EP0435270B1

EP0435270B1 - Process for preparing a silver iodobromide emulsion and a silver halide photographic light-sensitive material comprising the same

Info

Publication number: EP0435270B1
Application number: EP90125540A
Authority: EP
Inventors: Katsumi C/O Fuji Photo Film Co. Ltd. Makino
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1989-12-26
Filing date: 1990-12-27
Publication date: 1997-04-09
Anticipated expiration: 2010-12-27
Also published as: DE69030431D1; DE69030431T2; JP2627202B2; JPH03196138A; EP0435270A1

Description

The present invention relates to a process for preparing a silver iodobromide emulsion and to a silver halide photographic light-sensitive material having a high sensitivity/fog ratio and improved storage stability during storage after exposure and comprising at least one at this emulsion in an emulsion layer.
The subject recently assigned to reseachers specialized in silver-halide color photographic light-sensitive materials is to develop a light-sensitive material having a very high sensitivity, such as an ISO 1,600 photographic light-sensitive material, and also a light-sensitive material which can be used in photography by means of a small-formatted camera such a a 110-size system or a disk-size system, either exihibitying good graininess, high sharpness and high color-reproducibility.
A technique of increasing the sensitivity of a silver halide emulsion is important since it can provide a silver halide photographic material which has a sufficient light-sensitivity even though the silver halide grains it contains are relative large.
Examples of a conventional method known as a chemical sensitization method of increasing the sensitivity of a silver halide photographic emulsion are sulfur sensitization, selenium sensitization, noble metal sensitization, reduction sensitization, and hydrogen sensitization. These sensitization methods are used singly or in a combination of two or more thereof. The sensitization methods are described in T.H. James, "The Theory of the Photographic Process", 4th ed., Macmillan Co., 1977, pp. 149 to 160 and pp. 164 and 165.
In addition to the above sensitization methods, various types of emulsion manufacturing methods using a silver halide solvent or a so-called stabilizer have been proposed as the technique of increasing sensitivity.
In addition to the sensitization methods described above, the grain size of an emulsion is increased as the sensitivity of a photographic light-sensitive material is increased. In particular, in order to increase the sensitivity of a light-sensitive material having ISO sensitivity of 1,600 or more, the grain size of an emulsion must be increased (to be 1.4 µm or more).
Although the sensitivity of an emulsion can be increased by the above means, when light sensitivity is to be increased by improving a sensitization method or by increasing the grain size of an emulsion to increase the number of photons to be absorbed by one grain, the following two problems arise:

1) Fog is increased.
2) Sensitivity is increased during storage after exposure (this phenomenon will be referred to as "latent image sensitization" hereinafter).

As a conventional method of preventing fog, the use of compounds represented by the following formulas (I) to (III) and polymers having as a repearting unit a divalent-group derived from the compounds of formulas (I), (II) or (III) is proposed in US-A-3,047,393 for a silver iodobromide emulsion and JP-A-63-30425 (hereinafter "JP-A-" means unexamined published Japanese patent application) for a high-temperature silver emulsion.

(I) R-SO₂S-M

(II) R-SO₂S-R¹

(III) R-SO₂S-Lm-SSO₂-R²

where R, R¹, and R² may be the same or different and independently represent an aliphatic group, an aromatic group, or a heterocyclic group, M represents a cation, L represents a divalent linking group, and m represents 0 or 1.
EP-A-0 421 452, which is a document in accordance with Article 54(3) EPC, discloses a silver halide photographical material comprising a silver halide emulsion having a silver chloride content of 90 mol-% or more.
EP-A-0 371 338, which is also a document in accordance with Article 54(3) EPC, discloses a silver halide photographic light sensitive material comprising at least one silver halide emulsion layer. A sensitizing dye is added to the emulsion after the completion of the chemical sensitization prior to coating.
EP-A-0 350 046, which is also a document in accordance with Article 54(3) EPC, relates to a silver halide photographic material which does not substantially contain silver iodide and which contains silver chlorobromide or silver chloride grains having a silver chloride content of at least 95 mol-%.
These proposals, however, do not mention the problem of item 2) above at all. In a color photograph, this problem causes a variation in color balance or gradation balance between blue-, green-, and red-sensitive layers because storage stability after exposure is poor. This means deterioration and a variation in photographic properties.
It is thus an object of the present invention to provide a process for preparing a silver iodobromide emulsion so that much better results in regard to fog, sensitivity and storage stability during storage after exposure are obtained.
The solution of this object is as laid down in the independent claims 1 and 7. Preferred features of the invention are contained in the subclaims 2 to 6.
In the present invention, an oxidizing agent for silver is a compound having an effect of converting metal silver into silver ions. In particular, a compound capable of converting very small silver, which is by-produced during a silver halide grain formation process, into silver ions is effective. The produced silver ions may form a silver salt which is hardly dissolved in water such as a silver halide, silver sulfide, or silver selenide, or may form a silver salt which is readily dissolved in water such as silver nitrate.
The oxidizing agent for silver is an organic thiosulfononic acid derivative selected from the compound represented by formula (I) and polymers having as a repeating unit a divalent group derived from said compound represented by formula (I) which converts silver into silver sulfide.

