SILVER HALIDE GRAINS, PREPARATION THEREOF AND LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL CONTAINING SAID GRAINS

Abstract: Disclosed are silver halide grains which has (110) crystal faces and comprises a silver halide composition consisting sub­ stantially of silver bromide or silver iodobromide; a preparation thereof which comprises controlling pAg at 8.0 to 9.5 during a period until at least 30 mole % of the total silver halide is formed in the step of preparing the silver halide grains while permitting at least one selected from the compounds repre­ sented by the formula (I), (II), (III) or (IV) shown below and the compounds having the recurring units represented by the for­ mula (V) shown below to exist during the period: wherein R₁, R₂ and R₃, which may be either the same or different, each represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a derivative of an amino group, an alkyl group, a derivative of an alkyl group, an aryl group, a derivative of an aryl group, a cycloalkyl group, a derivative of a cycloalkyl group, a mercapto group, a derivative of a mercapto group or -CONH-R₄ (R₄ is a hydrogen atom, an amino group, a derivative of an alkyl group, a derivative of an amino group, a halogen atom, a cycloalkyl group, a derivative of a cycloalkyl group, an aryl group or a derivative of an aryl group), R₁ and R₂ may be bonded together to form a ring, R₅ represents a hydrogen atom or an alkyl group, X represents a monovalent group formed by eliminating one hydrogen atom from the com­ pounds represented by the formula (I), (II), (III) or (IV), and J represents a divalent linking group; and a light-sensitive silver halide photographic material having a light-sensitive silver halide emulsion layer on a support, the emulsion layer containing silver halide grains having (110) crystal faces and comprising a silver halide composition con­ sisting substantially of silver bromide or silver iodobromide, or at least one of the light-sensitive emulsion layers containing sil­ ver halide grains having semi-(110) faces and comprising a sil­ ver halide composition consisting substantially of silver bro­ mide or silver iodobromide.

Description: This invention relates to light-sensitive silver halide grains suitable for higher sensitization, to a preparation thereof and to light-sensitive silver halide photographic materials. The present invention further concerns silver halide emulsions having epitaxial hybridized silver salt crystals comprising developable silver salt crystals, such as silver chloride or silver halochloride, epitaxially junctioned onto silver iodobromide or silver bromide host crystals, which have excellent sensitivity and developability. In recent years, silver halide emulsions for photography have had to satisfy increasingly severe requirements, namely high sensitivity, excellent graininess, high sharpness, low fog density and sufficiently high optical density. As a high sensitivity emulsion responding to such requirements, silver iodobromide emulsions containing 0 to 10 mol % iodine are well known. Methods for preparing these emulsions are those in which the pH and pAg are controlled, such as the ammoniacal method, the neutral method, the acidic method, and mixing methods such as the single jet method or the double jet method. On the basis of these known techniques, in order to accomplish even higher sensitization, improvment of graininess, high sharpness and low fog, very precise technical means have been investigated and applied. For the silver iodobromide emulsion aimed at by the present invention, studies have been done on emulsions with controlled iodine concentration distributions within the individual silver halide grains, and crystal habits and grain size distribution. The most orthodox method for accomplishing high sensitivity, excellent graininess, high sharpness, low fog density and sufficiently high covering power is to improve the quantum efficiency of a silver halide. For this purpose, knowledge about solid physics have been applied. A study which calculates theoretically the quantum efficiency and speculates about the effect of grain size distribution is disclosed in, for example, the pretext of the Tokyo Symposium concerning Progress in Photography in 1980, entitled "Interactions between Light and Materials for Photographic Applications", on page 91. According to this study, it is predicted that the quantum efficiency can be improved in a mono-dispersed emulsion by narrowing the grain size distribution. In addition, for accomplishing sensitization of a silver halide emulsion, in the step of chemical sensitization as described hereinafter in detail, it is resonable to estimate that a mono-dispersed emulsion would be advantageous for accomplishing efficiently high sensitivity while maintaining low fogging. For the industrial preparation of a mono-dispersed emulsion it is necessary to control the feeding rate of silver ions and halogen ions to the reaction system, theoretically determined under sufficient stirring conditions, on the basis of pAg and pH, as disclosed in Japanese Provisional Patent Publication No. 48521/1979. Silver halide emulsions prepared under these conditions comprise the so-called normal crystal grains having (100) faces and (111) faces, having either cubic, octahedral or tetradecahedral shapes in various proportions. Higher sensitization has been known to be possible with such crystal grains. On the other hand, a silver iodobromide emulsion comprising poly-dispersed twin crystal grains is known in the art as a silver halide emulsion suitable for use in a high sensitivity photographic film. In Japanese Provisional Patent Publication No. 113927/1983 and others, a silver halide emulsion containing flat plate twin crystal grains is disclosed. Although these techniques contribute to higher sensitization, demands for higher sensitization always exist. On the other hand, for broadening the exposure region, it is known to employ two or more emulsions with different sensitivities, for example by mixing two or more emulsions with different average grain sizes. By combination of the above higher sensitization technique and the technique for broadening the exposure region, it is possible to obtain a light-sensitive photographic material having a high sensitivity to some extent and a broad exposure region. However, development of techniques for realizing further improvements still exist. On the other hand, a silver halide emulsion containing epitaxial hybridized silver halide crystals comprising polygonal crystals of silver iodide and silver chloride crystals formed through epitaxial junction onto the polygonal crystals is known to have both the radiation sensitivity of silver iodide and rapid developability of silver chloride, and also release a relatively large quantity of iodide ions when developed, thereby giving a the preferred photographic effect obtainable by iodide ions, as disclosed in Japanese Provisional Patent Publication No. 10372/1978. To improve the processability of this emulsion, European Patent Application No. 0019917 (published on December 10, 1980) discloses a silver halide emulsion containing crystals of a silver halide with less than 10 mole % of silver iodide formed through epitaxial junction onto silver halide crystals containing 15 to 40 mol % of silver iodide. The use of highly concentrated iodide is avoided in the host grains in the above emulsion in Japanese Provisional Patent Publication No. 133540/1984. In this technique, silver iodobromide with a low silver iodide content is employed as the host grains. By use of these techniques, light-sensitive photographic materials capable of giving images excellent in sharpness through the edge effect can be obtained, but they still have low sensitivity for practical application. Therefore a technique to enhance sensitivity is required. EP-A-0145440, which has a earlier priority date than those of the present application but which was published after the priority dates of the present application, discloses a process for preparing silver iodobromide grains in the presence of a tetrazaindene compound. However, no indication is given that grains having (110) or semi-(110) crystal faces are formed. FR-A-2137880 discloses silver halide grains having (110) crystal planes, wherein the silver halide is silver chloride and/or silver chlorobromide. The present invention seeks to provide firstly silver halide grains and a light-sensitive silver halide photographic material having an excellent sensitivity-fog relationship, and secondly a process for the preparation of such grains. The present invention also seeks to provide a light-sensitive silver halide photographic material having excellent graininess, sharpness and sensitivity-fog relationship and also a broad exposure region, and light-sensitive silver halide grains suitable for use in such a material. The present invention additionally seeks to provide a silver halide photographic emulsion and a light-sensitive silver halide photographic material containing epitaxial hybridized silver salt crystals having excellent developing effect (the effect of improving sharpness through the edge effect) and developability, and also having improved sensitivity. The first object of the present invention can be accomplished by silver halide grains, having (110) and/or semi-(110) crystal faces and comprising a silver halide composition consisting substantially of silver bromide or silver iodobromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride, a light-sensitive silver halide photographic emulsion comprising said grains and a light-sensitive silver halide photographic material comprising said emulsion provided on a support. The object of the present invention can also be accomplished by a process for producing silver halide grains consisting substantially of silver iodobromide or silver bromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride, which comprises controlling the pAg at from 8.0 to 9.5 during the period until at least 30 mole % of the total silver halide is formed in the step of preparing the silver halide grains, in the presence of at least one compound of formula (I), (II), (III) or (IV) or compound having recurring units of formula (V) shown below: wherein R₁, R₂ and R₃, which may be the same or different, each represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a derivative of an amino group, an alkyl group, a derivative of an alkyl group, an aryl group, a derivative of an aryl group, a cycloalkyl group, a derivative of a cycloalkyl group, a mercapto group, a derivative of a mercapto group or -CONH-R₄ (wherein R₄ is a hydrogen atom, an alkyl group, an amino group, a derivative of an alkyl group, a derivative of an amino group, a halogen atom, a cycloalkyl group, a derivative of a cycloalkyl group, an aryl group or a derivative of an aryl group), or wherein R₁ and R₂ may be bonded together to form a ring (for example, a 5 to 7 membered carbon ring or a heterocyclic ring), R₅ represents a hydrogen atom or an alkyl group, X represents a monovalent group formed by eliminating one hydrogen atom from a compound of formula (I), (II), (III) or (IV) (for example, those formed by eliminating one hydrogen atom from R₁ to R₃ or from a OH group), and J represents a divalent linking group. The silver halide grains may have crystals faces having ridgelines on the center of the (110) faces. The other objects of the present invention can be accomplished by hybridized silver salt crystal grains, or a silver halide photographic emulsion comprising said grains, said grains comprising developable silver salt crystals formed by epitaxial junction on host silver halide grains consisting substantially of silver iodobromide or silver bromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride, and having (110) and/or semi-(110) cystal faces (faces having ridgelines on the (110) faces), and a light-sensitive silver halide photographic material comprising at least one said emulsion layer on a support. The objects of the present invention can further be accomplished by silver halide grains, and a light-sensitive silver halide photographic material comprising said grains, said grains having (110) faces and/or semi-(110) faces and a core/shell structure, and comprising a silver halide composition consisting substantially of silver iodobromide or silver bromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride. Figs. 1 to 9 show the crystal forms of silver halide grains of the present invention having (110) faces. Figs. 10 to 17 show those of silver halide grains of the present invention having semi-(110) faces. Figs. 19 to 24 are electron microscopic photographs of silver halide grains of the present invention; Figs. 18 and 25 are those of silver halide grains for comparative purpose; Figs. 26 to 29 are those of the silver halide grains of the present invention; Figs. 30 and 31 are electron microscopic photographs the hybridized silver halide crystals of the present invention; and Fig. 32 is the characteristic curve of Example 17. The silver halide grains according to the present invention are crystals having Miller indices (110) face and/or face having a ridgeline at the center of the (110) face (hereinafter called a semi-(110) face) on their outer surfaces. They may be either normal crystals or twin crystals (including multiple twins). Said grains include those defined in the following paragraphs (1) to (4): (1) Crystals having a proportion of the surface area of the (110) or semi-(110) faces to the total surface area of at least 30 %. In the determination of this proportion, when the boundary between two crystal faces is unclear (for example, because the boundary has a roundness), the line of intersection of the two faces is determined as the boundary. (2) The crystal forms shown in Figs. 1 to 17 wherein 1 shows a (110) face, 2 a semi-(110) face, 3 a central ridgeline of the (110) face, 4 a (100) face and 5 a (111) face. (3) The crystal forms shown in the electron microscope photographs in Figs. 19 to 24 and 26 to 31. (4) Crystals having proportions of diffraction line intensities on the (111), (200) and (220) faces of said emulsion coated