EP0368304B1

EP0368304B1 - Method of manufacturing silver halide photographic emulsion

Info

Publication number: EP0368304B1
Application number: EP19890120772
Authority: EP
Inventors: Mikio Fuji Photo Film Co. Ltd. Ihama; Yuuji Fuji Photo Film Co. Ltd. Kume; Hiroshi Fuji Photo Film Co. Ltd. Takehara
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1988-11-11
Filing date: 1989-11-09
Publication date: 1994-02-16
Anticipated expiration: 2009-11-09
Also published as: DE68913145D1; EP0368304A1

Description

The present invention relates to a method of manufacturing a silver halide photographic emulsion having a high sensitivity and a low fogging density, as well as a method of preparing a silver halide color light-sensitive material.
U.S. Patent 2,448,060 discloses that the sensitivity of an emulsion can be increased by adding a palladium compound and ascorbic acid to the emulsion after sulfur sensitization and before coating of the emulsion. U.S. Patent 2,598,079 discloses that especially the low-intensity sensitivity of an emulsion can be increased by adding a palladium compound to the emulsion after gold-plus-sulfur sensitization and before coating of the emulsion. U.S. Patents 2,472,627, 2,472,631, 2,566,245, and 2,566,263 disclose that the storage stability of a photosensitive material at high temperatures and high humidities can be improved by adding a palladium compound to the emulsion after chemical sensitization of the emulsion.
British Patent 1,351,309 discloses the addition of a noble metal salt in an amount of 3 x 10⁻⁷ to 3 x 10⁻⁵ mol per mol of silver halide during the formation of silver halide grains (during conversion).
U.S. Patent 4,092,171 discloses that a high sensitivity can be obtained and that the storage stability can be improved by adding an organic phosphinic acid complex of a palladium compound to an emulsion.
JP-A-61-67845 ("JP-A" means unexamined published Japanese patent application) discloses a method of manufacturing a silver halide emulsion, in which monodisperse core/shell type silver halide grains having different silver iodide contents in the portions near the surface and the inside thereof are chemically ripened in the presence of at least one member of a chalcogen sensitizer, a gold sensitizer, and a water-soluble palladium salt. JP-A-62-212641 discloses a method of manufacturing a silver halide emulsion, in which silver halide grains having an (nnl) face are chemically sensitized in the presence of at least one member of a chalcogen sensitizer, a gold sensitizer, and a compound of a Group VIII of the periodic table.
JP-A-48-87825 discloses that the sensitivity is increased while the gradation is reduced by adding a reducing agent in a process of forming silver halide grains. JP-B-58-1410 ("JP-B" means examined Japanese patent application) discloses that the sensitivity is increased without reducing the gradation by adding a reducing agent in a process of forming silver halide grains and then adding an oxidizing agent before the silver halide grains reach their final size.
It is the object of the present invention to provide a method of manufacturing a silver halide photographic emulsion and a silver halide color light-sensitive material emulsion with high sensitivity and low fogging density.
The above object is achieved by a method of manufacturing a silver halide photographic emulsion, wherein a palladium compound is added in an amount of 5 x 10⁻⁵ mol to 1 x 10⁻³ mol per mol of silver halide after a grain formation step and before a desalting step. The present invention also refers to a method of manufacturing a silver halide color light-sensitive material using the above prepared silver halide emulsion.
It is preferred to subject the silver halide grains to a reduction sensitization in the grain formation step.
The present invention will be described in detail below.
A process of manufacturing a silver halide emulsion is roughly divided into grain formation, desalting, chemical sensitization, and coating steps. The grain formation step is further classified into e.g. nucleation, ripening, and precipitation. These steps are not necessarily performed in the above-mentioned order. For example, grain formation and chemical sensitization are simultaneously performed, or chemical sensitization is repeatedly performed. "To add a palladium compound after a grain formation step and before a desalting step" means that the palladium compound is added during a time interval from the time at which the addition of the silver salt solution is completed in the grain formation step to the time at which the desalting step is started. That is, the palladium compound can be added simultaneously with completion of the addition of the silver salt solution or added at an arbitrary time after completion of the addition of the silver salt solution and before the desalting step. The total amount of the palladium compound can be added at once, can be divided and added several times, or can be continuously added over a predetermined time. The emulsion may be ripened after the addition of the palladium compound and before the desalting step or left to stand at a high temperature for a long time period after the addition of the palladium compound and before the desalting step.
In the present invention, the palladium compound is added in an amount of 5 x 10⁻⁵ mol to 1 x 10⁻³ mol per mol of silver halide. Preferably, the palladium compound is added in an amount of 1 x 10⁻⁴ mol to 5 x 10⁻⁴ mol per mol of silver halide. If the amount is less than 1 x 10⁻⁵ mol the effect of the present invention cannot be obtained. If the amount is more than 1 x 10⁻³ mol, other problems occurs.
In the present invention, a palladium compound means a divalent or tetravalent palladium salt. The palladium compound is preferably represented by R₂PdX₆ or R₂PdX₄ wherein R represents hydrogen, an alkali metal atom, or a ammonium group and X represents halogen, e.g., chlorine, bromine, or iodine. More specifically, K₂PdCℓ₄, (NH₄)₂PdCℓ₆, Na₂PdCℓ₄, or (NH₄)₂PdCℓ₄ is preferable. Although PdCℓ₂, PdCℓ₂·2H₂O, Pd(NH₃)₄Cℓ₂, (NH₃)₂PdCℓ₂, PdI₂, Pd(OH)₂, Pd(SO₄), Pd(NO₃)₂, Na₂Pd(NO₃)₄, or (NH₃)₂PdCℓ₄ can be used, a water-soluble palladium compound is preferable. Most preferably, these palladium compounds are used in combination with thiocyanate ions in a molar amount of not less than five times that of the palladium compound.
The conditions for adding the palladium compound are arbitrary. The temperature may be 30°C to 80°C, and preferably, 40°C to 70°C. The pH and the pAg may have arbitrary values. The pH is preferably 4 to 10.
In the present invention, the above palladium compound is most preferably added after groin formation of the silver halide grains, which have been subjected to a reduction sensitization in the groin formation step, and before the desalting step.
"Reduction sensitization is performed during the grain formation step of a silver halide emulsion" means that a reduction sensitization is performed during nucleation, ripening, or precipitation. Reduction sensitization may be performed during nucleation or physical ripening in the initial stage of grain formation, or during precipitation. Most preferably, the reduction sensitization is performed during precipitation of the silver halide grains. The method of performing the reduction sensitization during precipitation includes a method in which the reduction sensitization is performed while the silver halide grains are grown by physical ripening or addition of a water-soluble silver salt and a water-soluble alkali halide and a method in which the reduction sensitization is performed while the precipitation is temporarily stopped and then the grains are further precipitated.
In the present invention, the reduction sensitization can be selected from a method in which a known reducing agent is added to the silver halide emulsion, a method called "silver ripening" in which precipitation or ripening is performed in a low-pAg atmosphere at a pAg of 1 to 7, and a method called "high-pH ripening" in which precipitation or ripening is performed in a high-pH atmosphere at a pH of 8 to 11. Alternatively, these methods can be performed in a combination of two or more thereof.
A method of adding a reduction sensitizer is preferable since the level of reduction sensitization can be finely adjusted.
Known examples of reduction sensitizers are a stannous salt, amines and polyamines, a hydrazine derivative, formamidine sulfinic acid, a silane compound, and a borane compound. In the present invention, these known compounds can be used singly or in a combination of two or more thereof. Preferred reduction sensitizers are stannuous chloride, thiourea dioxide, and dimethylamineborane. The addition amount of the reduction sensitizer must be properly selected since it depends on the emulsion manufacturing conditions. The addition amount is preferably 10⁻⁸ to 10⁻³ mol per mol of silver halide. Ascorbic acid or its salts can be preferably used as a reduction sensitizer. In this case, this reduction sensitizer is used in an amount of 5 x 10⁻⁵ to x 10⁻¹, preferably 5 x 10⁻⁴ to 1 x 10⁻², and most preferably, 1 x 10⁻³ to 1 x 10⁻² mol per mol of silver halide.
The reduction sensitizer can be dissolved in water, alcohols, glycols, ketones, esters, and amides and then added during grain formation. Although the reduction sensitizer can be added in a reaction vessel beforehand, it is preferably added at an arbitrary time during grain formation. Alternatively, the reduction sensitizer may be added to an agueous solution of a water-soluble silver salt or water-soluble alkali halide, and grain formation may be performed by using these solutions. A method in which a solution of the reduction sensitizer is added several times or continuously added as grain formation progresses is also preferable.
The present inventors have studied in detail the effects of the addition timing and addition amount of a palladium compound on, e.g. the sensitivity and the fogging density of a prepared emulsion, and have found that the best results can be obtained when a predetermined amount or more of a palladium compound is added before the desalting step. Although a preferable effect can also be obtained when the palladium compound is added after the desalting step and before chemical sensitization, this effect is inferior to that obtained when the compound is added before the desalting step. More specifically, a preferable effect is obtained by a silver halide photographic emulsion manufactured by performing a reduction-sensitization in the grain formation step and chemical sensitization in the presence of a palladium compound in an amount of 1 x 10⁻⁴ mol or more per mol of silver halide. The reduction sensitization can be performed during nucleation or physical ripening in the initial stages of grain formation, and precipitation. Most preferably, the reduction sensitization is performed during precipitation of the silver halide grains. The terms "during precipitation" and "reduction sensitization" are defined as described above. The silver halide emulsion subjected to the reduction-sensitization is desalted and then chemically sensitized in the presence of a palladium compound in an amount of 1 x 10⁻⁴ mol or more per mol of a silver halide. More preferably, chemical sensitization is performed in the presence of 2 x 10⁻⁴ mol or more of the palladium compound. In this case, the upper limit is 5 x 10⁻³ mol. More preferably, chemical sensitization is performed in the presence of 1 x 10⁻³ mol or less of the palladium compound. Most preferably, chemical sensitization is performed by using, together with the palladium compound, thiocyanate ions in a molar amount of five times or more that of the palladium compound. In this case, the expression "chemical sensitization in the presence of a palladium compound" beans that a palladium compound is added and chemical sensitization at a high temperature is performed. Chemical sensitization is preferably performed at a temperature or 45°C or more, and more preferably, at 50°C or more. Chemical sensitization is preferably performed for five minutes or more, and more preferably, 10 to 120 minutes. In this chemical sensitization, a sulfur sensitization method using an active gelatin or a compound containing sulfur capable of reacting with silver (e.g., thiosulfate, thioureas, mercapto compounds, and rhodanines); a reduction sensitization method using a reducing agent (e.g., stannous salt, amines, a hydrazine derivative, formamidine sulfinic acid and a silane compound); and a noble metal sensitization method using a noble metal compound (e.g., gold complex salt and complex salts of Group VII metals of the periodic table, e.g., Pt and Ir), can be used singly or in a combination of two or more thereof. The most preferable method is a combination of sulfur sensitization and gold sensitization (this is also called "gold-plus-sulfur sensitization") or a combination of sulfur sensitization, reduction sensitization, and gold sensitization. Chemical sensitization in the presence of a palladium compound is performed within pH and pAg ranges to be described later.
Generally, a silver halide photographic emulsion which is desalted and then chemically sensitized in the presence of a palladium compound in an amount of 1 x 10⁻⁴ to 5 x 10⁻³ mol per mol of a silver halide can achieve a higher sensitivity and a lower fogging density than those of an emulsion to which no palladium compound is added. The sensitivity of this emulsion, however, tends to vary in accordance with sedimentation conditions in the desalting step. In addition, the resulting sensitivity of this emulsion is lower than that of an emulsion to which is added a palladium compound before the desalting step.
More preferably, at least one compound selected from compounds represented by formulae (I), (II), and (III) below is used in a process of manufacturing a silver halide emulsion subjected to reduction sensitization:

