JPH0285846A - Silver halide photographic sensitive material having high sensitivity and improved graininess - Google Patents

Abstract

PURPOSE:To improve sensitivity and graininess by incorporating specified silver halide particles. CONSTITUTION:A silver halide photographic sensitive material contg. silver halide particles each having an inner phase made of silver iodobromide having >=10mol% silver iodide content and a shell made of silver iodobromide having <=7mol% silver iodide content is produced. When the silver halide particles having >=1.5mol% average silver iodide content are produced, >=80% of the silver iodide in the inner phase is formed by a halogen substitution method before 50% of the inner phase is grown. High sensitivity and graininess can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a silver halide photographic material, and particularly to a silver halide photographic material having high sensitivity and improved graininess.

[Background of the invention]

In recent years, with the development of photographic technology, there has been a strong desire for higher sensitivity and higher image quality of silver halide photographic materials. In response to these demands, emulsions comprising core/shell type silver halide grains having a silver iodobromide phase with a high silver iodide content have been extensively studied.

In particular, much research has been conducted on silver iodobromide emulsions containing core/shell type grains having a high silver iodide content phase of 10 mol % or more inside the grains. For example, JP-A-60-14
3331, JP-A-62-3247, JP-A-62-7
Each publication No. 039 discloses a core/shell type emulsion having a high silver iodide content in the core portion.

On the other hand, there is a strong demand for faster processing of photosensitive materials. Especially in recent years, with the increase in consumption of photosensitive materials,
There is a strong demand for rapid processing in a short time. This can be said in any field of photosensitive materials, but for example, in the field of medical X-ray photosensitive materials, the number of X-ray photographs is increasing due to a rapid increase in the number of diagnoses and an increase in the number of test items. It is necessary to notify the examinee of the results as soon as possible, and therefore rapid processing is desired. In particular, for angiography, intraoperative photography, etc., it is essentially necessary to view the photographs as quickly as possible.

Against this background, various rapid processing technologies have been attempted. For example, in image forming processing, high pH and high temperature (30 to 40 °C
) Attempts have been made to accelerate processing by developing with
This resulted in deterioration of the photographic images obtained. In particular, when processing is performed using an automatic processor, under the above conditions, the pressure resistance of the photosensitive material deteriorates, and so-called roller marks are generated due to the pressure of the conveying roller, which may lead to deterioration of image quality.

In this way, along with the trend toward higher sensitivity and higher image quality as mentioned above, and in conjunction with the above-mentioned demand for faster processing, the demand for improved pressure characteristics in silver halide photographic materials has also increased more than ever before. There is.

For this reason, various methods have been considered for improving the pressure characteristics, and techniques using additives, such as adding plasticizers, have been attempted. However, the prevailing view is that a technique for improving the pressure resistance of the silver halide grains itself is more practically preferable than such means, and is also more effective. Examples of prior art developed from this perspective include Japanese Patent Application Laid-Open No. 60-35726,
A technique disclosed in Japanese Unexamined Patent Publication No. 198324/1983 is known. Both are core/shell type emulsions and contain a phase substituted with halogen by iodide inside the grains.

As shown in these prior art techniques, silver halide grains obtained by the halogen substitution method using iodide certainly have improved pressure characteristics, but on the other hand, the average silver iodide content of the entire grain is comparatively low. It has the drawbacks of poor graininess, poor development performance, and deterioration of graininess, so it is not necessarily satisfactory. Deterioration of graininess is an important problem in terms of photographic performance, and may lead to misdiagnosis, for example, in X-ray photographs that are directly interpreted using a shadowed film.

Therefore, emulsions containing grains with the above problems are
For example, it is not preferred as an emulsion for light-sensitive materials in which graininess is a serious problem, such as light-sensitive materials for X-ray photography.

[Purpose of the invention]

The present invention solves the above-mentioned problems of the prior art, and is a silver halide photographic light-sensitive material that is highly sensitive and has improved graininess, and therefore can produce images with good graininess even when processed rapidly, for example. The purpose is to provide

[Structure of the invention]

The object of the present invention was achieved by a silver halide photographic material containing the following silver halide grains. That is, the silver halide photographic material of the present invention has a silver iodide content of 1
It has at least an internal grain phase consisting of silver iodobromide with a silver iodide content of 0 mol% or more, and a grain outer shell consisting of silver iodobromide with a silver iodide content of 7 mol% or less, and has an average silver iodide content. 1.5 mol%
The above silver halide grains are obtained by forming 80% or more of the silver iodide in the internal phase of the grain by a halogen substitution method by 50% of the growth of the internal phase of the grain. It contains. The present inventor has discovered that a photosensitive material containing such silver halide grains (hereinafter also referred to as "silver halide grains according to the present invention") meets the object of the present invention,
This led to the completion of the present invention.

