JPS63285534A - Silver halide photographic sensitive material having high sensitivity and graininess - Google Patents

Abstract

PURPOSE:To make the titled material to the high sensitivity and graininess by incorporating a high concn. silver iodobromide in the inner core of the silver halide particle, and a low concn. silver iodobromide in the outer shell of said particle, respectively. CONSTITUTION:The titled material comprises an emulsion layer contg. the silver halide particle, and the inner core (the core part) of said particle is substantially composed of silver iodobromide, and the outer shell (the shell part) of said particle is composed of the silver iodobromide having a different composition from that contd. in the inner core. The inner core contains >=20mol.%. silver iodide, and the outer shell contains 0.05-3mol.% silver iodide. And, the mean silver iodide content is >=5mol.% based on the total silver halide particle. The intermediate layer between the inner core and the outer shell has preferably an intermediate value of the silver iodide content between those of the inner core and the outer shell. Accordingly, as the titled material contains the silver halide particle as mentioned above, the sensitivity and graininess of the titled material are improved.

Description

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

[Conventional technology]

11. Improving Il quality for silver halide photographic materials!
The gate is getting higher and higher. In particular, the commercialization of high-speed films of 1,501,000 or higher in the field of cuff negative film and the spread of small 7-matte compact cameras, such as disc film, have led to an expansion of photographic opportunities, but on the other hand, the quality of the finished prints has increased. decline in W18
Improvements are desired. In particular, with regard to graininess, which is an important factor determining the quality of color photographic images, much research has been carried out focusing on silver halide ILs.

Silver iodobromide emulsions containing 5 mol % or more of silver iodide are already known as silver halide emulsions having t4 sensitivity and excellent graininess. 'l: Core/shell type silver halide emulsions containing 5 mol% or more of silver iodide have been actively researched as improved silver iodobromide emulsions. Many studies have been conducted on the core/shell type silver iodobromide emulsions having the above-mentioned high silver iodide-containing phase as single-cuff 7y films and mmm.

No. 60-138538, No. 60-254032 nig* Grain a There are disclosures of core/shell type emulsions with improved a, but no examples of emulsions in which the core content is 20 mol % or more are given.

JP-A No. 80-143319 and JP-A No. 60-147727 disclose core/shell emulsions in which the core portion contains 20 mol% or more of silver iodide, but there are no examples in which the shell is pure silver bromide. It was only shown.

JP-A-61-245151 discloses a core/shell type emulsion in which the core content is 20 mol% or more, but when the silver iodide content of the core is 20 to 50 mol%, the core content is less than 20 mol%. There was a drawback that the sensitivity and graininess were deteriorated compared to emulsions having a silver iodide content of .

The present inventors investigated the cause of this in detail and found that silver iodide 20
It has been found that non-uniform growth tends to occur when a core/shell emulsion having cores of mol % or more is produced (a drawback is that the actual silver iodide content of the grain surface layer increases).

Therefore, a core/shell type halogen having an average silver iodide content of 5 mol% or more, a core silver iodide content of 20 mol%, and a surface layer silver iodide content of 0.05 to 3 mol%. Silver oxide emulsions are still unknown.

[Purpose of the invention]

An object of the present invention is to provide a silver halide photographic material with high sensitivity and high graininess.

[Structure of the invention]

As a result of extensive studies, the present inventors have developed an internal core consisting essentially of silver iodobromide and an iodobromide which is provided outside the internal core and has a composition different from that of the inner core. A silver halide photographic material having at least one emulsion layer containing silver halide grains having an outer IN (shell) made of silver, wherein the core of the silver halide grains is 20
contains silver iodide of mol% or more, and the silver iodide content of the surface layer of the silver halide grains is 0.05 to 3 mol%, and the average silver iodide content is 5 mol% or more. It has been found that this can be achieved by a silver halide photographic light-sensitive material having certain characteristics.