(I) R-SO₂S-M

wherein R represents an aliphatic group, an aromatic group, or a heterocyclic group and M represents a cation. When R represents an aliphatic group, it is a saturated or unsaturated, straight-chain, branched, or cyclic aliphatic hydrocarbon group and is preferably an alkyl group having 1 to 22 carbon atoms or an alkenyl or alkinyl group having 2 to 22 carbon atoms. These groups may have substituents. Examples of the alkyl group are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, isopropyl, and t-butyl. Examples of the alkenyl group are allyl and butenyl. Examples of the alkinyl group are propargyl and butynyl.
When R represents an aromatic group, it is an aromatic group of a monocyclic or condensation-ring, preferably having 6 to 20 carbon atoms. Examples of such an aromatic group are phenyl and naphthyl. These groups may be substituted.
When R represent a heterocyclic group, it is a 3- to 15-membered ring, preferably, a 3-to 6-membered ring having at least one element selected from nitrogen, oxygen, sulfur, selenium, and tellurium and at least one carbon. Examples of the heterocyclic group are a pyrrolidine ring, a piperidine ring, a pyridine ring, a tetrahydrofurane ring, a thiophene ring, an oxazole ring, a thiazole ring, an imidazole ring, a benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a selenazole ring, a benzoselenazole ring, a tellurazole ring, a triazole ring, a benzotriazole ring, a tetrazole ring, an oxadiazole ring, and a thiadiazole ring.
Examples of the substituent on R are an alkyl group (e.g., methyl, ethyl, and hexyl), an alkoxy group (e.g., methoxy, ethoxy, and octyloxy), an aryl group (e.g., phenyl, naphthyl, and tolyl), a hydroxy group, a halogen atom (e.g., fluorine, chlorine, bromine, and iodine), an aryloxy group (e.g., phenoxy), an alkylthio group (e.g., methylthio and butylthio), an arylthio group (e.g., phenylthio), an acyl group (acetyl, propionyl, butyryl, and valeryl), a sulfonyl group (e.g., methylsulfonyl and phenylsulfonyl), an acylamino group (e.g., acetylamino and benzoylamino), a sulfonylamino group (e.g., methanesulfonylamino and benzenesulfonylamino), an acyloxy group (e.g., acetoxy and benzoxy), carboxyl, cyano, sulfo, amino, -SO₂SM (wherein M represents a monovalent cation), and -SO₂R¹.
M is preferably a metal ion or an organic cation. Examples of the metal ion are a lithium ion, a sodium ion, and a potassium ion. Examples of the organic cation are an ammonium ion (e.g., ammonium, tetramethylammonium, and tetrabutylammonium), a phosphonium ion (tetraphenylphosphonium), and a guanidyl group.
When the oxidizing agent used in the present invention is one of polymers having as a repeating unit a divalent group derived from the compound of formula (I), the examples of the repeating unit are as follows:
Each of the polymers mentioned above can be a homopolymer or a copolymer with another copolymerizable monomer.
Examples of the compounds represented by formula (I) and polymers having as a repeating unit a divalent group derived from the formula (I) are listed in Table A below. However, the compounds are not limited to those shown in Table A. The compounds of formula (I) can easily be synthesized by the methods described in JP-A-54-1019, British Patent 972,211, and Journal of Organic Chemistry, Vol. 53, p. 396, 1988.
An addition amount of the oxidizing agent for silver per mol of silver salt of the present invention is preferably 10^-7 to 10^-1 mol, more preferably, 10^-6 to 10^-2 mol, and most preferably, 10^-5 to 10^-3 mol.
An addition timing of the oxidizing agent of the present invention will be described below.
A method of manufacturing a silver iodobromide emulsion mainly comprises grain formation, desalting, chemical sensitization, and coating. The grain formation includes nucleation, ripening, and growth. These steps may be performed not in the order mentioned. Some of these steps may be performed in a reverse order further one or more steps may be performed repeatedly.
An effect of the present invention cannot be obtained unless the oxidizing agent is added after 50% of water-soluble silver salt used in grain formation of an emulsion are added and before chemical sensitization is performed. When the oxidizing agent is to be added during grain formation, it is preferably added after 80% of a water-soluble silver salt used in grain formation are added. More preferably, thiosulfonate is added after grain formation is ended and before chemical sensitization is started. When the oxidizing agent is to be added during the desalting step, it can be added at any time during the step. When the oxidizing agent is to be added before chemical sensitization is performed, it is added before a sensitizer such as a gold, sulfur, or selenium sensitizer is added. If a sensitizing dye is added prior to chemical sensitization, the oxidizing agent is preferably added before addition of the sensitizing dye.
In order to add oxidizing agents represented by formula (I), any conventional method normally used to add additives to a photographic emulsion can be applied. For example, the water-soluble compound can be added in the form of an aqueous solution having any appropriate concentration, and the compound which is insoluble or hardly dissolved in water can be dissolved in a proper organic solvent, e.g., alcohol, glycol, ketone, ester, or amide which is miscible with water and has no influence on photographic properties and added as a solution.
An average silver iodobromide composition of the entire silver halide grains of the present invention is silver iodobromide, containing 1 to 30 mol% of silver iodide. Preferably, this composition contains 7 to 20 mol% of silver iodide, and may contain 10 mol% or less of silver chloride.
A silver iodobromide grain to be used in the present invention can be selected from a regular crystal not including a twinned crystal face and those described in Japan Photographic Society ed., "Silver Salt Photographs, Basis of Photographic Industries", (Corona Co., p. 163) such as a single twinned crystal including one twinned crystal face, a parallel multiple twinned crystal including two or more parallel twinned crystal faces, and a non-parallel multiple twinned crystal including two or more non-parallel twinned crystal faces in accordance with its applications. In the case of a regular crystal, a cubic grain consisting of (100) faces, an octahedral grain consisting of (111) faces, and a dodecahedral grain consisting of (110) faces disclosed in JP-B-55-42737 ("JP-B-" means examined published Japanese patent application) and JP-A-60-222842 can be used. In addition, a grain consisting of (hll) faces, e.g., (211) faces, a grain consisting of (hhl), e.g., (331) faces, a grain consisting of (hk0), e.g., (210) faces, and a grain consisting of (hkl), e.g., (321) faces as reported in "Journal of Imaging Science", Vol. 30, p. 247, 1986 can be selectively used in accordance with an application although a preparation method must be improved. A grain including two or more types of faces, e.g., a tetradecahedral grain consisting of both (100) and (111) faces, a grain consisting of both (100) and (110) faces, and a grain consisting of both (111) and (110) faces can be selectively used in accordance with an application.
The silver iodobromide grain of the present invention may be a fine grain having a grain size of 0.1 microns or less or a large grain having a projected surface area diameter of 10 microns.
Although the effect of the present invention can be achieved by either a monodisperse or polydisperse emulsion, a monodisperse emulsion is more preferable. In this case, "monodisperse" is defined such that at least a variation coefficient of a circle-equivalent diameter of a projected area of a grain or a variation coefficient of a sphere-equivalent diameter of a grain volume is 20% or less, and more preferably, 15% or less.
The photographic emulsion for use in the present invention can be prepared by using methods described in, for example, P. Glafkides, "Chimie et Physique Photographique", Paul Montel, 1967; Duffin, "Photographic Emulsion Chemistry", Focal Press, 1966; and V.L. Zelikman et al., "Making and Coating Photographic Emulsion", Focal Press, 1964. That is, the photographic emulsion can be prepared by, e.g., an acid method, a neutralization method, and an ammonia method. Also, as a system for reacting a soluble silver salt and a soluble halide, the single-jet method, the double-jet method, or a combination thereof can be used. Also, a so-called reverse mixing method of forming silver halide grains in the presence of excessive silver ions can be used. As one system of the double-jet method, a so-called controlled double-jet method wherein the pAg in the liquid phase generated by the silver halide is kept at a constant value can be used. According to this method, a silver halide emulsion having a regular crystal form and almost uniform grain sizes is obtained.
The silver iodobromide emulsion containing the above-described regular silver iodobromide grains can be obtained by controlling the pAg and pH during grain formation. More specifically, such a method is described in "Photographic Science and Engineering" Vol. 6, 159-165 (1962); "Journal of Photographic Science", Vol. 12, 242-251 (1964); U.S. Patent 3,655,394, and British Patent 1,413,748.
A tabular grain having an aspect ratio of 3 or more can also be preferably used in the present invention. The tabular grain can be easily prepared by methods described in, for example, Cleve, "Photography Theory and Practice", (1930), p. 131; Gutoff, "Photographic Science and Engineering", Vol. 14, pp. 248 to 257, (1970); and U.S. Patents 4,434,226, 4,414,310, 4,433,048, and 4,439,520, and British Patent 2,112,157. When the tabular grain is used, covering power and a color sensitizing efficiency of a sensitizing dye can be advantageously improved as described in detail in U.S. Patent 4,434,226.
The tabular grains are preferably used in the emulsion of the present invention. In particular, tabular grains in which grains having aspect ratios of 3 or more account for 60% or more of a total projected area are preferable. Tabular grains in which grains having aspect ratios of 3 to 10 account for 60% or more of a total projected area are most preferable. Also in the case of tabular grains, a grain size distribution is preferably monodisperse. A variation coefficient of a circle-equivalent diameter of a projected area or a sphere-equivalent diameter of a volume is preferably 25% or less, more preferably, 20% or less, and most preferably, 15% or less.
In the silver iodobromide emulsion used in the present invention, a crystal structure of the silver iodobromide grain may be uniform, may have different halogen compositions inside and outside a crystal, or may be a layered structure. These emulsion grains are disclosed in, e.g., British Patent 1,027,146, U.S. Patents 3,505,068 and 4,444,877, and Japanese Patent Application No. 58-248469. In addition, silver iodobromides having different compositions may be bonded by an epitaxial junction, or a compound other than silver halides such as silver rhodanate or zinc oxide may be bonded.
If the silver iodobromide emulsion of the present invention has a uniform halogen composition, the emulsion preferably comprises silver iodobromide containing 20 mol% or less of silver iodide. A preferable silver iodide content changes in accordance with an application. For example, if an emulsion is required to have a high developing rate, the content of silver iodide is preferably 10 mol% or less, and more preferably, 5 mol% or less. If an emulsion is required to have a soft tone, the emulsion is sometimes designed to have a comparatively high silver iodide content. In this case, the silver iodide content is preferably 5 mol% or more.
The silver iodobromide emulsion of the present invention preferably can have a distribution or structure of a halogen composition in its grain. A typical example is a core-shell type or double structured grain having different halogen compositions in the interior and surface layer of the grain as disclosed in, e.g., JP-B-43-13162 (Hereinafter "JP-B-" means Examined Published Japanese Patent Application), JP-A-61-215540, JP-A-60-22284, and JP-A-61-75337. In such a grain, the shape of a core portion is sometimes identical to or sometimes different from that of the entire grain with a shell. More specifically, while the core portion is cubic, the grain with a shell is sometimes cubic or sometimes octahedral. On the contrary, while the core portion is octahedral, the grain with a shell is sometimes cubic or sometimes octahedral. In addition, while the core portion is a clear regular grain, the grain with a shell is sometimes slightly deformed or sometimes does not have any definite shape. Furthermore, not a simple double structure but a triple structure as disclosed in JP-A-60-222844 or a multilayered structure of more layers can be formed, or a silver halide having a different halogen composition can be thinly formed on the surface of a core-shell double structure grain.
In order to give the structure inside the grain, a grain having not only the above surrounding structure but a so-called junction structure can be made. Examples of such a grain are disclosed in, e.g., JP-A-59-133540, JP-A-58-108526, EP 199290A2, JP-B-5824772, and JP-A-59-16254. A crystal to be bonded can be produced to have a composition different from that of a host crystal and in contact with an edge, corner, or face portion of the host crystal. Such a junction crystal can be formed regardless of whether the host crystal has a homogeneous halogen composition or a core-shell structure.
The junction structure can be naturally made by a combination of silver halides. In addition, the junction structure can be made by combining a silver salt compound not having a rock salt structure, e.g., silver rhodanate or silver carbonate with a silver iodobromide. A non-silver salt compound such as PbO can also be used as long as the junction structure can be made.