The present invention will be explained in more detail below. First, the silver halide grains contained in the light-sensitive material of the present invention will be explained.

Silver halide grains are generally produced and used in the form of silver halide emulsions containing the grains.

The silver halide grains according to the present invention have a silver iodide content of 10
The grain has an internal phase consisting of silver iodobromide in a mole % or more. The term "internal phase of the grain" as used herein refers to such an internal region having a high iodine content. The silver iodide content of the internal phase is preferably 10
-45 mol%, particularly preferably 15-40 mol%
It is.

Further, the silver halide grains according to the present invention have a grain outer shell composed of silver iodobromide containing 7 mol % or less of silver gold iodide. A particle outer shell is a layer existing on the surface side of a particle. The silver iodide content in the outer shell of the grains is more preferably 5 mol % or less.

The silver iodobromide constituting the inner phase and outer shell is essentially silver iodobromide, and may include other substances (such as other silver halides) to the extent that they do not inhibit the properties of silver iodobromide. It does not prevent the mixture of

The average silver iodide content of the silver halide grains according to the present invention is 1
．． It is 5 mol% or more. Preferably 1.5-30 mol%
It is.

The silver halide grains according to the present invention preferably consist essentially of silver iodobromide as a whole.

However, silver halide of other compositions, such as silver chloride, may be contained within a range that does not impair the effects of the present invention.

Further, the silver halide grains according to the present invention are preferably used in the form of a silver halide emulsion containing the grains, but the emulsion is preferably also substantially a silver iodobromide emulsion. However, grains other than the silver halide grains according to the present invention may be contained, or an emulsion containing the silver halide grains according to the present invention and other emulsions may be mixed and used.

In obtaining the emulsion containing silver halide grains according to the present invention, a method is used in which a core/shell type silver halide emulsion is grown starting from seed grains, as in the method described in JP-A-60-138538. In this case, the grain center may have a silver halide composition region (composition region of the seed grain) different from the core forming the internal phase of the grain. In such a case, the silver halide composition of the seed grains may be any composition such as silver bromide, silver iodobromide, silver chloroiodide, silver chlorobromide, silver chloride, etc. The content rate of
Silver iodobromide or silver bromide of 0 mol % or less is preferred. In this case, the proportion of the seed grains in all silver halide grains is preferably 50% or less, particularly preferably 10% or less.

The silver halide grains according to the present invention necessarily have the above grain inner layer and grain outer shell layer, but may also have one or more intermediate layers between them.

Further, it is possible to have an extremely thin outermost layer on the outside of the outer shell layer.

The distribution state of silver iodide in the silver halide grains according to the present invention can be detected by various physical measurement methods. This can be investigated by measuring luminescence at low temperatures or by X-ray diffraction.

The standard measurement method for X-ray diffraction is to use Cu as the target, use α rays as the radiation source, set the tube voltage at 40 ν, and the tube current at 100 mA to measure silver halide (420).
This method uses the powder method to obtain the diffraction curve of a surface. Generally, in order to improve the resolution of the measuring instrument, it is necessary to appropriately select the slit width and scanning recording speed, set the step angle of the goniometer to 0.02 degrees, and correct the diffraction temperature by inserting a standard sample such as silicon. Furthermore, silver halide emulsion samples are usually used after gelatin is removed using enzymes and dried.

For example, the fact that the core has a silver iodide content of 5 mol% or more means that in the X-ray diffraction curve of the silver halide emulsion, the diffraction intensity region corresponds to the α line for Cu of 5 mol% or more of silver iodobromide. At any one point, the diffraction angle is 1 with respect to the peak intensity.
This can be confirmed by the presence of 0% or more.

The shape, crystal form, crystal habit, etc. of the silver halide grains according to the present invention are arbitrary. For example, it may be a normal crystal, ie, a normal crystal such as a cube, a tetradecahedron, an octahedron, a dodecahedron, etc., or may take any other form.

