JPH04139442A - Silver halide photographic emulsion and production thereof - Google Patents

Abstract

PURPOSE:To obtain the photographic emulsion which has a high sensitivity, the stability of the particles themselves and the high degree of freedom of the selection of spectral sensitizing dyes by incorporating joint type particles joined with crystals substantially consisting of a silver iodide in the respective corner parts of octehetral silver halide particles and/or the intersected lines of twin faces into this emulsion. CONSTITUTION:The joint type particles joined with the crystals substantially consisting of the silver iodide in the respective corner parts of the octehetral silver halide particles and/or the intersected lines of the twin faces are incorporated into this emulsion. The silver iodide particles to be added are preferably as fine as possible and are easily soluble again. These particles are preferably used in the shortest possible time after the prepn. The photographic emulsion which has the high stability, the high degree of freedom of the selection of the dyes in the case of execution of spectral sensitization and has the high degree of the freedom of the selection of the spectral sensitizing dyes is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a light-sensitive fine grain emulsion comprising silver halide grains and a method for producing the same.

(Prior art) A large number of studies have been carried out on bonded grains of silver halide. For example, if we express the relationship between guest and host as guest/host, MaskaSkV has investigated the relationship between silver nitrate and silver halide in an emulsion containing hexagonal Agl. By simultaneous addition of a solution of chloride salt, AgCj! /^gr type bonded particles were obtained (J, E, MaskaskyPhotogr, Sc
i, Eng, vol. 25, p. 96 (1981); U.S. Pat. No. 4,094,684, U.S. Pat.
Bonded particles of (U.S. Pat. No. 4,142,900;
Unexamined Japanese Patent Publication No. 55-149933, No. 55-1,449,93
4, No. 55-163.532).

All of these are A on the (00011 plane) of the host particle Agl.
gCJ and AgBr (C1) take advantage of the characteristic of selective growth.Furthermore, a spectral sensitizing dye is adsorbed to the octahedral AgBr or AgBr1, and Ag(1!) is grown on the corners and ridges of the octahedron. It is also known that A particles are added to the corners of AgCl1 by using a partial substitution reaction with bromide ions for AgCl particles (U.S. Pat. No. 4,463.087).
A g Br / A g produced by selectively growing gBr
Cl type particles (JP-A-62-7040) and the like are also known.

Research has been conducted on these bonded particles in hopes of improving sensitivity, gradation, graininess, spectral sensitization performance, etc. that cannot be obtained with host particles alone.
limited to the host interface and only the guest is developed first (J, E, Maskasky J, I+*ag,
Sci, vol. 32, p. 160 (1988)). However, most bonded grains obtained using silver iodobromide as a host are prepared in a site-limited manner in the presence of a spectral sensitizing dye or other adsorptive substance. Some of them are prepared without a site director, such as AgBr/AgCβ bonded particles (Japanese Patent Application Laid-open No. 627040) obtained by substitution reaction of silver chloride with bromide ions, but even these particles cannot be prepared as is. The guest particles are extremely unstable and unless a highly adsorbent substance such as a spectral sensitizing dye or mercaptotetrazole is immediately added to fix them, the guest particles will deform and virtually disappear. On the other hand, bonded grains obtained using silver iodide as a host are prepared without a site director and are generally highly stable. but,
This type of bonded grain, which is mainly composed of silver iodide, has a slow development speed and has not been put to practical use to date. Therefore, to date, there has been no known case in which silver iodide is grown as getos in the corners of an octahedral silver halide host. If such emulsion grains could be obtained without a site director by some method, they would not only be extremely stable but also have sufficient development activity, and the degree of freedom in selecting dyes for spectral sensitization would be great. Since they are no different from ordinary grains, if the high sensitivity and other advantages generally found in bonded grains are added, it is expected that a very useful emulsion will be obtained.

(Problems to be Solved by the Invention) The object of the present invention is to form site directors on the corners of octahedral silver halide grains, which are extremely practical as photographic emulsion grains, and/or on the intersection lines of the grain surfaces and twin planes. It is an object of the present invention to provide a photographic emulsion containing bonded grains which are made by epitaxially growing silver iodide without the use of silver iodide, have high sensitivity, are stable grains themselves, and have a high degree of freedom in selecting a spectral sensitizing dye, and a method for producing the same.