with orientation on a substrate as determined by powder X-ray diffraction (see the Bulletin of the Society of Scientific Photography of Japan, Vol. 13, page 5) of: (220)/(111) ≧ 8 % (220)/(200) ≧ 5 %, preferably: (220)/(111) ≧ 50 % (220)/(200) ≧ 50 %. The "crystal face having a ridgeline at the center of the (110) face" (this crystal face is referred to as the semi-(110) face) which may be possessed by the silver halide grains of the present invention is now described by referring to the drawings. Fig. 10 shows a silver halide grain having a semi-(110) face. In Fig. 10, 2 is the semi-(110) face. Fig. 11 is a partial plan view of the portion including the (110) face as viewed from the direction perpendicular to the (110) face 1 shown by a broken line Figs. 12 and 13 are the front view and side view thereof respectively. In these Figures, 3 is the central ridgeline of the (110) face of 1 and 2 the semi-(110) face. In the silver halide grains according to the present invention, the form of the semi-(110) face is not limited to those as shown in Figs. 10 to 13; the angle between the two semi-(110) faces of the roof-like ridgeline may be more obtuse than 110°. Examples of these are shown in Figs.14 to 17. The photographic emulsion of the present invention, which employes the grains of the present invention as described above, as host grains for hybridized silver salt crystals, has a higher sensitivity than a photographic emulsion containing hybridized silver salt crystals using host grains of the prior art. While the mechanism is not yet clear, increased sensitivity results probably because of the following reason. Due to the special property of the surfaces of the (110) face and semi-(110) face, epitaxial junctions will selectively occur at particular sites. Thus the epitaxial portions which are the sites for latent image formation are restricted. This reduces the loss by latent image dispersion. A dodecahedron has 14 corners, of which 8 corners consist of boundaries of three (110) faces (corner a ), and the remaining 6 corners consist of boundaries of four (110) faces (corner b ). From the electron microscopic photograph it can be seen that epitaxial growth has occurred selectively at the corner portions of the dodecahedron crystal, and more selectively on corner a . The corner a should microscopically consist of a (111) face with a minute area, while the corner b should consist of a (100) face (although not clearly resolved by the electron microscope). Accordingly, it may be assumed that selectivity for such corners is created through a difference in reactivity between the microscopically existing (100) face and (111) face. It has been impossible to restrict the reactive site to the specific site through utilization of the difference in reactivities between the minutely existing (100) face and (111) face in the crystals of the prior art consisting only of two faces, a (100) face and a (111) face. In the crystals of the prior art, if the surface area of one of the faces is enlarged, the other face will be made smaller, with consequential changes in crystal habit and shape. In the crystals of the present invention, due to the presence of three types of faces, the surface areas of the (100) and (111) faces can be varied independently of each other, whereby selection of the reactivity which could not be obtained in the crystals of the prior art is mode possible. The "epitaxy" as mentioned in the present specification has the same meaning as the term disclosed in Japanese Provisional Patent Publication No. 103725/1978 (hereinafter called Literature 1) and U.S. Patent No. 4,142,900 (hereinafter called Literature 2). That is, it means that the crystallographic orientations of silver salt atoms such as silver chloride, silver chlorobromide, silver iodobromide and silver chloroiodobromide junctioned onto the host grains of silver iodobromide or silver bromide are controlled by the crystals of silver iodobromide or silver bromide as the host grains during growth of these. The epitaxial relationship between the developable epitaxial silver salts such as silver chloride, silver chlorobromide, silver iodobromide and silver chloroiodobromide and the portion of the silver halide as the host grains of silver iodobromide or silver bromide in the hybridized silver salt crystal is entirely different from the direct physical contact between the crystals such as silver iodide, silver chloride, silver iodobromide and silver chlorobromide. The host grains in the hybridized silver salt crystals of the present invention are silver halide grains having a silver halide composition consisting substantially of silver iodobromide or silver bromide as defined above (such a silver halide composition may hereinafter be referred to merely as silver iodobromide). As silver iodobromide grains, there are known in the prior art poly-dispersed grains comprising the so-called normal crystal grains consisting of (100) faces and (111) faces, namely grains having cubic, octahedral or tetradecahedral shapes or twin crystals. The normal crystal grains are grains which are primarily mono-dispersed. The host silver iodobromide crystals known in the prior art are normal crystals having octahedral, tetradecahedral or cubic shapes consisting of (100) and/or (111) faces or twin crystal grains. The host silver iodobromide crystals used in the present invention have (110) and/or semi-(110) faces. This is a novel product having an entirely different surface from the normal crystal or twin crystal described above. The present inventors have discovered that a highly sensitive emulsion can be obtained when the crystals having the novel surface are used as the host crystals for the epitaxial emulsion. The silver halide grains and the host grains for the hybridized silver salt crystals are silver halide grains having a silver halide composition consisting substantially of silver iodobromide or silver bromide as defined above. Here, "consisting substantially of silver iodobromide or silver bromide" means that other silver halides than silver bromide and silver iodide, for example, silver chloride, may be contained within the range which does not interfere with the effect of the present invention. More specifically, in the case of silver chloride, its proportion is 1 mole % or less. The proportion of silver iodide in the silver halide grains according to the present invention should preferably be 0 to 20 mole %, more preferably 1 to 15 mole %. The proportion of silver iodide in the host silver halide grains according to the present invention should preferably be 0 to 40 mole %, and the content of silver iodide should be set at an optimum value depending on the purpose. More specifically, when it is desired to obtain an optical density by developing most of the host silver halide crystals, it is preferred to use AgI in an amount within the range which does not interfere with developability. Depending on the light-sensitive material to be employed, the optimum AgI content is preferably 2 to 10 mole % in the case of color negative light-sensitive materials, and 0 to 4 mole % in the case of X-ray sensitive materials. On the other hand, when it is desired to utilize positively the development inhibiting effect of I ⊖ contained in the host crystals, for example, when it is intended to improve the image sharpness through the edge effect or to improve color reproduction through the interimage effect in a multi-layer color light-sensitive material, the AgI content should be as high as 10 mole % or more, preferably 15 mole % or more, more preferably 30 mole % or more, so that a large amount of I ⊖ is released. The upper limit of the AgI concentration is not limited from the use viewpoint, but the content at which it can exist stably thermodynamically as a solid solution is limited. This is 40 mole % at ordinary emulsion preparation temperatures (20 °C - 90 °C). The silver halide grains according to the present invention preferably comprise cores having a silver halide composition comprising 3 to 40 mole % of silver iodide and shells covering said cores having a silver halide composition comprising 0 to 10 mole % of silver iodide, with the difference in silver iodide content between the shells and cores being 2 to 30 mole %. The silver iodide content at the boundary between the core and the shell may be changed as desired, for example, continuously or stepwise. The proportion of silver iodide in the silver halide grains is, for example, 1 to 20 mole %. The core may contain a portion with silver iodide content of 0 (e.g. the portion corresponding to the seed grain in the preparation thereof). The shell should desirably have a thickness which does not shield the preferred inherent properties of the core, and yet to the contrary which does shield the unpreferred inherent properties of the core. Specifically, the shell should preferably have a thickness of from 0.01 to 0.3 µm. The proportion of the surface areas of the (110) faces and/or semi-(110) faces relative to the total surface area of the host grains is preferably 30% or more. In the silver halide grains according to the present invention, the silver halide composition consisting substantially of silver iodobromide means that silver halides other than silver iodobromide (e.g. silver chloride) may also be contained, provided that the effect of the present invention is not impaired. Specifically, the content of silver halides other than silver iodobromide is less than 10 mole %. The grain size of the silver halide grains according to the present invention is not particularly limited, but the present invention is most effective if the size is within the preferred range of 0.1 to 3.0 µm. In the present specification, the grain size of the silver halide refers to the length of one side of a cubic body which is equal to its volume. The silver halide grains according to the present invention are generally prepared and used when dispersed in a dispersing medium such as gelatin, namely is the form of an emulsion. The grains may be either mono-dispersed or poly-dispersed, and may be a mixture thereof. It can be selected suitably depending on the uses. In the case of hybridized silver salt crystals comprising developable silver salt crystals formed through epitaxial junction onto host grains, a mono-dispersed emulsion is preferred, since epitaxial growth should desirably occur uniformly in crystals. The mono-dispersed emulsion is one in which the fluctuation coefficient of grain size distribution (percentage of the standard deviation of grain sizes relative to the average grain size) is 20 % or less, preferably 15 % or less, more preferably 10 % or less. For the preparation of the silver halide grains according to the present invention, in the step of forming silver halide grains by mixing a solution of a water-soluble silver salt and a solution of a water-soluble halide in the presence of a protective colloid, the pAg of the emulsion is controlled to from 8.0 to 9.5 within a certain period of time. During this period at least one compound of formula (I), (II), (III) or (IV) or a compound having recurring units of formula (V) is incorporated in the emulsion. Among the compounds of formulae (I), (II), (III) and (IV), the compound of formula (I) is preferred. In the process for the preparation of the silver halide grains according to the present invention, seed grains may be employed which may be grown by forming silver halide on their surfaces. When seed grains are employed, their silver halide composition may be within the scope of that which is capable of forming the silver halide grains according to the present invention. The above period of time for controlling the pAg may be at any desired point within the term when silver halide can be formed, namely at the initial stage, in the course of or at the end of the silver halide formation step. This period should preferably be continuous, but it can also be intermittent within the range which does not interfere with the effect of the present invention. The pAg within this period should preferably be from 8.0 to 9.5, more preferably from 8.4 to 9.2. During this period, the pH of the emulsion should preferably be maintained at from 7 to 10. The pAg of the silver halide outside this period of time should appropriately be from 4 to 11.5, preferably from 6 to 11, and the pH appropriately be from 2 to 12, preferably from 5 to 11. In the process for preparation of the silver halide grains of the present invention, the step of forming silver halide grains should preferably be carried out by adding an aqueous ammoniacal silver nitrate solution and an aqueous halide solution in the presence of ammonia according to the double jet method. It is also preferred to add the silver and halide solutions so that no new crystal nuclei are formed during grain growth. In the formulae (I) to (IV), the alkyl group represented by R₁ to R₄ may include, for example, a methyl group, an ethyl group, a propyl group, a pentyl group, a hexyl group, an octyl group, an isopropyl group, a sec-butyl group, a t-butyl group and a 2-norbornyl group; the derivative of alkyl group may include, for example, alkyl groups substituted with an aromatic residue (which may be bonded through a divalent linking group such as -NHCO-) (e.g. a benzyl group, a phenethyl group, a benzhydryl group, a 1-naphthylmethyl group, a 3-phenylbutyl group and a benzoylaminoethyl group), alkyl groups substituted with an alkoxy group (e.g. a 2-methoxymethyl group, a 2-methoxyethyl group, a 3-ethoxypropyl group and a 4-butoxybutyl group), alkyl groups substituted with a halogen atom, a hydroxy group, a carboxy group, a mercapto group, an alkoxycarbonyl group or a substituted or unsubstituted amino group (e.g. a monochloromethyl group, a hydroxymethyl group, a hydroxyethyl group, a 3-hydroxybutyl group, a carboxymethyl group, a 2-carboxyethyl group, a 2-(methoxycarbonyl)ethyl group, an aminomethyl group and a diethylaminomethyl group), alkyl groups substituted with a cycloalkyl group (e.g. a cyclopentylmethyl group) and alkyl groups substituted with a monovalent group formed by eliminating one hydrogen atom from the compounds of formulae (I) to (IV). The