In the present invention, at least one of the silver halide emulsion layers contains a core/shell type silver iodobromide emulsion.

The core/shell type silver iodobromide emulsion is a grain composed of a core and a shell covering the core, and the shell is formed of one or more layers. The silver iodide content of the core and shell is different.

The silver iodide content in the core portion is preferably 20 mol% or more, more preferably 20 to 45 mol%, particularly preferably 25 to 40 mol%. The silver iodide content of the shell portion forming the outermost layer is 0.05 to 3 mol%, more preferably 0.1 to 2 mol%. The ratio of the shell portion of the core/shell type silver halide grains is preferably 10 to 80%, more preferably 15 to 70%, particularly preferably 20 to 60%.

The ratio of the core portion to the entire particle is preferably 10 to 80%, more preferably 20 to 50%.

In the present invention, the silver iodide content of silver halide grains is
The difference in content between the core with low content and the shell with low content may have a sharp boundary, or the boundary may not necessarily be clear and the content may vary continuously. It is also preferable to use an intermediate layer interposed between the core and the shell and having a silver iodide content between that of the core and the outermost shell.

In the case of core/shell type silver halide grains having the above-mentioned intermediate layer, the preferred volume of the intermediate layer is 5% of the entire grain.
~60%, more preferably 20-55%.

The difference in silver iodide content between the shell and the intermediate layer and between the intermediate layer and the core is preferably 3 mol % or more, respectively.

In the present invention, the core/shell type octalodenated II fL agent is silver iodobromide, and the average silver iodide content is 5 mol% or more, more preferably 6 to 15 mol%. * Silver chloride is contained within a range that does not impair the effects of the present invention.

The core/shell type emulsion according to the present invention is disclosed in JP-A-59-177.
No. 535, No. 60-138538, No. 59-5223
89, No. 60-143331, No. 6G-35726, No. 60-258536, No. 61-245151, etc.

In producing the silver halide emulsion of the present invention, p at the time of production is
Control of Ag is extremely important.

The pAg during core growth is preferably 8.8 to 9.2, and the pAg during shell growth is 9.8 to 10.
．． 1 is preferred, and the change in 9Ag between the core and shell during formation may be changed stepwise or continuously;
It is preferable to change it continuously.

In producing the silver halide emulsion of the present invention, stirring conditions during production are also extremely important. As the agitator, use the agitator shown in Taiyo No. 57-92532 and No. 57-92524, and the stirring rotation speed is 500 to 1,200.
Preferably, it is revs/min.

Furthermore, when a core/shell type silver halide emulsion is grown starting from seed grains as in the method described in Taiyuan Sho 60-138538, it is possible that the center of the grains has a halogen composition region different from that of the core. could be.

In such a case, the halogen composition of the seed grains may be of any composition such as silver bromide, silver iodobromide, silver chloroiodobromide, silver chlorobromide, or silver chloride, but if the silver iodide content is 10 mol% or less of silver iodobromide*silver bromide is preferred.

*The proportion of the seed grains in total silver helodenide is preferably 50% or less, particularly preferably 10% or less.

The distribution state of silver iodide in the above-mentioned core/shell type silver octalodenide grains can be detected by various physical measurement methods. This can be achieved by measurements of luminescence at low temperatures, such as X-ray diffraction, and X-ray photoelectron spectroscopy.

The standard measurement method for X-ray diffraction is tarded Cu
In this method, the white diffraction line of the (420) plane of silver herodenide is determined by the powder method using a Cu beam as a radiation source, a tube voltage of 40 kV, and a tube current of 100-^. , 11 In order to increase the resolution of the analyzer, it is necessary to set the slit width and scanning recording speed appropriately to V, set the step angle of the goniometer to 0.02 degrees, and correct the diffraction angle by inserting a standard sample such as silicon. . In addition, the gelatin of the silver tetradenide emulsion sample is removed using an enzyme and dried before use.