In the silver halide grains according to the present invention, 80% or more of the silver iodide in the internal phase is formed by the halogen substitution method by 50% of the growth of the internal phase of the grain. The halogen substitution method in the present invention mainly means a method of causing halogen substitution by adding iodide, and the compounds to be added include, for example, potassium iodide, sodium iodide, iodized steel (II) ( Culz), their aqueous solutions, silver iodide (
Silver iodide may be added by forming silver iodide, or may be added by adding silver ions and iodide ions, for example, by mixing a silver nitrate solution and an iodide solution at the same time), Examples include silver iodide emulsion. The iodide addition position (point of time of addition) may be any position as long as it is up to 50% of the internal phase growth, and the iodide may be added at two or more positions within this period. The iodide addition time may be rush addition in which all iodide is added in a short time (or it may be added over several minutes or more).

pAg during internal phase growth of silver halide grains according to the present invention
The value is preferably 8.4 or less, more preferably 7 or more and 8.4 or less. In addition, the pH during internal phase growth
The value is preferably 9.8 or more, more preferably,
It is preferably 10 or more and 11 or less.

When producing an emulsion containing silver halide grains of the present invention, or when producing an emulsion containing silver halide grains other than the present invention to be used together (the same applies to the description of emulsions below), JP-A-60-138538 As mentioned above, it is possible to use a method of growing a core/shell type silver halide emulsion starting from seed grains, as in the method described in the above-mentioned patent.

Further, in preparing an emulsion containing silver halide grains, a known silver halide solvent such as ammonia, thioether, thiourea, etc. can be present during grain growth.

Furthermore, silver halide grains are treated with cadmium salts, zinc salts, lead salts,
At least one metal ion selected from thallium salts, iridium salts (including complex salts), rhodium salts (including complex salts), and iron salts (including complex salts) is added to the inside of the particles and/or
Alternatively, these metal elements can be contained in the particle surface layer, and reduction sensitizing nuclei can be provided inside and/or on the particle surface by placing the particle in an appropriate reducing atmosphere.

Unnecessary soluble salts may be removed from the silver halide emulsion after the growth of silver halide grains is completed, or they may be left contained. When removing the salts, Research Disclosure (Research Disclosure) is required.
Closure (hereinafter abbreviated as RD)> This can be carried out based on the method described in No. 17643, Section 3.

The silver halide grains may be grains in which latent images are mainly formed on the surface or grains in which latent images are mainly formed inside the grains, and the size of the silver halide grains is preferably 0.05 to 30 μm, preferably 0.1-20μm1
More preferably, the thickness is 0.2 to 10 μm.

As the silver halide photographic emulsion used in the light-sensitive material of the present invention, any one can be used, such as a polydisperse emulsion with a wide grain size distribution or a monodisperse emulsion with a narrow grain size distribution.
Each may be used alone, or a mixture of several types may be used. In carrying out the present invention, monodispersed emulsions are preferred.

The monodisperse silver halide emulsion is preferably one in which the weight of silver halide contained within a 20% range of grain sizes centered on the average grain size f is 60% or more of the weight of all silver halide grains. More preferably 70% or more, still more preferably 8
It is 0% or more.

Here, the average particle diameter f is defined as the particle diameter ri when the product n1 5
people).

In the case of spherical silver halide grains, the grain size ri is the diameter thereof, and in the case of grains having shapes other than spherical, it is the diameter when the projected image thereof is converted into a circular image of the same area.

The particle size can be obtained, for example, by photographing the particle with an electron microscope at a magnification of 10,000 to 50,000 times and measuring the particle diameter or projected area on the print (
The number of particles to be measured shall be 1°000 or more indiscriminately).

Particularly preferred highly monodisperse emulsions are those with a distribution width of 20% or less, more preferably 15% or less.

Here, the average particle diameter and standard deviation are determined from ri defined above.

A method for obtaining a monodispersed emulsion is to add a water-soluble silver salt solution and a water-soluble halide solution to a gelatin solution containing seed particles at pA
There is a method of adding by double jet method under the control of g and pH, and such means can be used.

In determining the addition rate, refer to JP-A-54-48521.
No. 5B-49938.

As a method for obtaining a more advanced monodispersed emulsion, JP-A-60-1
The silver halide emulsion used in the practice of the present invention, which contains the tetrazaindene disclosed in No. 22935, can be brought to a pAg ion concentration suitable for chemical sensitization by an appropriate method after the growth of silver halide grains is completed. . For example, research disclosure No. 17643 (Research Disc.
Losure No. 17643).