aryl groups represented by R₁ to R₄ may include, for example, a phenyl group and a 1-naphthyl group, and the derivative of an aryl group may include, for example, a p-tolyl group, an m-ethylphenyl group, an m-cumenyl group, a mesityl group, a 2,3-xylyl group, a p-chlorophenyl group, an o-bromophenyl group, a p-hydroxyphenyl group, a 1-hydroxy-2-naphthyl group, an m-methoxyphenyl group, a p-ethoxyphenyl group, a p-carboxyphenyl group, an o-(methoxycarbonyl)phenyl group, an m-(ethoxycarbonyl)phenyl group and a 4-carboxy-1-naphthyl group. The cycloalkyl group represented by R₁ to R₄ may include, for example, a cycloheptyl group, a cyclopentyl group and a cyclohexyl group. The derivative of a cycloalkyl group may include, for example, a methylcyclohexyl group. The halogen atom represented by R₁ to R₄ may be, for example, fluorine, chlorine, bromine and iodine. The derivative of an amino group represented by R₁ to R₄ may be exemplified by a butylamino group, a diethylamino group and a anilino group. The derivative of a mercapto group represented by R₁ to R₃ may include, for example, a methylthio group, an ethylthio group and a phenylthio group. The alkyl group represented by R₅ may preferably have 1 to 6 carbon atoms, such as a methyl group and an ethyl group. R₅ is particularly preferred to be a hydrogen atom or a methyl group. J is a divalent linking group, preferably having from 1 to 20 carbon atoms. Of such linking groups, those represented by formula (J - I) or (J - II) shown below are preferred: In the above formulae, Y represents -O- or (wherein R₆ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms); and Z represents an alkylene group (preferably having up to 10 carbon atoms), optionally having an intermediary amide linkage, an ester linkage or an ether linkage therein, as exemplified by a methylene group, an ethylene group, a propylene group, -CH₂OCH₂-, -CH₂CONHCH₂-, -CH₂CH₂COOCH₂-, -CH₂CH₂OCOCH₂-, and -CH₂NHCOCH₂-, -O-alkylene group, -CONH-alkylene group, -COO-alkylene group, -OCO-alkylene group or -NHCO-alkylene group (these alkylene groups preferably having up to 10 carbon atoms) or an arylene group (preferably having 6 to 12 carbon atoms), such as a p-phenylene group. The divalent linking group particularly preferred as J may include the following: -CONHCH₂-, -CONHCH₂CH₂-, -CONHCH₂OCOCH₂-, -CONHCH₂CH₂CH₂-OCOCH₂-, -COOCH₂-, -COOCH₂CH₂-, -COOCH₂CH₂OCOCH₂-, -COOCH₂CH₂CH₂OCOCH₂- and The compound having the units of formula (V) may be either a homopolymer or a copolymer. The copolymer may be, for example, a copolymer of a monomer such as acrylamide, methacrylamide, an acrylate and a methacrylate. Examples of the compounds of formula (I), (II), (III) or (IV) or of the compounds having recurring units of formula (V) (hereinafter referred to as tetraazaindene compounds to be used in the present invention) are: The tetraazaindene compound used in preparation of the silver halide grains of the present invention may be added in an amount which depends on the preparation conditions such as the desired silver halide grain size, temperature of the emulsion, pH, pAg and the content of silver iodide. It is preferably used within the range of from 10⁻⁵ to 2 x 10⁻¹ mole per mole of the total silver halide to be formed. When the tetraazaindene compound is a compound having recurring units of formula (V), the moles of the tetraazaindene moiety is reckoned as the amount added. Further preferred amounts relative to the grain sizes are listed in Table 1. The amounts to be added relative to the grain sizes other than those listed in Table 1 can be determined according to the extrapolation method or the interpolation method from the grain sizes, which are inversely proportional to the amounts added. Further preferred amounts added relative to the pAg and the silver iodide content are listed in Table 2. The tetraazaindene compound may be previously added in a protective colloid solution, or added gradually with the growth of the silver halide grains, or is a combination of these. In the process for producing silver halide grains of the present invention, seed grains may be used and grains may be grown by forming silver halide on the surfaces thereof. When employing seed grains, their silver halide compositions may be that which can form the silver halide grains according to the present invention. In the silver halide grains of the present invention, a core/shell type is preferred. The core/shell type silver halide grains can be prepared by forming shells over silver halide grains prepared as cores. Shells can be formed by depositing a soluble halide solution and a soluble silver salt solution on the cores by the double jet method. Methods for preparation of the above core/shell type silver halide grains are disclosed in, for example, West German Patent No. 11 69 290, British Patent No. 1,027,146, Japanese Provisional Patent Publication No. 154232/1982 and Japanese Patent Publication No. 1417/ 1976. The silver halide grains of the present invention can be subjected to reductive sensitization at any point during their preparation. Reductive sensitization may be performed by stirring the emulsion under low pAg conditions, namely by silver ripening, or by the use of a suitable reducing agent such as stannous chloride, dimethylamine borane, hydrazine or thiourea dioxide. The silver halide grains of the present invention may be doped with various metal salts or metal complexes on formation of silver halide by precipitation, during growth of grains or after completion of growth. Examples of metal salts or complexes are those of gold, platinum, palladium, iridium, rhodium, bismuth, cadmium and copper. The excessive halides or by-produced or unnecessary salts such as nitrates or ammonium salts and other compounds may be removed from the dispersing medium for said grains. The method for removal may be the Noodel water washing method, the dialysis method or the coagulation precipitation method conventionally used for emulsions in general. The silver halide grains of the present invention can also be subjected to various chemical sensitizing methods used on emulsions in general. Chemical sensitization can be effected with the use of a chemical sensitizer or a combination of chemical sensitizers selected from active gelatin; noble metal sensitizers such as water-soluble gold salts, water-soluble platinum salts, water-soluble palladium salts, water-soluble rhodium salts and water-soluble iridium salts; sulfur sensitizers; selenium sensitizers; and reductive sensitizers as mentioned above. The silver halide grains can furthermore be sensitized optically to a desired wavelength region. The method for optical sensitization of the emulsion of the present invention is not particularly limited. The emulsion can be sensitized optically by using optical sensitizers either individually or in combination, for example, cyanine dyes such as zeromethyne dyes, monomethyne dyes, dimethyne dyes or trimethyne dyes or melocyanine dyes (e.g. ultra-color sensitization). These techniques are also disclosed in U.S. Patents No. 2,688,545, No. 2,912,329, No. 3,397,060, No. 3,615,635 and No. 3,628,964; British Patents No. 1,195,302, No. 1,242,588 and No. 1,293,862, West German OLS No. 20 30 326 and No. 21 21 780; and Japanese Patent Publications No. 4936/1968 and No. 14030/1969. These sensitizers can be chosen as desired depending on the purpose and uses of the light-sensitive material, such as the wavelength to be sensitized and sensitivity. The silver halide grains of the present invention can be used either as such or as a blend of two or more types of grains with different average grain sizes, which may be formulated to a desired tone at any time after formation of the grains. They can also be used as a mixture with silver halide grains other than those of the present invention. The hybridized silver salt crystals of the present invention are formed by epitaxial junction of a developable silver salt on the polyhedron crystal of silver iodobromide or silver bromide. Here, "developable" means that the silver salt can be developed with a known developer for silver halide. The silver salt is insoluble or substantially insoluble in water. Preferred examples of silver salts for epitaxial junction include silver halide crystals such as silver iodobromide, silver bromide, silver chlorobromide and silver chloride, and developable silver salts other than silver halides, for example silver thiocyanate, silver cyanate, silver carbonate, silver ferricyanate, silver arsenate, silver arsenite and silver chromate. When the silver salt to be epitaxially junctioned is a silver iodobromide, it is preferred to use a silver halide with lower silver iodide content than the host crystals. When the host crystals are silver bromide, the silver halide to be epitaxially junctioned is preferably silver chlorobromide or silver chloride. Formation of the crystals of silver halide having epitaxially junctioned crystalline structures may be performed according to the following methods. [A] The method in which crystals of, for example, silver chloride, silver chlorobromide, silver iodobromide or silver chloroiodobromide are epitaxially junctioned on polyhedral crystals of silver iodobromide by simultaneous mixing of a solution containing water-soluble halides with a silver salt solution. [B] The method in which crystals of silver chloride are epitaxially junctioned onto polyhedral crystals of silver iodobromide, followed by junction of crystals of, for example silver chlorobromide, silver chloroiodobromide or silver iodobromide, onto the crystals of said silver chloride by simultaneous mixing of a solution containing, for example, water-soluble chloride, water-soluble bromide or water-soluble iodide, with a silver salt solution. [C] The method in which crystals of, for example, silver chlorobromide, silver chloroiodobromide or silver iodobromide are epitaxially junctioned onto polyhedral crystals of silver iodobromide according to the conversion method as disclosed in Literature 2. [D] The methods in which crystals of, for example, silver chloride, silver chlorobromide, silver iodobromide or silver chloroiodobromide are epitaxially junctioned by adding a solution containing, for example, water-soluble chloride, water-soluble bromide or water-soluble iodide, into a solution containing polyhedral cryatals of silver iodobromide as the host grains, water-soluble silver salt and protective colloid. In the case of epitaxial crystals having a composition outside the range specified above, they can be prepared similarly as described above. In the present invention, at least a half of the polyhedral crystal faces of silver iodobromide or silver bromide of the host crystals are substantially free from epitaxial silver halide. It is preferred that said epitaxial silver halide is restricted to 75 mole % or less of the hybridized silver halide as a whole. The epitaxial crystals in the hybridized silver salt crystals in the present invention can be subjected to reductive sensitization and doping with a metal salt or complex similarly as the above host grains. It is also possible to remove excessive halides and other unnecessary compounds after formation of epitaxial crystals, similarly as in the case of the above host crystals. The hybridized silver salt crystals of the present invention can be subjected to the various chemical sensitization methods generally applied for emulsions in general. They can be subjected to chemical sensitization by using chemical sensitizers either individually or in combination, including active gelatin; noble metal sensitizers such as water-soluble gold salts, water-soluble platinum salts, water-soluble palladium salts, water-soluble rhodium salts, water-soluble iridium salts; sulfur sensitizers; selenium sensitizers; and the reductive sensitizers described above. The photographic emulsion according to the present invention exhibits a preferred interimage effect and edge effect. For example, it is possible to use in the present invention iodide ions released in the developing step for inactivation of the surface of an unhomogeneous catalyst as employed in the redox amplification reaction between, for example, an oxidizing agent (e.g. cobalt hexamine or hydrogen peroxide) and a dye image forming reducing agent (color forming developing agent or redox dye releasing agent, which is used together with for example, an electron transfer agent). The photographic emulsion of the present invention can be applied on a suitable support and dried, subjected to imagewise exposure by visible light and developed under appropriate developing conditions to give a photographic silver image. Even under redox amplification reaction conditions, the iodide ions released during development can be used as the redox amplification catalyst for inactivation of the silver image. The photographic emulsion according to the present invention, by containing a dye forming coupler, can give both a silver image and dye image, and yet these images have the advantages of small graininess and grain size. The photographic emulsion of the present invention is capable of selective developing, such as developing of the epitaxial silver salt and developing of both the epitaxial silver salt and the host grains. Accordingly, the photographic emulsion according to the present invention has the advantage that the graininess and grain size of the photographic image or the release of iodide ions can be controlled or that the developing conditions for controlling the maximum density of the image obtained can be selected. An example according to the present invention is now described in more detail. The photographic emulsion according to the present invention may, for example, contain hybridized crystals of silver iodobromide containing 0 to 40 mole % of silver iodide with the silver salt as mentioned above. The host grain for each hybridized crystal is a crystal of silver iodobromide, which has the same photosensitivity as the silver iodide crystals detailed in Literatures 1 and 2. The silver iodobromide used in the present invention should preferably have a minimum grain size of at least 0.2 µm. On the other