(Means for Solving the Problems) The above objects of the present invention were achieved by the following fll and (2).

(1) A silver halide photographic hole side containing bonded grains in which crystals substantially made of silver iodide are bonded to each corner of octahedral silver halide grains and/or on the intersection line of twin planes.

(2) Silver halide fine grains containing at least a portion of silver iodide with a solid solution ratio of 95 mol% or more are added to octahedral silver halide host grains, and the corners of the host grains are redissolved. A manufacturing method in which silver iodide is selectively grown on the intersection of the grain surface and the twin plane.

In addition, when simply referred to as silver iodide in the present invention, the solid solution ratio is 95.
% or more of silver iodide.

In the present invention, it is desirable that the silver iodide fine particles added be as fine as possible and easily redissolved. In that sense, the average diameter is preferably 0.1 μm or less, more preferably 0.05 μm or less, and most preferably 0.01 μm.
m or less.

It is also preferable to use the silver iodide fine grains as soon as possible after preparation, and preferably to add them to the host system within 1 minute after preparation. It is more preferable that the time is within 10 seconds, and most preferable that it is within 3 seconds. For this purpose, fine silver iodide particles are produced by guiding both warm liquids of soluble silver salt and soluble halide into a coaxial nozzle consisting of a T-shaped tube, Y-shaped tube, or double tube, which is set somewhat deeper than the outlet of the outer circumferential tube. Preferably, the mixture is prepared by instantaneous mixing in the space between the outlet of the inner tube and the outlet of the outer tube, and immediately released into the solution containing the host particles. Of course, for this purpose, it is also possible to use a method in which silver nitrate and silver iodide are prepared in advance in a small tank for preparing silver iodide by the double jet method, and then introduced continuously into the host grain system. However, among these methods, the coaxial nozzle method is most preferable because it is simple, there is no risk of clogging of pipes due to aggregated particles, and the difference in scale is small.

It is preferable that the temperature for preparing silver iodide is as low as possible;
Normally, room temperature preparation is sufficient to achieve the purpose.

Of course, the solvent<i! It is more preferable that the temperature be lower than room temperature, with the lower limit being the freezing point of water (usually water).

When preparing silver iodide, especially when using a T-tube method, a Y-tube method, a vortex mixing nozzle method, or a coaxial nozzle method in which a silver salt solution is directly reacted with a nozzle solution, it is necessary to prevent agglomeration between grains. It is desirable to add a preservative to the halogen side and/or silver salt side. As the preservative, it is desirable to use low molecular weight gelatin (molecular weight of 50,000 or less), which does not set even at room temperature or lower temperatures, since it is usually prepared at low temperatures.

When using this low molecular weight gelatin, the amount of gelatin added is preferably 1% or more based on the weight of the silver iodide emulsion produced. Of course, ordinary gelatin may be used at a concentration of 1% or less, or other water-soluble polymers or surfactants having adsorption properties for silver halide may be used.

A variant of the soluble silver salt used to prepare silver iodide for addition is silver nitrate, and representative examples of soluble iodides include potassium iodide, sodium iodide, ammonium iodide, and the like. This halide solution may contain chloride ions and bromide ions in addition to iodide ions, but the amount of iodide ions added per unit time is at least 0.
It is necessary that the amount is 45 equivalents or more. In addition, it is preferable that the amount of iodide ions added per unit time does not greatly exceed the equivalent of silver ions, and should be equal to the molar amount of silver ions or slightly less than the molar amount of silver ions, or within a range that ensures excess halogen in the host pore side system. Best. The content of silver iodide contained in the ultrafine silver halide grains to be added is preferably 50% or more, and more preferably 80% or more.

Further, the concentration of the silver salt and iodide-containing halide used for addition to prepare ultrafine silver iodide grains is not particularly limited, but is preferably 0.5N or less in order to prevent agglomeration of the produced silver iodide fine grains. , especially 0. More preferably, it is less than IN.

The speed at which silver iodide grains are added is also an important factor; if it is added at a high speed, silver iodide will grow evenly at each corner of the octahedral host grain, but if it is added slowly, silver iodide will grow evenly at each corner of the octahedral host grain. Some of them grow significantly, for example to 1 or 2 points. The rate of addition of silver iodide is selected depending on the purpose of the sheet. Usually, the addition rate of silver iodide is in the range of 10-4 to 10-1 mol per minute per mol of host grains.

