JPH09218476A - Production of silver halide emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silver halide emulsion superior in sensitivity and image quality. SOLUTION: This silver halide emulsion contains flat silver halide grains occupying >=60% of the projection areas of the total silver halide grains and having an aspect ratio (diameter to thickness) of >=2 and parallel twin faces. The method for producing this emulsion comprises the following processes; (a) a first process of forming an emulsion comprising fine grain containing substantially no twin face by adding a silver salt solution and a halide salt solution into an aqueous solution of a dispersion medium and (b) a second process of forming the twin parallel faced on the fine grains of the first emulsion by adding a silver salt solution and a halide salt solution into the first fine grain emulsion.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for producing a silver halide (hereinafter referred to as "AgX") emulsion which is useful in the field of photography.

[0002]

The photographic characteristics of tabular AgX emulsion grains containing parallel twin planes are excellent as described in JP-A-2-838, but conventionally known methods for producing the tabular grains are parallel. Insufficient control of twin plane formation process. The formation of parallel twin planes depends on the dispersion medium solution conditions [gelatin concentration, p
H, halogen salt (hereinafter referred to as X ^- salt) concentration, temperature, etc.], addition rate of silver salt solution (hereinafter referred to as Ag ⁺ solution) and X ^- salt solution (hereinafter referred to as X ^- solution) are adjusted. It is done by doing. Therefore, some twin planes are formed immediately after the start of nucleation, and some twin planes are formed immediately before the end of nucleation, and the twin plane spacing cannot be sufficiently controlled. Therefore, sufficient improvement in the (sensitivity / granularity) ratio has not been achieved. Regarding these conventional techniques, JP-A-58-113
Nos. 926 to 113928, JP-A-2-838, US Pat. No. 5,171,659, Research Disclosure Magazine, Volume 501, Item 36544 (1994, 1994).
Month) can be referred to.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a process for producing a tabular AgX emulsion having a more controlled parallel twin plane spacing (sensitivity / granularity) ratio.

[0004]

The objects of the present invention have been achieved by the following items. (1) In the method for producing a silver halide emulsion having at least silver halide grains and a dispersion medium, 60% or more of the total projected area of the silver halide grains has an aspect ratio (diameter / thickness) of 2 or more. A tabular silver halide grain having parallel twin planes, the method comprising the following steps:
In addition, 20 to 100% of the number of parallel twin grains produced is c).
A method for producing a silver halide emulsion characterized in that it is formed in the process of. a) A silver salt solution and a halogen salt solution are added to an aqueous solution containing a dispersion medium to have substantially no twin planes (the number ratio of particles having two or more twin planes is 0 to 25%). Step of forming a silver halide first fine grain emulsion. b) subject the first fine grain emulsion to one or more of the following treatments. The dispersion medium concentration is reduced to the original 0.1-50%. Dispersion medium molecules are decomposed to lower the weight average molecular weight of the dispersion medium to 1 to 60% of the original weight. One or more groups of methionine group, imidazole group, alcohol group and amino group of gelatin are reduced to 0-60% of the original number. When added to the first fine grain emulsion, it is adsorbed on the first fine grains, and the first adsorbent forcibly increasing the parallel twin plane formation probability in the following step c) is added. c) A step of adding silver ions and halogen ions to the first fine grain emulsion to form parallel twin planes on the first fine grains. (2) The first adsorbent is N, P, S, Se, I, As,
Compounds containing at least one Sb or Sn atom onium base in one molecule, a nitrogen-containing heterocyclic compound,
SCN ^- salt compound, spectral sensitizing dye, antifoggant,
The method for producing (1), which is at least one of a divalent sulfur-containing heterocyclic compound, a divalent sulfur-containing organic compound, aminothioethers, thiourea or a derivative thereof. (3) The step (c) is performed after the step (a), after adding the first adsorbent and adsorbing the adsorbent on the first fine particles. Production method. (4) The method according to (1) above, wherein the first adsorbent is an ammonium base-containing compound (pyridinium quaternary salt, triazolium salt, protonated organic amine compound, quaternary ammonium compound).

Other preferred embodiments of the present invention are as follows. (5) The silver halide described in (1) above, wherein the silver ion added in the step c) is added in the form of a silver salt solution and the halogen ion is added in the form of a halogen salt solution. Emulsion manufacturing method. (6) A feature that the silver ions and the halogen ions added in the step c) are added in the form of silver halide fine particles having a diameter of 0.005 to 0.07 μm and are supplied by being dissolved. The method for producing a silver halide emulsion according to (1) above. (7) The halogen ion concentration of the emulsion in the step c) is
The method for producing a silver halide emulsion as described in (1) above, wherein the concentration of the halogen ions in step a) is 1.5 times or more. (8) After the step (c), the temperature is raised by 10 ° C. or more to ripen, and the projected area ratio of tabular grains is increased by 1.5 times or more, and the ripening step is included. A method for producing the silver halide emulsion described. (9) A silver ion and a halogen ion are supplied after the ripening step to grow the tabular grains.
(6) A method for producing a silver halide emulsion as described above.

[0006]

Next, the present invention will be described in more detail. A) AgX Emulsion Grain In the method for producing an AgX emulsion having at least AgX grains and a dispersion medium, the total projected area of the AgX grains is 60.
% Or more, preferably 80 to 100%, more preferably 9
5-100% has an aspect ratio (diameter / thickness) of 2 or more,
A plate-like A having preferably 3 to 50, more preferably 4 to 30 and having 2 or 3 parallel twin planes, preferably 2 parallel twin planes.
gX particles. The diameter of the tabular grains is 0.1 to 10 μm.
m is preferable, 0.2 to 5 μm is more preferable, and the thickness is 0.02 to 0.4 μm, preferably 0.04 to 0.3 μm.
m, and the halogen composition is AgCl, AgBr, AgB
rI (I ^- content is 40 mol% or less), and 2 of them
It is a mixed crystal in any proportion of at least one kind. Preferably AgC
l content is 49 mol% or less, more preferably 0 to 40 mol
%, More preferably 0 to 30 mol% AgBrClI. Examples of the shape of tabular grains include hexagonal main planes, triangles, and circles with rounded corners.
Adjacent side ratio [Within one particle, the length of the longest side of the hexagon
The length of the shortest side)] is 1 to 3, preferably 1 to 2, more preferably 1 to 1.5, or a particle having rounded corners is more preferable. In the case of the circular tabular grains, the linear portion ratio [(total length of linear portions on each side / total length of each side of hexagon formed when replenishing missing portions]] is 0.01 to 0.99, preferably 0.1 to 0.9. The coefficient of variation of the diameter distribution of the tabular grains and the coefficient of variation of the thickness distribution (standard deviation of distribution / average value) are 0.01 to.
0.4 is preferable, 0.01 to 0.3 is more preferable,
0.01 to 0.2 is more preferable. The diameter refers to the diameter of a circle having an area equal to the projected area when the projected shape is observed by a microscope with the main plane of the particle placed on the substrate surface. The [thickness / outermost parallel twin plane spacing (distance between two twin planes closest to the principal plane)] of the grains is 1.2 or more, preferably 2 to 500, and more preferably 3 to 100. The variation coefficient of the distribution of grains in the outermost parallel twin plane spacing is 0 to 0.5.
Is preferred, 0-0.4 is more preferred, and 0-0.2 is even more preferred.

B) Formation of Twin-Free Crystal Fine Particles In the method for producing AgX emulsion of the present invention, first, Ag ⁺ liquid and X ⁻ liquid are added to an aqueous dispersion medium solution to form AgX first fine particles having substantially no twin plane. Are first formed. Here, “having substantially no twin planes” means that the number ratio of particles having two or more twin planes is 25% or less, preferably 0 to 10%, more preferably 0 to 1%. More preferably, the twin plane is 1
The number ratio of particles to be included is 30% or less, preferably 0 to 1
0%, more preferably 0 to 1%. The projected particle diameter of the fine particles is 0.01 to 0.3 μm, preferably 0.02.
˜0.2 μm, more preferably 0.03 to 0.1 μm.

The fine particles may be formed under the condition that twin planes are not easily formed. Regarding the conditions, JP-A-2-1460
The description of No. 33 can be referred to. In the case of the present invention, it is particularly preferable to lower the X ^- salt concentration in the dispersion medium aqueous solution and increase the dispersion medium concentration. Since the ability of the X ⁻ salt to form twin planes is (I ⁻ > Br ⁻ > Cl ⁻ ) at the same concentration, it is particularly preferable to keep the concentrations of I ⁻ and Br ⁻ low. The X ⁻ concentration is preferably 10 ^−1.7 mol / liter or less, more preferably 10 ⁻⁴ to 10 ⁻² mol / liter.
The concentration of the dispersion medium is 0.1 to 10% by weight, preferably 0.3 to 10% by weight, more preferably 0.6 to 5% by weight.
It is. In addition, it is preferable to improve the stirring and mixing property during the addition of the Ag ⁺ liquid and the X ⁻ liquid. In this case, Ag ⁺ liquid and X ⁻
The number of liquids is 2 or more, preferably 10 to 10 ¹⁵ ,
More preferably, it is added below the liquid surface through 50 to ^{10 10} addition holes. For details, see JP-A-6-86.
The description of US Pat. No. 923, US Pat. No. 5,424,180 can be referred to. As a stirring and mixing method, it is preferable to use a closed mixing method or the like which does not foam even when vigorously mixed, and the details thereof can be referred to the description in JP-A-4-302605.