The fact that the core has a silver iodide content of 20 mole % or more means that in the X-ray diffraction curve of the silver halide emulsion, any part of the diffraction intensity region corresponding to Cu Kff 1411 of 20 mole % or more of silver iodobromide This can be confirmed by the presence of a diffraction angle of 10% or more with respect to the peak intensity at one point.

In addition, the silver iodide content of the surface layer of the silver halide emulsion is XAI
It can be measured by photoelectron spectroscopy.

X#! Prior to photoelectron spectroscopy and measurement, the emulsion is pretreated as follows. *O, 0 to 1 ml of emulsion
Add 1 wt% pronase aqueous solution'p/Xl0J and incubate at 40°C.
After stirring for 1 hour to decompose the gelatin, centrifugation is performed to sediment the emulsion particles, and after removing the supernatant, pronase water-soluble i! Add 10iif and perform gelatin decomposition again under the above conditions. This sample is centrifuged again, the supernatant liquid is removed, and distilled water 10-1 is added to redisperse the emulsion particles in distilled water, followed by centrifugation. , remove the supernatant. After repeating this water washing operation three times, the emulsion particles are redispersed in ethanol (work with these two is done in a dark room), and in a dimly lit room, the emulsion particles are coated thinly on a mirror-polished silicon cube and measured. Use as a sample. The samples applied onto the silicon sea urchin are measured within 24 hours using X-ray photoelectron spectroscopy.

For measurements by X-ray photoelectron spectroscopy, an ESCA/SAM580 model manufactured by PH1 is used as an apparatus. The sample is fixed in a holder tilted at 60 degrees, and after being evacuated for 10 minutes using a turbo molecular pump in the sample pre-evacuation chamber, it is introduced into the measurement chamber. Within 1 minute after introducing the sample, excitation X-rays (Hg
-Kff radiation) and immediately start measurement.

The measurement was performed using an X-ray source voltage of 15 kV, X*i[current 40-^
/(Conducted under the condition of X energy of 50 eV.

To determine the surface layer phytocomposition^g3 de Br3
Detect deI 3 d3/2 electrons. For detection of A customer 3d electrons, the binding energy is 381eV to 361eV II! ! ! Scan step 0 2eV, each step 100m5ec is measured once, and for detection of Br5cl electrons, the binding energy is -79eV to 59eVLf)1@Scan step 0°2eV, each step 100m5
ee was measured 5 times, and for the detection of 13d3/2 electrons, the range of binding energy from 644ev to 6Z4eV was measured using a step of 0.2eV and a step of 100m5ee for each step of 4.
Measure 0 times. The data is obtained by repeating the above operation twice and integrating it.

The integrated intensity of each peak is used to calculate the composition ratio.

The integrated intensity of the g3d peak is the intensity of the energy value obtained by adding 4 eV to the binding energy at which the g3d3/2 peak shows the maximum value, and the intensity of the energy value subtracted by 4 eV from the binding energy at which the g3d5/2 peak shows the maximum value. The straight line connecting them is used as the baseline, and the unit is eps-eV.
The integrated intensity of the Br5d peak is a straight line that connects the intensity of the energy value obtained by adding 4 eV to the binding energy at which the Br3 d5/2 peak exhibits the maximum value, and the intensity of the energy value subtracted by 3 eV from the binding energy at which the Br5d5/Z peak exhibits the maximum value. The integrated intensity of the l3d3/2 peak is the intensity of the energy value added by 4 eV to the binding energy at which the l3d3/2 peak shows the maximum value, and the 13d3/2 peak shows the maximum value. A straight line connecting the intensities of energy values obtained by subtracting 4 eV from the binding energy is used as a single line, and is determined in units of cps·eV.

When calculating the composition ratio from the integrated intensity of each peak, the relative sensitivity coefficient method is used, and 3g34 Br3 d+13
The relative sensitivity coefficient of d3/2 is 5, 10, 0, respectively.
By using 81°4.592, the composition ratio is given in atomic percent. Further, 1 mole percent is determined by dividing the atomic percent value of I by the sum of the atomic percent value of Dr and the atomic percent value of I.