The octahedral silver halide host grains are substantially pure silver bromide,
Alternatively, silver iodobromide is preferred, and the silver iodide content of the silver iodobromide solid solution should not exceed 45 mol%. However, the host particles may contain different kinds of sparingly soluble silver salts such as silver chloride, silver Rodan, silver sulfide, etc., as a solid solution or a bond. The solid solution rate of silver chloride is within the limit for obtaining octahedral grains, and in the case of other w1-soluble silver salts, the upper limit is 5 mol %. Further, the host octahedral grains may be normal crystals or may contain twin planes.

The molar ratio of silver iodide guest crystals to host grains is arbitrary, but is preferably in the range of 10-3 to 10-1, more preferably in the range of 10-2 to 5.times.10.sup.4.

If the addition speed of silver iodide is fast and not all of the silver iodide is redissolved and turned into guest crystals within the addition time, it is necessary to allow an appropriate amount of time for physical ripening.

The time varies depending on the addition speed and amount of silver iodide, the temperature of the host solution system, the presence or absence of a solvent, etc., but for example, 65°C
When the temperature is about 75°C and no solvent is used, the process is completed within about 30 minutes. Of course, if the addition rate is low and balanced with the redissolution rate, it is not necessary to take any particular time for physical ripening.

The octahedral silver halide emulsion having Agl guest grains of the present invention may be used in combination with other emulsions.

Although the mixing ratio is arbitrary, it is preferably 50% or more in terms of moles, and more preferably 80% or more.

In the process of silver halide grain formation or physical ripening,
A cadmium salt, a zinc salt, a lead salt, a thallium salt, an iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, an iron salt or an iron complex salt, etc. may be present.

The silver halide photographic emulsion of the present invention can be chemically sensitized if necessary.

For chemical exacerbations, e.g. H, Fr1eser kM
Die Grundlagen der Photog
raphischen Prozessewit S
ilberhalogeniden (Akade+si
scheVerlagsgesellschaft,
1968), pages 675-734, can be used.

That is, sulfur-containing compounds that can react with active gelatin and silver (e.g., thiosulfates, thioureas, mercapto compounds, rhodanine I); reducing substances (e.g., stannous salts, reduction sensitization using noble metal compounds (e.g., gold complex salts,
A noble metal sensitization method using complex salts of metals of group 1 of the periodic table such as pt, Ir, and Pd, a selenium sensitization method, etc. can be used alone or in combination.

Specific examples of these include U.S. Patent No. 1 for sulfur sensitization.
, 574,944, 2.410゜689, 2,278,947, 2゜728.668, 3.656,955, etc., regarding the reduction sensitization method in the United States. Patent No. 2,983.609, Patent No. 2.419,974
U.S. Pat. No. 2,399.083 and U.S. Pat. No. 2.448 for noble metal sensitization methods
It is described in various specifications such as No. 060 and British Patent No. 618,061.

In particular, gold sensitization, sulfur sensitization, or a combination thereof is preferred for the silver halide photographic emulsion of the present invention.

As the dispersion medium (binder or protective colloid) for the photographic emulsion of the present invention, it is advantageous to use gelatin, but other hydrophilic colloids can also be used.

For example, gelatin derivatives, graft polymers of gelatin and other polymers, proteins such as albumin and casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, and cellulose sulfates; sugar derivatives such as sodium alginate and starch derivatives; polyvinyl alcohol , polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid,
A wide variety of synthetic hydrophilic polymeric materials can be used, such as single or copolymers of polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, and the like.

Gelatin includes lime-processed gelatin, acid-processed gelatin, Bull, Soc, Sci, Phot, J
Enzyme-treated gelatin as described in APAN, N1116, page 30 (1966) may be used, and gelatin hydrolysates and enzymatically decomposed products may also be used.

Examples of gelatin derivatives include a wide variety of compounds such as acid halides, acid anhydrides, isocyanates, bromoacetic acids, alkanesultones, vinyl sulfonamides, maleimide compounds, polyalkylene oxides, and epoxy compounds. The product obtained by reacting is used.