hand, the second moiety of each hybridized crystal, namely the moiety formed through epitaxial junction on the polyhedron crystal of the silver iodobromide host grain, should preferably be a crystal of silver halide containing 10 mole % or less of silver iodide such as silver chloride, silver chlorobromide, silver iodobromide or silver choroiodobromide. The epitaxial hybridized crystal used in the present invention acts through the silver iodobromide crystal moiety as the first radiation receptor. Imagewise exposure of a photographic emulsion containing the hybridized crystals of the present invention to blue light results in the formation of a developable latent image. Exposure of the hybridized crystal can make the whole hybridized crystal developable, but only the epitaxial silver salt crystal moiety can be developed. The hybridized crystals used in the present invention should have no epitaxial silver salt crystals on at least a half of the polyhedral crystal faces of the silver iodobromide, and the epitaxial silver salt crystal is restricted to 75 mole % or less of the whole hybridized silver halide. The epitaxial silver salt crystal, when it reaches 75 mole %, will encroach on the sites of the silver iodobromide crystal faces at which epitaxial growth begins and the adjacent epitaxial crystal structures on the surfaces of the silver iodobromide crystal faces. The epitaxial silver salt crystal in the hybridized crystal of the present invention is not the first radiation receptor of said hybridized crystal. For this reason, the photographic speed of the photographic emulsion according to the present invention is not controlled solely by radiation irradiated upon the epitaxial silver salt crystals. The amount of the epitaxial silver salt crystal in the hybridized crystal should desirably be 1 to 50 mole % of the whole hybridized silver salt crystal, more preferably 5 mole % at its minimum. The epitaxial silver salt promotes the initial developing speed. The optimum amount of the epitaxial silver salt and its composition can be determined depending on, for example, the use of the photographic emulsion according to the present invention. For example, when characteristics of high radiation exposure level and rapid developing speed are required, higher levels of the epitaxial salt are employed than in the case of lower exposure radiation level and slower developing speed. On the other hand, for example, when the storage stability of the silver halide photographic emulsion having hybridized crystals is important, an epitaxial silver halide containing silver bromide or silver iodide is used. When it is used in one bath developing bleach-fixing processing, it is advantageous to control the balance between developing speed, bleaching speed and fixing speed by appropriate selection of the epitaxial silver salt composition. The six of the epitaxial silver salt crystals can also be controlled so as to make them developable without development of the silver iodobromide host grains. In this case, the graininess and the grain size of the photographic image will be determined by the limited size (diameter) of the epitaxial silver salt crystals (provided that there is no dissolving physical development). The photographic speed is determined by the silver iodobromide host grains. The hybridized epitaxial silver salt crystals of the present invention are reactive for surface developing, so long as no particular change is effected during their formation. In other words, the photographic emulsion according to the present invention can be developed with a surface developer after imagewise exposure. The surface developer can initiate developing of a latent image existing on the surface of the silver halide crystal, and contains substantially no soluble iodide or silver halide solvent. The hybridized crystals of the present invention can be formed structurally so that the latent image formed by exposure can exist internally of the crystalline structure rather an on its surface. That is, the epitaxial silver salt crystals in the hybridized crystals of the present invention can be formed as a crystals capable of forming primarily inner latent images. For making inner images readily formable in the hybridized crystals, an inner dopant may be introduced into the epitaxial silver salt crystals. Such inner dopants include, for example, silver, sulfur, iridium, gold, platinum, osmium, rhodium, tellurium and selenium. The photographic emulsion according to the present invention containing such hybridized crystals may be developed with an inner developer containing a silver halide solvent or a soluble iodide. In the preparation of hybridized crystals for forming primarily inner latent images, the epitaxial silver salt crystals are prepared in the presence of non-silver metal ions, preferably polyvalent metal ions. The epitaxial silver salt crystals are preferably formed in the presence of individual water-soluble metal salts, more preferably in an acidic medium. The polyvalent metal ions preferably employed include divalent metal ions (e.g. lead ions), trivalent metal ions (e.g. antimony, bismuth, arsenic, gold, iridium and rhodium ions) or tetravalent metal ions (e.g. iridium ions). Preferred polyvalent metal ions are iridium, bismuth or lead ions. The epitaxial silver salt crystals generally contain 10⁻⁹ mole %, preferably 10⁻⁶ mole %, of an inner dopant based on the epitaxial silver salt, and the dopant exists in the epitaxial silver salt crystals at a concentration less than about 10⁻¹ mole, preferably less than 10⁻⁴ mole, per mole of the epitaxial silver salt. The hybridized crystals of the present invention comprise epitaxial silver salt crystals formed on the polyhedral crystal faces of silver iodobromide host grains, prefeably by methods [A], [B], [C] or [D] described above. Preparation of the silver iodobromide crystal host grains has already been described above, and typical examples of preparation are also given in the Examples below. The silver halide photographic emulsion according to the present invention can be modified by blending it with a different emulsion to obtain the desired photographic characteristics. According to this method, it is possible to control the photographic sensitivity and contrast. In the photographic emulsion according to the present invention, in the case of the hybridized crystals co-existing with other blended silver halide crystals, the hybridized crystals will participate primarily in image formation, provided that the hybridized crystals of the present invention make up at least 50 % by weight of the total silver halide crystals. However, even by blending at a level of 50 % by weight or less, the interimage effect and the edge effect can effectively be controlled. In the present invention, silver chloride crystals can be blended with the hybridized crystals of the present invention. The blend with silver chloride crystals has the advantage that the developing speed and/or the silver image density can be substantially intensified by physical development of the silver chloride crystals, although these crystals are not directly or chemically developable under the conditions set for exposure or developing processing. The blending ratio of the silver chloride crystals to the hybridized silver halide crystals can be chosen as desired depending on the use. In order to obtain a marked effect by dissolving physical development, the silver chloride crystals should desirably be blended with the hybridized crystals of the present invention in an amount of 1 to 50 % by weight, more preferably 5 to 50 % by weight, of the total silver halide. As the binder for the silver halide emulsion according to the present invention or the dispersing medium to be used for preparation of said grains, hydrophilic colloids conventionally used for silver halide emulsions may be employed. The hydrophilic colloid includes not only gelatin (treated with either lime or acid), but also gelatin derivatives, for example, gelatin derivatives prepared by the reaction between gelatin and, for example, aromatic sulfonyl chloride, acid chloride, acid anhydride, isocyanate or 1,4-diketones as disclosed in U.S. Patent No. 2,614,928; gelatin derivatives prepared by the reaction between gelatin and trimellitic acid anhydrides as disclosed in U.S. Patent No. 3,118,766; gelatin derivatives prepared by the reaction between organic acids having active halogens and gelatin; gelatin derivatives prepared by the reaction between aromatic glycidyl ether and gelatin as disclosed in Japanese Patent Publication No. 26845/1967; gelatin derivatives prepared by the reaction between, for example, maleimide, maleamic acid or unsaturated aliphatic diamide and gelatin as disclosed in U.S. Patent No. 3,186,846; sulfoalkylated gelatin as disclosed in British Patent No. 1,033,189; polyoxyalkylene derivatives of gelatin as disclosed in U.S. Patent 3,312,553; polymer-grafted products of gelatin, for example, those prepared from vinyl monomers such as acrylic acid, methacrylic acid, esters thereof with monohydric or polyhydric alcohols, amides thereof, acrylo(or methacrylo)nitrile, styrene and other vinylic monomers either individually or in combination grafted onto gelatin; synthetic hydrophilic polymeric materials, for example, homopolymers or inter-copolymers of monomers such as vinyl alcohol, N-vinyl pyrrolidone, hydroxyalkyl (meth)acrylate, (meth)acrylamide or N-substituted (meth)acrylamide, or copolymers of these monomers with, for example, (meth)acrylate, vinyl acetate, or styrene, copolymers of any of the above monomers with, for example, maleic anhydride or maleamic acid; and natural hydrophilic macromolecular substances other than gelatin such as casein, agar, alginic acid or polysaccharides. These materials can be used either singly or as a mixture. The emulsion containing the silver halide grains according to the present invention can contain various additives conventionally used depending on the use. These additives may include, for example, stabilizers or antifoggants such as azaindenes, triazoles, tetrazoles, imidazolium salts, tetrazolium salts or polyhydroxy compounds; film hardeners such as aldehyde type, aziridine type, isoxazole type, vinyl sulfone type, acryloyl type, carbodiimide type, maleimide type, methanesulfonate type a triazine type compounds; developing acclerators such as benzyl alcohol or polyoxyethylene type compounds; image stabilizers such as couromane type, couramane type, bisphenol type or phosphite ester type compounds; and lubricants such as wax or glycerides of higher fatty acids. As the surfactants for coating aids, penetrability enhancers of processing solutions, defoaming agents or materials for controlling various physical properties, various kinds of anionic, cationic, nonionic and amphoteric surfactants can be used. As the antistatic agents, there may effectively be used, for example, diacetyl cellulose, styrene-perfluoroalkylsodium maleate copolymer or alkali salts of the reaction product of a styrene-maleic anhydride copolymer and p-aminobenzenesulfonic acid. The matting agent may include polymethyl methacrylate, polystyrene and alkali-soluble polymers. Furthermore, colloidal silicon oxide may also be used. As the latex to be added for improvement of film properties, there may be employed, for example, copolymers of an acrylate a vinyl ester with monomers having ethylenic groups. The gelatin plasticizer may be, for example, glycerine or a glycolic compound, and the thickener may include styrene-sodium maleate copolymers or alkyl vinyl ether-maleic acid copolymers. The silver halide grains according to the present invention may be used effectively in light-sensitive photographic materials for various uses, such as general black-and-white, X-ray, color, infrared, micro-photography, silver dye bleaching, reversal and diffusion transfer. The hybridized silver salt crystals according to the present invention may also effectively be used in light-sensitive photographic materials for various uses such as high contrast photography, photothermography or heat developing sensitive materials. The emulsion comprising the silver halide grains of the present invention can have abundant exposure latitude by mixing or coating in multiple layers at least two kinds of emulsion having different average grain sizes and different sensitivities. The light-sensitive silver halide photographic material according to the present invention has at least one light-sensitive silver halide emulsion layer comprising the silver halide grains according to the present invention on a support. The silver halide grains according to the present invention can be used in a color light-sensitive material by employment of the method and the materials conventionally used for color light-sensitive materials, for example by incorporating a combination of cyan, magenta and yellow couplers in the emulsions containing the silver halide grains according to the present invention, controlled to be red-sensitive, green-sensitive and blue-sensitive. As the yellow coupler, closed ketomethylene type couplers may be employed. Among them, benzoylacetoanilide type and pivaloylacetanilide type compounds are useful. As the magenta coupler, pyrazolone type compounds, indazolone type compounds and cyanoacetyl compounds are useful, while phenol type compounds and naphthol compounds may be used as the cyan coupler. In the light-sensitive silver halide photographic material, each of the red-sensitive, green-sensitive and blue-sensitive layers may consist of two or more layers. For example, in a light-sensitive color negative photographic material, two or three layers are preferably employed. The coating positions of the emulsions depend on the use of the material. When a plurality of layers of the same color sensitivity are employed, they can be separated from each other. The emulsion layer containing the silver halide grains according to the present invention may be any desired light-sensitive layer. When each light-sensitive layer consists of two or more layers with different sensitivities, the effect of the present invention can be greater when applied to the layer with higher