(I) R-SO₂S-M

(II) R-SO₂S-R¹

(III) RSO₂S-L_m-SSO₂-R²

wherein R, R¹, and R² may be the same or different and represent an aliphatic, aromatic, or heterocyclic group, M represents a cation, L represents a divalent bonding group, and m represents 0 or 1.
The compounds represented by formula (I), (II), or (III) may be a polymer containing a divalent group derived from a structure represented by formula (I), (II), or (III) as a repeating unit. If possible, R, R¹, R², and L may be bonded to form a ring.
The compounds represented by formulas (I), (II), and (III) will be described in more detail below. When each of R, R¹, and R² is an aliphatic group, it is a saturated or unsaturated, straight-chain, branched, or cyclic aliphatic hydrocarbon group, and preferably, alkyl having 1 to 22 carbon atoms or alkenyl or alkynyl having 2 to 22 carbon atoms. These groups may have a substituent group. Examples of the alkyl are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, isopropyl, and t-butyl.
Examples of the alkenyl are allyl and butenyl.
Examples of the alkynyl group are propargyl and butynyl.
An aromatic group of R, R¹, and R² is preferably a monocyclic or condensation ring aromatic group and preferably has 6 to 20 carbon atoms. Examples of such aromatic groups are phenyl and naphthyl. These groups can have a substituent group.
A heterocyclic group of R, R¹, and R² is a 3-to 15-membered ring having at least one element of nitrogen, oxygen, sulfur, selenium, and tellurium, and at least one carbon atom. Examples of the heterocyclic group are pyrrolidine, piperidine, pyridine, tetrahydrofuran, thiophene, oxazole, thiazole, imidazole, benzothiazole, benzoxazole, benzimidazole, selenazole, benzoselenazole, tellurazole, triazole, benzotriazole, tetrazole, oxadiazole, and thiadiazole.
Examples of the substituent group on R, R¹, and R² are alkyl (e.g., methyl, ethyl, and hexyl), alkoxy (e.g., methoxy, ethoxy, and octyloxy), aryl (e.g., phenyl, naphtyl, and tolyl), hydroxy, halogen (e.g., fluorine, chlorine, bromine, and iodine), aryloxy (phenoxy), alkylthio (methylthio and butylthio), arylthio (phenylthio), acyl (acetyl, propionyl, butyryl, and valeryl), sulfonyl (methyl sulfonyl and phenylsulfonyl), acylamino (e.g., acetylamino and benzoylamino), sulfonylamino (e.g., methanesulfonylamino and benzenesulfonylamino), acyloxy (e.g., acetoxy and benzoxy), carboxyl, cyano, sulfo, amino, -SO₂SM, and -SO₂R¹.
Examples of the divalent bonding group represented by L are an atom or atom group including at least one member selected from the group consisting of C, N, S, and O. More specifically, L is one or a combination of two or more of alkylene, alkenylene, alkinylene, arylene, -O-, -S-, -NH-, -CO-, and -SO₂-.
L is preferably a divalent aliphatic group or a divalent aromatic group. Examples of the divalent aliphatic group of L are

(n = 1 to 12), -CH₂-CH=CH-CH₂-, -CH₂C≡CCH₂-,

and a xylylene group. Examples of the divalent aromatic group of L are phenylene and napthylene.
These substituent groups may further have the above-mentioned substituent groups.
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 (e.g., tetraphenylphosphonium), and a guanidyl group.
When the compound represented by formula (I), (II), or (III) is a polymer, examples of its repeating unit are as follows.