Specifically, the dispersion medium used in the present invention is
Disclosure (RESEARCHDrSCLO3
URE) Volume 176, m17643 (December 1978
Month) is listed in ■ section.

The photographic emulsion used in the present invention can contain various compounds for the purpose of preventing fog during the manufacturing process, storage, or photographic processing of the light-sensitive material, or for stabilizing photographic performance. Namely, azoles such as benzothiazolium salts, nitroimidazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles. mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxadolinthion; azaindenes, e.g. Triazaindenes, tetraazaindenes (especially 4-hydroxy-substituted (1,3,3a,7) tetraazaindenes), pentaazaindenes, etc.; benzenethiosulfonic acid, benzenesulfinic acid, henzenesulfonic acid amide A number of compounds known as antifoggants or stabilizers can be added, such as.

For more detailed examples of these and how to use them, see, for example, U.S. Pat.
Those described in No. 82,947 and Japanese Patent Publication No. 52-28.660 can be used.

The photographic emulsion layer or other hydrophilic colloid layer of the light-sensitive material prepared using the present invention may contain coating aids, antistatic properties, smoothness improvement, emulsification dispersion, adhesion prevention, and photographic property improvement (e.g.
Various surfactants may be included for various purposes such as development acceleration, contrast enhancement, and sensitization.

For example, saponins (steroids), alkylene oxide derivatives (e.g. polyethylene glycol, polyethylene glycol/polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycols Nonionic surfactants such as alkylamines or amides, polyethylene oxide adducts of silicone), glycidol derivatives (e.g. alkenylsuccinic acid polyglycerides, alkylphenol polyglycerides), fatty acid esters of polyhydric alcohols, alkyl esters of sugars, etc. Agents; alkyl carboxylates, alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfur esters, alkyl phosphates, N-acyl-N-alkyl taurines, sulfosuccinates, sulfonate Carboxyl compounds such as alkyl polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl phosphates, etc.
Anionic surfactants containing acidic groups such as sulfo groups, phospho groups, sulfate ester groups, phosphate ester groups; amino acids;
Amphoteric surfactants such as aminoalkyl sulfonic acids, aminoalkyl sulfates or phosphates, alkyl betaines, and amine oxides; complexes such as alkyl amine salts, aliphatic or aromatic quaternary ammonium salts, pyridinium, and imidazolium. Cationic surfactants such as ring quaternary ammonium salts and phosphonium or sulfonium salts containing aliphatic or heterocycles can be used.

In the present invention, a fluorine-containing compound can be used for purposes such as antistatic, antiadhesion, improved slipperiness, and coating aid. As a specific compound, JP-A-49-1072
No. 2, No. 50-16525, No. 53-84712,
No. 54-48520, No. 54-14224, No. 56
-43636, 57-26719, 57-14
No. 6248, No. 56-114945, No. 58-196
No. 544, No. 58-200235, Patent Application No. 59-23
63901, British Patent No. 1.259,398, 1.
, 417.915 etc.,
Also, U.S. Patent Nos. 4,175,969 and 4,087,3
No. 94, No. 4,016°125, No. 3,676.12
No. 3, No. 3,679.411, No. 4,304,852
No., JP-A-52-129520, JP-A No. 54-15822
No. 2, No. 55-57842, No. 57-11342,
No. 57-19735, No. 57-179837, Japanese Patent Application No. 60-202438, “Chemistry Review Volume 27, New Fluorine Chemistry” (Nippon Kagaku Kinsen, 1980), “Functional Fluorine-containing High Molecules” (Nikkan Kogyo Shimbun, 1982), etc., or JP-A-16565-1985
Examples include the inorganic compounds described in No. 0.

For the purpose of increasing sensitivity, increasing contrast, or accelerating development, the photographic emulsion layer of the photographic light-sensitive material produced using the present invention contains, for example, polyalkylene oxide or its derivatives such as ethers, esters, and amines, thioether compounds, and thiomorpholine. class, quaternary ammonium salt compounds, urethane derivatives, urea derivatives, imidazole derivatives, 3-
It may also contain virazolidones and the like.