Further, it is preferable that at least one of the Ag ⁺ liquid and the X ⁻ liquid contains a dispersion medium. The concentration of the dispersion medium is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, still more preferably 0.3 to 2% by weight. Further, the temperature of the addition liquid may be warmed (25 to 60 ° C.) to be added. The temperature of the dispersion medium solution is preferably 1 to 60 ° C, more preferably 5 to 50 ° C. The pH may be 1 to 12, preferably 1.7 to 10. The fine grain emulsion may be added to the first container after being prepared in another container, or may be prepared by continuously or intermittently producing in another mixing container and accumulating in the first container. it can. For details, see JP-A-4-34544 and 2
-166442, 4-184326 to 184330.
You can refer to the description of the issue.

When the size of the fine particles is smaller, twin planes are more likely to be formed on the fine particles in the next step. Because the twin plane is small in area, the twin plane can be completed in a short time. Since the size is small, solute ions are rapidly diffused and supplied, and the stacking process of the AgX layer on the twin plane is short. This is because it occurs inside and the twin planes are no longer fixed. The size distribution of the fine particles is preferably narrow. This is because, when twin planes parallel to each other are formed on the surfaces of the fine particles facing each other in the next step, parallel twin grains having uniform twin plane intervals can be obtained. The variation coefficient of the size distribution is preferably 0 to 0.4, more preferably 0 to 0.3, and most preferably 0 to 0.2.

The ratio of the twin crystal grains can be determined as follows. The first fine particles are heated to a low temperature (25 to 40 ° C), (X
^- Without AgX solvent at a salt concentration> 10 ^-2.3 mol / l), without causing Ostwald ripening, and new nucleation even Ag ⁺ and X in occurs allowed without addition rate ^- was added, all nuclear about 0 Grow to a diameter of 2 μm or more. This can be confirmed by observing the transmission electron micrograph image (TEM image) of the replica film of the produced particles and determining the existence frequency of various shaped particles. Regarding this, the description in JP-A No. 2-146033 can be referred to.

C) Twin crystal plane formation process After the fine grain emulsion is prepared in this manner, a twin plane is then formed on the fine grains as a stacking fault. 30 to 100% of the total number of the tabular grains of the finally obtained AgX emulsion,
Preferably 60 to 100%, more preferably 90 to 10%
Parallel twin plane formation of 0% tabular grains is formed during this twin plane formation process. The following method can be mentioned as a method for forming the twin plane. (1) Ag ⁺ and X ^- are added while setting the conditions of the fine grain emulsion so that twin planes are easily formed. As a specific example, a)
X ^- salt solution is added to increase the X ^- concentration to 1.5 times or more, preferably 2-1000 times, more preferably 5-100 times. Examples of X ⁻ ion species include Cl ⁻ , Br ⁻ , and I ⁻ species. At a concentration conditions, the ability to form twin planes ^- the same ^{X (Cl - <Br - <} I -) forward a because of, in particular Br ^- concentration, I ^- it is more preferable to increase the concentration. The addition amount of Br ⁻ is preferably 10 ⁻¹ to
10 ^-2.7 mol / liter, more preferably 10 ^-1.5 to 10
It was ^-2.2 mol / l, I ^- The preferred amount of 10 ^-1.5 to 10 ^-4 mol / liter, preferably 10
^-1.7 to 10 ^-3.5 mol / l, Cl ^- The amount of the preferably 10 ^-0.7 ~10 ^-2.5 mol / l, more preferably 10 ^-1 ~10 ^-2 mol / liter.

B) The concentration of the dispersion medium is 0.1 to 50% of the original,
It is preferably reduced to 1 to 20%. The concentration of the dispersion medium is preferably 0.01 to 5% by weight, more preferably 0.1 to 3% by weight. Examples of the reducing method include a method of centrifuging an emulsion and removing a supernatant, and a method of removing a dispersion medium by an ultrafiltration method or a centrifugal filtration method. c) A method of decomposing the dispersion medium molecule to lower the molecular weight of the dispersion medium. In this case, the weight average molecular weight is 1 to 9 of the original molecular weight.
0% is preferable, 3 to 60%, and further 5 to 30
% Is more preferable. Examples of the method for lowering the molecular weight include an acid hydrolysis method, an alkali hydrolysis method and an enzymatic decomposition method. For details of the decomposition reaction, see Physics and Chemistry Dictionary, Iwanami Shoten (1987), Chemistry Dictionary, Kyoritsu Publishing (1960), Chemistry Dictionary, Tokyo Kagaku Dojin (1994).
"Hydrolysis", "Hydrolytic Enzymes", edited by Nobumasa Imura et al., Biochemistry Handbook, Chapters 20, 21 and Maruzen (1984).

D) Selection of the pH value of the emulsion. Br ^- concentration is 1
In the range of 0 ^-1 to 10 ^-2.5 mol / liter, the lower the pH,
The twin plane formation probability increases. Cl ^- concentration is 10 ^-0.7 to 1
In the 0 ^-2 mol / liter region, the twin plane formation probability increases as the pH increases. Therefore, the twin plane formation probability can be increased by selecting the pH value of the emulsion. pH is 1 to 1
The most preferable condition can be selected from 2, preferably 1.7 to 10.

E) A method of reducing the protective colloid property of the dispersion medium. For example, in the case of gelatin, by adding an oxidizing agent to oxidize the methionine group of gelatin to a methionine sulfoxide group, the protective colloid property is lowered and the twin plane formation probability is increased. Further, by adding phthalic anhydride to amidate the amino group of gelatin, the protective colloid property is lowered. That is, the number of adsorbing groups of the dispersion medium or the number of specific adsorbing groups is reduced to 0 to 90% of the original number, preferably 1 to 60%, and more preferably 1 to 30%. For gelatin,
It applies to the number of methionine groups, imidazole groups, alcohol groups, and amino groups. For the oxidizing agent, see Japanese Patent Laid-Open No.
1-3136, 61-3134, JP-A-6-13
No. 0528, No. 6-102485 and Japanese Patent Application No. 6-1
The description of No. 02485 can be referred to, and H ₂ O ₂ can be used more preferably. Regarding chemical modification of the dispersion medium, edited by Abiko Yoshihiro, Nishikawa and Gelatin, Maruzen Osaka Branch (1987), AG Ward et al., The Science an
d Technology of Gelatin, Academic Press, London
(1977), Biochemistry Experiment Course 1-IV, Tokyo Kagaku Dojin (1977) can be referred to.

F) In addition, a method of increasing the addition rate of the Ag ⁺ solution and the X ^- solution to 1.2 to 30 times, preferably 1.5 to 20 times that of the formation of the first fine particles, and the temperature to the first fine particles. There may be mentioned a method of lowering the temperature by 3 to 40 ° C., preferably 5 to 30 ° C. at the time of formation. In terms of the twin plane formation mechanism, it is considered that two or more twin-free grains are coalesced to form coalesced twin grains. However, the X ^- concentration is 10 ^-2.3 mol /
Even if the first fine grain emulsion is centrifuged under the condition of liter or more, and the grains are fused together, they are put into a gelatin solution and Ag ⁺ and X ^- are added to grow the grains, but twin crystal grains are formed. Did not occur. Therefore, this method is not an effective method.

2) The first adsorbent adsorbed on the surface of the AgX particles is adsorbed on the first fine particles, and the Ag ⁺ liquid and the X ⁻ liquid are added. The following compound examples can be given as specific examples of the first adsorbent. A nitrogen-containing heterocyclic compound (a compound containing a cyclic compound containing at least one nitrogen atom in a ring of 3 to 7 atoms), and specific examples include purine bases (eg, purine, adenine, guanine, kinetin, xanthine, uric acid, etc.). ), Pyrimidine bases (eg, uracil, cytosine,
Pyrimidine, thymine, etc.). In addition, a thiourea derivative described in JP-A-62-218959, a divalent sulfur-containing heterocyclic compound described in JP-A-62-299996, and JP-A-63-41845.
Compounds containing divalent sulfur described in JP-A-2-34
Japanese Patent Application No. 7-146891, pyridinium quaternary salt compounds, JP-A-3-212639 and 4-2.
Examples thereof include aminothioethers described in No. 83742, SCN ^- salt compounds described in US Pat. No. 5,061,617, and triazolium salts described in JP-A-4-335632.

Other examples include protonated organic amine compounds (primary to tertiary amine compounds), quaternary ammonium compounds, polyvinylpyrrolidone, polyvinylamine, polyvinylpyridine, and dichalcogen organic compounds. For details of these compounds, see US Pat. Nos. 4,400,463, 4,713,323 and 4,804.
No. 621, No. 5178997, No. 5178998,
No. 5183732, No. 5185239, No. 5176
No. 992, No. 5298387, JP-A-7-16830.
No. 0, New Experimental Chemistry Course, Volume 14 (III, IV), Maruzen (1
977), by LG Wade, Organic Chemistry, Prenti
ce-Hall (1987), Macromolecule Dictionary, Maruzen (199)
4 years) and European Patent No. 627657A can be referred to. Further, an effective adsorbent can be selected from conventionally known spectral sensitizing dyes and antifoggants, and the details of these compounds can be referred to the description of the literature described later. Pyridinium 4 as a more preferable adsorbent
Mention may be made of graded salts and divalent sulfur-containing compounds.

Next, the above compound will be described more systematically.
The nitrogen-containing heterocyclic compound is described in 4) in the broad sense of the pyridinium quaternary salt compound, triazolium salt, protonated organic amine compound, quaternary ammonium compound, (protonated embodiment of polyvinylamine, polyvinylpyridine). It is classified as an onium base-containing compound in 1), and is narrowly classified as an ammonium base-containing compound. Pyridinium quaternary salt compounds and triazolium salts are more narrowly defined as 2).
It is classified as a heterocyclic nitrogen quaternary base-containing compound. Antifoggants are classified in 4) and spectral sensitizing dyes are classified in 5).
Non-protonated polyvinylpyrrolidone and polyvinylpyridine are classified in 4).

