material as in claim 1, wherein the shell portion comprises at least one of silver chloride, silver chlorobromide and silver bromide.

8. A silver halide photographic material as in claim 7, wherein the content of silver iodide is not more than 5 mol %.

9. A silver halide photographic material as in claim 1, wherein the content of silver iodide in the silver holide surface region is from about 7 to 15 mol %.

10. A silver halide photographic material as in claim 9, wherein the content of silver iodide is not less than the silver iodide content in the core portion.

11. A silver halide photographic material as in claim 1, wherein the surface portion contains at least one of silver chloride, silver chlorobromide and silver bromide.

12. A silver halide photographic material as in claim 1, wherein the surface portion contains at least 40 mol % of silver bromide.

13. A silver halide photographic material as in claim 1, wherein the total content of silver iodide in the silver halide grains is at least about 7 mol %.

14. A silver halide photographic material as in claim 13, wherein the total content of silver iodide in the silver halide. graios is at most about 21 mol. %

15. A silver halide photographic material as in claim 1, wherein the emulsion contains tabular silver halide grains.

16. A silver halide photographic material as in claim 15, wherein the grains have a thickness of not more than about 0.5 µm, a diameter of at least 0.6 µm and an aspect ratio of at least 2, and the grains occupy at least about 50% of the total projected area of the silver halide grains in the emulsion.

17. A silver halide photographic material as in claim 1, wherein the emulsion is a monodisperse emulsion containing normal crystal grains and about 90% of the total silver halide grains have grain size within ±40% of the average grain size.

18. A silver halide photographic material as in claim 1, wherein the grain having a size of at least 1.0 µm are covered by a shell of at least 0.1 µm in thickness and grains having not more than 1.0 u.m are covered by a shell of at least 0.05 u.m.

19. A silver halide photographic material as in claim 1, wherein the ratio of silver content in the core portion to that the shell portion is in the range of from about 1:5:5:1.

20. A silver halide photographic material as in claim 1, wherein the silver halide grains are spectrally sensitized by at least one sensitizing dye selected from the group consisting of dyes represented by formula (I) or (II):

wherein Z₁and Z₂ each represents atomic group necessary for forming the same or different, substituted or substituted 5-or 6-membered, nitrogen-containing hetero rings, Q₁ represents an atomic group necessary for forming a 5 or 6-membered, nitrogen-containing ketomethylene ring,

R₁, R₂, R₃, and R₄ each represents a hydrogen atom a lower alkyl group a substituted or unsubstituted phenyl group a substituted or unsubstituted phenyl group, or aralkyl group; when l₁ represents 2 or 3 or when n represents 2 or 3, one R₁ and another R₁, one R₂ and another R₂, one R₃ and another R₃, or one R₄ and another R₄ may be linked to each other to form a 5-or 6-membered ring optionally containing an oxygen atom, a sulfur atom, a nitrogen atom,

R₅, R₆ and R₇, each represents a substituted or unsubstituted alkyl or alkenyl group containing up to 10 carbon atoms which may have an oxygen atom, a sulfur atom or a nitrogen atom in the carbon chain,

l₁ and n₁ each represents 0 or a positive integer of 1 to 3, with l₁ + n₁ being 1 to 3, when l₁ represents 1, 2 or 3, R₅ and R₁ may be connected to each other to form a 5-or 6-membered ring,

ji, k₁, and m₁ each represent 0 or 1,

X₁ represents an acid anion.

r₁ represents 0 or 1;

wherein Z₁₁ represents an atomic group necessary for forming a nitrogen-containing, substituted or unsubstituted 5-or 6-membered hetero ring,

Q₁₁ represents an atomic group necessary for forming a nitrogen-containing, 5-or 6-membered ketomethylene ring,

Q₁₂ represents an atomic group necessary for forming a nitrogen-containing, 5-or 6-membered ketomethylene ring,

R₁₁ represents a hydrogen atom or an alkyl group containing up to 4 carbon atoms, R₁₂ represents a hydrogen atom, a substituted or unsubstituted phenyl or alkyl group and, when m₂₁ represents 2 or 3, plural R₁₂ groups may be linked to form a 5-or 6-membered ring optionally containing an oxygen atom, a sulfur atom or a nitrogen atom,

R₁₃ represents a substituted or unsubstitutes alkyl, alkenyl or heteos ring group containing up to 10 carbon atoms and optionally containing an oxygen atom, a sulfur atom or a nitrogen atom in the carbon chain of the alkyl or alkenyl group,

R₁₄ and R,₅ each has the same definition as R₁₃, or each represents a hydrogen atom or substituted or unsubstitutes monocyclic aryl group,

m₂₁ represents 0 or a positive integer of 1 to 3, j₂₁ represents 0 or 1, and n₂₁ represents 0 or 1, when m₂₁ represents a positive integer of 1 to 3, R₁₁ and R₁₃ may be linked to form a 5-or 6-membered ring.

21. A silver halide photographic material as in claim 1, wherein the emulsion contains a sulfur-containing silver halide solvent.

22. A silver halide photographic material as in claim 21, wherein said sulfur-containing silver halide solvent is contained in an amount from about 125 x 10^-4 mol to 5.0 x 10^-2 mol per mol of silver.

23. A silver halide photographic material as in claim 1, wherein the emulsion contains a 2-equivalent type coupler.