In a silver iodobromide grain having the above structure, e.g., in a core-shell type grain, the silver iodide content may be high at a core portion and low at a shell portion or vice versa.
Also in a grain having a structure in the silver iodide content, a preferable silver iodide content on the grain surface changes in accordance with an application. For example, if an emulsion is required to have a high developing rate, the silver iodide content on the grain surface is preferably 10 mol% or less, and more preferably, 5 mol% or less. If an emulsion is required to have a soft tone, the emulsion is sometimes designed to have a comparatively high silver iodide content on the grain surface. In this case, the silver iodide content is preferably 5 mol% or more.
In order to obtain a desired silver iodide content on the grain surface, a silver iodide content in a shell portion may be set to be a desired content, or a thin silver halide having a desired composition may be adhered on the surface of a grain.
Similarly, in a grain having the junction structure, the silver iodide content may be high in a host crystal and relatively low in a junction crystal or vice versa.
In a grain having the above structure, a boundary between portions having different halogen compositions may be clear or unclear due to a crystal mixture formed by a composition difference. Alternatively, a continuous structure change may be positively made in the boundary portions.
The silver iodobromide emulsion for use in the present invention can be subjected to a treatment for rounding a grain as disclosed in, e.g., EP-0096727B1 and EP-0064412B1 or a treatment of modifying the surface of a grain as disclosed in DE-2306447C2 and JP-A-60-221320.
The silver iodobromide emulsion for use in the present invention is preferably of a surface latent image type. An interlal latent image type emulsion, however, can be used by selecting a developing solution or development conditions as disclosed in JP-A-59-133542. In addition, a shallow internal latent image type emulsion covered with a thin shell can be used in accordance with an application.
A silver iodobromide solvent can be effectively used to promote ripening for grains. For example, in a known conventional method, an excessive amount of iodobromide ions are supplied in a reactor vessel in order to promote ripening. Therefore, it is apparent that ripening can be promoted by only supplying a silver iodobromide solution into a reactor vessel. In addition, another ripening agent can be used. In this case, a total amount of these ripening agents can be mixed in a dispersion medium in the reactor vessel before a silver salt and a iodobromide are added therein, or they can be added in the reactor vessel together with one or more halides, a silver salt or a deflocculant. Alternatively, the ripening agents can be added independently, in steps of adding a halide and a silver salt.
Examples of the ripening agent other than the halogen ion are ammonia, an amine compound and a thiocyanate such as an alkali metal thiocyanate, especially sodium or potassium thiocyanate and ammonium thiocyanate.
The silver iodobromide grains of the present invention are subjected to at least one of sulfur sensitization, gold sensitization, and noble metal sensitization in an arbitrary step of silver iodobromide emulsion manufacturing steps, and typically, a grain formation step. Although these methods of chemical sensitization charge in accordance with the composition, structure, and shape of emulsion grains or an application of the emulsion, a chemical sensitization nucleus is embedded inside a grain, embedded in a shallow portion from the grain surface, or formed on the grain surface. Although the present invention is effective in any case, the chemical sensitization nucleus is most preferably formed in a portion near the surface. That is, the present invention is more effective in the surface latent image type emulsion than in the internal latent image type emulsion.
As chemical sensitization which can be preferably performed in the present invention (to be referred to as simply chemical sensitization hereinafter), gold sensitization, sulfur sensitization, and noble metal sensitization can be performed singly or in a combination of two or more thereof. Chemical sensitization can be performed by using active gelatin as described in T.H. James, "The Theory of the Photographic Process", 4th ed., Macmillan, 1977, pp. 67 to 76. Alternatively, chemical sensitization can be performed at a pAg of 5 to 10, a pH of 5 to 8 and a temperature of 30°C to 80°C by using sulfur, selenium, tellurium, gold, platinum, palladium or irridium, or a combination of a plurality of these sensitizers as described in Research Disclosure (to be referred to as simply "RD" hereinafter) Vol. 120, No. 12,008 (April, 1974) and Vol. 34, No. 13,452 (June, 1975), U.S. Patents 2,642,361, 3,297,446, 3,772,031, 3,857,711, 3,901,714, 4,266,018, and 3,904,415, and British Patent 1,315,755. Chemical sensitization is optimally performed in the presence of a gold compound and a thiocyanate compound, a sulfur-containing compound described in U.S. Patents 3,857,711, 4,266,018, and 4,054,457 or a sulfur-containing compound such as a hypo, thiourea compound and a rhodanine compound.
Chemical sensitization can also be performed in the presence of a chemical sensitization assistant. An effective example of the chemical sensitization assistant is a compound known to suppress fog and increase sensitivity in the chemical sensitization process such as azaindene, azapyridazine, and azapyrimidine. Examples of a chemical sensitization assistant modifier are described in U.S. Patents 2,131,038, 3,411,914, 3,554,757, JP-A-58-126526 and G.F. Duffin, "Photographic Emulsion Chemistry", pp. 138 to 143.
The emulsion of the present invention exhibits a preferable effect by using gold sensitization. A preferable amount of the gold sensitizer is 1 × 10^-4 to 1 × 10^-7 mol, and more preferably, 1 × 10^-5 to 5 × 10^-7 mol per mol of a silver halide.
A preferable amount of the sulfur sensitizer used with respect to silver halide grains of the present invention is 1 × 10^-4 to 10^-7, and more preferably, 1 × 10^-5 to 5 × 10^-7 mol per mol of a silver halide.
Both the above conditions are preferably used in gold·sulfur sensitization.
The silver iodobromide grains of the present invention are preferably reduction-sensitized during grain formation, after grain formation and before chemical sensitization, during chemical sensitization, or after chemical sensitization.
As a method of reduction sensitization, a method of adding a reduction sensitizer to a silver halide emulsion, a method called silver ripening in which growth or ripening is performed in a low-pAg atmosphere having a pAg of 1 to 7, and a method called high pH ripening in which growth or ripening is performed in a high-pH atmosphere having pH of 8 to 11 can be selectively used. Alternatively, these methods can be used in a combination of two or more thereof.
The method of adding a reduction sensitizer is preferable since the level of reduction sensitization can be finely adjusted.
Known examples of a reduction sensitizer are stannous chloride, ascorbic acid and its derivatives, amine and polyamine, a hydrazine derivative, formamidinesulfinic acid, a silane compound, and a borane compound. In the reduction sensitization of the present invention, these known reduction sensitizers can be used selectively or in a combination of two or more thereof. Preferable compounds as a reduction sensitizer are stannous chloride, thiourea dioxide, dimethylamineborane, and ascorbic acid and its derivatives. Although an addition amount of the reduction sensitizer must be selected in accordance with the emulsion manufacturing conditions, it is preferably 10^-7 to 10^-3 mol per mol of a silver iodobromide.
The reduction sensitizer is dissolved in water or a solvent such as alcohol, glycol, ketone, ester, or amide and added during grain formation. Although the reduction sensitizer may be added in a reactor vessel before again growth, it is more preferably added at an arbitrary timing during grain growth. The reduction sensitizer may be previously added to an aqueous solution of water-soluble silver salt or water-soluble alkali halide, and the solution may be used to precipitate silver iodobromide grains. Alternatively, a solution of the reduction sensitizer may be preferably added several times or continuously over a long time period as grain growth progresses.
The photographic emulsion of the present invention can contain various compounds in order to prevent fog during manufacture, storage, or a photographic treatment of the light-sensitive material or to stabilize photographic properties. Examples of the compound known as an antifoggant or stabilizer are azoles, e.g., benzothiazolium salt, nitroimidazole, nitrobenzimidazole, chlorobenzimidazole, bromobenzimidazole, mercaptothiazole, mercaptobenzothiazole, mercaptobenzimidazole, mercaptothiadiazole, aminotriazole, benzotriazole, nitrobenzotriazole, and mercaptotetrazole (especially, 1-phenyl-5-mercaptotetrazole); mercaptopyrimidine; mercaptotriadine; a thioketo compound such as oxadrinthione; azaindene, e.g., triazaindene, tetraazaindene (especially, 4-hydroxy-substituted (1,3,3a,7)tetraazaindene), and pentaazaindene. Examples are described in U.S. Patents 3,954,474 and 3,982,947 and JP-B-52-28660.
The photographic emulsion of the present invention can be spectrally sensitized with, e.g., a methine dye. Examples of the dye are a cyanine dye, a merocyanine dye, a composite cyanine dye, a composite merocyanine dye, a holopolar cyanine dye, a hemicyanine dye, a styryl dye, and hemioxonol dye. Most effective dyes are those belonging to a cyanine dye, a merocyanine dye, and a composite merocyanine dye. In these dyes, any nucleus normally used as a basic heterocyclic nucleus in cyanide dyes can be used. Examples of the nucleus are pyrroline nucleus, an oxazoline nucleus, a thiozoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus, and a pyridine nucleus; a nucleus obtained by fusing an alicyclic hydrocarbon ring to each of the above nuclei; and a nucleus obtained by fusing an aromatic hydrocarbon ring to each of the above nuclei, e.g., an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxadole nucleus, a naphthooxazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a benzoselenazole nucleus, a benzimidazole nucleus, and a quinoline nucleus. These nuclei may be substituted on a carbon atom.
As a merocyanine dye or a composite merocyanine dye, a 5- or 6-membered heterocyclic nucleus, e.g., a pyrazoline-5-one nucleus, a thiohydantoin nucleus, a 2-thioxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus, and a thiobarbituric acid nucleus can be used as a nucleus having a ketomethylene structure.
These sensitizing dyes can be used singly or in a combination of two or more thereof. A combination of the sensitizing dyes is often used especially in order to perform supersensitization. Typical examples of the combination are described in U.S. Patents 2,688,545, 2,977,229, 3,397,060, 3,522,052, 3,527,641, 3,617,293, 3,628,964, 3,666,480, 3,672,898, 3,679,428, 3,703,377, 3,769,301, 3,814,609, 3,837,862, 4,026,707, British Patents 1,344,281 and 1,507,803, JP-B-43-4936 and JP-B-53-12375, and JP-A-52-110618 and JP-A-52-109925.
The emulsion may contain, in addition to the sensitizing dye, a dye not having a spectral sensitizing effect or a substance substantially not absorbing visible light and having supersensitization.
The dye can be added in the emulsion at any timing conventionally known to be effective in emulsion preparation. Most ordinarily, the dye is added after completion of chemical sensitization and before coating. However, the dye can be added at the same time as a chemical sensitizer to simultaneously perform spectral sensitization and chemical sensitization as described in U.S. Patents 3,628,969 and 4,225,666, added before chemical sensitization as described in JP-B-58-113928, or added before completion of silver iodobromide grain precipitation to start spectral sensitization. In addition, as described in U.S. Patent 4,225,666, the above compound can be separately added such that a portion of the compound is added before chemical sensitization and the remaining portion is added thereafter. That is, as described in U.S. Patent 4,183,756, the compound can be added at any timing during silver halide grain formation.
Although the dye can be preferably added at any of the above addition timings in the present invention, it is more preferably added prior to chemical sensitization or before precipitation of silver halide grains is completed. Most preferably, the dye is added prior to chemical sensitization.
An addition amount of the dye may be 4 × 10^-6 to 8 × 10^-3 mol per mol of a silver iodobromide. In the case of a prefarable silver iodobromide grain size is 0.1 to 1.2 µm, an addition amount of about 5 × 10^-5 to 2 × 10^-3 mol per mol of a silver iodobromide is more effective.
The above various additives are used in the light-sensitive material of the present invention. In addition to the above additives, however, various additives can be used in accordance with applications.
These additives are described in RD., Item 17643 (Dec. 1978) and Item 18716 (Nov. 1979) and they are summarized in the following table.
A spectral sensitizing dye used in the present invention can be used together with a nitrogen-containing heterocyclic compound represented by the following formula described in JP-A062089952:
wherein R⁹ represents an aliphatic, aromatic, or heterocyclic group substituted by at least one -COOM¹ or -SO₃M¹ and M¹ represents a hydrogen atom, an alkali metal atom, a quaternary ammonium, or quaternary phosphonium.