1) Onium base-containing compound One or more onium bases represented by the following general formulas (I-1) to (I-8) in one molecule, preferably 2 to 10
Compounds containing ⁴ groups, more preferably 3 to 10 ³ groups.

[0021]

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In the formula, R ^{1 to} R ³ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkenyl group, an aralkyl group or an aryl group, and the number of hydrogen atoms is 2. The following is preferable, one or less is more preferable, and 0 is further preferable. That is, carbon number 1-2
A straight-chain or branched alkyl group having 0, a cycloalkyl group, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, and an aryl group are preferable. These groups may be substituted with the following substituents. Y ^- represents an anion (negatively charged atom or atomic group). For example, acid groups, OH ^- groups,
Halogen ions can be mentioned, and specific examples include C
_{^{l -, Br -, NO 3}} -, 0.5SO 4 2-, CH 3 CO
O ^- and p-toluenesulfonate can be exemplified.
R ² can also form a ring closure with R ¹ or R ³ . In the case of a compound having only one onium base in one molecule, or unless otherwise specified, (I-1) to (I-
The free bond of the formula 8) is bonded to the R ⁴ group. R ⁴ represents a group having the same definition as R ^{1 to} R ³ . Examples of the substitutable group include the following groups (hereinafter, these are collectively referred to as SB1). Halogen atom (for example, fluorine atom, chlorine atom, bromine atom, etc.), alkyl group (for example, methyl group, ethyl group, n-propyl group, isopropyl group,
t-butyl group, n-octyl group, cyclopentyl group, cyclohexyl group, etc., alkenyl group (eg, allyl group, 2-butenyl group, 3-pentenyl group, etc.), alkynyl group (eg, propargyl group, 3-pentynyl group) Aralkyl group (e.g., benzyl group, phenethyl group, etc.), aryl group (e.g., phenyl group, naphthyl group, 4-methylphenyl group, etc.), heterocyclic group (e.g.,
Furyl group, imidazolyl group, piperidyl group, morpholino group, etc.), alkoxy group (eg, methoxy group, ethoxy group, butoxy group, etc.), aryloxy group (eg, phenoxy group, 2-naphthyloxy group, etc.), amino group ( For example, unsubstituted amino group, dimethylamino group, ethylamino group, anilino group, etc., acylamino group (eg, acetylamino group, benzoylamino group, etc.), ureido group (eg, unsubstituted ureido group, N-methylureido group) , N-
Phenylureido group, etc.), urethane group (eg, methoxycarbonylamino group, phenoxycarbonylamino group, etc.), sulfonylamino group (eg, methylsulfonylamino group, phenylsulfonylamino group, etc.), sulfamoyl group (eg, unsubstituted sulfamoyl group) , N, N-
Dimethylsulfamoyl group, N-phenylsulfamoyl group, etc.), carbamoyl group (eg, unsubstituted carbamoyl group, N, N-diethylcarbamoyl group, N-phenylcarbamoyl group, etc.), sulfonyl group (eg, mesyl group, A sulfinyl group (eg, a methylsulfinyl group, a phenylsulfinyl group, etc.), an alkyloxycarbonyl group (eg, a methoxycarbonyl group,
Ethoxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenoxycarbonyl group, etc.), acyl group (eg, acetyl group, benzoyl group, formyl group, pivaloyl group, etc.), acyloxy group (eg, acetoxy group, benzoyloxy group, etc.) ), A phosphoric acid amide group (eg, N, N-diethylphosphoric acid amide group, etc.), an alkylthio group (eg, methylthio group, ethylthio group, etc.), an arylthio group (eg, phenylthio group, etc.), a cyano group, a sulfo group, A carboxy group, a hydroxy group, a phosphono group, a nitro group, a sulfino group, an ammonio group (for example, a trimethylammonio group, etc.), a phosphonio group, a hydrazino group, and the like. These groups may be further substituted. When there are two or more substituents, they may be the same or different. 1-30 are preferable and, as for the carbon atom total number of the onium base of (I-1)-(I-8), 2-20 are more preferable.

In the formula (I-1), R¹~ R^FourIs other than hydrogen atom
If the atom is⁺Is in the range of pH 1.0-12.0
Independently of pH, N⁺Keep. But R¹
~ R ^FourWhen one or more of are hydrogen atoms,
At pH values above the pKa value (Ka is the acid dissociation constant),
The hydrogen atom dissociates as a proton, not an onium base.
Increase the probability of becoming. In this case, (the pKa + 0.3)
Or less, preferably the pKa or less, more preferably (the p
Ka-0.3) and the compound in the reaction solution under pH conditions below.
Means to coexist.

Two or more of the above-mentioned onium bases are prepared in the following manner,
Preferably, 3 to 10 ³ groups can be linked together. (I)
Via the divalent linking group L via the free bond, or R ¹
It connects through a group. L is an alkylene, arylene, _{alkenylene, -SO 2 -, - SO -} , - O -, - S-,
—CO—, —NR ⁵ — (R ⁵ represents an alkyl group, an aryl group, or a hydrogen atom) alone or in combination. Preferred are alkylene and alkenylene. (Ii) Bonding with a polymer chain. The onium bases to be bonded may be of the same kind or different from each other, and may be an embodiment in which two or more kinds of groups of the formulas (I-1) to (I-8) are linked. In that case, the total of various onium groups is 2 to
It is 10 ⁴ , preferably 3 to 10 ³ .

The following method can be mentioned as a method for forming the polymer chain. (A) Sequential polymerization method A method utilizing a polycondensation reaction between two functional groups (eg, a polyamide-bonded chain, a polyester-bonded chain, an acid anhydride-bonded chain), and a polyaddition reaction between two functional groups. Methods (eg, polyurethane chains and polyurea chains) can be mentioned. (B) Chain polymerization For example, a monomer having an unsaturated bond is an active species (radical,
A mode in which a polymer is generated by repeating the reaction of adding to an anion or a cation (eg, a polyvinyl polymer or a polystyrene polymer by polymerization of a vinyl monomer). The compound having the onium base can be synthesized by polymerizing a monomer having the onium group as a substituent or by a substitution reaction to a polymer. As the polymer chain, a chain chain is preferable, and a network chain is not preferable because it is difficult to dissolve.

In particular, pKa is within the pH range of 1.5 to 12.0.
Having an acid dissociative group having a value (Ka is an acid dissociation constant)
Copolymers with mers are preferred. When expressed by a general formula, (I
-9) It is represented by a formula. Where R⁸Is R¹~ R^ThreeWhen
Represents a similar substituent. R⁹Is a substitution having the acid dissociative group
Represents a group. n1 is 1 to 5000, preferably 1 to 10
00, more preferably an integer of 2 to 300, and n
2, n3 is an integer of 0 or more, preferably 1 to 10^Four,Than
Preferably 2-10^ThreeRepresents the integer. In this case, the pH
By raising or lowering the pKa value
R⁹The degree of water solubility of the group is changed to improve the adsorptivity of the polymer.
It can be changed and is preferable. For example, the -COOH group
In the case of such an acid group, its pKa value or more, preferably (pK
a-0.3) or more by adjusting the pH (-COO
H → -COO^-+ H⁺), The hydrophilicity of the group increases
The desorption of the polymer adsorbed on the AgX particles is promoted.
You. That is, when the polymer is no longer needed, the reaction solution
By adjusting the pH value, the polymer was removed from the AgX particles.
It has the advantage of being removable and removable. -NH_TwoBased
In the case of such a base, the pKa value or less, preferably (pK
a-0.3) or lower (-NH_Two+ H⁺→
-NH_Three ⁺) Becomes more soluble in water. As the dissociative group
-SO_ThreeM, -SO_TwoM, -OSO_ThreeM, -COOM,
-NH _Two, -NHR¹, -NR¹R^Three, -SO_FourM,-
OPO_ThreeM_Two, (-O)_TwoYou can mention POM,
Preferably -SO_ThreeM, -SO_TwoM, -COOM, -N
H_Two, -NHR¹, -OPO_ThreeM_TwoIt is. Where M is
H, alkali metal, or -NH_FourRepresents

Further, by introducing a hydrophilic group into R ⁸ , (n1 / n
2) It is preferable to change the ratio variously, because the adsorption characteristics of the polymer can be changed almost continuously. As the water-soluble _{group, -OH, -CN, -CONH 2,} -COOC
_{H 3, - (CH 2 CH} 2 O) -, - CONH- can be exemplified. The compound represented by the formula (I-9) may be synthesized by polymerizing a monomer having these groups. The (n1 / n2) ratio and the (n1 / n3) ratio are 1
0 ^-4 to 10 ^4, preferably you can choose a preferred ratio of 10 ^-3 to 10 ³ region. Specific examples of the monomer include (I-11) to (I-16)

[0028]

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The following can be mentioned. Where R ¹⁰ is R ⁷
It refers to any of ~R ^9. R ¹¹ represents an alkyl group having 1 to 10 carbon atoms. Specific examples of the polymer chain include polyvinyl chain, polystyrene chain, polyamide chain, polyester chain, polyether chain, polyethersulfone chain, polyetherketone chain, polysilicone chain, polytriazine chain, polyene chain, polyglycose chain. I can give you
Polyvinyl chains, polyamide chains, and polyester chains are more preferable.

Specific examples of the copolymer of the formula (I-9) are shown in (I-21) to (I-24). Specific examples of these compounds are shown in (I-31) to (I-54). For details of the synthesis method of these polymer chains, see the Chemical Society of Japan, Chemical Handbook, Applied Chemistry, Chapter 8, Maruzen (1
986), edited by Shuichi Suzuki et al., Chemistry Handbook, Chapter VIII
Chapter, Asakura Shoten (1993), edited by The Chemical Society of Japan, New Laboratory Chemistry, Vol. 19, Maruzen (1978), US Patent No. 4
525446 can be referred to.