The photographic light-sensitive material produced using the present invention may contain a dispersion of a water-insoluble or I-soluble synthetic polymer in the photographic emulsion layer or other hydrophilic colloid layer for the purpose of improving dimensional stability. For example, alkyl (meth)acrylate, alkoxyalkyl (meth)acrylate, glycidyl (
Meth)acrylate, (meth)acrylamide, vinyl ester (e.g. vinyl acetate), acrylonitrile, olefin, styrene, etc. alone or in combination, or with acrylic acid, methacrylic acid, α, β unsaturated dicarboxylic acid, hydroxyalkyl ( A polymer containing a combination of meth)acrylate, sulfoalkyl(meth)acrylate, styrene sulfonic acid, etc. as a monomer component can be used.

Photographic emulsions using the present invention may be spectrally sensitized to relatively long wavelength blue, green, red or infrared light with an enhancing dye. As the sensitizing dye, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes, etc. can be used.

These sensitizing dyes are advantageously used at dye concentrations that do not substantially reduce the inherent sensitivity of the silver halide emulsion. Approximately 1.0 x 10- of sensitizing dye per mole of silver halide
It is preferred to use concentrations of from about 5.times.10@-3 moles to about 5.times.10@-3 moles, particularly from about 4.times.1 O-S to 2.times.10@-3 moles of sensitizing dye per mole of silver halide.

The sensitizing dye used in the present invention is RESEAR (J
IDISCLO3URE Volume 176 1te+*17
643 IT Section P, 23 (December 1978 issue).

Here, the sensitizing dye can be used in any step of the manufacturing process of the photographic emulsion, or can be present in any stage after manufacturing until immediately before coating. Examples of the former include a silver halide grain formation process, a physical ripening process, and a chemical ripening process.

The emulsions of the present invention include the following color image-forming couplers, i.e., aromatic primary amine developers (e.g.
It may also contain a compound that can develop color through oxidative coupling with phenylenediamine derivatives, aminophenol derivatives, etc.).

The coupler is preferably a non-diffusible coupler having a hydrophobic group called a ballast group in its molecule, or a polymerized coupler. The coupler may be either 4-equivalent or 2-equivalent to silver ions.

It may also contain a colored coupler that has a color correction effect or a coupler that releases a development inhibitor during development (so-called DIR coupler).

The product of the coupling reaction may also be colorless and include a colorless DIR cambling compound that releases a development inhibitor.

For example, magenta couplers include 5-pyrazolone couplers, pyrazolobenzimidazole couplers, cyanoacetylcoumarone couplers, open-chain acylacetonitrile couplers, and yellow couplers include acylacetamide couplers (e.g., benzoylacetanilides, pivaloylacetanilides), Examples of cyan couplers include naphthol couplers and phenol couplers.

The photographic material of the present invention may contain an inorganic or organic hardening agent in the photographic emulsion layer or other hydrophilic colloid layer. Examples include chromium salts (chromium alum, chromium acetate, etc.), aldehydes (formaldehyde, glyoxal, geltaraldehyde, etc.), N-methylol compounds (dimethylol urea, methylol dimethylhydantoin, etc.), dioxane derivatives (2,3-dihydroxydioxane, etc.) ), activated vinyl compound (1,3°5-triacryloyl-hexahydro-s-triazine, I,3
-vinylsulfonyl-2-propatol, etc.), active halogen compounds (2,4-dichloro-6-hydroxy-5
-) riazine, etc.), mucohalogen acids (mucochloric acid, mucophenoxychloric acid, etc.), etc. can be used alone or in combination.

The various additives mentioned above are used in the emulsion of the present invention.
CLO3URE 1st 7 6@, Item
1 7 6 43, p.

23-P, 28 (December 1978), Volume 187, rte+w18716, P, 648-P, 650
(November 1979).

Also, these RESEARCHDISCLO5Ul?
Other additives listed in E can also be used.

The silver halide emulsion of the present invention is coated on a support in one or more layers (for example, two or three layers) together with other emulsions if necessary.
can be provided. Moreover, it can be provided not only on one side of the support but also on both sides. Furthermore, they can be layered as emulsions with different color sensitivities.

The silver halide emulsion of the present invention can be used in black-and-white silver halide photographic materials (e.g., X-ray sensitive materials, lithographic materials, negative films for black-and-white photography, etc.) and color photographic materials (e.g., color negative films, color reversal films, etc.). , color paper, etc.). Furthermore, photosensitive materials for diffusion transfer (e.g., color diffusion transfer elements, silver salt diffusion transfer elements)
It can also be used in heat-developable photosensitive materials (black and white, color), etc.