An addition amount of the above compound is 1 × 10^-5 to 1 × 10^-2 mol, and preferably, 1 × 10^-4 to 1 × 10^-3 mol per mol of a silver halide.

Additives	RD No.17643	RD No.18716
1. Chemical sensitizer	page 23	page 648, right column
2. Sensitivity increasing agents		do
3. Spectral sensitizers, super sensitizers	page 23-24	page 648, right column to page 649, right column
4. Brighteners	page 24
5. Antifoggants and stabilizers	pages 24-25 pages 24-25	page 649, right column
6. Light absorbent, filter dye, ultra-violet absorbents	pages 25-26	page 649, right column to page 650, left column
7. Stain preventing agents	page 25, right column	page 650, left to right columns
8. Dye image stabilizer	page 25
9. Hardening agents	page 26	page 651, left column
10. Binder	page 26	do
11. Plasticizers, lubricants	page 27	page 650, right column
12. Coating aids, surfactants	pages 26-27	do
13. Antistatic agents	page 27	do

In this invention, various color couplers can be used in the light-sensitive material. Specific examples of these couplers are described in above-described RD., No. 17643, VII-C to VII-G as patent references.
Preferred examples of a yellow coupler are described in, e.g., U.S. Patents 3,933,501, 4,022,620, 4,326,024, and 4,401,752, JP-B-58-10739, and British Patents 1,425,020 and 1,476,760.
Examples of a magenta coupler are preferably 5-pyrazolone and pyrazoloazole compounds, and more preferably, compounds described in, e.g., U.S. Patents 4,310,619 and 4,351,897, EP 73,636, U.S. Patents 3,061,432 and 3,725,067, RD. No. 24220 (June 1984), JP-A-60-33552, RD. No. 24230 (June 1984), JP-A-60-43659, and U.S. Patents 4,500,630 and 4,540,654.
Examples of a cyan coupler are phenol and naphthol couplers, and preferably, those described in, e.g., U.S. Patents 4,052,212, 4,146,396, 4,228,233, 4,296,200, 2,369,929, 2,801,171, 2,772,162, 2,895,826, 3,772,002, 3,758,308, 4,334,011, and 4,327,173, West German Patent Application (OLS) No. 3,329,729, EP 121,365A, U.S. Patents 3,446,622, 4,333,999, 4,451,559, and 4,427,767, and EP 161,626A.
Preferable examples of a colored coupler for correcting additional, undesirable absorption of a colored dye are those described in RD. No. 17643, VII-G, U.S. Patent 4,163,670, JP-B-57-39413, U.S. Patents 4,004,929 and 4,138,258, and British Patent 1,146,368.
Preferable examples of a coupler capable of forming colored dyes having proper diffusibility are those described in U.S. Patent 4,366,237, British Patent 2,125,570, EP 96,570, and West German Patent Application (OLS) No. 3,234,533.
Typical examples of a polymerized dye-forming coupler are described in U.S. Patents 3,451,820, 4,080,211, and 4,367,282, and British Patent 2,102,173.
Couplers releasing a photographically useful residue upon coupling are preferably used in the present invention. Preferable examples of a DIR coupler releasing a development inhibitor are described in the patents cited in the above-described RD. No. 17643, VII-F, JP-A-57-151944, JP-A-57-154234, JP-A-60-184248, and U.S. Patent 4,248,962.
Preferable examples of a coupler imagewise releasing a nucleating agent or a development accelerator upon development are those described in British Patent 2,097,140, 2,131,188, and JP-A-157638 and JP-A-59-170840.
Examples of a coupler which can be used in the light-sensitive material of the present invention are competing couplers described in, e.g., U.S. Patent 4,130,427; poly-equivalent couplers described in, e.g., U.S. Patents 4,283,472, 4,338,393, and 4,310,618; DIR redox compound, a DIR coupler, a DIR coupler releasing coupler, and a DIR coupler releasing redox compound described in, e.g., JP-A-60-185950 and JP-A-62-24252; couplers releasing a dye which turns to a colored form after being split off described in EP 173,302A; bleaching accelerator releasing couplers described in, e.g., RD. Nos. 11449 and 24241 and JP-A-61-201247; and a legand releasing coupler described in, e.g., U.S. Patent 4,553,477.
The couplers for use in this invention can be introduced in the light-sensitive material by various known dispersion methods.
Examples of a high-boiling solvent used in an oil-in-water dispersion method are described in, e.g., U.S. Patent 2,322,027.
Examples of a high-boiling organic solvent to be used in the oil-in-water dispersion method and having a boiling point of 175°C or more at normal pressure are phthalic ester (e.g., dibutylphthalate, dicyclohexylphthalate, di-2-ethylhexylphthalate, decylphthalate, bis(2,4-di-t-amylphenyl)phthalate, bis(2,4-di-t-amylphenyl)isophthalate, and bis(1,1-diethylpropyl)phthalate), phosphate or phosphonate (e.g., triphenylphosphate, tricresylphosphate, 2-ethylhexyldiphenylphosphate, tricyclohexylphosphate, tri-2-ethylhexylphosphate, tridodecylphosphate, tributoxyethylphosphate, trichloropropylphosphate, and di-2-ethylhexylphenylphosphonate), benzoate (e.g., 2-ethylhexylbenzoate, dodecylbenzoate, and 2-ethylhexyl-p-hydroxybenzoate), amide (e.g., N,N-diethyldodecaneamide, N,N-diethyllaurylamide, and N-tetradecylpyrrolidone), alcohol or phenol (e.g., isostearylalcohol and 2,4-di-tert-amylphenol), aliphatic carboxylate (e.g., bis(2-ethylhexyl)sebacate, dioctylazelate, glyceroltributylate, isostearyllactate, and trioctylcitrate), an aniline derivative (e.g., N,N-dibutyl-2-butoxy-5-tert-octylaniline), and a hydrocarbon (e.g., paraffin, dodecylbenzene, diisopropylnaphthalene). An organic solvent having a boiling point of about 30°C or more, and preferably, 50°C to about 160°C can be used as a co-solvent. Typical examples of the co-solvent are ethyl acetate, butyl acetate, ethyl propionate, methylethylketone, cyclohexane, 2-ethoxyethylacetate, and dimethylformamide.
Steps and effects of a latex dispersion method and examples of an impregnating latex are described in, e.g., U.S. Patent 4,199,363 and West German Patent Application (OLS) Nos. 2,541,274 and 2,541,230.
The present invention can be applied to various color light-sensitive materials. Examples of the material are a color negative film for a general purpose or a movie, a color reversal film for a slide or a television, color paper, a color positive film, and color reversal paper.
When the present invention is used as a color photographic material, the present invention can be applied to light-sensitive materials having various structures and to light-sensitive materials having combinations of layer structures and special color materials.
Typical examples are: light-sensitive materials in which a coupling speed of a color coupler or diffusibility is combined with a layer structure, as disclosed in, e.g., JP-B-47-49031, JP-B-49-3843, JP-B-50-21248, JP-A-59-58147, JP-A-59-60437, JP-A-60-227256, JP-A-61-4043, JP-A-61-43743, and JP-A-61-42657; light-sensitive materials in which a single color-sensitive layer is divided into two or more layers, as disclosed in JP-B-49-15495 and U.S. Patent 3,843,469; and light-sensitive materials in which an arrangement of high- and low-sensitivity layers or layers having different color sensitivities is defined, as disclosed in JP-B-53-37017, JP-B-53-37018, JP-A-51-49027, JP-A-52-143016, JP-A-53-97424, JP-A-53-97831, JP-A-62-200350, and JP-A-59-177551.
Examples of a support suitable for use in this invention are described in the above-mentioned RD. No. 17643, page 28 and ibid., No. 18716, page 647, right column to page 648, left column.
The color photographic light-sensitive materials of this invention can be developed by the conventional methods as described in, e.g., the above-described Research Disclosure, No. 17643, pages 28 to 29 and ibid., No. 18716, page 651, left to right columns.
A color developer used in developing of the light-sensitive material of the present invention is, preferably, an aqueous alkaline solution containing, as a main component, an aromatic primary amine-based color developing agent. As the color developing agent, although an aminophenol-based compound is effective, a p-phenylenediamine-based compound is preferably used. Typical examples of the p-phenylenediamine-based compound are 3-methyl-4-amino-N,N-diethylaniline, 3-methyl-4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfonamidoethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methoxyethylaniline, and sulfates, hydrochlorides, and p-toluenesulfonates thereof. These compounds can be used in a combination of two or more thereof in accordance with applications.
In general, the color developer contains a pH buffering agent such as a carbonate, a borate or a phosphate of an alkali metal, and a development restrainer or antifoggant such as a bromide, an iodide, a benzimidazole, a benzothiazole or a mercapto compound. If necessary, the color developer may also contain a preservative such as hydroxylamine, diethylhydroxylamine, sulfite, a hydrazine, a phenylsemicarbazide, triethanolamine, a catechol sulfonic acid or a triethylenediamine(1,4-diazabicyclo[2,2,2]octane); an organic solvent such as ethyleneglycol or diethyleneglycol; a development accelerator such as benzylalcohol, polyethyleneglycol, a quaternary ammonium salt or an amine; a dye forming coupler; a competing coupler; a fogging agent such as sodium boron hydride; an auxiliary developing agent such as 1-phenyl-3-pyrazolidone; a viscosity imparting agent; and a chelating agent such as an aminopolycarboxylic acid, an aminopolyphosphonic acid, and alkylphosphonic acid or a phosphonocarboxylic acid. Examples of the chelating agent are ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, hydroxyethyliminodiacetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilo-N,N,N-trimethylenephosphonic acid, ethylenediamine-N,N,N',N'-tetramethylenephosphonic acid and ethylenediamine-di(o-hydroxyphenylacetic acid), and salts thereof.
In order to perform reversal development, black-and-white development is performed and then color development is performed. As a black-and-white developer, well-known black-and-white developing agents, e.g., a dihydroxybenzene such as hydroquinone, a 3-pyrazolidone such as 1-phenyl-3-pyrazolidone, and an aminophenol such as N-methyl-p-aminophenol can be used singly or in a combination of two or more thereof.
The pH of the color and black-and-white developers is generally 9 to 12. Although a replenishment amount of the developer depends on a color photographic light-sensitive material to be processed, it is generally 3 liters or less per m² of the light-sensitive material. The replenishment amount can be decreased to be 500 mℓ or less by decreasing a bromide ion concentration in a replenishing solution. In order to decrease the replenishment amount, a contact area of a processing tank with air is preferably decreased to prevent evaporation and oxidation of the solution upon contact with air. The replenishment amount can be decreased by using a means capable of suppressing an accumulation amount of bromide ions in the developer.
A color development time is normally set between 2 to 5 minutes. The processing time, however, can be shortened by setting a high temperature and a high pH and using the color developing agent at a high concentration.
The photographic emulsion layer is generally subjected to bleaching after color development. The bleaching may be performed either simultaneously with fixing (bleach-fixing) or independently thereof. In addition, in order to increase a processing speed, bleach-fixing may be performed after bleaching. Also, processing may be performed in a bleach-fixing bath having two continuous tanks, fixing may be performed before bleach-fixing, or bleaching may be performed after bleach-fixing, in accordance with applications. Examples of the bleaching agent are a compound of a multivalent metal such as iron (III), cobalt (III), chromium (VI) and copper (II); a peroxide; a quinone; and a nitro compound. Typical examples of the bleaching agent are a ferricyanide; a dichromate; an organic complex salt of iron (III) or cobalt (III), e.g., a complex salt of iron (III) or cobalt (III) with an aminopolycarboxylic acid such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, methyliminodiacetic acid, 1,3-diaminopropanetetraacetic acid, and glycoletherdiaminetetraacetic acid, or a complex salt of iron (III) or cobalt (III) with citric acid, tartaric acid or malic acid; a persulfate; a bromate; a permanganate; and a nitrobenzene. Of these compounds, an iron (III) complex salt of aminopolycarboxylic acid such as an iron (III) complex salt of ethylenediaminetetraacetic acid, and a persulfate are preferred because they can increase a processing speed and prevent an environmental contamination. The iron (III) complex salt of aminopolycarboxylic acid is effective in both the bleaching and bleach-fixing solutions. The pH of the bleaching or bleach-fixing solution using the iron (III) complex salt of aminopolycarboxylic acid is normally 5.5 to 8. In order to increase the processing speed, however, processing can be performed at a lower pH.
A bleaching accelerator can be used in the bleaching solution, the bleach-fixing solution and their pre-bath, if necessary. Effective examples of the bleaching accelerator are compounds having a mercapto group or a disulfide group described in, e.g., U.S. Patent 3,893,858, West German Patents 1,290,812 and 2,059,988, JP-A-53-32736, JP-A-53-57831, JP-A-53-37418, JP-A-53-72623, JP-A-53-95630, JP-A-53-95631, JP-A-53-104232, JP-A-53-124424, JP-A-53-141623, JP-A-53-28426, and RD. No. 17,129 (July, 1978); a thiazolidine derivative described in JP-A-50-140129; thiourea derivatives described in JP-B-45-8506, JP-A-52-20832, JP-A-53-32735, and U.S. Patent 3,706,561; an iodide described in West German Patent 1,127,715; polyoxyethylene compounds described in West German Patents 966,410 and 2,748,430; a polyamine compound described in JP-B-45-8836; compounds described in JP-A-49-42434, JP-A-49-59644, JP-A-53-94927, JP-A-54-35727, JP-A-55-26506, and JP-A-58-163940; and a bromine ion. Of these compounds, compounds having a mercapto group or a disulfide group are preferable since they have a great accelerating effect. In particular, compounds described in U.S. Patent 3,893,858, West German Patent 1,290,812, and JP-A-53-95630 are preferable. A compound described in U.S. Patent 4,552,834 is also preferable. These bleaching accelerators may be added in the light-sensitive material. These bleaching accelerators are effective especially in bleach-fixing of a photographic color light-sensitive material.
Examples of the fixing agent are a thiosulfate, a thiocyanate, a thioether-based compound, a thiourea and a large amount of an iodide. Of these compounds, a thiosulfate, especially, ammonium thiosulfate can be used in a widest range of applications. As a preservative of the bleach-fixing solution, a sulfite, a bisulfite or a carbonyl bisulfite adduct is preferred.
The photographic light-sensitive material of the present invention is normally subjected to washing and/or stabilizing steps after desilvering. An amount of water used in the washing step can be arbitrarily determined over a broad range in accordance with the properties (e.g., a property determined by used substance such as a coupler) of the light-sensitive material, the application of the material, the temperature of the water, the number of water tanks (the number of stages), a replenishing scheme representing a counter or forward current, and other conditions. The relationship between the amount of water and the number of water tanks in a multi-stage counter-current scheme can be obtained by a method described in "Journal of the Society of Motion Picture and Television Engineers", Vol. 64, pp. 248 - 253 (May, 1955).
According to the above-described multi-stage counter-current scheme, the amount of water used for washing can be greatly decreased. Since washing water stays in the tanks for a long period of time, however, bacteria multiply and floating substances may be undesirably attached to the light-sensitive material. In order to solve this problem in the process of the color photographic light-sensitive material of the present invention, a method of decreasing calcium and magnesium ions can be effectively utilized, as described in Japanese Patent Application No. 61-131632. In addition, a germicide such as an isothiazolone compound and cyabendazole described in JP-A-57-8542, a germicide of chlorine-series such as chlorinated sodium isocyanurate, and germicides such as benzotriazole described in Hiroshi Horiguchi, "Chemistry of Antibacterial and Antifungal Agents", Eiseigijutsu-kai ed., "Sterilization, Antibacterial, and Antifungal Techniques for Microorganisms", and Nippon Bokin Bokabi Gakkai ed., "Cyclopedia of Antibacterial and Antifungal Agents".
The pH of the water for washing the photographic light-sensitive material of the present invention is 4 to 9, and preferably 5 to 8. The water temperature and the washing time can vary in accordance with the properties and applications of the light-sensitive material. Normally, the washing time is 20 seconds to 10 minutes at a temperature of 15°C to 45°C, and preferably, 30 seconds to 5 minutes at 25°C to 40°C. The light-sensitive material of the present invention can be processed directly by a stabilizing agent in place of washing. All known methods described in JP-A-57-8543, JP-A-58-14834, and JP-A-60-220345 can be used in such stabilizing processing.
Stabilizing is sometimes performed subsequently to washing. An example is a stabilizing bath containing formalin and a surfactant to be used as a final bath of the photographic color light-sensitive material. Various chelating agents or antifungal agents can be added in the stabilizing bath.
An overflow solution produced upon replenishment of the washing and/or stablizing solution can be reused in another step such as a desilvering step.
The silver halide color light-sensitive material of the present invention may contain a color developing agent in order to simplify processing and increase a processing speed. For this purpose, various types of precursors of a color developing agent can be preferably used. Examples of the precursor are a compound of indoaniline-series described in U.S. Patent 3,342,597, a Shciff base type compound described in U.S. Patent 3,342,599 and RD. Nos. 14,850 and 15,159, an aldol compound described in RD. No. 13,924, a metal complex salt described in U.S. Patent 3,719,492, and a compound of urethane series described in JP-A-53-135,628.
The silver halide color light-sensitive material present invention may contain various 1-phenyl-3-pyrazolidones in order to accelerate color development, if necessary. Typical examples of the compound are described in JP-A-56-64339, JP-A-57-144547, and JP-A-58-115438.
Each processing solution in the present invention is used at a temperature of 10°C to 50°C. Although a normal processing temperature is 33°C to 38°C, processing may be accelerated at a high temperature to shorten a processing time, or image quality or stability of a processing solution may be improved at a lower temperature. In order to save silver for the light-sensitive material, processing using cobalt intensification or hydrogen peroxide intensification described in West German Patent No. 2,226,770 or U.S. Patent 3,674,499 may be performed.
The silver halide light-sensitive material of the present invention can also be applied to heat development light-sensitive materials described in, e.g., U.S. Patent 4,500,626, JP-A-60-133449, JP-A-59-218443, JP-A-61-238056, and EP 210,660A2.
When the light-sensitive material of the present invention is to be used in the form of a roll, it is preferably housed in a cartridge. A most general example of the cartridge is a currently used 135-format patrone. In addition, cartridges proposed in the following patents can be used.
The patents are unexamined Published Japanese Utility Model Application Nos. 58-67329, and 58-195236, JP-A-58-181035, JP-A-58-182634, JP-A-1-231045, JP-A-2-170156, JP-A-2-124564, Japanese Patent Application Nos. 1-21862, 1-25362, 1-30246, 1-20222, 1-21863, 1-37181, 1-33108, 1-85198, 1-172594, and 1-172595, and U.S. Patents 4,846,418, 4,848,693, 4,221,479, and 4,832,275.
Although the present invention will be described in more detail below by way of its examples, the present invention is not limited to these examples.