sensitivity than when applied to the layer with lower sensitivity. The support for the light-sensitive photographic material, is a suitable one depending on the use of the light-sensitive material. Examples of the support are baryta paper, polyethylene-coated paper, polypropylene synthetic paper, glass, cellulose acetate, cellulose nitrate, polyvinyl acetal, polypropylene, polyester film (e.g. polyethyleneterephthalate) and polystyrene. These supports may be subbed if desired. The light-sensitive photographic material having the silver halide grains according to the present invention can be developed according to known methods conventionally used after exposure. A suitable monochromatic developer is an alkali solution containing a developing agent such as a hydroxybenzene, aminophenol or aminobenzene, which may otherwise contain sulfites, carbonates, bisulfites, bromides and iodides. When the light-sensitive photographic material is for color, color developing can be carried out according to the color developing method conventionally employed. According to the reversal method, developing is performed first with a monochromatic negative developer, then the material is subjected to white exposure or treatment with a bath containing a foggant and further subjected to color developing with an alkali developer containing a color developing agent. The processing method is not particularly limited; all processing methods may be applicable. Typically, after color developing, bleach-fixing processing is conducted and further, if desired, water washing and stabilizing processing may be performed. Alternatively, after color development, bleaching and fixing are separately conducted, followed further by water washing and stabilizing processing, if desired. For the developing processing of the light-sensitive photographic material having the silver halide emulsion layer comprising the hybridized silver salt crystals according to the present invention, the methods shown in Literatures 1 and 2 may be applicable. Thus, the light-sensitive material of the present invention can be physically developed according to the prior art technique and used in conventional transfer systems (e.g. a colloid transfer system, silver salt diffusion transfer system, inhibition transfer system or color transfer system). For developing only the epitaxial crystals or both the epitaxial crystals and the silver iodobromide crystal host grains in the hybridized crystals in the photographic emulsion according to the present invention, it will suffice only to choose a suitable developing agent and further control merely the developing conditions. When a potent developing agent such as hydroquinone, catechol or phenidone is used, complete development of the hybridized silver salt crystals can be obtained. Similarly, when a color developing agent such as an aminophenol or p-phenylenediamine is used together with a dye forming coupler, substantially complete development of the hybridized silver salt crystals can be obtained. On the other hand, when the color developing agent is used in the absence of a color forming coupler, only the epitaxial crystals are selectively developed. This is because developing is initiated at, for example, silver chloride, silver chlorobromide, silver iodobromide, silver chloroiodobromide or silver thiocyanate. At a relatively slow developing speed and without stirring, developing will cease after development of the epitaxial crystals has substantially been completed and before initiation of developing of the host silver iodobromide. The amount of the iodide ions released during developing can also be controlled. The photographic emulsion according to the present invention can suitably be used in the redox amplification system in which an unhomogeneous catalyst enabling the reaction between an oxidizing agent and a reducing agent is required. The oxidizing agents, the reducing agents and details of the system to be used are described in Literatures 1 and 2. Also, as described in the same Literatures, the photographic emulsion according to the present invention is also applicable for heat-sensitive light-sensitive photographic materials. For the light-sensitive silver halide photographic material utilizing the photographic emulsion containing the hybrid silver halide grains of the present invention, the one bath developing bleach-fixing processing and the color image reinforcing processing as disclosed in, for example, Japanese Provisional Patent Publications No. 20025/1977 and No. 30430/1977, and Japanese Provisional Patent Publications No. 126028/1979, No. 137332/1979, No. 161332/1979 and No. 161335/1979 may be used. The present invention now further described in the following Examples. Example 1 By use of the five kinds of solutions shown below, silver iodobromide emulsions EM - 1 to EM - 3 containing 2.6 mole % of silver iodide were prepared. The seed emulsion was a mono-dispersed silver iodobromide emulsion containing 2 mole % of silver iodide, said emulsion grains having a average grain size of 0.27 µm and a fluctuation coefficient of grain size distribution of 12 %. At 40 °C, by means of a mixing stirrer as disclosed in Japanese Provisional Patent Publications No. 92523/1982 and No. 92524/1982, the solution A₁ - 1 was mixed with the solution D₁ - 1 and the solution B₁ - 1 according to the simultaneous mixing method over the minimum time during which no generation of small grains occured. The pAg, pH and the addition rate of the solution D₁ - 1 during the simultaneous mixing were controlled as shown in Table 4. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution E₁ - 1, the solution F₁ - 1 and the solution B₁ - 1. Two minutes after completion of the addition of the solution D₁ - 1, pAg of the mixture was adjusted to 10.4 with the solution E₁ - 1, and further 2 minutes later, adjusted to pH 6.0 with the solution F₁ - 1. Next, the desalting and washing was carried out in a conventional manner, and the mixture was dispersed in an aqueous solution containing 25.6 g of ossein gelatin and the total amount was adjusted to 600 ml with distilled water. Each of an average grain diameter was found to be 0.8 µm and a fluctuation coefficient of the grain distribution was 11 %. The electron microscopic photographs of the silver halide grains in the EM - 1 to EM - 3 are shown in Figs. 18 to 20. Example 2 Silver bromide emulsions EM - 4 and EM - 5 were prepared in the same manner as in Example 1 except that a silver halide composition of the seed grain was changed to silver bromide, the amount of KBr in the solution B₁ - 1 was 161.8 g, the amount of KI was 0 and the amount of tetraazaindene was those as shown in Table 5, and the conditions of the grain growth was set as shown in Table 6. Each of the average grain size was found to be 0.8 µm and a fluctuation coefficient of the grain distribution being 10 %. The electron microscopic photographs of the EM - 4 and EM - 5 are shown in Figs. 21 and 22, respectively. Example 3 Silver iodobromide emulsions EM - 6 and EM - 7 were prepared in the same manner as in Example 1 except that the silver halide composition of the seed grain was changed to silver iodobromide containing 15 mole % of silver iodide, the amount of KBr in the solution B₁ - 1 was 138.4 g, the amount of KI was 34.77 g and the amount of tetraazaindene was those as shown in Table 7, and the conditions of the grain growth was set as shown in Table 8. Each of the average grain size was found to be 0.8 µm and a fluctuation coefficient of the grain distribution being 13 %. The electron microscopic photographs of the EM - 6 and EM - 7 are shown in Figs. 23 and 24, respectively. The results of X-ray diffractmetries of EM - 1 to EM - 7 are shown in Table 9. Example 4 Multi-layer color films Samples No. 1 and No. 2 were prepared with the layer constitution as shown in Table 10 below by providing them on a support having a halation preventive layer provided by coating thereon. In Table 10, B, G and R represent a blue-sensitive layer, a green-sensitive layer and a red-sensitive layer, respectively, H, H₁ and H₂ high-sensitivity layers, L a low-sensitivity layer, I an intermediate layer, Pr a protective layer and Base a support. Each amount of the components indicated for respective layers of the sample shows an amount per 1 m². Further, an amount of the silver halide and colloidal silver were shown as calculated on silver. The respective layers are as follows: RL A low-sensitivity red-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.8 g of tricresyl phosphate (TCP), 0.70 g of a red-sensitive color sensitized emulsion (EM - 8) comprising AgBrI containing 2 mole % of AgI and having an average grain diameter (hereinafter referred to as γ) of 0.40 µm and a fluctuation coefficient of grain distribution of 18 %, 0.7 g of red-sensitive color sensitized emulsion (EM - 9) comprising AgBrI containing 4 mole % of AgI and having an average grain diameter of 0.80 µm and a fluctuation coefficient of grain distribution of 20 %, 1.0 g of 1-hydroxy-4-[β-(methoxyethyl)aminocarbonyl]methoxy-N-[δ-(2,4-di-t-amylphenoxy)butyl]-2-naphthoamide (C - 1), 0.075 g of 1-hydroxy-8-acetamide-3,6-disulfo-2-naphthylazo)phenoxy]-N-[δ-(2,4-di-t-amylphenoxy)butyl-2-naphthoamido·disodium (CC - 1), 0.01 g of 1-hydroxy-2-[δ-(2,4-di-t-amylphenoxy)-n-butyl]naphthoamide (C - 2) and 0.07 g of 2-bromo-4-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononanoylamino-7-nitro-2-(1-phenyl-5-tetrazolylthio)-1-indanone (D - 1), and emulsifying them into an aqueous solution containing 2.2 g of gelatin. RH A high-sensitivity red-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.3 g of TCP, 1.5 g of a red-sensitive color sensitized silver iodo-bromide emulsion (EM - 10) comprising AgBrI containing 6 mole % of AgI and having an average grain diameter of 1.50 µm and a fluctuation coefficient of grain distribution of 40 %, 0.26 g of the cyan coupler (C - 1) and 0.03 g of the colored cyan coupler (CC - 1), and emulsifing them into an aqueous solution containing 1.2 g of gelatin. GL A low-sensitivity green-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.95 g of TCP, 0.70 g of the EM - 8 sensitized to green-sensitive, 0.70 g of the EM - 9 sensitized to green-sensitive, 0.8 g of 1-(2,4,6-trichlorophenyl)-3-[3-(2,4-di-t-amylphenoxyacetamido)benzamido]-5-pyrazolone (M - 1), 0.15 g of 1-(2,4,6-trichlorophenyl)-4-(1-naphthylazo)-3-(2-chloro-5-octadecenylsuccinimidoanilino)-5-pyrazolone (CM - 1) and 0.012 g of the DIR compound (D - 1), and emulsifying them into an aqueous solution containing 2.2 g of gelatin. GH A high-sensitivity green-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.25 g of TCP, 1.6 g of the EM - 10 sensitized to green-sensitive, 0.20 g of the magenta coupler (M - 1) and 0.049 g of the colored magenta coupler (CM - 1), and emulsifying them into an aqueous solution containing 1.9 g of gelatin. BL A low-sensitivity blue-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.6 g of TCP, 0.5 g of The EM - 9 sensitized to blue-sensitive and 1.5 g of α-pyvalyol-α-(1-benzyl-2-phenyl-3,5-dioxoimidazolidine-4-yl)-2'-chloro-5'-[α-dodecyloxycarbonyl)ethoxycarbonyl]acetanilide (Y - 1), and emulsifying them into an aqueous solution containing 19 g of gelatin. BH₁ A high-sensitivity blue-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.65 g of TCP, 0.8 g of an octahedral mono-dispersed emulsion (EM - 11) comprising AgBrI containing 6 mole % of AgI and having an average grain diameter of 1.60 µm and a fluctuation coefficient of grain distribution of 12 % applied optimally with gold and sulfur sensitization and also subjected to blue-sensitive sensitization and 0.65 g of the yellow coupler (Y - 1), and emulsifying them into an aqueous solution containing 1.5 g of gelatin. BH₂ A high-sensitivity blue-sensitive emulsion layer which is the same as the above BH₁ except for replacing the emulsion (EM - 11) in the above layer BH₁ with a dodecahedral mono-dispersed emulsion (EM - 12) comprising AgBrI containing 6 mole % of AgI and having an average grain diameter of 1.60 µm and a fluctuation coefficient of grain distribution of 12 % according to the present invention. I An intermediate layer containing 0.8 g of gelatin and dibutylphthalate (DBP) having dissolved therein 0.07 g of 2,5-di-t-octylhydroquinone (HQ - 1). Pr A protective gelain layer. The thus prepared each of Samples No. 1 and No. 2 was carried out a wedge exposure by using a white light and then the following developing processings were carried out. The compositions of the processing solution used in each of the processing steps are as follows: The obtained results of an S₁ sensitivity, an S₂ sensitivity and a fog are shown in Table 11. In this case, the S₁ sensitivity and the S₂ sensitivity and fog are shown by the relative value to the Sample No. 1 as the reciprocal of the developing quantity providing D min + 0.1 and D min + 0.5 when the minimum concentration is defined as D min' respectively. These values with respect to a blue light (B) are shown in Table 11. As seen from Table 10, it is understood that the light-sensitive photographic material or the present invention has extremely high sensitivity. Example 5 Each EM - 1 (Comparative) and EM - 3 (this invention) was carried out optimally a gold sensitization and color sensitized to the blue color sensitive. Then, 0.8 g of these emulsions were mixed with a dispersion prepared by dissolving, in 0.65 g of TCP, 13.0 g of the yellow coupler (Y - 1) and emulsifying and dispersing in an aqueous solution containing 1.5 g of gelatin, and the mixtures were applied onto the support with a single layer to obtain light-sensitive materials, respectively. These materials were exposed to blue light (B) as in Example 4, and developing processings and measurements were carried out. The resultant S₁ sensitivity, S₂ sensitivity and fog are shown in Table 12. The calculation manner of the S₁ sensitivity and S₂ sensitivity are the same as in Example 4. The silver halide grains produced in the following Examples 6 to 8 have semi-(110) faces, ie ridgelines on the (110) faces. Example 6 By use of the 5 kinds of solutions, silver bromide emuldions EM - 13 to EM - 15 were prepared. A seed grain was a mono-dispersed silver bromide emulsion and each of the emulsion grain has an average grain diameter of 0.8 µm and a fluctuation coefficient of the grain distribution being 10 %. At 40 °C, by means of a mixing stirrer as in Example 1, the solution A₂ - 1 was mixed with the solution D₂ - 1 and the solution B₂ - 1 according to the simultaneous mixing method over minimum time during which no generation of small grains occured. The pAg, pH and the addition rate of the solution D₂ - 1 during the simultaneous mixing were controlled as shown in Table 14. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution E₂ - 1, the solution F₂ - 1 and the solution B₂ - 1. Two minutes after from the completion of the addition of the solution D₂ - 1, pAg of the mixture was adjusted to 10.4 with the solution E₂ - 1, and further 2 minutes later, adjusted to pH 6.0 with the solution F₂ - 1. Next, the desalting and washing were carried out in a conventional manner, and the mixture was dispersed in the aqueous solution containing 22.7 9 of ossein gelatin and the total amount was adjusted to 600 ml with distilled water. The average grain diameters of the EM - 13 to EM - 15 were 1.8 µm, respectively. The fluctuation coefficients of the grain distribution were 10 % in EM - 13 and 12 % in EM - 14 and EM - 15, respectively. The electron microscopic photographs of the silver halide grains in the EM - 13 to EM - 15 are shown in Figs. 25 to 27, respectively. Example 7 By use of the 5 kinds of solutions and use of conditions as shown in Tables 15 and 16, silver iodobromide emuldions EM - 16 and EM - 17 each having a silver iodide content of 8 mole % were prepared. A seed grain was a mono-dispersed silver iodobromide emulsion having a silver iodide content of 8 mole % and each of the emulsion grain has an average grain diameter of 0.8 µm and a fluctuation coefficient of the grain distribution being 13 %. At 50 °C, by means of a mixing stirrer as in Example 1, the solution A₂ - 2 was mixed with the solution D₂ - 2 and the solution B₂ - 2 according to the simultaneous mixing method over minimum time during which no generation of small grains occured. The pAg, pH and the addition rate of the solution D₂ - 2 during the simultaneous mixing were controlled as shown in Table 16. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution E₂ - 2, the solution F₂ - 2 and the solution B₂ - 2. Two minutes after from the completion of the addition of the solution D₂ - 2, pAg of the mixture was adjusted to 10.4 with the solution E₂ - 2, and further 2 minutes later, adjusted to pH 6.0 with the solution F₂ - 2. Next, the desalting and washing was carried out in a conventional manner, and the mixture was dispersed in the aqueous solution containing 25.3 g of ossein gelatin and the total amount was adjusted to 600 ml with distilled water. Each of the EM - 16 and EM - 17 has an average grain diameter of 1.6 µm and a fluctuation coefficient of the grain distribution were 11 %. The electron microscopic photographs of the silver halide grains in the EM - 16 and EM - 17 are shown in Figs. 28 and 29, respectively. Example 8 Multi-layer color films Samples No. 3-1 to No. 5-2 were prepared with the layer constitution as shown in Table 17 below by providing them on a support having a halation preventive layer provided by coating thereon. In Table 17, B, G and R represent a blue-sensitive layer, a green-sensitive layer and a red-sensitive layer, respectively, H, H₁ and H₂ high-sensitivity layers, L a low-sensitivity layer, I an intermediate layer, Y a yellow filter layer, Pr a protective layer and Base a support. Each amount of the components indicated for respective layers of the sample shows an amount per 1 m². Further, the silver halide and colloidal silver were shown as calculated on silver. The respective layers are as follows: RL A low-sensitivity red-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.8 g of TCP, 0.70 g of a red-sensitive color sensitized emulsion (EM - 8') comprising AgBrI containing 2 mole % of AgI and having an average grain diameter of 0.40 µm and a fluctuation coefficient of grain distribution of 18 %, 0.7 g of red-sensitive color sensitized emulsion (EM - 9') comprising AgBrI containing 4 mole % of AgI and having an average grain diameter of 0.80 µm and a fluctuation coefficient of grain distribution of 20 %, 1.0 g of the cyan coupler (C - 1), 0.075 g of the colored cyan coupler (CC - 1) and 0.07 g of the DIR compound (D - 1), and emulsifying them into an aqueous solution containing 2.2 g of gelatin. RH A high-sensitivity red-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.3 g of TCP, 1.5 g of a red-sensitive color sensitized silver iodobromide emulsion (EM - 10') comprising AgBrI containing 6 mole % of AgI and having an average grain diameter of 1.50 µm and a fluctuation coefficient of grain distribution of 40 %, 0.26 g of the cyan coupler (C - 1) and 0.03 g of the colored cyan coupler (CC - 1), and emulsifing them into an aqueous solution containing 1.2 g of gelatin. GL A low-sensitivity green-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.95 g of TCP, 0.70 g of the EM - 8' sensitized to green-sensitive, 0.70 g of the EM - 9' sensitized to green-sensitive, 0.8 g of the magenta coupler (M - 1), 0.15 g of the colored magenta coupler (CM - 1) and 0.012 g of the DIR compound (D - 1), and emulsifying them into an aqueous solution containing 2.2 g of gelatin. GH A high-sensitivity green-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.25 g of TCP, 1.6 g of the EM - 10 sensitized to green-sensitive, 0.20 g of the magenta coupler (M - 1) and 0.049 g of the colored magenta coupler (CM - 1), and emulsifying them into an aqueous solution containing 1.9 g of gelatin. GH₁ A high-sensitivity green-sensitive emulsion layer which is the same as the above GH except for replacing the emulsion (EM - 10') in the layer with an octahedral mono-dispersed emulsion (EM - 18) comprising AgBrI containing 3 mole % of AgI and having an average grain diameter of 1.6 µm and a fluctuation coefficient of grain distribution of 11 %. GH₂ A high-sensitivity green-sensitive emulsion layer which is the same as the above GH except for replacing the emulsion (EM - 10') in the layer with a mono-dispersed emulsion (EM - 18) of the present invention comprising AgBrI containing 3 mole % of AgI and having an average grain diameter of 1.6 µm and a fluctuation coefficient of grain distribution of 12 % and having a semi-(110) face on the outer surface. BL A low-sensitivity blue-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.65 g of TCP, 0.5 g of the EM - 9' sensitized to blue-sensitive and 1.5 g of the yellow coupler (Y - 1), and emulsifying them into an aqueous solution containing 19 g of gelatin. BH₁ A high-sensitivity blue-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.65 g of TCP, 0.8 g of an octahedral mono-dispersed emulsion (EM - 7') comprising AgBrI containing 8 mole % of AgI and having an average grain diameter of 1.60 µm and a fluctuation coefficient of grain distribution of 12 % applied optimally with gold and sulfur sensitization and also subjected to blue-sensitive sensitization and 0.65 g of the yellow coupler (y - 1), and emulsifying them into an aqueous solution containing 1.5 g of gelatin. BH₂ A high-sensitivity blue-sensitive emulsion layer which is the same as the above BH₁ except for replacing the emulsion EM - 7' in the above layer with the emulsion EM - 17 according to the present invention. I An intermediate layer containing 0.8 g of gelatin and dibutylphthalate (DBP) having dissolved therein 0.07 g of 2,5-di-t-octylhydroquinone (HQ - 1). Y A yellow filter layer containing 0.11 g of DBP having dissolved 0.15 g of a yellow colloidal silver and 0.2 g of an anti-contamination agent (HQ - 1), and 1.5 g of gelatin. Pr A protective gelain layer. The thus prepared each of Samples was carried out a wedge exposure by using a white light and then the developing processings were carried out in the same manner as in Example 4. The results of an S₁ sensitivity, an S₂ sensitivity and a fog obtained by the multi-layer coated samples are shown in Table 18. In this case, the S₁ sensitivity and the S₂ sensitivity are shown by the relative value to the Sample No. 1 as the reciprocal of the developing quantity providing D min + 0.1 and D min + 0.5 when the minimum concentration is defined as D min , respectively, and the measured values of the samples of the present invention were shown as relative values to those of the comparative sample having the same layer constitution. The result of the fog was also shown in the same manner. Namely, with respect to Sample 3-2 and Sample 3-3, they were shown as relative values to the measured value of Sample 3-1 as 1. In the same manner, the value of Sample 4-2 is a relative value to Sample 4-1 and that of Sample 5-2 is to Sample 5-1. As seen from Table 18, it is understood that the light-sensitive photographic materials of the present invention are extremely excellent in the relation of sensitivity-fog. Example 9 By use of the 5 kinds of solutions, host silver iodobromide emulsions EM - 1H to EM - 4H were prepared. A seed grain was a mono-dispersed silver iodobromide containing 2 mole % of silver iodide, and each of the emulsion grain has an average grain size of 0.27 µm and a fluctuation coefficient of the grain distribution being 10 %. At 40 °C, by means of a mixing stirrer as shown in Example 1, the solution A₃ - 1 was mixed with the solution D₃ - 1 and the solution B₃ - 1 according to the simultaneous mixing method over minimum time during which no generation of small grains occured. The pAg, pH and the addition rate of the solution D₃ - 1 during the simultaneous mixing were controlled as shown in Tables 21 to 24. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution E₃ - 1, the solution F₃ - 1 and the solution B₃ - 1. Two minutes after of the completion of the addition of the solution D₃ - 1, pAg of the mixture was adjusted to 10.4 with the solution E₃ - 1, and further 2 minutes later, adjusted to pH 6.0 with the solution F₃ - 1. Next, the desalting and washing was carried out in a conventional manner, and the mixture was dispersed in the aqueous solution containing 25.6 g of ossein gelatin and the total amount was adjusted to 600 ml with distilled water. The results of the electron microscopic photographs' observation were shown in Table 25. Example 10 By use of the three kinds of solutions as shown in Table 26, emulsions of which pure silver halide was epitaxialy grown on the silver iodobromide used in Example 9 were prepared. At 35 °C, to the solution C₃ - 2 were simultaneously added, 27 ml of the solution A₃ - 2 and 27 ml of the solution B₃ - 2 over 10 minutes by using the double jet method. After completion of the addition, washing and desalting were carried out according to the following procedures. To the solution were added a 5 % aqueous solution of Demol N (trade name, produced by Kao Atlas K. K.) and a 20 % aqueous solution of magnesium sulfate in the ratio of 10 : 9 as precipitants until precipitates were generated. After the precipitates were sedimented by left to stand and the supernatent was removed by decantation, 800 ml of distilled water was added thereto to disperse again. Then, a 20 % aqueous solution of magnesium sulfate was further added thereto until precipitates were regenerated. After the precipitates were sedimented, the supernatant was removed by decantation. An aqueous solution of osein gelatin containing 10 g of gelatin was added to the precipitates, and the mixtrue was stirred at 35 °C for 20 minutes to obtain dispersion and was added distilled water to adjust the total amount thereof to 150 ml. Hereinafter referred to these emulsions as EM - 1E to EM - 4E, respectively. The electron microscopic phorographs of EM - 1E are shown in Fig. 30 and Fig. 31. Example 11 A mono-dispersed silver iodide emulsion was prepared by using the following three kinds of the solutions. To the solution A₃ - 3 were dipped a commercially available iodine ion electrode and a double junction type silver/silver chloride referencial electrode (junction solution: a 1 mole % aqueous solution of KNO₃), and a potential of the solution was measured. To the above solution were added the solutions B₃ - 3 and C₃ - 3 while keeping the potential (- 175 mV) thereof during the addition of the solutions by controlling the flow rate of the solution B₃ - 3. The addition rate of the solution C₃ - 3 was set to as 0.5 ml/min for 6 minutes from the start of the addition and thereafter linearly increased in the ratio of 0.385 ml/min per 10 minutes. It was required to add the whole the solution C₃ - 3 thereto for 197 minutes and the temperature during the physical ripening was kept to 35 °C. The addition was ceased at which all the the solution C₃ - 3 had been added thereto, and washing and desalting were carried out according to the following procedures. To the solution were added a 5 % aqueous solution of Demol N (trade name, produced by Kao Atlas K. K.) and a 20 % aqueous solution of magnesium sulfate in the ratio of 10 : 9 as precipitants until precipitates were generated. After the precipitates were sedimented by left to stand and the supernatent was removed by decantation, 3000 ml of distilled water was added thereto to disperse again. Then, a 20 % aqueous solution of magnesium sulfate was further added thereto until precipitates were regenerated. After the precipitates were sedimented, the supernatant was removed by decantation. An aqueous solution of ossein gelatin containing 56.6 g of gelatin was added to the precipitates, and the mixtrue was stirred at 35 °C for 20 minutes to obtain dispersion and was added distilled water to adjust the total amount thereof to 1703 ml. This emulsion was referred to as EM - 5H. It was found that this EM - 5H emulsion has an average grain diameter of 0.25 µm and a standard deviation of the grain being 20 % of the average grain diameter by the electron microscopic photograph thereof. Further, it was found that this EM - 5H emulsion was composed of a β-phase silver iodide containing little amount of α-phase or γ-phase thereof. Example 12 In the