These polymers may be a homopolymer or a copolymer with another copolymerizable monomer.
Examples of compounds represented by formula (I), (II), or (III) are listed in Table A.
The compounds represented by formula (I), (II), or (III) can be easily synthesized by methods described or cited in JP-A-54-1019; British Patent 972,211; "Journal of Organic Chemistry", Vol. 53, page 396 (1988); and "Chemical Abstracts", Vol. 59, 9766e.
The compound represented by formula (I), (II), or (III) is preferably added in an amount of 1 x 10⁻⁷ to 1 x 10⁻¹ mol per mol of silver halide. The addition amount is more preferably 1 x 10⁻⁶ to 1 x 10⁻² mol/molAg and most preferably 1 x 10⁻⁵ to 1 x 10⁻³ mol/molAg.
A conventional method of adding an additive in a photographic emulsion can be adopted to add the compounds represented by formulas (I) to (III) in a process of manufacturing silver halide emulsions. For example, a water-soluble compound can be added in the form of an aqueous solution having an arbitrary concentration, and a water-insoluble or water-retardant compound is dissolved in an arbitrary organic solvent such as alcohols, glycols, ketones, esters, and amides, which is miscible with water and does not adversely affect the photographic properties, and then added as a solution.
The compound represented by formula (I), (II), or (III) can be added at any time in a manufacturing process, e.g., during grain formation of the silver halide emulsion or before or after chemical sensitization. The compound is preferably added before or during reduction sensitization. Reduction sensitization is preferably performed in the presence of the thiosulfonic acid compound during the silver halide grain formation step.
Although the compound can be added in a reaction vessel beforehand, it is preferably added at an arbitrary time during grain formation. In addition, the compound represented by formula (I), (II), or (III) can be added in an aqueous solution of a water-soluble silver salt or water-soluble alkali halide to perform grain formation by using the aqueous solution. A method of adding a solution of the compound represented by formula (I), (II), or (III) several times or continuously adding it over a long time period during grain formation is also preferable.
The most preferable compound used in the present invention is represented by formula (I).
A silver halide of any of silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide, and silver chloride can be used in a photographic emulsion layer of the photographic light-sensitive material used in the present invention. The preferable silver halide is silver iodobromide, or silver chlorobromide containing 30 mol% or less of silver iodide, or silver bromide, or silver bromochloride.
The silver halide grains to be used in the present invention can be selected from regular crystals not including a twined crystal face and grains having twined crystals described in Japan Photographic Society ed., "Silver Salt Photographs, Basis of Photographic Industries", (Corona Co., P. 163) such as single twined crystals including one twined crystal face, parallel multiple twined crystals including two or more parallel twined crystal faces, and non-parallel multiple twined crystals including two or more non-parallel twined crystal faces in accordance with its application. In the case of regular crystals, cubic grains having (100) faces, octahedral grains having (111) faces, and dodecahedral grains having (110) faces disclosed in JP-B-55-42737 and JP-A-60-222842 can be used. In addition, grains having (hl1), e.g., (211) faces, grains having (hh1), e.g., (331) faces, grains having (hk0), e.g., (210) faces, and grains having (hk1), e.g., (321) faces as reported in "Journal of Imaging Science", Vol. 30 P. 247, 1986 can be selectively used in accordance with the application although the preparation method must be improved. Grains including two or more types of faces, e.g., tetradecahedral grains having both (100) and (111) faces, grains having both (100) and (110) faces, and grains having both (111) and (110) faces can be selectively used in accordance with the application.
The grains of the silver halide may be fine grains having a grain size of 0.1 µm or less or large grains having a projected surface area diameter of 10 µm. The emulsion may be a monodisperse emulsion having a narrow distribution or a polydisperse emulsion having a wide distribution.
A so-called monodisperse silver halide emulsion having a narrow size distribution, i.e., in which 80% or more (the number or weight of grains) of all grains fall within the range of ±30% of an average grain size, can be used in the present invention. In order to satisfy target gradation of the light-sensitive material, two or more types of monodisperse silver halide emulsions having different grain sizes can be coated in a single layer or overlapped in different layers in emulsion layers having substantially the same color sensitivity. Alternatively, two or more types of polydisperse silver halide emulsions or a combination of monodisperse and polydisperse emulsions can be mixed or overlapped.
The photographic emulsions 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, a single mixing method, a double jet method, or a combination thereof can be used. Also, a so-called back mixing method for 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 halide emulsion containing the above-described regular silver halide 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.
Tabular grains having an aspect ratio of 3 or more can also be used in the present invention. Tabular grains 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 tabular grains are used, covering power and a spectrally sensitizing efficiency of a sensitizing dye can be advantageously improved as described in detail in U.S. Patent 4,434,226.
Tabular grains are preferably used in the method of the present invention. In particular, tabular grains in which grains having aspect ratios of 3 to 8 occupy 50% or more of the total projected surface area are preferable.
In the silver halide emulsion for use in the present invention the crystal structure may be uniform, may have different halogen compositions inside and outside the 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, a silver halide having different compositions may be bonded by an epitaxial junction, or a compound other than silver halide such as silver rhodanate or zinc oxide may be bonded.
The silver halide emulsion prepared in the present invention preferably has a distribution or structure of a halogen composition in its grain. A typical example is a core-shell type or double structured grains having different halogen compositions in the interior and surface layer of the grains as disclosed in, e.g., JP-B-43-13162, JP-A-61-215540, JP-A-60-222845, and JP-A-61-75337. In such grains, the shape of the core portion is sometimes identical to or sometimes different from that of the entire grains with a shell. More specifically, while the core portion is cubic, the grains with a shell are sometimes cubic or sometimes octahedral. On the contrary, while the core portion is octahedral, the grains with a shell are sometimes cubic or sometimes octahedral. In addition, while the core portion is comprised of clear regular grains, the grains of the shell are sometimes slightly deformed or sometimes do 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 thin film of silver halide having a different composition can be formed on the surface of the core-shell double structure grains.
In order to give a structure inside the grains, grains having not only the above surrounding structure but a so-called junction structure can be made. Examples of such grains are disclosed in, e.g., JP-A-59-133540, JP-A-58-108526, EP 199290A2, JP-B-58-24772, and JP-A-59-16254. Crystals to be bonded having a composition different from that of the host crystals can be produced and bonded to an edge, corner, or face portion of the host crystals. Such junction crystals can be formed regardless of whether the host crystals have 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 halide. A non-silver salt compound such as PbO can also be used as long as the junction structure can be made.
In silver iodobromide grains having the above structure, e.g., in core-shell type grains, the silver iodide content may be high at the core portion and low at the shell portion or vice versa. Similiarly, in grains having the junction structure, the silver iodide content may be high in the host crystals and relatively low in the junction crystals or vice versa.
In grains having the above structure, the boundary portion between 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.
The silver halide emulsion for use in the present invention can be subjected to a treatment for rounding the grains as disclosed in, e.g., EP-0096727B1 and EP-0064412B1 or a treatment of modifying the surface of the grains as disclosed in DE-2306447C2 and JP-A-60-221320.
The silver halide emulsion for use in the present invention is preferably of a surface latent image type. An internal 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 the application.
A silver halide solvent can be effectively used to promote ripening. For example, in a known conventional method, an excessive amount of halogen ions is supplied in a reaction vessel in order to promote ripening. Therefore, it is apparent that ripening can be promoted by only supplying a silver halide solution into a reaction vessel. In addition, another ripening agent can be used. In this case, the total amount of these ripening agents can be mixed in a dispersion medium in the reaction vessel before a silver salt and a halide are added therein, or they can be added in the reaction vessel together with one or more halides, a silver salt or a deflocculant. Alternatively, the ripening agents can be added in separate steps together with a halide and a silver salt.
Examples of the ripening agent other than halide ions are ammonium, an amine compound and a thiocyanate such as an alkali metal thiocyanate, especially sodium or potassium thiocyanate and ammonium thiocyanate.
After the grain formation step is performed (after precipitation or physical ripening) and a palladium compound is added, removal of soluble salts (a desalting step) is performed. For this purpose, a conventional noodle washing method of gelling gelatin or flocculation utilizing inorganic salts consisting of multivalent anions such as sodium sulfate, an anionic surfactant, an anionic polymer (e.g., polystyrene sulfonic acid, or a gelatin derivative (e.g., aliphatic acylated gelatin, aromatic acylated gelatin, or aromatic carbamoylated gelatin) may be used.
An emulsion manufactured according to the method of the present invention is subjected to chemical sensitization after it is desalted. Chemical sensitization is preferably performed at 45°C or more, and more preferably, at 50°C or more. Chemical sensitization is preferably performed for five minutes or more, and more preferably for ten minutes or more. In this chemical sensitization, a sulfur sensitization method using active gelatin or a compound containing sulfur which can react with silver (e.g., thiosulfate, thioureas, mercapto compounds, and rhodanines); a selenium sensitization method; a reduction sensitization method using a reducing substance (e.g., a primary tin salt, amines, a hydrazine derivative, formamidine-sulfinic acid, and a silane compound); and a noble metal sensitization method using a noble metal compound (in addition to a gold complex salt, a complex salt of Pt or Ir) can be used singly or in a combination of two or more thereof. Of these methods, the sulfur sensitization method, the selenium sensitization method, or the sensitization method using a gold complex salt is preferably used singly or in a combination of two or more thereof to perform chemical sensitization.
In the present invention, the most preferable chemical sensitization is a combination of sulfur sensitization and gold sensitization (also called as gold-plus-sulfur sensitization). Chemical sensitization is performed at a pH of 4 or more, preferably, 5 or more, and most preferably 6 or 6.5 or more. The upper limit of the pH is 9 or less, and preferably, 8.5 or less.
Chemical sensitization is normally performed at a pAg of 6 to 10, and preferably, 7 to 9.
The photographic emulsion for use in the present invention can contain various compounds in order to prevent fogging during the 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 salts, nitroimidazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, and mercaptotetrazoles (especially, 1-phenyl-5-mercaptotetrazole); mercaptopyrimidines; mercaptotriadines; a thioketo compound such as oxadrinthione; azaindenes, e.g., triazaindenes, tetraazaindenes (especially, 4-hydroxy-substituted-(1,3,3a,7)tetraazaindenes), and pentaazaindenes. Examples are described in U.S. Patents 3,954,474 and 3,982,947 and JP-B-52-28660.
The photographic emulsion for use in the present invention can be spectrally sensitized with, e.g., methine dyes. Examples of the dyes are a cyanine dye, merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a hemicyanine dye, a styryl dye, and hemioxonol dye. The most effective dyes are a cyanine dye, a merocyanine dye, and a complex merocyanine dye. In these dyes, any nucleus normally used as a basic heterocyclic nucleus in cyanine dyes can be used. Examples of the nucleus are a 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 condensing an alicyclic hydrocarbon ring to each of the above nuclei; and a nucleus obtained by condensing an aromatic hydrocarbon ring to each of the above nuclei, e.g., an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxazole 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.
For a merocyanine dye or complex 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 time 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-A-58-113928, or added before completion of silver halide 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 time during silver halide grain formation.
The addition amount may be 4 x 10⁻⁶ to 1 x 10⁻² mol per mol of silver halide. More preferably, when the silver halide grain size is 0.2 to 1.2 µm, an addition amount of about 5 x 10⁻⁵ to 6 x 10⁻³ mol is more effective.
The above various additives are used in the light-sensitive material prepared in the present invention. In addition to the above additives, however, various additives can be used in accordance with applications.