Example 1

In Example 1, emulsions using tabular grains will be described.

Preparation of emulsion A

21 g of inert gelatin and 7.0 g of potassium bromide were dissolved in 1.4 ℓ of distilled water, and 70 ml (cc) of an aqueous solution containing 12.0 g of silver nitrate and 70 ml (cc) of an aqueous solution containing 8.0 g of potassium bromide and 0.5 g of potassium iodide were simultaneously added by the double-jet method at predetermined flow rates over 45 seconds to the above solution under stirring at 50°C (1st addition). 220 g of a 10% aqueous solution of inert gelatin were added to the resultant solution, and the solution was heated up to 65°C. 30 minutes after the temperature reached 65°C, 434 ml (cc) of an aqueous solution containing 130 g of silver nitrate were added to the resultant solution over 35 minutes, while 700 ml (cc) of an aqueous solution containing 200 g of potassium bromide and 4.3 g of potassium iodide were added to maintain a pBr at 2.3 (2nd addition).
After the 2nd addition, 45 ml (cc) of a 1 N solution of potassium thiocyanate were added to the resultant solution. Two minutes after the addition, 317 ml (cc) of an aqueous solution containing 95 g of silver nitrate were added to the solution, while 700 cc of an aqueous solution containing 200 g of potassium bromide and 4.3 g of potassium iodide were added to maintain the pBr at 2.3 (3rd addition).
10 minutes after the addition, a desalting step was started. After the desalting step was finished, the resultant solution was redispersed and optimally gold·sulfur-sensitized at 60°C. After the chemical sensitization was finished, a dye A (to be described at the end of this Example) was added at a temperature of 40°C in an amount of 6 × 10^-4 mol per mol of silver nitrate.