In the case of chemical sensitization, ordinary sulfur sensitization, reduction sensitization, noble metal sensitization, and combinations thereof are used. More specific chemical sensitizers include sulfur sensitizers such as Allyl thiocarbamide, thiourea, thiosulfate, thioether and cystine; Rose date (Po
tassililchlororo palladate)
and reduction sensitizers such as tin chloride, phenylhydrazine, and retactone.

Photographic emulsions used in the practice of this invention may be spectrally sensitized with cyanine dyes and others. Sensitizing dyes may be used alone or in combination, and combinations of enhancing dyes are often used particularly for the purpose of supersensitization.

Various hydrophilic colloids can be used as binders in the photographic emulsion used in the present invention.

Colloids used for this purpose include, for example, gelatin, colloidal albumin, polysancharides, cellulose derivatives, synthetic resins, polyvinyl compounds including polyvinyl alcohol derivatives, acrylamide polymers, etc. Colloids can be mentioned.

The silver halide photosensitive material of the present invention can be prepared by using a photographic hardening agent commonly used in its coating solution, such as an aldehyde-based hardening agent or an aziridine-based hardening agent (for example, PB Rev. 9,921, U.S. Pat.
, No. 950.197, No. 2.964.404, No. 2,983.611, No. 3.271.175, Japanese Patent Publication No. 46-40898, Japanese Unexamined Patent Publication No. 51-91
No. 315), isoxazole systems (e.g., those described in U.S. Pat. No. 331,609), and epoxy systems (e.g., U.S. Pat. No. 3,047,39).
No. 4, West German Patent No. 1,085,663, British Patent No. 1
, 033,518, Japanese Patent Publication No. 48-3549
ili), vinyl sulfone type (e.g. PB report 19,920, West German patent cylinder 1,100)
, 942, British Patent No. 1,251,091, Japanese Patent Application No. 45-54236, Japanese Patent Application No. 4B-110996, and US Patent No. 353.964, and US Patent No. 3,490,911. acryloyl type (e.g., those described in Japanese Patent Application No. 48-27949 and U.S. Pat. No. 3,640,720), carbodiimide type (e.g., U.S. Pat. No. 2,938,892) ,Special Public Service 1977-
38715 and Japanese Patent Application No. 49-15095), maleimide-based, acetylene-based, methanesulfonic acid ester-based, triazine-based, and polymer hardening agents can be used. In addition, as a thickening agent, for example, US Pat. No. 3,167.410, Belgian Patent No. 558.
No. 143, polyols as gelatin plasticizers (e.g., U.S. Pat. No. 2,960,404)
specification, Japanese Patent Publication No. 43-4939, Japanese Patent Publication No. 48-63
715), and as latexes, U.S. Patent Nos. 766 and 979, and French Patent Sections 1 and 3.
95,544, those described in Japanese Patent Publication No. 48-43125, and the matting agent described in British Patent No. 1,
221,980 and the like can be used.

Furthermore, desired coating aids can be used in the component layers of the silver halide photographic material of the present invention, such as saponin or sulfosuccinic acid surfactants, such as those described in British Patent No. Gansho 47-89630
or as anionic surfactants such as those described in Japanese Patent Publication No. 43-18166,
U.S. Patent Section 3,514,293, French Patent Section 2,
Specifications of No. 025,688, Japanese Patent Publication No. 43-10247
Those described in the No. 1 publication can be used.

Various compounds can be added to the above-mentioned photographic emulsion in order to prevent a decrease in sensitivity and the occurrence of fog during the manufacturing process, storage or processing of the light-sensitive material. These compounds include 4-hydroxy-6-methyl-1°3.3a, 7-chitrazaindene, 3-methyl-benzothiazole, 1-phenyl-3-mercaptotetrazole, many heterocyclic compounds, mercury-containing compounds, A large number of compounds such as mercapto compounds and metal salts have been known for a long time.

An example of a compound that can be used is K. Mies (K.

The Theory of the Photographic Process
Photographic Process) (3rd edition, 1966) lists the original documents, as well as JP-A Nos. 49-81024, 5o-6306, and 50
Any of the antifogging agents well known in the art, such as those described in No. 19429 and US Pat. No. 3,850,639, can be used.