Additives are described in Research Disclosures, Item 17643 (Dec. 1978) and Item 18716 (Nov. 1979) and they are summarized in the following table.

	Additives	RD No.17643	RD No.18716
1.	Chemical sensitizers	page 23	page 648, right column
2.	Sensitivity increasing agents		do
3.	Spectral sensitizers, super sensitizers	pages 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, ultraviolet 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 column	page 26	page 651, left
10.	Binder	page 26	do
11.	Plasticizers, lubricants	page 27	page 650, right column
12.	Coating aids, surface active agents	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 Research Disclosure, 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.
Preferred examples of magenta couplers are 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, Research Disclosure No. 24220 (June 1984), JP-A-60-33552, Research Disclosure No. 24230 (June 1984), JP-A-60-34659, 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 Research Disclosure 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. DIR couplers, i.e., couplers releasing a development inhibitor are described in the patents cited in the above-described Research Disclosure 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-59-157638 and JP-A-59-170840.
Examples of a coupler which can be used in the light-sensitive material prepared according to 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 or DIR coupler releasing couplers 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 released 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 ligand 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 materials 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 esters (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), phosphates or phosphonates (e.g., triphelphosphate, tricresylphosphate, 2-ethylhexyldiphenylphosphate, tricyclohexylphosphate, tri-2-ethylhexylphosphate, tridodecylphosphate, tributyoxyethylphosphate, trichloropropylphosphate, and di-2-ethylhexylphenylphosphonate), benzoates (e.g., 2-ethylhexylbenzoate, dodecylbenzoate, and 2-ethylhexyl-p-hydroxybenzoate), amides (e.g., N,N-diethyldodecaneamide, N,N-diethyllaurylamide, and N-tetradecylpyrrolidone), alcohols or phenols (e.g., isostearylalcohol and 2,4-di-tert-amylphenol), aliphatic carboxylates (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 hydrocarbons (e.g., paraffin, dodecylbenzene, and 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, cyclohexanone, 2-ethoxyethylacetate, and dimethylformamide.
Steps and effects of a latex dispersion method and examples of a loadable 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.
In a silver halide color light-sensitive material which comprises at least one blue-sensitive silver halide emulsion layer containing a yellow coupler, at least one green-sensitive silver halide emulsion layer containing a magenta coupler, and at least one red-sensitive silver halide emulsion layer containing a cyan coupler on a support, at least one of the emulsion layers contains a silver halide photographic emulsion manufactured by performing addition of palladium compound in amount of 5 x 10⁻⁵ mol to 1 x 10⁻³ mol per mol of silver halide after a grain formation step and before a desalting step.
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 to prepare a material for color photographing, 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-59-38147, 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 prepared by this invention can be processed by ordinary processes as described, for example, in 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 is preferably an aqueous alkaline solution containing an aromatic primary amine-based color developing agent as a main component. 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-methoxyehtylaniline, and sulfates, hydrochlorides and p-toluenesulfonates thereof. These compounds can be used in a combination of two or more thereof in accordance with the 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, a hydrazine sulfite, 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, an 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 the replenishment amount of the developer depends on the 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 less by decreasing the bromide ion concentration in the replenishing solution. In order to decrease the replenishment amount, the contact area of the 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.
The 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 the 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 an aminopolycarboxylic acid such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, methyliminodiacetic acid, and 1,3-diaminopropanetetraacetic acid, and glycoletherdiaminetetraacetic acid, or a complex salt of 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 the 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-53-28426, and Research Disclosure No. 17129 (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; iodide salts described in West German Patent 1,127,715 and JP-A-58-16235; 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 bromide ions. Of these compounds, the compound having a mercapto group or disulfide group is preferable because it has a significant accelerating effect. The most preferable compounds are those described in U.S. Patent 3,893,858, West German Patent 1,290,812, and JP-A-53-95630. 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 an ammonium thiosulfate, can be used in a wide 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 prepared by the present invention is normally subjected to washing and/or stabilizing steps after desilvering. The 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 an used material such as 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), the 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 present invention, a method of decreasing calcium and magnesium ions can be effectively utilized, as described in JP-A-61-131632. In addition, a germicide such as an isothiazolone compound and cyabendazole described in JP-A-57-8542, a chlorine-based germicide 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 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 can be processed directly by a stabilizing solution 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, further, subsequently to said washing. An example is a stabilizing bath containing formalin and a surface-active agent to be used as a final bath of the photographic color light-sensitive material. Various chelating agents or antifungal agents can also be added in the stabilizing bath.
An overflow solution produced upon washing and/or replenishment of the stabilizing solution can be reused in another step such as a desilvering step.
The silver halide color light-sensitive material prepared by the present invention may contain a color developing agent in order to simplify processing and increase the processing speed. For this purpose, various precursors of a color developing agent are preferably used. Examples of the precursor are an indoaniline-based compound described in U.S. Patent 3,342,597, Schiff base type compounds described in U.S. Patent 3,342,599, and Research Disclosure Nos. 14,850 and 15,159, an aldol compound described in RD No. 13,924, a metal salt complex described in U.S. Patent 3,719,492, and a urethane-based compound described in JP-A-53-135628.
The silver halide color light-sensitive material 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 the normal processing temperature is 33°C to 38°C, processing may be accelerated at a high temperature to shorten the 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 prepared according to the present invention can also be applied to thermal 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.
The present invention will be described in detail below by way of examples.