[0031]

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[0032]

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[0033]

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[0034]

[Chemical 6]

[0035]

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Another specific example is a triazolium salt which is an onium form of triazoles,
Specific examples of the compounds are shown in (I-55) to (I-58). For other details of the compound, see JP-A No. 4-3
No. 35632 can be referred to. Among these, sulfonium base, phosphonium base, selenonium base, arsonium base, stibonium base, stannonium base, iodonium base, and heterocyclic quaternary base-containing compound are more preferable.

(2) Heterocyclic nitrogen quaternary base-containing compound Among the onium bases described in (1) above, a heterocyclic nitrogen quaternary base-containing compound is more preferable. The base is represented by the general formulas (II-1) to (II-4). The group is 1
A compound having one or more groups, preferably 2 to 300 groups, and more preferably 3 to 100 groups in the molecule. Where A _{1 to} A ₄
Represents a non-metal atom group for completing the nitrogen-containing organic heterocycle, and each may be the same or different. O,
It may contain N and S atoms, and the benzene ring may be condensed. The heterocycle composed of A _{1 to} A ₆ may have a substituent, and the substituents may be the same or different. Examples of the substituent include SB1 described above. As a preferred example, A _{1 to} A ₄ can be a 5- or 6-membered ring (for example, a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, a pyrazine ring, a pyrimidine ring, etc.), and a more preferred example is a pyridine ring. I can give you. (II-1) to (II-4) cation groups are linked to each other via a divalent linking group L or a polymer chain (a compound having two or more cation groups). I can name it. The cationic groups to be linked may be the same as or different from each other. L represents the same divalent linking group as L above. As a preferred example, alkylene,
You can give alkenylene. Examples of the polymer chain include the polymer chains described in the above (B)-(1). R ²¹ and R ²² represent the same group as defined for R ¹ and R ^3, and Y ⁻ also represents the same group as Y ⁻ . Specific examples of the compound are shown in (II-11) to (II-15). That is,
(I-9) expression (B1-R ⁷⁾ repeatedly as a unit (II-11) can be mentioned aspects of introducing a cation-containing repeating units of ~ (II-15). In this case, the rules for n1, n2, and n3 are the same as the above rules.

The compound more preferable than (i) is represented by the general formula (II-
21) and (II-22). Where R^{twenty three},
R^{twenty four}Is R¹, R^TwoRepresents a substituent similar to_Five~ A₈
Is A ₁~ A_ThreeSame as above, to complete the nitrogen-containing heterocycle
Represents a non-metallic atomic group of
May be. n11 represents 0 or 1, which is an intramolecular salt.
In some cases it is zero. n12 represents 0 or 1. L is
It represents the same divalent linking group as described above. Y^-Is the same as above
Represents Nion. Specific examples of the compound (II-31) to
(II-42). Other details about the compound
For details, see Japanese Patent Application Laid-Open Nos. 8-29902 and 2-34.
You can refer to the article.

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As a more preferable example of the compound (ii), a compound represented by the general formula (III-1) can be given. Here, R ³¹ represents the same substituent as R ¹ and R ^2, and R ^{32 to} R ³⁶ may be the same or different and each represents an H atom or a group substitutable with it. Examples of the substitutable group include SB1. ^R32 and ^R33 , ^R33 and ^R34 , ^R34 and ^R35 , ^R35 and ^R36
May be fused. However, it is more preferable that at least one of R ^{32 to} R ³⁶ is an aryl group and R ³¹ is an aralkyl group. Y ^- is the Y ^- is the same as. R
³² and R ³³ , R ³³ and R ³⁴ , R ³⁴ and R ³⁵ , and R ³⁵ and R ³⁶ may be fused to form a quinoline ring, isoquinoline ring or acridine ring. Specific compound examples of the compound are shown in the following (III-2) to (III-14). For the other details of the compound, the description in Japanese Patent Application No. 7-146891 can be referred to.

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(Iii) As a more preferred compound example,
The compound represented by the formula (I-9), and the onium base represented by the formula (II-3) or (II-4). Further, there can be mentioned a compound containing at least one heterocyclic nitrogen quaternary base and at least one acyclic quaternary ammonium base in one molecule. Preferably each is 1 to 10
Examples thereof include compounds containing ⁴ groups, preferably 2 to 10 ³ groups. Specific examples of the compounds are shown in (III-21). For details of the compound, refer to World Patent No. 94-205.
No. 51 can be referred to. (1),
Regarding the synthetic method and other details of the compound of (2), US Pat. No. 3,017,270 and European Patent No. 039209.
2B1, U.S. Pat.
6, JP-A-2-2933838 and JP-A-7-306489.
You can refer to the description of the issue.

(3) One or more iodo groups and one aromatic ring
In the aromatic compound in which the -OH groups or more are substituted, the iodine group is preferably substituted by 1 to 8 groups, preferably 2 to 5 groups, and the hydroxy group is substituted by 1 to 3 groups. preferable. Here, the aromatic compound means a carbocyclic compound having a benzene nucleus, and a compound in which another benzene ring or a heterocycle is condensed with the benzene ring (for example, naphthalene, anthracene,
Quinoline and indole) are also included. The aromatic ring includes the benzene nucleus, the condensed benzene ring, and the condensed heterocycle, and preferably the benzene nucleus and the benzene ring. More preferably 8-containing at least one iodo substituent
Hydroxyquinoline [general formula is represented by formula (IV-1)], a phenol having at least two iodo-substituents, and specific compound examples thereof are (IV-2) to (IV-1).
2).

(IV-2) 8-Hydroxy-7-iodo-5-quinolinesulfonic acid (IV-3) 5,7-diiodo-8-hydroxyquinoline (IV-4) 5-chloro-8-hydroxy-7 -Iodoquinoline (IV-5) 8-hydroxy-7-iodo-5-quinolinecarboxylic acid For details of these compounds, see US Pat. No. 54118.
The description of No. 53 and No. 5411852 can be referred to.

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4) Nitrogen-Containing Heterocyclic Compound One heterocyclic ring containing one or more nitrogen atoms in a 3- to 7-membered ring is used.
It is a compound containing one or more molecules, and the following compounds are preferred. (A) Azaindenes More preferred are tetraazaindenes, and specific examples thereof include xanthinoids [represented by the general formula (V-1), and specific examples thereof include xanthine and uric acid], aminoaza Examples thereof include indenes (specific examples thereof include purine, adenine, guanine, and kinetin). (B) Diazines (pyridazines, pyrimidines, pyrazines) Of these, substituted pyrimidines are preferable. Examples of the substituent include SB1. Specific examples of compounds include uracil, cytosine, thymine, (V-2) to (V-
5) Compounds of the formula can be mentioned. For details of these compounds, see JP-B-5-40298.
No. 5,265,111, and No. 5-204077.
No. 5,232,612, JP-A-64-8325,
Reference can be made to the description in the New Experimental Chemistry Course, Volume 14, Chapter 9, Maruzen (1978), edited by The Chemical Society of Japan. Examples of nitrogen-containing heterocyclic compounds known as antifoggants include azoles, mercaptopyrimidines, mercaptotriazines, and azaindenes. 5) Spectral sensitizing dyes: cyanine dyes, merocyanine dyes, and complex merocyanine dyes can be mentioned. The cyanine dye refers to a dye having a cation structure in which two nitrogen-containing heterocycles are bonded by a methine group —CH═ or a chain thereof, and preferably has one or more acid groups, more preferably one or two acid groups. Here, the acid group is-
It refers to SO ₃ ⁻ , —OSO ₃ ⁻ , and —COO ⁻ , preferably the —SO ₃ ⁻ group. Imidacyanin, oxacyanine, thiacyanine, serenacyanine and complex cyanines of the two are preferable, and imidacyanin and oxacyanine are more preferable. For details of these 4) and 5) compounds, see Research Disclosure, Volume 501, Item 3.
6544, September 1994 (hereinafter referred to as “RD 1994
Year ”), edited by TH James, Theory of Photographic Process, 8th
Chapters, Macmillan, Inc. (1977) and the references below can be referred to. Examples of specific compounds (VI-
1) to (VI-3). Spectral sensitizing dyes are also one type of compounds containing ammonium base.

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(V-2) 4,5,6-triaminopyrimidine (V-3) 4,6-diaminopyrimidine-hemisulfate-monohydrate (V-4) 2,4-diamino-1,3 , 5-Triazine (V-5) 4,6-bis (methylamino) pyrimidine 6) SCN ^- salt compound As specific compound examples, HSCN, NaSCN, KSC
N, can be mentioned NH ₄ SCN. In the general formula, M ₁ ⁺ SCN ⁻ , M ₂ ²⁺ (SCN) ₂ ²⁻ , M
₁ ⁺ represents a monovalent cation, and M ₂ ²⁺ represents a divalent cation. It means a soluble salt having a solubility in water at 40 ° C. of 10 ⁻³ mol / liter or more, preferably 10 ⁻² mol / liter or more.

7) In addition, compounds having a divalent sulfur-containing heterocyclic group described in JP-A-62-299961; divalent sulfur-containing organic compounds described in JP-A-63-41845; Kaihei 3-212639, 4-
The amino thioethers described in JP-A-283374 and the thiourea or its derivatives described in JP-A-62-218959 can be mentioned. The general formulas of these compounds are represented by (VII-1) to (VII-4)
Are shown in the formulas, and specific examples of these compounds (VII-1a) to
It is shown in the formula (VII-4d). The details of these compounds can be referred to the description of the above-mentioned literature corresponding to each compound.

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Z ⁷⁰ in the formula represents an atomic group necessary for forming a substituted or unsubstituted saturated or unsaturated heterocycle with a sulfur atom, and is an atom composed of a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom. It is a group. The heterocyclic ring is a 3- to 8-membered ring, and the ring may be condensed with another ring to form a condensed ring. The heterocycle may have one or more substituents. Examples of the substituent include SB1.