Preparation of emulsion B

An emulsion B was prepared following the same procedures as for the emulsion A except that a thiosulfonic acid compound (1-5) listed in Table A below was added in an amount of 1 × 10^-4 mol per mol of silver nitrate at the time when 10 minutes had passed since the beginning of the 2nd addition in the emulsion A.

Preparation of emulsion C

An emulsion C was prepared following the same procedures as for the emulsion B except that the thiosulfonic acid compound was added at the time when 22 minutes had passed since the beginning of the 2nd addition in the emulsion B.

Preparation of emulsion D

An emulsion D was prepared following the same procedures as for the emulsion B except that the thiosulfonic acid compound was added at the same time that the 3rd addition was started in the emulsion B.

Preparation of emulsion E

An emulsion E was prepared following the same procedures as for the emulsion B except that the thiosulfonic acid compound was added at the time when 15 minutes had passed since the beginning of the 3rd addition in the emulsion B.

Preparation of emulsion F

An emulsion F was prepared following the same procedures as for the emulsion B except that the thiosulfonic acid compound was added at the time when 10 seconds had passed since the completion of the 3rd addition in the emulsion B.

Preparation of emulsion G

An emulsion G was prepared following the same procedures as for the emulsion B except that the same number of mols of hydrogen peroxide was added in place of the thiosulfonic acid compound in the emulsion B.

Preparation of emulsion H

An emulsion H was prepared following the same procedures as for the emulsion E except that the same number of mols of hydrogen peroxide was added in place of the thiosulfonic acid compound in the emulsion E.

Preparation of emulsion B-2

An emulsion B-2 was prepared by performing the following chemical sensitization after the desalting step was finished in the emulsion B. That is, the dye A was added in an amount of 6 × 10^-4 mol per mol of silver nitrate at 60°C, and gold·sulfur sensitization was optimally performed at 60°C, 20 minutes after the addition.

Preparation of emulsion F-2

An emulsion F-2 was prepared by performing the following chemical sensitization after the desalting step was finished in the emulsion F. That is, the dye A was added in an amount of 6 × 10^-4 mol per mol of silver nitrate at 60°C, and gold·sulfur sensitization was optimally performed at 60°C, 20 minutes after the addition.
Each of the above emulsions A to H, B-2, and F-2 comprised tabular grains having an average circle-equivalent diameter of 0.6 µm, an average aspect ratio of 5.5, and a variation coefficient of a circle-equivalent diameter of 19%.
Samples 101 to 108 coated with the emulsions A to H and samples 109 and 110 coated with the emulsions B-2 and F-2 were formed as follows.

Formation of sample 101

The following emulsion and protective layers were formed on a triacetylcellulose film support having an undercoating layer.

Formation of samples 102 to 110

Instead of the emulsion A used in the sample 101, samples 102 to 108 were formed by using the emulsions B to H, respectively, and samples 109 and 110 were formed by using the emulsions B-2 and F-2, respectively.
The samples 101 to 110 were subjected to sensitometry exposure (1/100s) ((1/100")) and the following color development.
The developed samples were subjected by density measurement by using a green filter. The obtained results of photographic properties are summarized in Table 1.
In addition, two sets of the samples, each set consisting of samples 101 to 110, were prepared and subjected to sensitometry exposure (1/100s) ((1/100")). One set of the samples was left to stand at a temperature of 30°C and a relative humidity of 60% for one month, and the other set was left to stand at a temperature of 40°C and a relative humidity of 60% for two weeks. Thereafter, these samples were subjected to the following color development and density measurement by using a green filter. The results are summarized in Table 1.
Of the above results of photographic properties, the sensitivity is represented by relative sensitivity assuming that the sensitivity (fog + optical density of 0.2) of the sample 101 is 100.

(Color Development Process Method)

The color development process was performed at 38°C in accordance with the following process steps.

Color development 2 min. 45 sec.

Bleaching 6 min. 30 sec.

Washing 2 min. 10 sec.

Fixing 4 min. 20 sec.

Washing 3 min. 15 sec.

Stabilization 1 min. 05 sec.
The processing solution compositions used in the respective steps were as follows.

Color development solution

Diethylenetriamine pentaacetic acid	1.0 g
1-hydroxyethylidene-1,1-diphosphonic acid	2.0 g
Sodium sulfite	4.0 g
Potassium carbonate	30.0 g
Potassium Bromide	1.4 g
Potassium Iodide	1.3 mg
Hydroxylamine sulfate	2.4 g
4-(N-ethyl-N-β-hydroxyethylamino)-2-methylanilinesulfate	4.5 g
Water to make	1.0 ℓ
pH	10.0

Bleaching solution

Fixing solution

Disodium Ethylenediaminetetraacetate	1.0 g
Sodium sulfite	4.0 g
Ammonium thiosulfate aqueous solution (70%)	175.0 mℓ
Sodium bisulfite	4.6 g
Water to make	1.0 ℓ
pH	6.6

Stabilizing solution

Formalin (40%)	2.0 mℓ
Polyoxyethylene-p-mononolylphenylether (average polymerization degree = 10)	0.3 ℓ
Water to make	1.0 ℓ

Table 1

	Immediately after exposure		Left to stand at 40°C and 60% for 2 weeks after exposure		Left to stand at 30°C and 60% for 1 month after exposure
	Fog	Sensitivity	Fog	Sensitivity	Fog	Sensitivity
Sample 101 (Comparative Example)	0.32	100	0.45	129	0.38	117
Sample 102 (Comparative Example)	0.12	82	0.15	68	0.13	62
Sample 103 (Comparative Example)	0.13	87	0.18	76	0.15	71
Sample 104 (Comp. Ex.)	0.15	95	0.20	89	0.18	85
Sample 105 (Comp. Ex.)	0.20	101	0.26	96	0.23	94
Sample 106 (Comp. Ex.)	0.21	110	0.27	114	0.24	112
Sample 107 (Comparative Example)	0.15	76	0.18	60	0.16	54
Sample 108 (Comp. Ex.)	0.25	93	0.31	85	0.28	81
Sample 109 (Comparative Example)	0.12	84	0.15	71	0.13	63
Sample 110 (Present Invention)	0.20	126	0.24	126	0.22	126

As is apparent from Table 1, each emulsion of the present invention had a high fog/sensitivity ratio (i.e., produced low fog) by an effect of the oxidizing agent for silver and did not increase the sensitivity but was stable during storage in which heat and humidity were applied after exposure.

Example 2

Silver iodobromide seed crystals A having a homogeneous halogen distribution structure and containing 6 mol% of silver iodide were prepared. The seed crystals A were octahedral regular grains having a sphere-equivalent diameter of 0.50 µm and had a variation coefficient indicating a size distribution of about 14%.
Silver iodiobromide containing 6 mol% of silver iodide was grown starting from the seed crystals A to obtain grains having a sphere-equivalent diameter of 1.4 µm, by means of controlled double jet method of flow rate-accelerated type, thereby preparing emulsion I.
This emulsion I was redispersed at 40°C after a normal desalting step.
Subsequently, the emulsion I was optimally gold·sulfur-sensitized. After this chemical sensitization, the dye A described in Example 1 was added to the emulsion I at 40°C in an amount of 2 × 10^-4 mol per mol of silver nitrate.
Emulsions J to P were formed following the same procedures as for the emulsion I except that the oxidizing agent for silver was added at timings as shown in the following Table 2 during grain formation.
In addition, an emulsion J-2 was prepared by changing the chemical sensitization of the emulsion J as follows. That is, after the redispersion, the dye A was added at 60°C in an amount of 2 × 10^-4 mol per mol of silver nitrate, and gold·sulfur sensitization was optimally performed at 60°C from the time when 20 minutes had passed since the addition.
An emulsion N-2 was prepared by changing the chemical sensitization of the emulsion N as described above.
Samples 201 to 208 coated with the emulsions I to P, respectively, and samples 209 and 210 coated with the emulsions J-2 and N-2, respectively, were formed as follows.

Formation of sample 201

Formation of samples 202 to 210

Instead of the emulsion used in the sample 201, samples 202 to 208 were formed by using the emulsions J to P, respectively, and samples 209 and 210 were formed by using the emulsions J-2 and N-2, respectively.
The samples 201 to 210 were subjected to sensitometry exposure (1/100s) ((1/100") and color development following the same procedures as in Example 1.
The developed samples were subjected to density measurement by using a green filter. The obtained results of photographic properties are summarized in Table 3.
In addition, another set of the samples 201 to 210 was subjected to sensitometry exposure (1/100s) ((1/100")) and left to stand at a temperature of 40°C and a relative humidity of 60% for one month. Thereafter, these samples were subjected to color development following the same procedures as in Example 1, and the developed samples were subjected to density measurement by using a green filter. The results are summarized in Table 3.
Of the results of photographic properties summarized in Table 3, the sensitivity is represented by relative sensitivity assuming that the sensitivity (fog + optical density of 0.2) of the sample 101 is 100.

As is apparent from Table 3, each emulsion comprising octahedral grains of the present invention had a high fog/sensitivity ratio (i.e., produced low fog) by an effect of the oxidizing agent for silver and did not increase the sensitivity but was stable during storage in which heat and humidity were applied after exposure.