EXAMPLE 1

The present invention will be described below by comparing it with comparative examples.

Preparation Method of Em-A

1,000 mℓ of an aqueous solution containing 40 g of gelatin and 0.2 g of KBr were strongly stirred at 75°C. 208 mℓ of an aqueous silver nitrate solution (containing 1.46 g of AgNO₃) and 208 mℓ of an aqueous KBr solution (containing 1.1 g of KBr) were simultaneously added to the resultant solution over 17 minutes. The silver potential of the resultant solution was adjusted to -25 mV with respect to a saturated calomel electrode, and 0.6 mg of thiourea dioxide were added in the form of an aqueous solution. Thereafter, 471 mℓ of an aqueous silver nitrate solution (containing 94.2 g of AgNO₃) and an aqueous KBr solution (KBr = 14.6 wt%) were simultaneously added to the resultant solution over 33 minutes. In this addition, the flow rates of the aqueous silver nitrate solution were adjusted to 1 mℓ/min and 19 mℓ/min at the initial and final stages, respectively, maintaining the silver potential of the reaction solution at -25 mV. After addition, the resultant solution was ripened for 10 minutes and then desalted by a flocculation method. 43 g of gelatin were added, the pH was adjusted to 6.9 and pAg was adjusted to 8.0 at 40°C, thereby obtaining a yield of 700 g. 3.0 x 10⁻³ mol/molAg of potassium thiocyanate, 3.0 x 10⁻⁵ mol/molAg of sodium thiosulfate, and 1.2 x 10⁻⁶ mol/molAg of potassium chloroaurate were added and the mixture was stirred at 60°C for 40 minutes to perform chemical sensitization, thereby preparing Em-A. The prepared emulsion consisted of monodisperse octahedral grains having an average circle-equivalent diameter of 0.60 µm and a variation coefficient of a circle-equivalent diameter of 9%.

Preparation Method of Em-B

Em-B was prepared following the same procedures as for Em-A except that 4 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ₄ and 2 x 10⁻³ mol/molAg of potassium thiocyanate were added over three minutes from 20 minutes after addition of the aqueous silver nitrate solution at the second stage was started to 10 minutes before it was finished.

Preparation Method of Em-C

Em-C was prepared following the same procedures as for Em-A except that 4 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ₄ and 2 x 10⁻³ mol/molAg of pottasium thiocyanate were added 10 minutes before a chemical sensitizer was added in chemical sensitization.

Preparation Method of Em-D

Em-A was dissolved at 40°C, and 4 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ₄ and 2 x 10⁻³ mol/molAg of potassium thiocyanate were added to the solution. The resultant mixture was stirred for 30 minutes to prepare Em-D.

Preparation Method of Em-E

Em-E was prepared following the same procedures as for Em-A except that 4 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ₄ and 2 x 10⁻³ mol/molAg of potassium thiocyanate were added two minutes after addition of the aqueous silver nitrate solution at the second stage was finished and stirred for eight minutes, and then the solution mixture was desalted by a flocculation method.

Preparation Method of Em-F

Em-F was prepared following the same procedures as for Em-A except that 4 x 10⁻⁴ mol/molAg of (NH₄)₂Cℓ₄ and 2 x 10⁻³ mol/molAg of potassium thiocyanate were added immediately before desalting was performed by the flocculation method.
Emulsion layer of Em-A to Em-F and protective layer were coated in amounts as listed in Table 1 on triacetylcellulose film supports having undercoating layers, thereby preparing samples.
These samples were left to stand at a temperature of 40°C and a relative humidity of 70% for 14 hours and exposed for 1/100 seconds through a continuous wedge, thereby performing the following color development.
Densities of the developed samples were measured using a green filter.

Processing Method

Process	Time	Temperature
Color Development	2 min 00 sec	40°C
Bleach-Fixing	3 min 00 sec	40°C
Washing (1)	20 sec	35°C
Washing (2)	20 sec	35°C
Stabilizing	20 sec	35°C
Dry	50 sec	65°C

The processing solution compositions will be described below.

Color Developing Solution:	(g)
Diethylenetriaminepentaacetic Acid	2.0
1-Hydroxyethylidene-1,1-diphosphonic Acid	3.0
Sodium Sulfite	4.0
Potassium Carbonate	30.0
Potassium Bromide	1.4
Potassium Iodide	1.5 mg
Hydroxylamine Sulfate	2.4
4-(N-Ethyl-N-β-hydroxyethylamino)-2-methylaniline Sulfate	4.5
Water to make	1.0 ℓ
pH	10.05

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 & Haas Co.) and an OH type 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 sodium dichloroisocyanurate 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

The sensitivity is represented by the relative value of the reciprocal of the exposure amount in units of lux/sec at a fogging density of 0.2.
The results are summerized in Table 2.
As is apparent from Table 2, a high sensitivity was realized at a low fogging density only when a palladium compound was added after the grain formation step and before the desalting step in accordance with the present invention. When the palladium compound was added during grain formation (Em-B), no image could be obtained.

Processes for preparing Em-A and Em-E were repeated three times to prepare Em-A₁, Em-A₂, and Em-A₃ and Em-E₁, Em-E₂, and Em-E₃, respectively. These emulsions were coated, exposed, and developed following the same procedures as described above, thereby obtaining the results shown in Table 3.

Table 3

Comparison of Sensitivity/Fogging Density of Em-A to Em-E
Emulsion No.	Relative Sensitivity	Fogging Density
Em-A₁	105	0.58
Em-A₂	112	0.52
Em-A₃	95	0.82
Em-E₁	135	0.18
Em-E₂	135	0.20
Em-E₃	141	0.18

As is apparent from Table 3, the repeating reproducibility of an emulsion was significantly improved when the palladium compound was added after the grain formation step and before the desalting step in accordance with the present invention. That is, the manufacture of the silver halide photographic emulsion was stabilized.