X ⁷⁰ represents an amino group which may be alkyl-substituted, a quaternary alkylammonio group, or a carboxy group, and L ⁷⁰ , L ⁷¹ and L ⁷² are divalent organic linking groups having the same definition as L above. Represents Y ⁻ represents an anionic group and has the same definition as Y ⁻ . m is the same as the number of quaternary alkylammonio groups. The alkyl group preferably has 1 to 3 carbon atoms. M ⁷⁰ represents a hydrogen atom, an alkali metal, an alkaline earth metal, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. X ⁷¹ represents CO or SO ₂ . R ⁷⁵ represents a hydroxy group, substituted or unsubstituted (alkyl group or aryl group, or heterocyclic group, amino group, alkoxy group, aryloxy group). Examples of the substituent include SB1 described above. The total number of carbon atoms in the molecule of the formula (VII-4) is preferably 25 or less, more preferably 20 or less. As the first adsorbent, one or more, preferably two or more of these are added, and the addition amount of the first adsorbent is preferably 0.1 to 100% of the saturated adsorption amount, and 1 to 80%. More preferably, 3-60% is still more preferable. As the twin plane forming method, at least one, preferably two or more of the methods (1) to (f) in (1) and 1) to 7) in (2) above may be used in combination. it can. The twin plane formation method includes b) in the above (1)
To e) are preferable, b), c) and e) are more preferable, and the methods of c) and e) are further preferable. The method of (2) is more preferable with respect to the method of (1), among the method of (2), 1) to 6) are preferable, 1), 2) and 6) are more preferable, 1), 2) is more preferable.

A cationic organic compound such as a quaternary salt of pyridinium adsorbs to the halogen ion X ⁻ on the {111} plane of the AgX particles, and suppresses the growth of the {111} plane. This is because, for example, when the ionic conductivity of the particles is measured by a dielectric loss measurement method, the ionic conductivity is increased, and the adsorption equilibrium constant for the particles in an aqueous solution is obtained, and the cube {10
It is concluded by comparing with the constant for the 0 ° plane. The adsorption is believed to be based on electrostatic interactions. When a pyridinium quaternary salt compound is adsorbed on non-twinned octahedral AgBr particles and Ag ⁺ liquid and Br ⁻ liquid are added and the particles are grown, the particles become twinned particles. This is because the adsorbent shifts the stacking position of Ag ⁺ and Br ⁻ ions from the normal position to the metastable position as shown in FIG. 1 to forcibly increase the stacking fault formation probability. . Since the cation also interacts with Br ⁻ in the aqueous solution and is in an equilibrium state of adsorption and desorption, when desorbed, Ag ⁺ and Br ⁻ are laminated at the desorption site to complete the twin plane layer. In the case of a pyridinium salt, the pH for the adsorptivity at pH 3 to 10
Dependence is small. This is because the molecular structure does not change in the pH range. However, at pH 3 or lower, competitive adsorption with the -NH ₃ ⁺ group of gelatin occurs, and the electrostatic action force decreases due to the increase in ionic strength of the solution.
Desorption probability increases. Therefore, when desorbing the adsorbent in a later step, pH 1 to 3 can be used.

In the case of the nitrogen-containing heterocyclic compounds such as the purine bases and pyrimidine bases, the adsorptivity to AgX particles shows pH dependence in the pH range. Assuming that the acid dissociation constant of the compound is Ka, the adsorptivity increases at a pH of pKa or more. At a pH below pKa, the adsorbability decreases due to proton addition. Therefore, the compound is preferably
Ka-0.3) or more, more preferably pKa to (pKa
+2), more preferably (pKa + 0.2) to (pKa)
Adsorb on the first fine particles at a pH of +1). Then Ag ⁺
The liquid and the X ⁻ liquid are added to form twin planes as stacking faults on the first fine particles.

One twin plane was formed on the grain (FIG. 2).
After (a) embodiment), where the next twin plane is formed will be described with reference to FIG. The manner in which the second twin plane is formed immediately above the first twin plane as shown in (b) is more unstable and difficult to achieve. Further, as shown in FIG. 1, when the adsorbent is adsorbed, it is difficult for AgX to grow on the adsorbent, and thus twin planes are not easily formed on the surface. When one twin plane is formed, growth nucleation is promoted at the edge of the twin plane, and normal growth thereafter occurs. Therefore, a new twin plane is formed on the plane adjacent to the twin plane. Are difficult to form. That is, it is difficult to form the aspect of FIG. This situation continues while there is a dip angle at the edge of the single twin plane. Therefore, the surface opposite to the surface on which the twin plane is formed is the surface on which the twin plane is most likely to be formed.
That is, the mode of FIG. If the system is oversaturated,
The probability that twin planes will be formed on all the planes at substantially the same time will be high, making it difficult to separate the twin planes. On the other hand, if the degree of supersaturation is too low, twin planes are less likely to be formed. In this way, parallel double twin planes with controlled twin plane spacing are formed.

In the case of a pyridinium salt, since a twin plane is formed in a state of being adsorbed on X ⁻ on the surface of AgX particles, Ag ⁺
It is considered that stacking faults occur when are stacked. On the other hand, in the case of adenine or the like, a twin plane is formed in a state of being adsorbed by Ag ⁺ on the surface of AgX particles, and therefore it is considered that a stacking fault occurs when X ⁻ is stacked. The parallel twin plane formation can be formed not only on the first fine particles but also on new nuclei, but it is more preferable to form on the first fine particles. Here, the new nuclei are A added at the time of twin plane formation.
Refers to the new nucleus produced by g ⁺ and X ⁻ . It is preferable that 20% or more, preferably 40 to 100%, and more preferably 80 to 100% of the number of the generated parallel twin grains is based on the first fine particles. Further, 20% or more, preferably 40 to 100%, and more preferably 80 to 100% of the number of finally produced parallel twin grains is on the opposite surface of the first fine particles in the process of c). It is preferable that the particles are parallel double twin grains having twin planes.

Conventionally, twin plane formation has been performed during the formation of the first fine particles. It increases the degree of supersaturation of the reaction solution,
This is because twin planes are easily formed when the nuclei are initially formed. At this time, since the size of the nucleus is small, the stacking fault surface is completed in a short time, and before the rearrangement of the stacking fault surface occurs, the stacking of AgX occurs on the fault surface, and the fault surface is fixed. This is because it is easy. In this case, if the first fine particles are formed under the condition that the defect plane formation probability is high, it is difficult to form only parallel twin planes, and many non-parallel twin planes are mixed. Regardless of whether it is parallel twin planes or non-parallel twin planes, most of the twin planes generated are fixed because the growth of stable nuclei occurs within a short time. is there. On the other hand, the method of the present invention aims to eliminate the process of fixing any twin planes by slightly shifting the twin plane formation time from the start of nucleation. This makes it possible to form twin planes with a high ratio of (number of parallel twin grains / total number of grains) = a ₁ , preferably (number of parallel double twin grains / total number of grains) = a ₂ .
The addition method of the Ag ⁺ and X ⁻ is 0.0
05-0.07 μm, preferably 0.005-0.05
A mode in which an AgX fine grain emulsion of μm prepared in advance is added and the emulsion is supplied by dissolution can also be mentioned.

D) Process after formation of twin planes After the twin planes have been formed in this way, the process begins to grow, and the following three methods can be mentioned as the way of entering. 1)
After forming the parallel twin planes by the method (1) and (2) of the above item C, the temperature is then 10 ° C or higher, preferably 20 to 80 ° C.
More preferably, the temperature is raised by 30 to 70 ° C., aging is performed at Ostwald ripening, tabular grains are grown, other grains are extinguished, and the projected area ratio of tabular grains is 1.5 times or more, preferably 3 to 300 times, More preferably, it is increased 6 to 100 times. Thereby, the projected area ratio of tabular grains is 60 to 1
Increase to 00%, preferably 80-100%. In this case, Ag ⁺ solution and X ^- (if added at more addition rate, addition rate new nuclei are generated) fluid the critical addition rate 0.1
Aging can also be carried out while adding at an addition rate of ˜35%, preferably 1 to 20%. It is also possible to add Ag ⁺ solution and X ^- solution to preferentially grow tabular grains to increase the size difference from the other grains and then ripen the Ostwald.

2) In the case of item (1) of item C, the growth process can be started next, or the growth process can be started after the second adsorbent is adsorbed. In particular, the AgCl content of the first fine particles is 5
The latter step is more preferable in the case of ˜100 mol%, preferably 20-100 mol%. The addition amount of the second adsorbent is 0.1 to 100%, preferably 3 to 90% of the saturated adsorption amount of particles. In the case of item (2) of item C, the growth process can be started next, or the growth process can be started after desorption of the first adsorbent. Furthermore, after the desorption, the first adsorbent can be removed from the system by centrifugation or the like, and then the growth process can be started. Further, it is possible to start the growth process after adsorbing a new second adsorbent. The second adsorbent is a grain growth modifier, and can be selected from the above-mentioned first adsorbent, or can be selected from known antifoggants, sensitizing dyes, and surfactants. Specific examples thereof include the pyridinium salt compound, SCN ^- salt, and polyalkylene oxide compound. The details of these compounds are described in the following references and US Pat. Nos. 5,171,659, 5,147,771, 5,439,787, and 54.
11851, JP-A-7-225444, Japanese Patent Application No. 5-
The description of No. 263128 can be referred to. 3) After forming twin planes in 1) and 2), the growth process is started. Alternatively, after adsorbing the second adsorbent, the growth process starts.