Example 1 A stirring blade was applied to 11 aqueous solutions kept at 65°C containing 0.2 mol of monodisperse octahedral silver bromide particles with an average equivalent sphere diameter of 0.86 μm, KB r 10-” sol, and 20 g of gelatin. A double-pipe coaxial nozzle 3 as shown in Fig. 1 is installed below (the inner pipe 4 has an inner diameter of 1 m and an outer diameter of 2 m).
m, the outer peripheral tube 5 is made of steel with an inner diameter of 2.2 mm and an outer diameter of 32 mm,
The outlet 6 of the inner ring pipe is 21111 higher than that of the lower outlet of the outer pipe.
The inner tube (set at the back) was filled with Kl solution 2 containing 0.05N 2wt% gelatin with a molecular weight of 20,000, and the same <0.05N was placed on the outer tube.
05N AgN0. While simultaneously adding solution 1 at a rate of 100-min for 1 min, reaction product 8 was released and physical ripening was performed for 15 min. As seen in Figure 2, new crystals were selectively formed in the corners. is formed (emulsion 1-A>). It is clear from the Cukα and XwA diffraction profiles of the Cukα and line in FIG. 3 that this newly formed crystal at the corner is γ-Agr. is in solid solution).

As a comparative example, in the case of grains (emulsion 1B) obtained under the same conditions except for normal simultaneous addition without using a coaxial nozzle, Agl was generated not only in the corner areas but also in the edge areas, resulting in decreased site selectivity. It can be seen that (Fig. 4), and the nitrate Mw
When only the Kl solution was added in the same manner without adding Kl (emulsion 1-C), the grain photograph was as shown in FIG. 5, and Agl was formed only at the edges. It has been shown that when a part of the AgBr particles is directly converted to Agl with concentrated iodine ions, two-dimensional nucleation of the epitaxially grown Agl phase occurs on the edges of AgBr. Therefore, it can be seen that the double jet method that does not use a coaxial nozzle is exactly between the conversion method using Kl alone and the coaxial nozzle method, and that secondary nucleation of Agl occurs at both corners and edges.

Example 2 0.025 N was added to an 800-aqueous solution kept at 65° C. containing 0.1 mol of monodisperse octahedral silver bromide with an equivalent sphere diameter of 0.86 μm, 0.01+gol of potassium bromide, and 13 g of gelatin. Nitrogen #silver and gelatin with a molecular weight of 20,000 2
Particles obtained by simultaneously adding 0.025 N potassium iodide aqueous solution containing 0.025 N potassium iodide aqueous solution for 1 minute through the axial nozzle between double tubes used in Example 1, and performing physical ripening for 15 minutes ( In emulsion ff-A), as in FIG. 2, silver iodide was grown evenly at the six corners of the octahedral silver bromide.

Meanwhile, the above solutions of silver nitrate and potassium iodide were each added at a rate of 1 min.
- when added over 100 minutes at a rate of (emulsion [[
A photograph of the particles of -B) is shown in FIG. In this case, no time is required for physical ripening, and each one of the six corners of the octahedral silver bromide has large silver iodide crystals at one or two extremely limited corners. It can be seen that it is growing.

Example 3 Monodisperse octahedral silver iodobromide AgBr0.9B±0.02 and 0°01 with an equivalent sphere diameter of 0.84 μm in 0, 1 s+ol
0.05N containing 0.05N silver nitrate and 2% by weight of gelatin with a molecular weight of 20,000 in an aqueous solution of 801)d kept at 75°C containing mol of potassium bromide and 13g of gelatin.
At the same time, 100 id of each potassium iodide aqueous solution was added over 1 minute through the double tube interaxial nozzle used in Example 1, and physical ripening was performed for 20 minutes (Sample III-A).