Em-C₁, Em-C₂, Em-E₄, and Em-E₅ were prepared following the same procedures as for Em-C and Em-E, respectively, except that the time required for flocculation was changed. These emulsions were coated, exposed, and developed following the same procedures as described above, thereby obtaining the results shown in Table 4.

Table 4

Comparison of Sensitivity/Fogging Density of Em-C to Em-E
Emulsion No.	Time Required for Flocculation	Relative Sensitivity	Fogging Density
Em-C₁	Short	132	0.38
Em-C₂	Long	118	0.33
Em-E₄	Short	135	0.18
Em-E₅	Long	135	0.18

As is apparent from Table 4, the reproducibility of the emulsion was significantly improved regardless of the flocculation time when the palladium compound was added after the grain formation step and before the desalting step in accordance with the present invention. That is, a stable method of manufacturing a silver halide photographic emulsion was achieved.

EXAMPLE 2

A palladium compound addition amount dependency of emulsion will be described below.

Preparation Method of Em-G

An aqueous solution containing gelatin and KBr was maintained at 40°C, and an aqueous silver nitrate solution (containing 32.7 g of AgNO₃) and a halogen solution (containing 24.9 g of KBr and 1.3 g of KI) were added to the solution over four minutes under constant stirring. After an aqueous solution containing KBr and gelatin was added, the resultant mixture was heated up to 70°C, and an aqueous solution containing 6 mg of dimethylamineborane and an aqueous solution containing 100 mg of compound 1-2 listed in Table A were simultaneously added. Thereafter, an aqueous silver nitrate solution (containing 152.3 g of AgNO₃) and an aqueous halogen solution (containing 5.3 wt% of KI with respect to KBr) were added over 32.1 minutes. In this addition, the silver potential of the reaction solution was maintained at 0 mV with respect to a saturated calomel electrode. Thereafter, an aqueous silver nitrate solution (containing 7.2 g AgNO₃) and an aqueous NaCℓ solution (containing 6.7 g of NaCℓ) were added over 1.5 minutes. The resultant mixture was desalted by a flocculation method five minutes after the addition was finished. Gelatin was added and the pH was adjusted to 6.9 and the pAg was adjusted to 8.0 at 40°C. This emulsion consisted of tabular grains having an average thickness of 0.13 µm, an average circle-equivalent diameter of 0.68 µm, a variation coefficient of a circle-equivalent diameter of 28%, and an aspect ratio of 5.2.
1.40 x 10⁻³ mol/molAg of a sensitizing dye A below were added to the above emulsion:

Sensitizing Dye A

Thereafter, 3.0 x 10⁻³ mol/molAg of potassium thiocyanate, 4.8 x 10⁻⁵ mol/molAg of sodium thiosulfate, and 1.0 x 10⁻⁶ mol/molAg of potassium chloroaurate were added at 64°C and stirred for 40 minutes. 5 x 10⁻⁴ mol/molAg of an antifoggant A below were added, and the resultant mixture was cooled, thereby preparing Em-G:

Antifoggant A

Preparation Method of Em-H

Em-H was prepared following the same procedures as for Em-G except that 1 x 10⁻⁵ mol/molAg of (NH₄)₂PdCℓ₄ and 5 x 10⁻⁵ mol/molAg of potassium thiocyanate were added 30 seconds after addition of silver nitrate was finished, and the resultant mixture was stirred for five minutes and desalted by the flocculation method.

Preparation Method of Em-I

Em-I was prepared following the same procedures as for Em-G except that 5 x 10⁻⁵ mol/molAg of (NH₄)₂PdCℓ₄ and 2.5 x 10⁻⁴ mol/molAg of potassium thiocyanate were added 30 seconds after addition of silver nitrate was finished, and the resultant mixture was stirred for five minutes and desalted by the flocculation method.

Preparation Method of Em-J

Em-J was prepared following the same procedures as for Em-G except that 1 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ₄ and 5 x 10⁻⁴ mol/molAg of potassium thiocyanate were added 30 seconds after addition of silver nitrate was finished, and the resultant mixture was stirred for five minutes and desalted by the flocculation method.

Preparation Method of Em-K

Em-K was prepared following the same procedures as for Em-G except that 4 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ and 2 x 10⁻³ mol/molAg of potassium thiocyanate were added 30 seconds after addition of silver nitrate was finished, and the resultant mixture was stirred for five minutes and desalted by the flocculation method.

Preparation Method of Em-L

Em-L was prepared following the same procedures as for Em-I except that 5 x 10⁻⁴ mol/molAg of (NH₄)₂PdCℓ₄ and 2.5 x 10⁻³ mol/molAg of potassium thiocyanate were added ten minutes before the chemical sensitizer was added in chemical sensitization.
A coating aid and a hardener were added to Em-G to Em-L and the resultants were coated on cellulose film bases in a Ag coating amount of 2 g/m². Each coated emulsion was exposed for one second through a continuous wedge to a tungsten electric lamp (color temperature = 2,854 K). The exposed coated emulsion was developed at 20°C for ten minutes by using the following surface developer (MAA-1).

Metol 2.5 g

d-ascorbic Acid 10.0 g

Potassium Bromide 1.0 g

Navox 35.0 g

Water to make 1,000 mℓ

The sensitivity of an obtained emulsion is represented by the relative value of the reciprocal of the exposure amount required to obtain an optical density of a fogging density plus 0.1.

The obtained results are summerized in Table 5.

Table 5

Comparison of Sensitivity/Fogging Density of Em-G to Em-L
Emulsion No.	Remarks	Addition Amount of Palladium Compound (mol/molAg)	Relative Sensitivity	Fogging Density
Em-G	Comparative Example	0	100	0.18
Em-H	Comparative Example	1 x 10⁻⁵	105	0.16
Em-I	Present Invention	5 x 10⁻⁵	115	0.10
Em-J	Present Invention	1 x 10⁻⁴	117	0.06
Em-K	Present Invention	4 x 10⁻⁴	132	0.03
Em-L	Present Invention	5 x 10⁻⁵ and 5 x 10⁻⁴ upon Chemical Sensitization	120	0.06

As is apparent from Table 5, a high sensitivity was obtained at a low fogging density when a palladium compound was added in an amount of 5 x 10⁻⁵ mol or more per mol of silver halide after the grain formation step and before the desalting step.

EXAMPLE 3

The effects of an emulsion of the present invention in a multilayered color light-sensitive material will be described below.
Layers having the following compositions were formed on an undercoated triacetylcellulose film support, thereby preparing a sample as a multilayered color light-sensitive material.

(Compositions of Light-Sensitive Layers)

The coating amount of a silver halide and colloid silver are represented in units of g/m² of silver, that of couplers, additives, and gelatin is represented in units of g/m², and that of a sensitizing dye is represented by the number of mols per mol of silver halide in the same layer. Symbols representing additives have the following meanings. Note that if an additive has a plurality of effects, only one of the effects is shown.