The core/shell type silver halide grains of the present invention are cubic,
It may be a normal crystal such as a tetradecahedron or an octahedron, it may be composed of twin crystals, or it may be a mixture thereof, but a normal crystal is preferable.

During the growth of silver halide grains, a known silver adenide solvent such as ammonia, thioether, 1,000 urea, etc. can be present.

Silver halide grains are produced by cadmium salt, zinc salt, lead salt, thallium salt, iridium salt (including complex salts), a') rum salt (
At least one metal ion selected from iron salts (including complex salts) and iron salts (including complex salts) is added to the inside of the particles and/*
Alternatively, these metal elements can be contained in the particle surface layer, and by placing the particle in an excessively reducing atmosphere, reduction sensitizing nuclei can be provided inside the particle and/or on the particle surface.

The silver halide emulsion may be freed of unnecessary soluble salts after the growth of the 112 silver denride grains has been completed, or may be left as such. Roscher (Research
This can be carried out based on the method described in Section 2 of No. 17643 (hereinafter abbreviated as RD).

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 as follows:
O,OS~30μ, preferably 0°1~ZOμ.

As the core/shell type halogenated emulsion 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. However, when carrying out the present invention, a monodisperse emulsion is preferable. ν1゜In the present invention, a monodisperse silver halide emulsion is defined as a mixture of ± The silver halide weight 1 contained within the 20% grain size range is 6 of the total silver halide grain weight.
It is preferably 0% or more, more preferably 70%
It is more preferably 80% or more.

Here, the frequency ni of particles having an average particle size 11 particle size ri
Define the grain size ri when the product r+1

That is, the grain size "i" is, in the case of spherical silver halide grains,
In the case of particles having a shape other than spherical, the diameter is the diameter when the projected image is converted into a circular image with the same area.

The particle size can be determined by, for example, examining the particles using an electron microscope. This can be obtained by taking a photo magnified from 10,000 to 50,000 times and actually measuring the particle diameter or projected area on the print (the number of measured particles is indiscriminately more than 1゜000). ).

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

Here, the average particle diameter and V standard deviation shall be determined from the above definition "i".

A method for obtaining a monodispersed emulsion is to add a water-soluble silver salt solution and a water-soluble/S ride solution to a gelatin solution containing seed particles.
/Ig and added by gupuruzoet method under pH control.

When determining the addition rate, please refer to ¥tN 1974-48521.
No. 58-49938.

As a method for obtaining a more advanced monodisperse emulsion,
The growth method in the presence of tetrazaindene disclosed in No. 122935 can be applied.

The silver halide emulsion of the present invention can be chemically sensitized by conventional methods.

The silver halide emulsion of the present invention can be optically sensitized to a desired wavelength range by using a dye known in the photographic industry as a sensitizing dye. However, two or more types may be used in combination.

The silver halide emulsion is added with an anti-capri agent, a stabilizer, etc. Gelatin is advantageously used as the binder for the emulsion.

The emulsion layer and other hydrophilic colloid layers can be hardened to make them light, and can also contain a plasticizer and a dispersion of a water-insoluble or sparingly soluble synthetic polymer.

A coupler is used in the emulsion layer of a light-sensitive material for color photography.

Furthermore, by coupling with a power coupler having a color correction effect, a competing coupler, and an oxidized form of a developing agent, various 7 fragments, namely development accelerators, bleaching accelerators,
7 photographically useful ragments such as developer, silver cdende solvent, toning agent, hardener, capri agent, anti-capri agent, chemical sensitizer, spectral sensitizer, and desensitizer. Compounds that release can be used.