Instead of the coaxial nozzle used in the above experiment,
Sample 11-B was prepared using a T-tube. Furthermore, instead of a coaxial nozzle, 0. 0.0% containing IN silver sulfate and 2% by weight of gelatin with a molecular weight of 20,000. An aqueous solution of potassium iodide (IN) was introduced into a small tank with an internal volume of 11 mm at a rate of 1 ml and a gelatin solution of 1 wt. Ultrafine silver grains were prepared, and the continuously produced silver iodide emulsion was extruded and passed through a 40 cm long tube with an inner diameter of 1 lIl.
Sample m-c was prepared by releasing the solution containing the host emulsion over a period of 1 minute in the effective stirring area and subjecting it to physical ripening for 20 minutes. In each of Samples A, B, and C, Agl crystals were grown evenly at each corner of the octahedral silver iodobromide. For comparison, grains obtained by the same method using a solution of silver nitrate and potassium iodide and the usual double jet method had silver iodide growing not only at the corners but also at the edges.

Example 4 1000 ml of monodisperse octahedral pure silver bromide particles with an equivalent sphere diameter of 0.86 μm, 0.01 wol of potassium bromide, and 20 g of gelatin kept at 65° C.
- to an aqueous solution of 0.05N silver nitrate and a 0.05N potassium iodide aqueous solution containing 2% by weight of gelatin with a molecular weight of 20,000 were added simultaneously through the double tube coaxial nozzle used in Example 1 for 1 minute each at 100 -. , physical aging was performed for 15 minutes. The epitaxial emulsion in which silver iodide crystals were evenly grown at the six corners of the octahedral silver bromide grains obtained in this way was washed by precipitation in accordance with a conventional method, and 30 g of water and gelatin were added to give a 1% Add KBr3.2d, lNNa
The pH was adjusted to 6.5 with OH to prepare a 440 g emulsion (emulsion IV-A). For comparison, Emulsion IV-B was prepared in the same manner except that the coaxial nozzle was not used and the silver nitrate and potassium iodide solutions were added by the conventional double jet method. As a comparison, the octahedral silver bromide host grains 0. 2+sol was washed with precipitation in the same manner without adding silver nitrate and potassium iodide solution, water and 30 g of gelatin were added, 1% KBr3.2- was added, and l
A 440 g emulsion adjusted to pH 6.5 with NNaOH was prepared (emulsion 1-C). Each emulsion IV-A, B, and C was subjected to chemical ripening using chloroauric acid and sodium thiosulfate to give the highest sensitivity to each emulsion. That is, emulsion rV
- For A and B, 75g each was heated to Naz at 60℃
SgO* 0.1% aqueous solution of HsH,o 1.0d1HA
A 0.5% aqueous solution of uCji4H4H20 at 0.5% was added and aged for 60 minutes. 0.01% for emulsion IV-C
NazS203 Hso,.

1.2'd, 0.01%1 (AuCj!, '48z0
0. 6- was added and aged at 60°C for 60 minutes. Coating aids were added to each of these emulsions to form dry gelatin.
[Apply the gelatin protective layer equivalent to 1.6 μm in one coat onto PET to give a silver content of 2.4 g/ffr,
Color temperature 28 through band pass filter BPB42
54°, 1000 lux, 1/10 second wedge exposure, developed with MAA-1 developer at 20°C for 10 minutes, fixed, washed with water, and dried to obtain fog + 0.1 optical power. The results of comparing the relative values of exposure amounts are shown in Table 1 (the smaller the number, the higher the sensitivity). However, samples IV-A, B,
C is a coating sample of emulsion IV-A, B, and C, respectively.

Thus, it can be seen that the sample of the present invention is superior in sensitivity to the comparative sample.