In addition, various techniques used in photography can be applied when implementing the present invention.

(Examples) Examples of the present invention will be described below.It should be noted that, as a matter of course, the present invention is not limited to the Examples described below.

Example-1 Reaction vessel conditions: 60°C, pAg=8, and pH=
While maintaining the average particle size of 0.3 using the double jet method,
A monodisperse cubic emulsion of silver iodobromide containing 2 mol % of silver iodide in micrometers was obtained. According to electron microscopic observation, the incidence of twins was 1% or less in number.

Using this emulsion as a seed crystal, it was further grown as follows.

(2) Preparation of Comparative Emulsion Em-1 A 2χ gelatin aqueous solution was kept at 40 DEG C. in a reaction vessel, the above seed crystals were dissolved therein, and aqueous ammonia and acetic acid were added to adjust the pH to 9.5. After adjusting the pAg to 7.3 with an ammoniacal silver ion solution, while keeping the pH and pAg constant, a solution containing an ammoniacal silver ion solution, potassium bromide, and potassium iodide was added using a double jet method, and silver iodide was adjusted to 30. A silver iodobromide layer containing mol% was formed (step -
1).

Next, after adjusting the pH to 9 and pAg to 9.0, an ammoniacal silver ion solution and potassium bromide were added at the same time,
After the growth, the particles were further grown to 90% of the particle size. At this time, the pH was gradually lowered from 9.0 to 8.20 (step-
2).

After adding potassium bromide solution to set pAg to 11, ammoniacal root ion solution and potassium bromide were further added to grow while gradually lowering the pH to 8, and the average particle size was 0.7μ.
m, a silver iodobromide emulsion containing 2 mol% of silver iodide was obtained (step -
3).

Next, as shown below, a desalting step was performed to remove excess salt.

The silver halide emulsion solution was kept at 40°C, and the following compound (a
) (exemplary compound ■-1 shown in JP-A-58-140322) to precipitate silver halide grains,
After draining the supernatant, add pure water at 40°C. Then, magnesium sulfate (MgSO3) is added to precipitate the silver halide grains again, and the supernatant liquid is removed. Have this again-
Repeatedly, 15g/AgX1 mol of gelatin was added, pH=
6.0, I) An emulsion with Ag=8.5 was obtained (Step-4).

(Note that AgX represents silver halide. The same applies hereinafter). This is designated as emulsion Em-1.

Compound (a) ■ Comparative emulsions Em-2 to Em-8 and emulsion Em-9 according to the present invention
Preparation of ~18 In step-1 in the preparation of emulsion Em-1, after adjusting the pH and pAg as shown in Table-1, the pH and pA
While keeping g constant, ammoniacal root ion solution and potassium bromide solution were added using the double jet method, and potassium iodide aqueous solution was added at different addition speeds using the method shown in Table 1. A silver iodobromide layer containing 30 mol % of silver iodide was formed. Thereafter, steps 2 to 4 were carried out in the same manner as for the emulsion Em-1, and the emulsion Em-1 as shown in Table-1 was prepared.
-2 to 18 were obtained.

At this time, the volume ratio of core and shell was unchanged from that of emulsion Em-1, and the average grain size was set to 0.7 μm.

■ Comparative emulsions Em-19 to 25 and emulsions Em-26 to 35 according to the present invention for 8 types In the above ■, instead of the potassium iodide aqueous solution added, silver iodide was added as shown in Table 2. A silver iodobromide layer containing 30 mol % of silver iodide was then formed by a halogen substitution method. Thereafter, steps 2 to 4 were carried out in the same manner as for emulsion Em-1 to obtain emulsions Em-19 to 35 as shown in Table 2.

In this case as well, the volume ratio of core and shell is emulsion Em-1
The average particle size was also set to 0.7 μm.

The emulsions Em-1 to Em-35 obtained in steps 1 to 3 above were kept at 55°C and chemically sensitized by adding chloroauric acid and hypo, and then added with the following sensitizing dyes (A) and (B). Potassium iodide was added for optimal spectral sensitization, and 4hydroxy-6-methyl-1,3,3a,7-chitrazyden was added to obtain a photosensitive emulsion.

(CHz) 3SO3H(CI□)+5(hO・(cz
ns) J The resulting photosensitive emulsion contains halogenated additives? 400 mg of t-butyl-catechol per mole of tuna.

Polyvinylpyrrolidone (molecular weight 10,000) 1.0
g.