The photosensitive material can be provided with auxiliary layers such as a filter layer, a /SS radiation prevention layer, and an irradiation prevention layer. These layers and/or the emulsion layer may contain dyes that are washed out or bleached from the light-sensitive material during the development process.

The photosensitive material contains formalin scavenger, optical brightener,
Addition of matting agents, lubricants, image stabilizers, surfactants, color anti-capping agents, development accelerators, development retardants and bleaching accelerators can be added.

As a support, paper laminated with polyethylene, etc.
Polyethylene terephthalate film, baryta paper, cellulose triacetate, etc. can be used.

To obtain a dye image using the photosensitive material of the present invention, after exposure,
Commonly known color photographic processing can be performed.

〔Example〕

Next, the present invention will be specifically explained with reference to Examples.

(Comparative Example 1) As comparative emulsions, core/shell type emulsions Em-1 and Em 2 having a core content of 20 mol % or more were prepared according to the method of JP-A-61-245151.

pAg during core growth is 8. 9Aff during shell growth was set to 10.2, and 9Aff was continuously varied during growth of the intermediate shell.

(Comparative Example 2) Two cores were prepared according to the method of JP-A-60-143331.
A core/shell type emulsion E-Rho 3 was prepared in which the concentration was 0 mol % and the shell was pure ΔgBr.

The following is a blank space ＼- Table 2 Be, 1, Dictionary (Example 1) The following solution was prepared and the core/shell type emulsion of the present invention ε--4
311g&.

L water 2.5150℃ B
-1 Waiting for solution 11! No. 57-92523, No. 57-9
Using the stirrer shown in No. 2524, 1, ooo rotation/
Stir for 1 minute. Solutions B-2 to B-4 for this B-1
and @@A-1 to A-2 were added according to the Gupurnoet method according to Table 3. Furthermore, the pn and pAg of Konotojuku were controlled using an aqueous Or solution and 56% acetic acid according to Table 3.

After the addition was completed, desalting and washing with water were carried out using conventional methods.

Emulsion Ea+-4 was thus obtained.

(Comparative Example-3) Em-5 was prepared in exactly the same manner as in Example 1 except that the stirring rotation speed was increased by 400 rotations.

(Comparative Example-4) E--6 was prepared in exactly the same manner as in Example 1 except that p/Ig was controlled as shown in Table 5.

(Example 2) In Example-1, solution l3- was used instead of solution fiB-4.
E--7 was created using exactly the same procedure except that No. 5 was used.

('A Example 3 Comparative Examples 1 to 4, Examples 1 to 2 breast symmetry IEm-1 to Em-
The silver iodide content in the core of No. 7 was determined by XM diffraction, and the silver iodide content in the surface layer was determined by X-ray photoelectron spectroscopy. Display the results -
7.

(Example 4) Emulsions Es-1 to Comparative Examples 1 to 4 and Examples 1 to 2
Em-7 was chemically ripened in the presence of sodium thiosulfate, chloroauric acid and ammonium thiocyanate, divided and 4-hydroxy-6-methyl-L3t3at7- was added with the sensitizing dye l-■ described later as a stabilizer. Added chitrazainden. Using these emulsions, each layer having the composition shown below was sequentially formed on a tria-7tylcellulose film support from the support side to prepare a multilayer color photographic wipe.

Sample - (Reference) 1st layer: Halene 1-blocking layer (HC-2) Gelatin layer containing black colloidal silver.

2nd layer: middle layer (1, L) gelatin layer.