same manner as in Example 10, an emulsion EM - 5E of which silver chloride was epitaxially juncted to the silver iodide host emulsion EM - 5H was prepared. Example 13 To each of silver halide emulsions EM - 1E, EM - 2E, EM - 3E, EM - 4E and EM - 5E were added, per mole of silver, 2.0 x 10⁻⁸ mole of hypo and 1.0 x 10⁻⁸ mole of sodium salt of chloroauric acid, and the mixture was stirred at 45 °C for 60 minutes. Subsequently, to the mixture were added 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene and 1-phenyl-5-mercaptotetrazole, and, before coating, were added bis(vinylsulfonylmethyl)ether and saponin. The mixture was coated on a support so as to contain 3.0 g/m² of silver and 2.0 g/m² of gelatin to form samples (Samples No. 1 to No. 10). These samples were subjected to a white exposure through a light wedge by using KS - 1 Type Photosensitometer (produced by Konishiroku Photo Industry Co., Ltd.), and processed by using the following developing solution at 20 °C for 10 minutes. The results are shown in Table 26. As seen from Table 26, it was found that the epitaxial emulsions of the present invention has excellent developability (high in D max and gamma) and excellent photosensitivity (high in sensitivity). Example 14 After emulsions EM - 1E, EM - 2E, EM - 3E and EM - 4E were chemical sensitized in the same manner as in Example 13, they were spectrally sensitized by adding 3.0 x 10⁻⁴ mole of the following sensitizing dye (I) per mole of silver and 3.5 x 10⁻⁴ mole of the following sensitizing dye (II) per mole of silver. Then, to the mixture were added 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene and 1-phenyl-5-mercaptoetrazol, and thereafter were further added, after emulsified, 60 g of tricresyl phosphate having dissolved therein 50 g of 1-(2,4,6-trichlorophenyl)-3-[3-(2,4-di-t-amylphenoxyacetamido)benzamido]-5-pyrazolone, 10 g of 1-(2,4,6-trichlorophenyl)-4-(1-naphthylazo)-3-(2-chloro-5-octadecenylsuccinimidoanilino)-5-pyrazolone and 1.5 g of 2-(1-phenyl-5-tetrazolylthio)-4-octadecylsuccinimido-1-indanone. Then, on a support comprising transparent cellulose triacetate base which was subbing treated was coated the above mixture to be contained 2.0 g/m² of silver. Thereater, these samples were subjected to the wedge exposure in the same manner as in Example 13 through a yellow filter and then carried out the following developing processings. The compositions of the processing solution used in each of the processing steps are as follows: [Bleaching solution] The same as in Example 4. [Stabilizing solution] The same as in Example 4. The results are shown in Table 27. As can be seen from the results in Table 27, the epitaxial emulsions of the present invention which employ a host crystal having (110) face have high sensitivities than the conventional epitaxial emulsions which employ a host crystal having (111) face and also the former is useful in color photographics. Example 15 By use of the seven kinds of solutions shown below, core/shell type silver iodobromide emulsions EM - 21 and EM - 22 each containing silver iodide content of 15 mole %, 5 mole % and 0.3 mole % from the inner portion of a grain in the order, respectively, were prepared. A seed grain was a mono-dispersed silver iodobromide emulsion containing 2.6 mole % of silver iodide and each of the emulsion grains has an average grain diameter of 0.8 µm and a fluctuation coefficient of the grain distribution of 11 %. In the above, the fluctuation coefficient means a parameter showing monodispersibility of the grain and can be defined as follows: At 50 °C, by means of a mixing stirrer as in Example 1, the solution A₄ - 1 was mixed with the solution E₄ - 1 and the solution B₄ - 1 according to the simultaneous mixing method, the solution G₄ - 1 was added thereto at which the same time with the addition completion of the solution B₄ - 1, and the solution D₄ - 1 was added thereto at which the same time with the addition completion of the solution C₄ - 1. The pAg, pH and the addition rate of the solution E₄ - 1 during the simultaneous mixing were controlled as shown in Table 29. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution F₄ - 1 and the solution G₄ - 1. Two minutes after from the completion of the addition of the solution E₄ - 1, pAg of the mixture was adjusted to 10.4 with the solution F₄ - 1, and further 2 minutes later, adjusted to pH 6.0 with the solution G₄ - 1. Next, by use of the 5 kinds of solutions shown below, silver iodobromide emulsions EM - 23 and EM - 24 each containing 3.7 mole % of silver iodide having no core/shell structure, respectively, were prepared. A seed grain was a mono-dispersed silver iodobromide emulsion containing 3.7 mole % of silver iodide and each of the emulsion grains has an average grain diameter of 0.8 µm and a fluctuation coefficient of the grain distribution of 12 %. At 50 °C, by means of a mixing stirrer as in Example 1, the solution A₄ - 2 was mixed with the solution E₄ - 2 and the solution B₄ - 2 according to the simultaneous mixing method. The pAg, pH and the addition rate of the solution E₄ - 2 during the simultaneous mixing were controlled as shown in Table 32. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution F₄ - 2 and the solution G₄ - 2. Two minutes after from the completion of the addition of the solution E₄ - 2, pAg of the mixture was adjusted to 10.4 with the solution F₄ - 2, and further 2 minutes later, adjusted to pH 6.0 with the solution G₄ - 2. Next, the desalting and washing were carried out in a conventional manner, and the mixture was dispersed in the aqueous solution containing 127 g of ossein gelatin and the total amount was adjusted to 3000 ml with distilled water. All EM - 21, EM - 22, EM - 23 and EM - 24 have an average grain size of 1.6 µm and a fluctuation coefficient of grain distribution of 11 %. Each of core/shell structures were shown in Table 32. (The same as in the following description.) Example 16 By use of the six kinds of solutions shown below, core/ shell type silver iodobromide emulsions EM - 25 and EM - 26 each containing silver iodide content of 3.5 mole % and 0.3 mole % from the inner portion of a grain in the order, respectively, were prepared. A seed grain was a mono-dispersed silver iodobromide emulsion containing 2.6 mole % of silver iodide and each of the emulsion grains has an average grain diameter of 0.27 µm and a fluctuation coefficient of the grain distribution of 12 %. At 40 °C, by means of a mixing stirrer as in Example 1, the solution A₄ - 3 was mixed with the solution D₄ - 3 and the solution B₄ - 3 according to the simultaneous mixing method, and the solution C₄ - 3 was added thereto at which the same time with the addition completion of the solution B₄ - 3. The pAg, pH and the addition rate of the solutions D₄ - 3, B₄ - 3 and C₄ - 3 during the simultaneous mixing were controlled as shown in Table 34. The controlling of the pAg and pH were carried out by using a flow rate variable roller tube pump while varing the flow rates of the solution E₄ - 3 and the solution F₄ - 3. Two minutes after from the completion of the addition of the solution D₄ - 3, pAg of the mixture was adjusted to 10.4 with the solution E₄ - 3, and further 2 minutes later, adjusted to pH 6.0 with the solution F₄ - 3. Next, the desalting and washing were carried out in a conventional manner, and the mixture was dispersed in the aqueous solution containing 128 g of ossein gelatin and the total amount was adjusted to 3000 ml with distilled water. Each of EM - 25 and EM - 26 has an average grain size of 0.8 µm and a fluctuation coefficient of grain distribution of 10 %. Each of the core/shell structures was shown in Table 35. Example 17 To 0.8 g of emulsions EM - 22, EM - 23 and EM - 24 as described in Table 31 of Example 15 each of which was applied optimally with gold and sufur sensitization and also subjected to blue-sensitive sensitization, were added a dispersion which had been prepared by emulsifying 0.6 g of TCP dissolved therein 1.30 g of the yellow coupler (Y - 1) in an aqueous solution containing 1.5 g of gelatin, an extender and a hardening agent which were conventional photographic additives, and the composition was coated on a film base which had been carried out a subbing treatment and dried to obtain Samples No. 20 to No. 22 (where Sample No. 20 was used EM - 22, Sample No. 21 was EM - 23 and Sample No. 22 was EM - 24). In the above, amounts of each components show amounts per 1 m². The silver halide is shown in terms of silver. The thus prepared each of Samples was subjected to a wedge exposure through a white light and then carried out a developing processing in the same manner by using the same solutions as in Example 4. The obtained characteristic curves are shown in Fig. 32. In the Figure, reference numeral 6 is Sample No. 20 (EM - 22), reference numeral 7 is Sample No. 21 (EM - 23) and reference numeral 8 is Sample No. 22 (EM - 24). Further, S₁ sensitivity and S₂ sensitivity are shown in Table 36. In this case, the S₁ sensitivity and the S₂ sensitivity are shown by the relative value to Sample No. 21 as the reciprocal of the developing quantity providing D min + 0.1 and D min + 0.5 when the minimum concentration is defined as D min , respectively. Further, γ represents a value showing a decline of the characteristic curve between two points of log E = 1.7 and log E = 1.0. As seen from Fig. 32 and Table 36, the emulsions containing silver halide grains of the present invention has extremely high sensitivity and wide exposure range. Example 18 Multi-layer color films Samples No. 23, No. 24 and No. 25 were prepared with the layer constitution as shown in Table 37 below by providing them on a support having a halation preventing layer provided by coating thereon. In Table 37, B, G and R represent a blue-sensitive layer, a green-sensitive layer and a red-sensitive layer, respectively, H, H₁, H₂ and H₃ high-sensitivity layers, L a low-sensitivity layer, I an intermediate layer, YC a yellow filter layer, Pr a protective layer and Base a support. Each amount of the components indicated for respective layers of the sample shows an amount per 1 m². Further, an amount of the silver halide and colloidal silver were indicated as calculated on silver. The respective layers are as follows: RL The same as RL in Example 4. RH The same as RH in Example 4. GL The same as GL in Example 4. GH The same as GH in Example 4. BL The same as GH in Example 4. BH₁ A high-sensitivity blue-sensitive emulsion layer containing dispersants prepared by dissolving, in 0.65 g of TCP, 0.8 g of a cubic mono-dispersed emulsion (EM - 23) comprising AgBrI containing 3.7 mole % of AgI and having an average grain diameter of 1.60 µm and a fluctuation coefficient of grain distribution of 11 % applied optimally with gold and sulfur sensitization and also subjected to blue-sensitive sensitization and 1.30 g of the yellow coupler (Y - 1), and emulsifying them into an aqueous solution containing 1.5 g of gelatin. BH₂ A high-sensitivity blue-sensitive emulsion layer which is the same as the above BH₁ except for replacing the emulsion (EM - 23) in the above layer BH₁ with a dodecahedral mono-dispersed emulsion (EM - 24) comprising AgBrI containing 3.7 mole % of AgI and having an average grain diameter of 1.60 µm and a fluctuation coefficient of grain distribution of 11 % according to the present invention. BH₃ A high-sensitivity blue-sensitive emulsion layer which is the same as the above BH₁ except for replacing the emulsion (EM - 23) in the above layer BH₁ with a dodecahedral mono-dispersed emulsion (EM - 22) comprising AgBrI containing 2.6 mole %, 15 mole %, 5 mole % and 0.3 mole % of AgI from the inner portion of the grain to the outer surface of the grain in the order and having an average grain diameter of 1.60 µm and a fluctuation coefficient of grain distribution of 11 % according to the present invention. YC An intermediate layer containing 0.04 g of n-dibutyl phthalate having dissolved therein 0.15 g of a yellow colored colloidal silver and 0.2 g of 2,5-di-t-octylhydroquinone (stain preventing agent), and 0.8 g of gelatin. I An intermediate layer containing 0.8 g of gelatin and dibutylphthalate (DBP) having dissolved therein 0.07 g of 2,5-di-t-octylhydroquinone (HQ - 1). Pr A gelatin protecting layer. The thus prepared each of Samples No. 23, No. 24 and No. 25 was subjected to a wedge exposure by using a white light and then the developing processings were carried out in the same manner as in Example 17. The obtained S₁ sentivity and S₂ sensitivity are shown in Table 38. In this case, the S₁ sensitivity and the S₂ sensitivity are shown by the relative value to Sample No. 23 as the reciprocal of the developing quantity providing D min + 0.1 and D min + 0.5 when the minimum concentration is defined as D min , respectively. Further, γ represents a value showing a decline of the characteristic curve between two points of log E = 1.7 and log E = 1.0. As seen from Table 38, the light-sensitive photographic material No. 25 of the present invention has extremely high sensitivity as compared with the Comparative Sample No. 323 and has improved latitude as compared with the Sample No. 24 which has no core/shell structure. The silver halide grain according to the present invention is excellent in sensitivity and fog relationship with respect to the shape of the photographic emulsion as compared with a normal grain of cubic, octahedral or tetradecahedral each comprising, the outer surface thereof, (100) face and (111) face, and a plane twin crystal. The light-sensitive photographic material according to this invention is excellent in sensitivity and fog relationship as compared with the light-sensitive material using the grain as mentioned above which comprises, the outer surface thereof, (100) face and (111) face. The preparative method of the present invention could be effected to preparation of the silver halide grain according to the present invention which is useful as mentioned above and novel. Further, according to the present invention, sensitivities of the silver halide emulsion having hybrid silver halide crystals and light-sensitive silver halide photographic materials.