Styrene-maleic anhydride copolymer 2.5g.

Trimethylol Propa 7 10g.

Diethylene glycol 5g/Nitrophenyl-triphenylphosphonium chloride
50 mg.

Ammonium 1.3-dihydroxybenzene-4-sulfonate 4 g.

Sodium 2-mercaptobenzimidazole-5-sulfonate 5111 g.

1.1-dimethylol-1-bromo-1-nitromethane 10 mg.

Furthermore, along with the protective layer, the following compounds were added as additives in the following amounts per 1 g of gelatin.

C1bCOO(CHz)9CH3 Na5Oz CHzCOO(CHz)zc41(CH
:+)zB Na5Os CHCOOCllz(CJn)JCHz
COOCIIz (Czl14) J
5ntgFIQC90+CHzCHzO+r-
1fCHHzCHz OH3mg Matting agent made of polymethylmethanol with an average particle size of 7μm
7mg colloidal silica with average particle size of 0.013μ 70mg formalin
29mg glyoxal
30mg 2-hydroxy-4,6-cyclotriazine sodium
30 mg of the photosensitive emulsions obtained from emulsions Em-1 to Em-35 as described above were coated uniformly on both sides of a 180-μ thick undercoated blue-colored polyethylene terephthalate film base, and dried. Samples 1-3
Got 5.

The obtained sample was sandwiched between X-ray photographic intensifying screens KS (manufactured by Konica Corporation) and irradiated with X-rays through a Venetrometer B type (manufactured by Konica Medical Corporation).
Processing was performed for 45 seconds using an RX-501 automatic developing machine and an XD-90SR development process.

The sensitivity of each sample developed as described above was evaluated. Sensitivity was expressed as a relative value, with 100 being the reciprocal of the amount of irradiation energy required to give sample 1 a density of fog+1.0.

In addition, the graininess can be reduced by exposing the entire surface to light and achieving a blackening density of 0°6 to 0.
．． Visual evaluation was performed on a 20 cm x 20 cm developed sample in area No. 8. On a five-point scale, 5: Very good, 4:
Good, 3: Practical, 2: Roughness within a practical range, 1: Severe roughness (not practical).

The measurement results are shown in Table-3.

As can be seen from Table 3, samples Nos. 9-18 and 26-35, which are samples according to the present invention, all have good sensitivity and excellent graininess.

Table-1 Table Example-2 In the same manner as emulsion Em-12 prepared in Example-1,
Silver iodobromide emulsion Em-36 with an average grain size of 0.7 μm and different silver iodide contents in the core and shell parts as shown in Table 4
~44 was obtained. However, the formation of silver iodobromide in the shell part
A shell portion was formed using a halogen ion solution and a silver ion solution so as to have the silver halide composition shown in Table 4 without using a halogen substitution method.

Furthermore, a photosensitive emulsion was obtained in the same manner as in Example 1, and this was coated on a film base in the same manner and dried to obtain Samples 36 to 4.
I got 4. These were evaluated regarding sensitivity, fog, and graininess. The sensitivity criteria are the same as in Example-1.

The measurement results are shown in Table-4.

Also in this example, the sample according to the present invention (sample fish 36
38.39.41-43°Sample N11 according to the present invention
It can be seen that the data of No. 12 (listed in Table 4) are excellent.

Continued 〔Effect of the invention〕 hand Continued Neho Positive calligraphy (spontaneous) As mentioned above, Silver halide photographic material of the present invention March 1, 1989 The fee is High sensitivity, And the effect of good graininess has.

1. Indication of the case Patent Application No. 238225 filed in 1988 2. Name of the invention Patent for silver halide photographic light-sensitive material with high sensitivity and improved graininess Applicant: Konica Co., Ltd. 3. Attorney for the person making the amendment, F.P., Phys. Relationship with Toru Takatsuki Incident

Claims (1)

[Claims] 1. At least a grain internal phase made of silver iodobromide with a silver iodide content of 10 mol% or more and a grain outer shell made of silver iodobromide with a silver iodide content of 7 mol% or less, and silver halide grains having an average silver iodide content of 1.5 mol % or more, wherein 80% of the silver iodide in the grain internal phase is grown by a halogen substitution method by 50% of the internal phase growth of the grain. A silver halide photographic light-sensitive material characterized by containing silver halide grains obtained by forming the above.