Table 3

	Immediately after exposure		Left to stand at 40°C and 60% for 1 month after exposure
	Fog	Sensitivity	Fog	Sensitivity
Sample 201 (Comparative Example)	0.28	100	0.40	125
Sample 202 (Comparative Example)	0.18	92	0.23	65
Sample 203 (Comparative Example)	0.19	92	0.24	73
Sample 204 (Comp. Ex.)	0.21	95	0.26	92
Sample 205 (Comp. Ex.)	0.22	107	0.27	104
Sample 206 (Comp. Ex.)	0.22	110	0.27	110
Sample 207 (Comparative Example)	0.20	80	0.26	64
Sample 208 (Comp. Ex.)	0.24	102	0.30	95
Sample 209 (Comparative Example)	0.16	93	0.21	67
Sample 210 (Present Invention)	0.21	132	0.25	132

Example 3

Silver iodide seed crystals B having a homogeneous halogen distribution structure and containing 6 mol% of silver iodide were prepared. The seed crystals B were parallel double twinned crystal tabular grains having a sphere-equivalent diameter of 0.60 µm and had a variation coefficient of a sphere-equivalent diameter of 23% and an average aspect ratio of all grains of 9.5.
Silver iodobromide containing 23 mol% of silver iodide was grown starting from the seed crystals B to obtain grains having a sphere-equivalent diameter of 1.15 µm, by means of controlled double jet method of flow rate-accelerated type, thereby preparing emulsion Q. In the emulsion Q, a variation coefficient of a sphere-equivalent diameter was 18%, and an average aspect ratio of all grains was 7.0.
This emulsion Q was subjected to a normal desalting step and then redispersed at 40°C.
Subsequently, the emulsion Q was optimally gold°sulfur-sensitized at 60°C. After this chemical sensitization, spectral sensitizing dyes V, VI, and VII listed in Table B below were mixed in amounts of 3.5 × 10^-5 mol, 8 × 10^-5 mol, and 3 × 10^-4 mol, respectively, per mol of silver nitrate and added at 40°C.
Emulsions R to X were prepared following the same procedures as for the emulsion Q except that the oxidizing agent for silver was added at addition timings as shown in Table 4 during grain formation.
In addition, an emulsion R-2 was prepared by changing the chemical sensitization of the emulsion R as follows. That is, after the redispersion, the spectral sensitizing dyes V, VI, and VII were mixed in amounts of 3.5 × 10^-5 mol, 8 × 10^-5 mol, and 3 × 10^-4 mol, respectively, per mol of silver nitrate and added at 60°C. At the time when 20 minutes had passed since the addition, gold·sulfur sensitization was optimally performed at 60°C.
Emulsions U-2 and V-2 were prepared by changing the chemical sensitization of the emulsions U and V, respectively, as described above.
Samples 301 to 308 coated with the emulsions Q to X, respectively, and samples 309 to 311 coated with the emulsions R-2, U-2, and V-2, respectively, were formed to have the same compositions as those of the coated samples described in Example 2.
The samples 301 to 311 were subjected to sensitometry exposure (1/100s) ((1/100")) and color development following the same procedures as in Example 1.
The developed samples were subjected to density measurement by using a green filter. The obtained results of photographic properties are summarized in Table 5.
In addition, another set of the samples 301 to 308 was subjected to sensitometry exposure (1/100s) ((1/100")) and left to stand at a temperature of 40°C and a relative humidity of 60% for one month. Thereafter, these samples were subjected to color development following the same procedures as in Example 1, and the developed samples were subjected to density measurement by using a green filter. The results are summarized in Table 5.
Of the results of photographic properties summalized in Table 5, the sensitivity is represented by a relative sensitivity assuming that the sensitivity (fog + optical density of 0.2) of the sample 101 is 100.

As is apparent from Table 5, each emulsion of the present invention produced low fog by an effect of the oxidizing agent for silver and did not increase the sensitivity but was stable during storage in which heat and humidity were applied after exposure.

Table 5

	Immediately after exposure		Left to stand at 40°C and 60% for 1 month after exposure
	Fog	Sensitivity	Fog	Sensitivity
Sample 301 (Comparative Example)	0.25	100	0.42	135
Sample 302 (Comparative Example)	0.15	95	0.21	70
Sample 303 (Comparative Example)	0.17	95	0.23	75
Sample 304 (Comp. Ex.)	0.18	96	0.24	90
Sample 305 (Comp. Ex.)	0.20	100	0.25	95
Sample 306 (Comp. Ex.)	0.20	108	0.25	110
Sample 307 (Comparative Example)	0.14	90	0.20	69
Sample 308 (Comp. Ex.)	0.21	98	0.26	90
Sample 309 (Comparative Example)	0.15	96	0.20	72
Sample 310 (Present Invention)	0.19	120	0.24	118
Sample 311 (Present Invention)	0.19	134	0.24	134

Example 4

The following dye groups 1 to 3 were added at 40°C to the emulsions Q to X prepared in Example 3 which were chemically sensitized but not added with the spectral sensitizing dyes, thereby preparing red-, green-, and blue-sensitive emulsions.
Sensitizing dyes II to VII in the following dye groups 1 to 3 are listed in Table B below.

Dye group 1 (red-sensitive dye)

Sensitizing dye IX	5.4 × 10^-5 mol/mol Ag
Sensitizing dye II	1.4 × 10^-5 mol/mol Ag
Sensitizing dye III	2.4 × 10^-4 mol/mol Ag
Sensitizing dye IV	3.1 × 10^-5 mol/mol Ag

Dye group 2 (green-sensitive dye)

Sensitizing dye V	3.5 × 10^-5 mol/mol Ag
Sensitizing dye VI	8.0 × 10^-5 mol/mol Ag
Sensitizing dye VII	3.0 × 10^-4 mol/mol Ag

Dye group 3 (blue-sensitive dye)

Sensitizing dye VIII 2.2 × 10^-4 mol/mol Ag
The emulsions R-2, U-2, and V-2 prepared in Example 3 were obtained by adding the dye group 2 to the emulsions R, U, and V, respectively, prior to gold·sulfur sensitization.
The dyes to be added following the same procedures as in the chemical sensitization for the emulsions R-2, U-2, and V-2 were changed to those of the dye group 1, thereby preparing emulsions R-3, U-3, and V-3, respectively.
In addition, the dyes to be added following the same procedures as in the chemical sensitization for the emulsions R-2, U-2, and V-2 were changed to that of the dye group 3, thereby preparing emulsions R-4, U-4, and V-4, respectively.
Using these emulsions, layers having the following compositions were coated on an undercoated cellulose triacetate film support, thereby manufacturing a multilayered color light-sensitive material.

(Compositions of light-sensitive layers)

The coating amounts of a silver halide and colloidal silver are represented in units of g/m² of silver, those of a coupler, an additive, and gelatin are represented in units of g/m², and that of a sensitizing dye is represented by the number of mols per mol of the silver halide in the same layer.
The structural formulas of the compounds identified below by using symbols are listed in Table C below.

Layer 1: Antihalation layer

Black colloidal silver coating silver amount	0.2
Gelatin	2.2
UV-1	0.1
UV-2	0.2
Cpd-1	0.04
Cpd-2	0.02
Solv-1	0.30
Solv-2	0.01

Layer 2: Interlayer

Fine silver iodobromide grain (AgI = 1.0 mol%, sphere-equivalent diameter = 0.07 µm) coating silver amount	0.15
Gelatin	1.0
ExC-4	0.03
Cpd-3	0.2

Layer 3: 1st red-sensitive emulsion layer

Layer 4: 2nd red-sensitive emulsion layer

Silver iodobromide emulsion (AgI = 8.5 mol%, internally high AgI type, sphere-equivalent diameter = 1.0 µm, variation coefficient of sphere-equivalent diameter = 25%, tabular grain, diameter/thickness ratio = 3.0) coating silver amount	0.85
Gelatin	0.7
ExS-1	3 × 10^-4
ExS-2	1 × 10^-4
ExS-3	0.3 × 10^-4
ExC-1	0.10
ExC-2	0.05
ExC-4	0.025
Solve-1	0.10

Layer 5: 3rd red-sensitive emulsion layer

Silver iodobromide emulsion I coating silver amount	1.50
Gelatin	0.6
ExC-2	0.08
ExC-4	0.01
ExC-5	0.06
Solv-1	0.12
Solv-2	0.12

Layer 6: Interlayer

Layer 7: 1st green-sensitive emulsion layer

Silver iodobromide emulsion (AgI = 5.0 mol%, surface high AgI type, sphere-equivalent diameter = 0.9 µm, variation coefficient of sphere-equivalent diameter = 21%, tabular grain, diameter/thickness ratio = 7.0) coating silver amount	0.28
Silver iodobromide emulsion (AgI = 4.0 mol%, internally high AgI type, sphere-equivalent diameter = 0.4 µm, tetradecahedral grain, variation coefficient of sphere-equivalent diameter = 18%) coating silver amount	0.16
Gelatin	1.2
ExS-5	5 × 10^-4
ExS-6	2 × 10^-4
ExS-7	1 × 10^-4
ExM-1	0.50
ExM-2	0.10
ExM-5	0.03
Solv-1	0.2
Solv-4	0.03

Layer 8: 2nd green-sensitive emulsion layer

Layer 9: Interlayer

Gelatin 0.5

Solv-1 0.02

Layer 10: 3rd green-sensitive emulsion layer

Silver iodobromide emulsion II coating silver amount	1.3
Gelatin	0.8
ExM-4	0.04
ExC-4	0.005
ExM-6	0.01
Cpd-5	0.01
Solv-1	0.2

Layer 11: Yellow filter layer

Cpd-6	0.05
Gelatin	0.5
Solv-1	0.1

Layer 12: Interlayer

Gelatin 0.5

Cpd-3 0.1

Layer 13: 1st blue-sensitive emulsion layer

Silver iodobromide emulsion (AgI = 2 mol%, homogeneous iodide type, sphere-equivalent diameter = 0.55 µm, variation coefficient of sphere-equivalent diameter = 25%, tabular grain, diameter/thickness ratio = 7.0) coating silver amount	0.2
Gelatin	1.0
ExS-8	3 × 10^-4
ExY-1	0.6
ExY-2	0.02
Solv-1	0.15

Layer 14: 2nd blue-sensitive emulsion layer

Layer 15: Interlayer

Fine silver iodobromide grain (AgI = 2 mol%, homogeneous iodide type, sphere-equivalent diameter = 0.13 µm) coating silver amount	0.2
Gelatin	0.36

Layer 16: 3rd blue-sensitive emulsion layer

Silver iodobromide emulsion III coating silver amount	1.55
Gelatin	0.5
ExY-1	0.2
Solv-1	0.07

Layer 17: 1st protective layer

Gelatin	1.8
UV-1	0.1
UV-2	0.2
Solv-1	0.01
Solv-2	0.01

Layer 18: 2nd protective layer

Fine silver chloride grain (sphere-equivalent diameter = 0.07 µm) coating silver amount	0.36
Gelatin	0.7
Polymethylmethacrylate grain (diameter = 1.5 µm)	0.2
W-1	0.02
H-1	0.4
Cpd-7	1.0

In addition to the above additives, B-1 (0.20 g/m² in total), 1,2-benzisothiazoline-3-one (about 200 ppm on the average with respect to gelatin), n-butyl, p-hydroxybenzoate (about 1,000 ppm on the average with respect to gelatin), and 2-phenoxyethanol (about 10,000 ppm on the average with respect to gelatin) were added to the layers.