E) Growth Process In the next growth process, the tabular grains were made to have a desired size by adding Ag ⁺ liquid and X ⁻ liquid, or by supplying AgX fine particles prepared in advance, or by a combination method thereof. Grow up to. In this case, in order to preferentially grow the edge faces of the tabular grains, it is preferable to grow them within a range where Ostwald ripening does not occur and under a low supersaturation degree. This is because under a low supersaturation degree, growth nuclei are preferentially formed in twin defect portions at the edges as compared with those on the main plane. Therefore, the method of adding fine particles can be used more preferably. The diameter of the fine particles is preferably 0.15 μm or less, and is 0.01 to 0.1.
μm is more preferred. The addition rate of the Ag ⁺ solution and the X ^- solution is preferably 1 to 90%, more preferably 3 to 60%, and further preferably 6 to 35% of the critical addition rate. Regarding the method of adding the fine particles, JP-A-4-34544 and 2-1664
No. 42 and No. 4-184326-184330 can be referred to.

In order to obtain a tabular grain having a high aspect ratio, parallel twin tabular grains may be selectively grown in the edge direction while suppressing the growth in the thickness direction. For that purpose, the tabular grains may be grown under a low supersaturation degree lower than the supersaturation degree required for growing the main plane. The dented portion of the twin plane edge of the edge surface has a structure capable of growing endlessly without the need for forming new growth nuclei, and can always grow even under a low supersaturation degree. However, according to the experimental results, the growth rate greatly depends on the dispersion medium species, and therefore the (adsorption ⇔ desorption) cycle of the adsorption dispersion medium species (that is, the strength of adsorption) determines the growth rate. Is one of. On the other hand, between the thickness d of the tabular grains and the growth rate (dA / dt), (dA / d
t) Since there is a relation of ∝1 / d, the diffusion supply rate of the solute is one of the factors controlling the growth rate. On the other hand, when tabular grains are grown in various gelatin solutions in which the methionine content and the phthalation rate are changed and the adsorption power to AgX particles is changed, the adsorption power is weakened to unmodified gelatin at first. As a result, the growth rate of each particle tends to become faster and uniform. It can be understood that this is an effect for making the adsorption force between gelatin molecules uniform. If the adsorption power is further reduced, the growth rate becomes faster, but the distribution of the growth rate between particles widens. Therefore, it is more preferable to grow using gelatin in the combination composition region in which the distribution between particles becomes narrow. In this case, the modified gelatin described in Japanese Patent Application No. 7-192609 can be more preferably used.
In this case, if the thicknesses are the same, it is considered that the growth rate per unit area of each edge surface is uniform and the multi-nucleus growth mechanism is established (the number of growth nuclei is 3 to ∞).

Grain growth is usually performed in the following process.
1) Process of adding and supplying solute ions → 2) Process of added solute ions diffusing to the reaction site on the particle surface → 3) New solute ion on the particle surface due to exchange adsorption of disperse medium molecules and solute ions Process of forming growth nuclei → 4) Growth of growth nuclei by exchange and adsorption of adsorbing dispersion medium molecules and solute ions. On the other hand, the order of magnitude of supersaturation required for each of the following phenomena to occur is as follows from the number of bonds and the Gibbs-Thomson equation. [A) Generation of new nuclei in bulk solution> b) Growth of AgX clusters generated in the vicinity of solute addition port> c) Formation of new growth nuclei on perfect crystal plane> In trough part of parallel twin grains Formation of growth nuclei> d) Growth of large growth nuclei]. Further, during the growth, there is always a relationship of (supersaturation degree of solute ions in bulk solution> supersaturation degree of solute ions on particle surface).

(Solute ion supply rate / second) is large,
If the process of 2) is slow, the degree of supersaturation in the bulk solution increases and the phenomenon of a) occurs. To prevent this, solute ions are supplied from 2 to 10 ¹⁵ pores, stirring and mixing properties are improved, and the particle density of tabular grains is increased [1-1.
00 / (10 μm) ³ ] is preferable. If the adsorption of the dispersion medium molecules is too strong, the speeds of 3) and 4) will decrease. If the supply rate in 1) is the same, the solute ion becomes (demand rate <supply rate), and the phenomenon in a) also occurs. In order to prevent this, it is preferable to use a dispersion medium having an appropriate adsorption power, and the modified gelatin described in Japanese Patent Application No. 7-192609 can be preferably used.

F) Others When desorbing the first adsorbent and the second adsorbent after the item D and the growth process, the following method can be used. 1) The desorption probability of the adsorbent increases with increasing temperature.
Therefore, the twin plane is formed at a low temperature, and at a higher temperature (10 ° C or higher, preferably 20 to 80 ° C, more preferably 30 to 7 ° C).
Desorption at 0 ℃). 2) Adjust pH. The pH dependence of the adsorption / desorption equilibrium is investigated, the pH condition at which desorption is most easily performed is determined, and desorption is performed under the pH. 3) adsorption-desorption equilibrium of the X ^-
The concentration dependence is investigated, the X ^- concentration condition that is most likely to be desorbed is determined, and desorption is performed under the X ^- concentration. 4) Exchange adsorption with another photographically effective adsorbent. For example, it is exchange adsorption with a spectral sensitizing dye, an antifoggant, and a surfactant. The exchange adsorbent remains in the AgX emulsion as it is, and even if coated,
It is preferably an effective adsorbent. 5) A method of selecting and extracting an organic solvent for the first adsorbent. Regarding the organic solvent that can be used, the description in Solvent Handbook, Kodansha Scientific (1976) can be referred to. 6) Add the above-mentioned oxidizing agent to oxidize the adsorption group to deactivate the adsorption ability. For example, in the case of an organic adsorbent containing a divalent chalcogen atom, the adsorption ability can be deactivated by oxidizing the chalcogen atom with H ₂ O ₂ or the like.

After the desorption, the removal to the outside of the system is carried out by a centrifugation method, an ultrafiltration method, a desorption method using a solid adsorbent, or a conventional A method.
The gX emulsion desalting method can be used, and for details thereof, reference can be made to JP-A-4-308840, JP-A-1-201651, and the description of the literature described later. The pH from the start to the end of the particle formation is 1 to 12, preferably 1.7 to 10, and the excess concentration of X ⁻ is 10 ⁻¹ to 10 ⁻³ mol /.
Liter, and more preferably 10 ^-1.4 ~10 ^{-2 .5} mol / l. The most preferable concentration of AgX solvent can be selected from 0 to 1 mol / liter. The dispersion medium concentration is 0.01 to 10 g / liter, preferably 0.1.
From 1 to 5 g / liter, the temperature is 10 to 100 ° C,
Preferably, each preferable condition can be selected from 20 to 90 ° C. The details of the AgX solvent and the dispersion medium can be referred to the description of the literature described later.

The tabular grains thus obtained have an edge surface of 1 to 100%, preferably 5 to 80% of the total edge area of {100}.
Can have a face. For details of the twin plane formation process, the process after twin plane formation, the growth process, the grain structure of the tabular grains and the halogen composition structure in the grains, see JP-A Nos. 58-113926 to 113928, 63-151618, 63-311244, JP-A-2-838, 1-158426, 2-298.
No. 935, No. 3-121445, No. 4-34544.
No. 5-204086, Japanese Patent Application No. 6-184128
No., the documents described in the section C, and the documents described later can be referred to.

The particles thus obtained may be used as host particles to form epitaxial particles. Further, particles having dislocation lines therein may be formed using the particles as a core. Alternatively, the particles may be used as a substrate, and AgX layers having a different halogen composition from the substrate may be laminated to produce various known particles having various particle structures. Regarding these, the description in the following literature can be referred to. Further, a shallow inner latent emulsion may be formed and used by using the tabular grains as a core. Also, core /
Shell type particles can also be formed. Regarding this, JP-A-59-133542 and 63-151618.
U.S. Pat. Nos. 3,206,313 and 3,317,
No. 322, No. 3,761,276, No. 4,269,9
The description in No. 27 and No. 3,367,778 can be referred to.

The AgX emulsion grains produced by the method of the present invention may be blended with one or more other AgX emulsions, or two or more emulsion grains of the present invention having different grain sizes may be blended and used. You can also The blend ratio (moles of guest AgX emulsion / moles of AgX emulsion after blending) is preferably in the range of 0.99 to 0.01, and an appropriate ratio can be appropriately selected and used. There are no particular restrictions on the additives that can be added to the emulsion of the present invention during the period from the grain formation to the coating step, and the amounts thereof can be added, and any conventionally known photographic additives can be added in optimal amounts. For example, an AgX solvent, a dopant for AgX particles (for example, a Group 8 noble metal compound, another metal compound, a chalcogen compound, an SCN compound, etc.), a dispersion medium, an antifoggant, a sensitizing dye (blue, green,
Red, infrared, panchromatic, ortho, etc.), supersensitizers, chemical sensitizers (sulfur, selenium, tellurium, gold and Group 8 noble metal compounds, phosphorus compounds, rhodan compounds, reduction sensitizers alone and Two or more of these), fogging agents, emulsion sedimenting agents, surfactants, hardeners, dyes, color image forming agents, color photographic additives, soluble silver salts, latent image stabilizers, developers (hydroquinone System compounds, etc.), pressure desensitizing agents, matting agents, antistatic agents, dimensional stabilizers and the like.