Claims: Silver halide grains, having (110) and/or semi-(110) crystal faces and comprising a silver halide composition consisting substantially of silver bromide or silver iodobromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride. Silver halide grains according to Claim 1, wherein said silver halide grains have 30% or more of (110) or semi-(110) crystal faces based on the total grain surfaces. Silver halide grains according to Claim 1 or 2, wherein the proportions of the diffraction line intensities on the (111), (200) and (220) faces as determined by powder X-ray diffraction are: (220)/(111) ≧ 8 %; and (220)/(200) ≧ 5 %. Silver halide grains according to any one of the preceding Claims, wherein the content of silver iodide in said silver halide grains is from 0 to 20 mole %. Silver halide grains according to any one of the preceding Claims wherein the silver halide grains have a semi-(110) face. Hybridized silver salt crystal grains, comprising developable silver salt crystals formed by epitaxial junction on host silver halide grains as defined in any one of the preceding claims. Hybridized silver salt crystal grains according to Claim 6, wherein the proportion of the diffraction line intensities on the (111), (200) and (220) faces of the hybridized grains as determined by powdery X-ray diffraction are: (220)/(111) ≧ 8 %; and (220)/(200) ≧ 5 %. Hybridized silver salt crystal grains according to Claim 6 or 7, wherein the content of silver iodide in the host grains is from 0 to 40 mole %. Hybridized silver salt crystal grains according to any one of Claims 6 to 8, wherein the silver salt epitaxially junctioned is at least one selected from silver iodobromide, silver bromide, silver chlorobromide, silver chloride, silver thiocyanate, silver cyanide, silver carbonate, silver ferricyanate, silver arsenate, silver arsenite and silver chromate. Hybridized silver salt crystal grains according to any one of Claims 6 to 8, wherein the silver salt epitaxially junctioned is selected from silver chloroiodide, silver chloroiodobromide and silver iodobromide containing from 0 to 10 mole % of silver iodide. Silver halide grains, having (110) faces and/or semi-(110) faces and a core/shell structure, and comprising a silver halide composition consisting substantially of silver iodobromide or silver bromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride. Silver halide grains according to Claim 11, wherein the proportion of the surface of areas of the (110) faces and/or semi-(110) faces relative to the total surface area of the host grains is 30 % or more. Silver halide grains according to Claim 11 or 12, wherein the proportion of silver iodide in the silver halide grains is 1 to 20 mole %. Silver halide grains according to any one of Claims 11 to 13, wherein the content of silver iodide in the cores of the silver halide grains is 3 to 40 mole %. Silver halide grains according to any one of Claims 11 to 14, wherein the content of silver iodide in the shells of the silver halide grains is 0 to 10 mole %. Silver halide grains according to any one of Claims 11 to 15, wherein the difference in silver iodide content between the cores and the shells is 2 to 30 mole %. Silver halide grains according to any one of Claims 11 to 16, wherein the shells have thicknesses of 0.01 to 0.3 µm. A process for producing silver halide grains as defined in any one of Claims 1 to 17, which comprises controlling the pAg at from 8.0 to 9.5 during the period until at least 30 mole % of the total silver halide is formed in the step of preparing the silver halide grains, in the presence of at least one compound of formula (I), (II), (III) or (IV) or compound having recurring units of formula (V) shown below: wherein R₁, R₂ and R₃, which may be the same or different, each represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a derivative of an amino group, an alkyl group, a derivative of an alkyl group, an aryl group, a derivative of an aryl group, a cycloalkyl group, a derivative of a cycloalkyl group, a mercapto group, a derivative of a mercapto group or -CONH-R₄ (wherein R₄ is a hydrogen atom, an amino group, a derivative of an alkyl group, a derivative of an amino group, a halogen atom, a cycloalkyl group, a derivative of a cycloalkyl group, an aryl group or a derivative of an aryl group), or wherein R₁ and R₂ may be bonded together to form a ring, R₅ represents a hydrogen atom or an alkyl group, X represents a monovalent group formed by eliminating one hydrogen atom from a compound of formula (I), (II), (III) or (IV), and J represents a divalent linking group. A process according to Claim 18, wherein said pAg is from 8.4 to 9.2. A process according to Claim 18 or 19, wherein the pH in the period until at least 30 mole % of the total silver halide is formed is from 7 to 10. A process according to any one of Claims 18 to 20, wherein the production steps include the step of adding an aqueous ammoniacal silver nitrate solution and a halide solution according to the double jet method. A process according to any one of Claims 18 to 20, wherein the production steps include a grain growth step of adding an aqueous silver nitrate solution and a halide solution so that no new crystal nucleus is formed. A process according to any one of Claims 18 to 22, wherein the amount of the at least one compound of formulae (I) through (IV) or compound having recurring units of formula (V) is from 1 x 10⁻⁵ to 2 x 10⁻¹ mole per mole of the silver halide formed. A silver halide photographic emulsion, comprising grains as defined in any one of Claims 1 to 17. A light-sensitive silver halide photographic material having an emulsion as defined in Claim 24 provided on a support. CLAIMS FOR THE FOLLOWING CONTRACTING STATE:DE Silver halide grains, having semi-(110) crystal faces and comprising a silver halide composition consisting substantially of silver bromide or silver iodobromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride. Silver halide grains according to Claim 1, wherein the proportions of the diffraction line intensities on the (111), (200) and (220) faces as determined by powder X-ray diffraction are: (220)/(111) ≧ 8 %, and (220)/(200) ≧ 5 %. Silver halide grains, having (110) and/or semi-(110) crystal faces and comprising a silver halide composition consisting substantially of silver bromide or silver iodobromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride, wherein the proportions of the diffraction line intensities on the (111), (200) and (220) faces as determined by powder X-ray diffraction are: (220)/(111) ≧ 8 %; and (220)/(200) ≧ 5 %. Silver halide grains according to any one of the preceding Claims, wherein said silver halide grains have 30% or more of (110) or semi-(110) crystal faces based on the total grain surfaces. Silver halide grains according to any one of the preceding Claims, wherein the content of silver iodide in said silver halide grains is from 0 to 20 mole %. Hybridized silver salt crystal grains, comprising developable silver salt crystals formed by epitaxial junction on host silver halide grains as defined in any one of the preceding claims or on host silver halide grains having (110) crystal faces and comprising a silver halide composition consisting substantially of silver bromide or silver iodobromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride. Hybridized silver salt crystal grains according to Claim 6, wherein the proportion of the diffraction line intensities on the (111), (200) and (220) faces of the hybridized grains as determined by powdery X-ray diffraction are: (220)/(111) ≧ 8 %; and (220)/(200) ≧ 5 %. Hybridized silver salt crystal grains according to Claim 6 or 7, wherein the content of silver iodide in the host grains is from 0 to 40 mole %. Hybridized silver salt crystal grains according to any one of Claims 6 to 8, wherein the silver salt epitaxially junctioned is at least one selected from silver iodobromide, silver bromide, silver chlorobromide, silver chloride, silver thiocyanate, silver cyanide, silver carbonate, silver ferricyanate, silver arsenate, silver arsenite and silver chromate. Hybridized silver salt crystal grains according to any one of Claims 6 to 8, wherein the silver salt epitaxially junctioned is selected from silver chloroiodide, silver chloroiodobromide and silver iodobromide containing from 0 to 10 mole % of silver iodide. Silver halide grains, having semi-(110) faces and a core/shell structure, and comprising a silver halide composition consisting substantially of silver iodobromide or silver bromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride. Silver halide grains according to Claim 11, wherein the shells have thicknesses of 0.01 to 0.3 µm. Silver halide grains, having (110) faces and a core/shell structure, and comprising a silver halide composition consisting substantially of silver iodobromide or silver bromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride, wherein the shells have thickneses of 0.01 to 0.3 µm. Silver halide grains according to any one of Claims 11 to 13, wherein the proportion of the surface of areas of the (110) faces and/or semi-(110) faces relative to the total surface area of the host grains is 30 % or more. Silver halide grains according to any one of Claims 11 to 14, wherein the proportion of silver iodide in the silver halide grains is 1 to 20 mole %. Silver halide grains according to any one of Claims 11 to 15, wherein the content of silver iodide in the cores of the silver halide grains is 3 to 40 mole %. Silver halide grains according to any one of Claims 11 to 16, wherein the content of silver iodide in the shells of the silver halide grains is 0 to 10 mole %. Silver halide grains according to any one of Claims 11 to 17, wherein the difference in silver iodide content between the cores and the shells is 2 to 30 mole %. A process for producing silver halide grains as defined in any one of Claims 1 to 17, or silver halide grains having (110) crystal faces and comprising a silver halide composition consisting substantially of silver bromide or silver iodobromide, 0 to less than 10 mole % of other silver halides and 0 to 1 mole % silver chloride, which comprises controlling the pAg at from 8.0 to 9.5 during the period until at least 30 mole % of the total silver halide is formed in the step of preparing the silver halide grains, in the presence of at least one compound of formula (I), (II), (III) or (IV) or compound having recurring units of formula (V) shown below: wherein R₁, R₂ and R₃, which may be the same or different, each represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a derivative of an amino group, an alkyl group, a derivative of an alkyl group, an aryl group, a derivative of an aryl group, a cycloalkyl group, a derivative of a cycloalkyl group, a mercapto group, a derivative of a mercapto group or -CONH-R₄ (wherein R₄ is a hydrogen atom, an amino group, a derivative of an alkyl group, a derivative of an amino group, a halogen atom, a cycloalkyl group, a derivative of a cycloalkyl group, an aryl group or a derivative of an aryl group), or wherein R₁ and R₂ may be bonded together to form a ring, R₅ represents a hydrogen atom or an alkyl group, X represents a monovalent group formed by eliminating one hydrogen atom from a compound of formula (I), (II), (III) or (IV), and J represents a divalent linking group. A process according to Claim 19, wherein said pAg is from 8.4 to 9.2. A process according to Claim 19 or 20, wherein the pH in the period until at least 30 mole % of the total silver halide is formed is from 7 to 10. A process according to any one of Claims 19 to 21, wherein the production steps include the step of adding an aqueous ammoniacal silver nitrate solution and a halide solution according to the double jet method. A process according to any one of Claims 19 to 21, wherein the production steps include a grain growth step of adding an aqueous silver nitrate solution and a halide solution so that no new crystal nucleus is formed. A process according to any one of Claims 19 to 23, wherein the amount of the at least one compound of formulae (I) through (IV) or compound having recurring units of formula (V) is from 1 x 10⁻⁵ to 2 x 10⁻¹ mole per mole of the silver halide formed. A silver halide photographic emulsion, comprising grains as defined in any one of Claims 1 to 18. A light-sensitive silver halide photographic material having an emulsion as defined in Claim 25 provided on a support.

Inventors: AKAMATSU, HIDEO, MATSUZAKA, SYOJI, NISHIWAKI, SHU, SUDA, YOSHIHIKO
Applicants: KONICA CORPORATION
Application year: 1985
Main classification: G03C1
IPC codes: G03C1