The silver iodobromide emulsions I, II, and III of the layers 5, 10 and 16 were prepared by adding any one of the dye groups 1 to 3 into any one of the emulsions Q to X prepared in Example 3, which emulsions Q to X were gold·sulfur sensitized but not mixed with spectral sensitizing dye. Samples 401 to 408 of multilayered color photographic light-sensitive materials listed in the following Table 6 were formed, by incorporating the emulsions I, II and III into the layers 5, 10 and 16 respectively. The table 6 shows combinations of the dye groups 1 to 3 and the emulsions Q to X, which are employed respectively in the emulsion I (layer 5), emulsion II (layer 10) and the emulsion III (layer 16) of the samples 401 to 408.

Table 6

Sample Name	Layer Name	Emulsion Name	Used Sensitizing Dye
Example 401 (Comparative Example)	Layer 5	Q	Dye group 1
	Layer 10	Q	" 2
	Layer 16	Q	" 3
Example 402 (Comparative Example)	Layer 5	R	Dye group 1
	Layer 10	R	" 2
	Layer 16	R	" 3
Example 403 (Comparative Example)	Layer 5	S	Dye group 1
	Layer 10	S	" 2
	Layer 16	S	" 3
Example 404 (Comp. Ex.)	Layer 5	T	Dye group 1
	Layer 10	T	" 2
	Layer 16	T	" 3
Example 405 (Comp. Ex.)	Layer 5	U	Dye group 1
	Layer 10	U	" 2
	Layer 16	U	" 3
Example 406 (Comp. Ex.)	Layer 5	V	Dye group 1
	Layer 10	V	" 2
	Layer 16	V	" 3
Example 407 (Comparative Example)	Layer 5	W	Dye group 1
	Layer 10	W	" 2
	Layer 16	W	" 3
Example 408 (Comp. Ex.)	Layer 5	X	Dye group 1
	Layer 10	X	" 2
	Layer 16	X	" 3

In addition, multilayered color photographic light-sensitive materials 409 to 411 were formed by incorporating the emulsions R-2, R-3, and R-4, U-2, U-3, and U-4, and V-2, V-3, and V-4, respectively, added with the dye groups 1 to 3 prior to gold·sulfur sensitization. Combinations of the dye groups 1 to 3 and the emulsions Q to X in that layers 5, 10 and 16 of samples 409 to 411 are summarized in the following Table 7.

Table 7

Sample Name	Layer Name	Emulsion Name	Used Sensitizing Dye
Example 409 (Comparative Example)	Layer 5	R-3	Dye group 1
	Layer 10	R-2	" 2
	Layer 16	R-4	" 3
Example 410 (Present Invention)	Layer 5	U-3	Dye group 1
	Layer 10	U-2	" 2
	Layer 16	U-4	" 3
Example 411 (Present Invention)	Layer 5	V-3	Dye group 1
	Layer 10	V-2	" 2
	Layer 16	V-4	" 3

These samples 401 to 411 were subjected to sensitometry exposure (1/100s) ((1/100)) and the following color development.
The developed samples were subjected to density measurement by using red, green, and blue filters.
In addition, another set of the samples 401 to 411 was subjected to sensitometry exposure (1/100s) ((1/100")) and left to stand at a temperature of 40°C and a relative humidity of 60% for one month. Thereafter, these samples were also subjected to the following color development.
The developed samples were subjected to density measurement by using red, green, and blue filters. Processing method
The color development process was performed at 38°C in accordance with the following process steps.

Color development 3 min. 15 s

Bleaching 6 min. 30 s

Wishing 2 min. 10 s

Fixing 4 min. 20 s

Washing 3 min. 15 s

Stabilization 1 min. 05 s
The processing solution compositions used in the respective steps were as follows.

Color development solution

Diethylenetriamine pentaacetic acid	1.0 g
1-hydroxyethylidene-1,1 diphosphonic acid	2.0 g
Sodium sulfite	4.0 g
Potassium carbonate	30.0 g
Potassium bromide	1.4 g
Potassium iodide	1.3 mg
Hydroxylamine sulfate	2.4 g
4-(N-ethyl-N-β-hydroxyethylamino)-2-methylanilinesulfate	4.5 g
Water to make	1.0 ℓ
pH	10.0

Bleaching solution

Ferric ammonium ethylenediaminetetraacetate	100.0 g
Disodium ethylenediaminetetraacetate	10.0 g
Ammonium bromide	150.0 g
Ammonium nitrate	10.0 g
Water to make	1.0 ℓ
pH	6.0

Fixing solution

Stabilizing solution

Formalin (40%)	2.0 mℓ
Polyoxyethylene-p-mononolylphenylether (average polymerization degree = 10)	0.3 g
Water to make	1.0 ℓ

The obtained results corresponded to the results obtained in Example 3, i.e., a light-sensitive material which produced low fog and did not increase the sensitivity but was stable during storage in which heat and humidity were applied after exposure was obtained in the multilayered color light-sensitive material using the emulsions T, U, V, and X of the present invention. In particular, the results obtained by the emulsion in which the spectral sensitizing dyes were present prior to gold·sulfur sensitization upon chemical sensitization corresponded to the results obtained in Example 3, and in that case particularly preferable results were obtained.

Example 5

The samples 401 to 408 and were used to conduct the experiment following entirely the same procedures as in Example 4 except for the processing method to be presented below. Color development was performed by using an automatic developing machine in accordance with the following method.

(Processing method)

Step	Time	Temperature
Color development	3 min. 15 s	38°C
Bleaching	1 min. 00 s	38°C
Bleach-fixing	3 min. 15 s	38°C
Washing (1)	40 s	35°C
Washing (2)	1 min. 00 s	35°C
Stabilization	40 s	38°C
Dry	1 min. 15 s	55°C

The processing solution compositions will be described below.

(Bleach-fixing solution)	(g)
Ferric ammonium ethylenediaminetetraacetate (dihydrate)	50.0
Disodium ethylenediaminetetraacetate	5.0
Sodium sulfite	12.0
Ammonium thiosulfate aqueous solution (70%)	240.0 mℓ
Ammonia water (27%)	6.0 mℓ
Water to make	1.0

(Washing solution)

Tap water was supplied to a mixed-bed column filled with an H type strongly acidic cation exchange resin (Amberlite IR-120B: available from Rohm & House Co.) and an OH type strongly basic anion exchange resin (Amberlite IR-400) to set the concentrations of calcium and magnesium to be 3 mg/ℓ or less. Subsequently, 20 mg/ℓ of dichlorinated sodium isocyanurate and 1.5 g/ℓ of sodium sulfate were added. The pH of the solution fell within the range of 6.5 to 7.5.

(Stabilizing solution)	(g)
Formalin (37%)	2.0 mℓ
Polyoxyethylene-p-monononylphenylether (average polymerization degree = 10)	0.3
Disodium ethylenediaminetetraacetate	0.05
Water to make	1.0 ℓ
pH	5.0 to 8.0

By the effect of the present invention, preferable results were obtained in also the above processing as in Example 4.

Example 6

The samples 401 to 408 were subjected to the experiments following the same procedures as in Example 4 and processed by using an automatic developing machine in accordance with the following method.

Processing method

Step	Time	Temperature
Color development	2 min. 30 s	40°C
Bleach-fixing	3 min. 00 s	40°C
Washing (1)	20 s	35°C
Washing (2)	20 s	35°C
Stabilization	20 s	35°C
Dry	50 s	65°C

The processing solution compositions will be described below.

(Washing solution)

Tap water was supplied to a mixed-bed column filled with an H type strongly acidic cation exchange resin (Amberlite IR-120B: available from Rohm & House Co.) and an OH type strongly basic anion exchange resin (Amberlite IR-400) to set the concentrations of calcium and magnesium to be 3 mg/ℓ or less. Subsequently, 20 mg/ℓ of dichlorinated sodium iocyamurate and 1.5 g/ℓ of sodium sulfate were added. The pH of the solution fell within the range of 6.5 to 7.5.

Claims

A process for preparing a silver iodobromide emulsion by adding an organic thiosulfonic acid derivative as an oxidizing agent for silver during the manufacture of said emulsion,
characterized by
adding at least said oxidizing agent after 50% of the water-soluble silver salt used in grain formation of the silver iodobromide emulsion are added and before chemical sensitization is performed, and

adding at least one spectral sensitizing dye prior to chemical sensitization, wherein

said organic thiosulfonic acid derivative is at least one selected from the compound represented by the formula (I) and polymers having as a repeating unit a divalent group derived from said compound having the formula (I):

R - SO₂ S - M (I)

wherein R represents an aliphatic group, an aromatic group or a heterocyclic group and M represents a cation.
A process according to claim 1, characterized in that R represents an alkyl group having 1 to 22 carbon atoms or an aryl group having 6 to 20 carbon atoms.
A process according to claim 1 or 2, characterized in that the addition amount of said oxidizing agent for silver per mol of silver salt is 10^-6 to 10^-2 mol.
A process according to any one of the claims 1 to 3 characterized in that oxidizing agent for silver is added after 80 to 100 % of water-soluble silver salt used in grain formation of the silver iodobromide emulsion are added.
A process according to any one of the claims 1 to 4 characterized in that said silver iodobromide grains are regular grains and a size distribution of said grains is monodispersed.
A process according to any one of the claims 1 to 5 characterized in that said silver iodobromide grains are tabular grains having aspect ratios of 3 or more.
A silver halide photographic light-sensitive material comprising a support and at least one silver halide emulsion layer formed on said support, wherein said emulsion layer contains at least one silver iodobromide emulsion prepared in accordance with the process of any one of the claims 1 to 6.