The AgX emulsion prepared by the method of the present invention can be used in all conventionally known photographic light-sensitive materials. For example, black-and-white silver halide photographic light-sensitive materials [for example, X-ray light-sensitive materials, printing light-sensitive materials, photographic paper, negative films, microfilms, direct positive light-sensitive materials, ultrafine dry plate light-sensitive materials (for LSI photomasks, shadow masks) , Liquid crystal masks)], color photographic light-sensitive materials (eg, negative film, photographic paper, reversal film, direct positive color light-sensitive material, silver dye bleaching method, etc.)
Can be used. In addition, diffusion transfer photosensitive materials (for example, color diffusion transfer elements, silver salt diffusion transfer elements), photothermographic materials (black and white, color), high-density digital recording photosensitive materials,
Examples include holographic materials. The silver coating amount can be selected to be a preferable value of 0.01 g / m ² or more. AgX emulsion production method (grain formation, desalting, chemical sensitization, spectral sensitization, photographic additive addition method, etc.) and equipment, AgX grain structure, support, undercoat layer, surface protective layer,
There are no restrictions on the composition of the photographic material (for example, layer composition, silver / coloring material molar ratio, silver ratio between layers, etc.), product form and storage method, emulsification and dispersion of photographic additives, exposure, development method, etc. , Any technology known or known in the future,
Embodiments can be used. For details of these, the description of the following literature can be referred to.

Research Disclosure
Disclosure) Volume 176 (Item 17643) (12
Mon, 1978), Volume 307 (Item 30710)
May, November, 1989), by Duffin, Photographic Emulsion Chemistry, Focal
Press, New York (1966), Bill (EJ Bir
r), photographic silver halide emulsion stabilization (Stabilization o)
f Photographic Silver Halide Emulsion, Focal Press, London (1974), James Ed. (TH James), Theory of Photographic Process (The Theor)
y of PhotographicProcess) 4th Edition, Macmil
lan), New York (1977)

P. Glafkides, Chemistry and Physics of Photography (Chimie et Physique Photographique), No. 5.
Edition, edition da lysine Novel
UsineNouvelle, Paris (1987), 2nd edition, Paul Montell, Paris (1957), Zerikman et al.
L. Zelikman et al.), Making and coating photographic emulsions (Making an
d Coating Photographic Emulsion), Focal Press (1
964), KR Hollister, Journal of Imaging Science
science), volume 31, p. 148-156 (1987
), JE Maskasky, pp. 30, p.
247-254 (1986) 32 volumes, 160-17
7 (1988), 33 volumes, 10-13 (1989)
Year),

Freezer et al., The Basics of Silver Halide Photographic Process (Die Grundlagen Der Photogrphischen Prozesse M
it Silverhalogeniden), Akademische Verlaggesellschaft, Frankfurt (1968). Helmut Gernscheim,
The History of Photography, Thames and Hudson, Lond
on (1969), JCIA Monthly Report, 1984, December issue, p.
18-27, Journal of the Photographic Society of Japan, Volume 49, 7-12 (19)
1986), 52 volumes, 144-166 (1989),
52, 41-48 (1989), JP-A-58-1
13926-113928, 59-90841, 58-111936, 62-99751, 60-1.
43331, same 60-143332, same 61-1463.
0, 62-6251,

JP-A-1-131541 and JP-A-2-838,
2-146033, 3-155539, 3-20
0952, same 3-246534, same 4-34544, same 2-28638, same 4-109240, same 2-7334.
6, Japanese Patent Application Nos. 2-326222 and 6-215513,
Other Japanese patents in the field of AgX photography, US patents, European patents, world patents, Journal of Imaging Science, Journal of Photographic Science.
graphic Science, Photographic Science and Engineering
d Engineering), Journal of the Photographic Society of Japan, Proceedings of the Photographic Society of Japan, International Congress of Photographic Scien
ce and The International East-West Symposiumon th
Lecture summary of e Factors Influencing Photographic Sensitivity. Japanese Patent Application Nos. 6-104065 and 5-32450
No. 2. The emulsions of the present invention are disclosed in JP-A Nos. 62-269958, 62-266538, 63-220238 and 6-62.
3-305343, 59-242539, 62
-253159, JP-A-1-131541 and 1-
No. 297649, No. 2-42, No. 1-158429.
Nos. 3-226730, 4-151649, Japanese Patent Application No. 4-179961 and European Patent 0508398A1.
It can be preferably used as a constitutional emulsion of the coated sample of the above example.

[0080]

Next, the present invention will be described in more detail by way of examples, but embodiments of the present invention are not limited thereto. Example 1 Gelatin solution-1 (1.2 liters of H ₂ O, 25 g of gelatin having an average molecular weight of about 100,000, KBr were added to the first reaction vessel.
Including 0.36g, pH 6.0 was added, the temperature was kept at 30 ° C, and Ag-1 solution (AgNO _{3 in} 1 ml) was stirred.
0.1g) and solution X-1 (0.0ml of KBr in 1ml).
706 g and 0.01 g of gelatin) were simultaneously mixed and added at 20 ml / min for 50 seconds to prepare a first fine grain emulsion. 2 ml of the emulsion was sampled, 0.5 ml of the dye-1 solution (0.1% by weight solution) was added and mixed, and the direct electron microscope observation was performed. The average particle diameter was about 0.04 μm.

Compound-1 solution (containing 30 ml of H ₂ O and 0.2 g of compound-1) and KBr-1 solution (KBr in 1 ml).
(Including 0.1 g) was added and mixed for 3 minutes, then Ag
Solution-1 and solution X-1 were simultaneously added at 15 ml / min for 3 minutes. 12 ml of KBr-1 solution was added, the temperature was raised to 70 ° C., and the mixture was aged for 15 minutes. Ag-1 solution at 3 ml / min 7
After addition minutes, and (NH _{4) 2} SO ₄ -1 solution [H ₂ O 20 ml
(Containing ₄ g of (NH ₄ ) ₂ SO ₄ ] and NaOH 1N solution, p
It was set to H9.0. After aging for 12 minutes, H ₂ SO ₄ 1
The pH was adjusted to 6 with the N liquid, and p was obtained using Ag-1 liquid and X-1 liquid.
Simultaneous mixed addition was performed while maintaining Br2.1. The Ag-1 solution was added at an initial flow rate of 3 ml / min and a linear flow rate acceleration amount of 0.18 ml / min for 38 minutes. After stirring for 2 minutes, the sensitizing dye-1 was adsorbed by 70% of the saturated adsorption amount. A precipitating agent was added, the temperature was lowered to 40 ° C., the pH was adjusted to 4.0, and the emulsion was coagulated and precipitated. After washing the emulsion 4 times with the conventional settling water washing method, a gelatin solution was added and redispersed to obtain a pH of 6.4 and pB.
The r was 2.8 and the yield was 1 liter. Antifoggant TAI
(4-Hydroxy-6-methyl-1,3,3a, 7-tetrazaindene) was added in an amount of 10 ^-3 mol / mol AgX.

[0082]

Embedded image

A 1 ml portion of the emulsion was sampled and a replica T of the grain was prepared.
When the EM image was observed, 95% of the total projected area of the grains were tabular grains having an aspect ratio of 3 or more, and the average grain diameter was 1.3 μm and the average thickness was 0.13 μm. The emulsion was heated to 55 ° C. and the gold sensitizer (chloroauric acid: NaSC
(N = 1: 50 molar ratio aqueous solution) in an amount of 6 × 10 ⁻⁶ mol / gold
Only mol AgX was added, and 2 minutes later, a Na ₂ S ₂ O ₃ .5H ₂ O aqueous solution (0.01 wt%) was added at 1 × 10 ⁻⁵ mol / mol AgX and the mixture was aged for 30 minutes. The temperature was lowered to 40 ° C., a thickener and a coating aid were added, and the mixture was coated on a cellulose triacetate base together with a protective layer at an Ag amount of 0.8 g / m ² . Sample 1 was dried and cut. Before adding the precipitant, 1.0 ml of the emulsion was sampled, and 2 ml of dye-1 liquid (0.01% aqueous solution) was added and mixed. Take out 0.1 ml,
It was diluted with 30 ml of pure water and the emulsion was centrifuged. The supernatant was discarded, 10 ml of pure water was added, and redispersed. 0.1 ml was taken and diluted with 100 ml of pure water. That 0.00
1 ml was taken, placed on a silver plate and dried. The grains were observed with a super SEM (scanning electron microscope), and the total number of tabular grains was about 550. On the other hand, an AgX emulsion was prepared with the same formulation except that the addition of the compound-1 was omitted in Example 1. When the number of tabular grains in the obtained emulsion was determined by the same method, it was three. Therefore, 9 of the produced tabular grains
It shows that 9% or more was generated by addition of the compound-1.

Example 2 By the same process as in Example 1, the same first fine grain emulsion as in Example 1 was first prepared. The gelatin degrading enzyme actinase (15 mg) was added to the emulsion and the mixture was allowed to stand at 30 ° C. for about 40 minutes to lower the gelatin molecular weight. The average molecular weight determined by measuring the viscosity reduction ratio of the emulsion and comparing it with the previously determined relationship (average molecular weight of gelatin-viscosity of aqueous gelatin solution) was about 10,000. Next, 5 ml of H ₂ O ₂ (3.1% by weight) solution was added, and after stirring for 10 minutes, 15 ml of KBr-1 solution was added, and then 20 ml of Ag-1 solution and X-1 solution were added.
Simultaneous mixed addition for 3 minutes. Then raise the temperature to 75 ° C,
Aged for 20 minutes. At this time, the enzyme was inactivated. Then A
Solution g-1 was added at 3 ml / min for 6 minutes. (NH _{4) 2} SO ₄ -1
The solution and NaOH 1N solution were added to adjust the pH to 9.0. After aging for 12 minutes, the pH was adjusted to 6 with H ₂ SO ₄ 1N solution, and Ag-
While maintaining pBr 1.8 using solution 1 and solution X-1,
Simultaneous addition was performed. The Ag-1 solution was added for 32 minutes at an initial flow rate of 3 ml / min and a linear flow rate acceleration amount of 0.2 ml / min. After stirring for 2 minutes, the sensitizing dye-1 was adsorbed by 65% of the saturated adsorption amount. Add a precipitating agent, lower the temperature to 40 ° C, and adjust the pH.
The emulsion was coagulated and set to 4.0. The subsequent steps were the same as in Example 1 to obtain a coated sample 2. The emulsion 1
ml was collected and the TEM image of the particle replica was observed,
96% of the total projected area of the grains were tabular grains having an aspect ratio of 3 or more, and the average grain diameter was 1.6 μm and the average thickness was 0.15 μm. Before adding the precipitating agent, 1.0 ml of the emulsion was sampled, and the dye-1 solution (0.01
% Aqueous solution), and mixed. 0.1 ml was taken out, diluted with 30 ml of pure water, and the emulsion was centrifuged. The supernatant was discarded, 10 ml of pure water was added, and redispersed. That 0.1
ml was sampled and diluted with 10 ml of pure water. That 0.0
01 ml was taken, placed on a silver plate and dried. The grains were observed with a super SEM (scanning electron microscope), and the total number of tabular grains was about 600. On the other hand, an AgX emulsion was prepared with the same formulation except that the addition of the degrading enzyme and H ₂ O ₂ was omitted in Example 2. When the number of tabular grains in the obtained emulsion was determined by the same method, it was 8. Therefore, it is shown that 98% or more of the produced tabular grains were produced by the addition of the degrading enzyme and H ₂ O ₂ . The emulsion collected just before the start of grain growth was spun down, and the supernatant was taken out and concentrated under reduced pressure. After cooling to 10 ° C. or lower to cause gelation, it was washed with cold water and desalted. Amino acid analysis revealed that the methionone content was 0 μmol / g. The methionine content of the original gelatin was 48 μmol / g.