UV; ultraviolet absorbent, Solv; high-boiling organic solvent, ExF; dye, ExS; sensitizing dye, ExC; cyan coupler, ExM; magenta coupler, ExY; yellow coupler, and Cpd; additive

Layer 1: Antihalation Layer
Black Colloid Silver	0.15
Gelatin	2.9
UV-1	0.03
UV-2	0.06
UV-3	0.07
Solv-2	0.08
ExF-1	0.01
ExF-2	0.01

Layer 2: Low-Speed Red-Sensitive Emulsion Layer
Silver Iodobromide Emulsion (AgI = 4 mol%, homogeneous AgI type, circle-equivalent diameter = 0.6 µm, thickness = 0.2 µm, variation coefficient of circle-equivalent diameter = 37%, tabular grain, diameter/thickness ratio = 3.0) coating silver amount	0.4
Gelatin	0.8
ExS-1	6.9 x 10⁻⁴
ExS-2	5.2 x 10⁻⁴
ExS-5	6.9 x 10⁻⁴
ExS-7	2.4 x 10⁻⁵
ExC-1	0.17
ExC-2	0.03
ExC-3	0.13

Layer 3: Medium-Speed Red-Sensitive Emulsion Layer
Silver Iodobromide Emulsion (AgI = 6 mol%, internally high AgI type having core/shell ratio of 2 : 1, sphere-equivalent diameter = 0.65 µm, variation coefficient of sphere-equivalent diameter = 25%, tabular grain, diameter/thickness ratio = 2.0) coating silver amount	0.65
Silver Iodobromide Emulsion (AgI = 4 mol%, homogeneous AgI type, sphere-equivalent diameter = 0.4 µm, variation coefficient of sphere-equivalent diameter = 37%, tabular grain, diameter/thickness ratio = 2.0) coating silver amount	0.1
Gelatin	1.0
ExS-1	2 x 10⁻⁴
ExS-2	1.2 x 10⁻⁴
ExS-5	2 x 10⁻⁴
ExS-7	7 x 10⁻⁶
ExC-1	0.31
ExC-2	0.01
ExC-3	0.06

Layer 4: High-Speed Red-Sensitivity Emulsion Layer
Silver Iodobromide Emulsion I (internally high AgI type having core/shell ratio of 2 : 1, sphere-equivalent diameter = 0.7 µm, variation coefficient of sphere-equivalent diameter = 25%, tabular grain, diameter/thickness ratio = 2.5) coating silver amount	0.9
Gelatin	0.8
ExS-1	1.6 x 10⁻⁴
ExS-2	1.6 x 10⁻⁴
ExS-5	1.6 x 10⁻⁴
ExS-7	6 x 10⁻⁴
ExC-1	0.07
ExC-4	0.05
Solv-1	0.07
Solv-2	0.20
Cpd-7	4.6 x 10⁻⁴

Layer 5: Interlayer
Gelatin	0.6
UV-4	0.03
UV-5	0.04
Cpd-1	0.1
Polyethylacrylate Latex	0.08
Solv-1	0.05

Layer 6: Low-Speed Green-Sensitive Emulsion Layer
Silver Iodobromide Emulsion (AgI = 4 mol%, homogeneous AgI type, sphere-equivalent diameter = 0.4 µm, variation coefficient of sphere equivalent diameter = 37%, tabular grain, diameter/thickness ratio = 2.0) coating silver amount	0.18
Gelatin	0.4
ExS-3	2 x 10⁻⁴
ExS-4	7 x 10⁻⁴
ExS-5	1 x 10⁻⁴
EXM-5	0.11
ExM-7	0.03
ExY-8	0.01
Solv-1	0.09
Solv-4	0.01

Layer 7: Medium-Speed Green-Sensitive Emulsion Layer
Silver Iodobromide Emulsion (AgI = 4 mol%, surface high AgI type having core/shell ratio of 1 : 1, circle-equivalent diameter = 1.0 µm, thickness = 0.2 µm, variation coefficient of circle-equivalent diameter = 15%, tabular grain, diameter/thickness ratio = 5.0) coating silver amount	0.27
Gelatin	0.6
ExS-3	4 x 10⁻⁴
ExS-4	1.4 x 10⁻³
ExS-5	2 x 10⁻⁴
ExM-5	0.17
ExM-7	0.04
ExY-8	0.02
Solv-1	0.14
Solv-4	0.02

Layer 8: High-Speed Green-Sensitive Emulsion Layer
Silver Iodobromide Emulsion (AgI = 8.7 mol%, multilayered structure grain having silver ratio of 3 : 4 : 2 from inside, AgI contents = 24, 0, and 3 mol% from inside, sphere-equivalent diameter = 0.7 µm variation coefficient of sphere-equivalent diameter = 25%, tabular grain, diameter/thickness ratio = 1.6) coating silver amount	0.7
Gelatin	0.8
ExS-4	5.2 x 10⁻⁴
ExS-5	1 x 10⁻⁴
ExS-8	0.3 x 10⁻⁴
ExM-5	0.1
ExM-6	0.03
ExY-8	0.02
ExC-1	0.02
ExC-4	0.01
Solv-1	0.25
Solv-2	0.06
Solv-4	0.01
Cpd-7	1 x 10⁻⁴

Layer 9: Interlayer
Gelatin	0.6
Cpd-1	0.04
Polyethylacrylate Latex	0.12
Solv-1	0.02

Layer 10: Donor Layer having Interlayer Effect on Red-Sensitive Layer
Silver Iodobromide Emulsion (AgI = 6 mol%, internally high AgI type having core/shell ratio of 2 : 1, sphere-equivalent diameter = 0.7 µm, variation coefficient of sphere-equivalent diameter = 25%, tabular grain, diameter/thickness ratio = 2.0) coating silver amount	0.68
Silver Iodobromide Emulsion (AgI = 4 mol%, homogeneous AgI type, sphere-equivalent diameter = 0.4 µm, variation coefficient of sphere-equivalent diameter = 37%, tabular grain, diameter/thickness ratio = 2.5) coating silver amount	0.19
Gelatin	1.0
ExS-3	6 x 10⁻⁴
ExM-10	0.19
Solv-1	0.20

Layer 11: Yellow Filter Layer
Yellow Colloid Silver	0.06
Gelatin	0.8
Cpd-2	0.13
Solv-1	0.13
Cpd-1	0.07
Cpd-6	0.002
H-1	0.13

Layer 12: Low-Speed Blue-Sensitive Emulsion Layer
Em-G to Em-L coating silver amount	0.45
Gelatin	1.8
ExC-1	0.06
ExC-4	0.03
ExY-9	0.14
ExY-11	0.89
Solv-1	0.42

Layer 13: Interlayer
Gelatin	0.7
ExY-12	0.20
Solv-1	0.34

Layer 14: High-Speed Blue-Sensitive Emulsion Layer
Silver Chloroiodobromide Emulsion (AgI = 10 mol%, internally high AgI type, AgCℓ = 7 mol%, inner shell AgCℓ type, circle-equivalent diameter = 2.0 µm, thickness = 0.3 µm, variation coefficient of circle-equivalent diameter = 30%, tabular grain, diameter/thickness ratio = 7.0) coating silver amount	0.5
Gelatin	0.5
ExS-6	7 x 10⁻⁴
ExY-9	0.01
ExY-11	0.20
ExC-1	0.02
Solv-1	0.10

Layer 15: 1st Protective Layer
Fine Grain Silver Bromide Emulsion (AgI = 2 mol%, homogeneous AgI type, sphere-equivalent diameter = 0.07 µm) coating silver amount	0.12
Gelatin	0.9
UV-4	0.11
UV-5	0.16
Solv-5	0.02
H-1	0.13
Cpd-5	0.10
Polyethylacrylate Latex	0.09

Layer 16: 2nd Protective Layer
Fine Grain Silver Iodobromide Emulsion (AgI = 2 mol%, homogenous AgI type, sphere-equivalent diameter = 0.07 µm) coating silver amount	0.36
Gelatin	0.55
Polymethylmethacrylate Grain (diameter = 1.5 µm)	0.2
H-1	0.17

In addition to the above components, a stabilizer for emulsion Cpd-3 (0.07 g/m²) and a surfactant Cpd-4 (0.03 g/m²) were added as coating aids to each layer.
In addition, SPC-1 and SPC-2 were added in order to stabilize processing properties and film physical properties. Formulas of the used compounds are listed in Table B.
Samples in which Em-G, Em-H, Em-I, Em-J, Em-K, and Em-L prepared in Example 2 were used in the layer 12, are designated samples 301, 302, 303, 304, 305, and 306, respectively.