Table 1 Relative sensitivity comparison between Sample IV-A, B, and C Example 5 4.5 g of KBr, 7 g of gelatin with a molecular weight of 20,000, IN K
To 11 aqueous solutions containing OH1,2id kept at 30 °C, 25-2NAgN (h) and 2.08NKBr were each added simultaneously over 1 minute, and after 1 minute, IN
35 containing KOH5,5d and 32g ossein gelatin
Add solution at 60 °C (ld for 30 seconds, then 7 minutes for 30 minutes)
After a few seconds, the reactor solution was raised to 75°C over 10 minutes, kept at 75°C for 12 minutes, and then
AgN (h) was added over 3 minutes at a rate of 6.3 d/min. After 2 minutes, 25% NH320ad and 50% NI1.
A mixed solution of N (h 20 lR1) was added, and after 8 minutes, 3N AgN0. and 3N KBr were added to pBr by 2.
They were simultaneously added over a period of 4 minutes while maintaining the temperature at 60°C. however,
The flow rate of 3NAgNO+ at this time was 16 d per minute. After that, 3N A was applied while keeping the pBr at 1.75.
g) JO, and 3N KBr were added simultaneously over a period of 14 minutes and 30 seconds. However, the addition rate of 3N AgN (h) at this time was 40-min/min. Then water and gelatin are added, and the resulting emulsion is p
It was adjusted to H6.5, contained 200 g of gelatin, and had a total weight of 2360 g (average equivalent sphere diameter 0.95 μm). Add 59g of this emulsion, 2g of KBrl, and 5g of gelatin.
The emulsion made by adding g to 1j2 was heated to 65°C, and 1.25X
1ON AgNO3 and 1! A 1.25 x 10-" NKI containing 2% by weight of gelatin with a molecular weight of 20,000 was introduced into the coaxial nozzle shown in Example 1, and 100-" NKI was added at a constant speed for 1 minute each, and then allowed to stand for 15 minutes. The final product contained 20 g of gelatin, had a total weight of 217 g, had a pH of 6.5, and had a pAg of 8.

Emulsion No. 4 was obtained. This emulsion is referred to as Emulsion 'v''-A, and an electron micrograph of its grains is shown in Figure 7 using the replica method.As is clear from the photograph, Ag+ guest crystals are located at the corners of the octahedral twin grains and in the grains. It is generated on the intersection line between the surface and the twin plane.

On the other hand, for comparison, water and gelatin were added to 59 g of an octahedral twin emulsion, which is the host emulsion of emulsion V-A, to obtain emulsion V-B having the same composition as emulsion V-A. Furthermore, according to the usual method, the average equivalent sphere diameter, which does not include twin planes, is 0. Octahedral silver bromide grains of 97 μm were prepared, and an emulsion having the same composition as emulsion V-A was prepared (emulsion V-C).

Thereafter, chemical sensitization was performed to give the optimum sensitivity for each emulsion. That is, per 75 g of emulsion, emulsion V-A contains Na.
0101% solution of zSzO3.5 LO 8-1HAuC
fs H4)1. A 0.01% solution of NazS 4- was added to emulsions V-B and V-C, and 0.001% NazS
zOx H51 (208m, 0.001% HAuCf
-・4) 1zo 4 d was added and the mixture was aged at 60°C for 60 minutes. These emulsions were coated on a PET base so that the amount of silver coated per 1 d was 1.2 g, and the relative sensitivities were compared under the same exposure and development conditions as in Example 4.

As in Example 4, Table 2 shows the relationship between the relative exposure amounts required to reach fog +0.1 in terms of optical density.

Table 2 Comparison of relative sensitivity among Samples V-A, B, and C It can be seen that the sample of the present invention is superior in sensitivity to the comparative sample.

[Brief explanation of the drawing]

Figures 1 to 7 show the following, respectively. Figure 1: Coaxial nozzle used in Example 1. Figure 2: Electron micrograph of the grain structure of emulsion 1-A obtained by the coaxial nozzle method. Figure 3: X-ray diffraction profile (CuKαl line) of bonded grains of emulsion 1-A. Figure 4: Electron micrograph of the grain structure of Emulsion 1-B. Figure 5: Electron micrograph of the grain structure of emulsion I-C. Figure 6: Electron micrograph of the grain structure of Emulsion 11-B. Figure 7: Electron micrograph of the grain structure of emulsion V-A. The numbers in FIG. 1 have the following meanings: 1: Soluble silver salt solution 2: Halide solution 3: Double coaxial nozzle 4: Inner tube 5: Outer tube 6: Inner tube outlet A: Outer tube outlet 8: Reaction product Patent applicant Fuji Photo Film Co., Ltd. Figure 2 Figure 2θ Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A silver halide photographic emulsion containing bonded grains in which crystals substantially consisting of silver iodide are bonded at each corner of octahedral silver halide grains and/or on the intersection line of twin planes. (2) Silver halide fine grains containing at least a portion of silver iodide with a solid solution ratio of 95 mol% or more are added to octahedral silver halide host grains, and the corners of the host grains are redissolved. A manufacturing method in which silver iodide is selectively grown on the intersection of the grain surface and the twin plane.