Comparative Example 1 Gelatin solution-11 (containing 1.2 liters of H ₂ O, 15 g of gelatin, 1.0 g of KBr and 0.15 g of compound-1) was placed in a reaction vessel and the temperature was kept at 30 ° C. with stirring. Solution Ag-1 and solution X-1 were simultaneously mixed and added at 15 ml / min for 3 minutes. Next, 12 ml of KBr-1 solution was added, the temperature was raised to 70 ° C., and the mixture was aged for 15 minutes. 3 ml of Ag-1 solution
(NH ₄ ) ₂ SO ₄ -1 liquid and NaOH 1
Liquid N was added to adjust the pH to 9.0. After aging for 12 minutes,
The pH was adjusted to 6 with H ₂ SO ₄ 1N solution, and Ag-1 solution and X-1 solution were simultaneously mixed and added while maintaining pBr2.1. The Ag-1 solution was subjected to an initial flow rate of 3 ml / min and a linear flow rate acceleration amount of 0.2 ml / min for 38 minutes. After stirring for 2 minutes, the sensitizing dye-1 was adsorbed by 70% of the saturated adsorption amount. After the step of adding the precipitating agent, the same treatment as in Example 1 was carried out to obtain a coated sample 11. Observation of a TEM image of a grain replica in the emulsion revealed that 95% of the total projected area of the grain was a tabular grain having an aspect ratio of 3 or more, and the average grain diameter was 1.
The thickness was 2 μm and the average thickness was 0.14 μm. Samples 1, 2,
11 was exposed for 1/100 seconds through an optical wedge and a minus blue filter, and MAA-1 developer [2.5 g of metol, 10 g of ascorbic acid, 1.0 g of KBr, 35 g of sodium metaborate, and H ₂ O were added to make 1 liter. Then, development was performed at 20 ° C. for 10 minutes. The stop solution, the fixing solution and the washing solution were passed through and dried. The results of the photographic properties were compared in relative ratio (sensitivity / granularity). Sensitivity is (fog +
It is expressed by the reciprocal of the exposure amount giving a density of 0.2), and the granularity was measured according to the conventional method after uniformly exposing the sample with a light amount giving a density of (fog + 0.2) and performing the developing treatment. . The measurement results were as follows. Sample 11 (10
7), sample 2 (109), sample 11 (100). It was found that the example is superior to the comparative example. The coefficient of variation of the twin plane spacing variation of each tabular grain was determined by observation with a low-temperature electron microscope, and Example 1 (0.25),
It was Example (0.27) and Comparative Example 1 (0.43), and twin plane spacings were more uniform in Examples 1 and 2. 80 ml of the first fine particles of Example 1 was taken out, and a gelatin solution (gelatin 6 g, H ₂ O 120 ml, KBr 0.6 g) was used.
Including). While keeping the pBr value of the solution constant, Ag ⁺ solution and X ^- solution were added at an addition rate that does not generate new nuclei at 35 ° C and does not cause Ostwald ripening.
The first fine particles were grown to have a diameter of about 0.25 μm. When the TEM image of the replica of the generated particles was observed, the number was 99.7.
% Were twin-free grains.

Example 3 Gelatin solution-3 (1200 ml of H ₂ O, 25 g of oxidized gelatin having a methionine content of 0 μmol / g, KB) was placed in a reaction vessel.
pH of 6.0) containing 0.3 g of r
While maintaining the above, the Ag-1 solution and the X-1 solution were simultaneously mixed and added at 8 ml / min for 2 minutes. Then, the compound 3-1 in Table 1 was 8 ×
Only 10 ⁻⁴ mol was added and mixed with stirring for 10 minutes. Next, the temperature was raised to 60 ° C. and the pH was adjusted to 2.8 with HNO ₃ (3N) solution. 10 ml of KBr-1 solution was added. Ag-1 solution and X
Solution-1 was simultaneously mixed and added at 4 ml / min for 10 minutes. Next, the pH of the solution was adjusted to 9.0, 12 ml of KBr-1 solution was added, and the mixture was aged for 18 minutes. Next, the Ag-1 solution and the X-1 solution were simultaneously mixed and added while keeping the silver potential at -20 mV (vs. room temperature saturated calomel electrode potential). The start addition rate of Ag-1 solution is 5 ml / min, and the linear flow rate acceleration is 0.1 ml / min.
Minutes. After stirring for 2 minutes, the sensitizing dye-1 was adsorbed by 70% of the saturated adsorption amount. A precipitating agent was added, the temperature was lowered to 35 ° C., and the pH was adjusted to around 4 to coagulate and precipitate the emulsion. The subsequent steps were the same as in Example 1 to obtain a coated sample 3-1. The compound to be added is the same except that 3-2 to 3-11 is added instead of 3-1 in Table 1 to Ag.
X emulsion formation was performed. The same treatments as in Example 1 were carried out in the steps after particle formation, and the corresponding coated samples were 3-1 to 3-11. Table 1 shows the results of observing the TEM of the replica film of AgX particles obtained in each case. Sample 1
Exposure, development processing and photographic performance determination were carried out in the same manner as in Example 1, and the results are shown in Table 1. The sensitivity and granularity were determined in the same manner as above, and the results are shown in Table 1. In addition, the compound number in Table 1 refers to the compound having the number described in the text. a1 (%) indicates the projected area ratio% of tabular grains having an aspect ratio of 3.0 or more in the obtained AgX emulsion. a2 represents the relative value of (sensitivity / granularity). The photographic properties of the samples 3-1 to 3-11 were all better than that of Comparative Example 1.

[0087]

[Table 1]

[0088]

The AgX emulsion produced by the method of the present invention is excellent in (sensitivity / granularity).

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of an atomic model of the method of the present invention in which an adsorbent is adsorbed on silver halide grains to form twin planes.

FIG. 2 is a schematic view of a grain cross section when two twin planes are formed on the {111} plane of the first fine particles.

[Explanation of symbols]

11 …… Molecule of the first adsorbent 12 …… Ag ⁺ atom 13 …… Halogen ion 14 …… Stacking fault atomic layer 21 …… Silver halide first fine particles 22 …… Twin plane

Claims (4)

[Claims] 1. A method for producing a silver halide emulsion having at least silver halide grains and a dispersion medium, wherein 60% or more of the total projected area of the silver halide grains has an aspect ratio (diameter / thickness) of 2 or more. It is a tabular silver halide grain having the above parallel twin planes, the production method includes the following process, and the number of parallel twin grains to be generated is from 20 to 100.
% Is formed in the step c), a method for producing a silver halide emulsion. a) A silver salt solution and a halogen salt solution are added to an aqueous solution containing a dispersion medium to have substantially no twin planes (the number ratio of particles having two or more twin planes is 0 to 25%). Step of forming a silver halide first fine grain emulsion. b) subject the first fine grain emulsion to one or more of the following treatments. The dispersion medium concentration is reduced to the original 0.1-50%. Dispersion medium molecules are decomposed to lower the weight average molecular weight of the dispersion medium to 1 to 60% of the original weight. One or more groups of methionine group, imidazole group, alcohol group and amino group of gelatin are reduced to 0-60% of the original number. When added to the first fine grain emulsion, it is adsorbed on the first fine grains, and the first adsorbent forcibly increasing the parallel twin plane formation probability in the following step c) is added. c) A step of adding silver ions and halogen ions to the first fine grain emulsion to form parallel twin planes on the first fine grains. 2. The first adsorbent is N, P, S, Se,
Compounds containing one or more onium bases of I, As, Sb, and Sn atoms in one molecule, nitrogen-containing heterocyclic compounds, SCN ^- salt compounds, spectral sensitizing dyes, antifoggants, and divalent compounds Sulfur-containing heterocyclic compounds, divalent sulfur-containing organic compounds, aminothioethers,
2. One or more of thiourea or a derivative thereof.
A method for producing a silver halide emulsion as described above. 3. The step c) is performed after the step a), after adding the first adsorbent and adsorbing the adsorbent onto the first fine particles. 1. The method for producing a silver halide emulsion according to 1. 4. The halogen according to claim 1, wherein the first adsorbent is an ammonium base-containing compound selected from pyridinium quaternary salts, triazolium salts, protonated organic amine compounds and quaternary ammonium compounds. Method for producing silver halide emulsion.