The samples of color photographic light-sensitive materials 301 to 306 as described above were exposed and processed (until the accumulated replenishing amount of a bleaching solution became three times the capacity of the mother solution tank) by using an automatic developing machine in accordance with the following method.

Processing Method
Process	Time	Temperature	Replenishing* Amount	Tank Volume
Color Development	3 min 15 sec	38°C	15 mℓ	20 ℓ
Bleaching	6 min 30 sec	38°C	10 mℓ	40 ℓ
Washing	2 min 10 sec	35°C	10 mℓ	20 ℓ
Fixing	4 min 20 sec	38°C	20 mℓ	30 ℓ
Washing (1)	1 min 05 sec	35°C	Counter flow piping from (2) to (1)	10 ℓ
Washing (2)	1 min 00 sec	35°C	20 mℓ	10 ℓ
Stabilization	1 min 05 sec	38°C	10 mℓ	10 ℓ
Drying	4 min 20 sec	55°C

*) The replenishing amount per meter of a 35-mm wide sample.

The compositions of the process solutions will be presented below.

Color Developing Solution:

	Mother Solution (g)	Replenishment Solution (g)
Diethylenetriaminepentaacetate	1.0	1.1
1-Hydroxyethylidene-1,1-diphosphonic Acid	3.0	3.2
Sodium Sulfite	4.0	4.9
Potassium Carbonate	30.0	30.0
Potassium Bromide	1.4	-
Potassium Iodide	1.5 mg	-
Hydroxylamine Sulfate	2.4	3.6
4-(N-Ethyl-N-β-hydroxylethylamino)-2-methylaniline Sulfate	4.5	7.2
Water to make	1.0 ℓ	1.0 ℓ
pH	10.05	10.10

Bleaching Solution:

	Mother Solution (g)	Replenishment Solution (g)
Ferric Sodium Ethylenediaminetetraacetate Trihydrate	100.0	140.0
Disodium Ethylenediaminetetraacetate	10.0	11.0
Ammonium Bromide	140.0	180.0
Ammonium Nitrate	30.0	40.0
Ammonia Water (27%)	6.5 mℓ	2.5 mℓ
Water to make	1.0 ℓ	1.0 ℓ
pH	6.0	5.5

Fixing Solution:

	Mother Solution (g)	Replenishment Solution (g)
Disodium Ethylenediaminetetraacetate	0.5	1.0
Sodium Sulfite	7.0	12.0
Sodium Bisulfite	5.0	9.5
Ammonium Thiosulfate Aqueous Solution (70%)	170.0 mℓ	240.0 mℓ
Water to make	1.0 ℓ	1.0 ℓ
pH	6.7	6.6

Wash Solution: Common for mother and replenishment solutions

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 & Haas Co.) and an OH type strongly basic anion exchange resin (Amberlite IR-400) to set calcium and magnesium ion concentrations to be 3 mg/ℓ or less. Subsequently 20 mg/ℓ of sodium dichloroisocyanurate 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:

	Mother Solution (g)	Replenishment Solution (g)
Formalin (37%)	2.0 mℓ	3.0 mℓ
Polyoxyethylene-p-monononylphenylether (average polymerization degree = 10)	0.3	0.45
Disodium Ethylenediaminetetraacetate	0.05	0.08
Water to make	1.0 ℓ	1.0 ℓ
pH	5.0 - 8.0	5.0 - 8.0

The sensitivity is represented by the relative value of the reciprocal of the exposure amount for giving a density higher than a fogging density by 1.0 with respect to a characteristic curve of a yellow image.

The results are summerized in Table 6.

Table 6

Comparison of Sensitivity of Samples 301 to 306
Sample No.	Emulsion No.	Remarks	Relative Sensitivity
301	Em-G	Comparative Example	100
302	Em-H	Comparative Example	107
303	Em-I	Present Invention	135
304	Em-J	Present Invention	158
305	Em-K	Present Invention	178
306	Em-L	Present Invention	151

As is apparent from Table 6, a high sensitivity was obtained when a palladium compound was added in an amount of 5 x 10⁻⁵ mol or more per mol of a silver halide after the grain formation step and before the desalting step.
According to the present invention, a stable method of manufacturing a silver halide photographic emulsion can be achieved. In particular, a stabilized method of manufacturing a silver halide photographic emulsion subjected to a reduction sensitization in the grain formation step can be achieved.

Claims

A method of manufacturing a silver halide photographic emulsion, wherein a palladium compound is added in an amount of 5 x 10⁻⁵ mol to 1 x 10⁻³ mol per mol of silver halide after a grain formation step and before a desalting step.
The method of claim 1, characterized in that the silver halide grains are subjected to a reduction sensitization in the grain formation step.
The method of claim 1, characterized in that said palladium compound is added in an amount of 1 x 10⁻⁴ to 5 x 10⁻⁴ mol per mol of silver halide.
The method of claim 1, characterized in that said palladium compound is represented by R₂PdX₆ or R₂PdX₄ wherein R represents a hydrogen atom, an alkaline metal atom, or an ammonium group, and X represents a halogen atom.
The method of claim 4, characterized in that said palladium compound is used together with thiocyanate ions in a molar amount of not less than five times that of said palladium compound.
The method of claim 1, characterized in that at least one compound selected from the group consisting of compounds represented by formulae (I), (II), and (III) is used in a process of manufacturing a reduction-sensitized silver halide emulsion:

(I) R-SO₂S-M

(II) R-SO₂S-R¹

(III) RSO₂S-L_m-SSO₂-R²

wherein R, R¹, and R² may be the same or different and represent an aliphatic group, an aromatic group, or a heterocyclic group, M represents a cation, L represents a divalent bonding group, m represents 0 or 1,
wherein the compounds represented by formulae (I) to (III) may be polymers containing divalent groups derived from structures represented by formulae (I) to (III) as a repeating unit, and if possible, R, R¹, R² and L may be bonded with each other to form a ring.
The method of claim 6, characterized in that a compound represented by formula (I) is used.
The method of claim 6, characterized in that 1 x 10⁻⁶ to 1 x 10⁻² mol of the compounds represented by formulae (I), (II) or (III) per mol of silver are used.
The method of claim 1, characterized in that said silver halide emulsion comprises regular silver halide grains.
The method of claim 1, characterized in that said silver halide emulsion is a monodisperse silver halide emulsion having a grain size distribution in which not less than 80% of all grains fall within the range of ±30% of the average grain size, the percentage representing the number or weight of the grains.
The method of claim 1, characterized in that said silver halide emulsion comprises tabular silver halide grains having an aspect ratio of not less than 3.
The method of claim 1, characterized in that not less than 50% of the total projected area of the silver halide emulsion is occupied by tabular grains having aspect ratios of 3 to 8.
A method of manufacturing a silver halide color light-sensitive material which comprises at least one blue-sensitive silver halide emulsion layer containing a yellow coupler, at least on green-sensitive silver halide emulsion layer containing a magenta coupler and at least one red-sensitive silver halide emulsion layer containing a cyan coupler on a support, wherein in at least one of said emulsion layers a silver halide photographic emulsion prepared by the method of any of claims 1 to 12 is used.