3rd layer: low red sensitivity? -% silver lodenide emulsion layer (RL-
2> Average particle size (';) 0.80 μL, 8 gI 9 mol%
A monodisperse emulsion consisting of 8 gBrl containing and an average grain size (F
) Monodispersed emulsion (emulsion B) consisting of 8 gBrl containing 8 mol% of 0.4μ15^gI... coated silver! 1.71F
/z” Sensitizing dye ■... 25X 10-4 mol sensitizing dye ■ per 1 mol fIA
... 1.3X 10-'Moruncapfuu (C-1) per 1 mol of silver Colored cyan coupler (ce-i) 0.08 mol per 1 mol of silver (ce-i)...Silver 0.004 mol to 1 mol DIR compound (D-4)... o, ooos mol to 1 mol of silver 4th layer: Intermediate layer (1, L) 5th gelatin layer: Low sensitivity green sensitivity Silver halide emulsion layer (GL-2) Sensitizing dye ■... 1,9X 10-' mol sensitizing dye ■... per 1 mole of silver
... 1,9X to-' mole magenta coupler for 1 mole of silver (M-1)... 0.06 mole of 2-do magenta coupler for 1 mole of silver (CM-1) ---Silver 1
0.0 per mole. σ12 mole 6th layer: Intermediate layer (1, L) Gelatin layer 7th layer: Low sensitivity blue-sensitive silver helodenide emulsion layer (BL-2
) Emulsion ＾-... Coated silver 111.0fI/Silver 2 sensitizing dye V.
... 4.2X 10-' mol yellow coupler (Y -1)...0.06 mol per mol silver DIR compound (D -4)... 1 mol silver 0.004 mol 8th layer: Intermediate layer (1, L) Gelatin layer containing the emulsified dispersion of D-4 #9 layer: High-sensitivity red-sensitive silver halide emulsion layer (R■-2) Monodisperse iodine Silver bromide emulsion (Em-1)... Coated silver fi 2,127z2 Sensitizing dye! ... 1,3X 10-' mol sensitizing dye for 1 mol of silver.
... 6.3X 10-' Morcian coupler for 1 mol of silver (C-2)... 0.015 mol cyan coupler for 1 mol of silver (C-3)--... For 1 mol of silver 0.015 Molca Food Cyan Kabufu (CC-1)...fIA1
20,002 mol R compound (D-4) per mole
...- 0.004 mol per mol of silver 10th layer: Intermediate layer (1, L) Gelatin layer containing the emulsified dispersion of D-4 11th layer: High-sensitivity green-sensitive silver halide emulsion layer (GH -2
) Monodisperse silver iodobromide emulsion (he-1) ...Amount of coated silver 2,48+/I" Sensitizing dye■...7.OX 10-' mol sensitizing dye■ per 1 mol of WA
... 7.0 for 1 mole of silver. OX 10"' mole magenta coupler (M-1)... 0.020 mole colored magenta coupler (CF2-1) per mole of silver (CF2-1) -...
o, ooz mol per mol of silver 12th layer: Gelatin layer containing an emulsified dispersion of D-4 13th layer: Highly sensitive blue-sensitive emulsion layer (BH-2) Monodisperse silver iodobromide emulsion (Em -1) Coated silver amount: 2.1 g/m" Sensitizing dye V: 1.9X 10-' mole per mole of silver Yellow coupler (y-i): per mole of silver 0.08 mol DIR compound (D-1)... 0.0007 mol per mol of silver 14th layer: First protective layer (Pro-3) Average particle size 0.
07μm8f1 to 1mol%ΔgBr! ...Coated silver amount 0
．． 2g/m" gelatin layer containing ultraviolet absorbers UV-1 and [IV-2] 15th layer: 2nd protective layer (Pro 4) polymethyl methacrylate particles (diameter 1.5μ) and 1 formalin scavenger (HS) -1) Gelatin layer containing e In addition to the above composition, each layer also contains a gelatin hardener (H-1).
(H-2), slip agent (H^-1) dispersion (0,0
5y/z2) and a surfactant were added.

The compounds contained in each layer of Sample 1 are as follows.

Sensitizing dye I; anhydro-5,5'-cyclo9-ethyl-3,3'-cy(3-sulfopropyl)thiacarposi7ine hydroxide sensitizing dye ■; anhydro-9-ethyl-3,3'-no (3-Sulfobrovir)-4,5,4',5'-dibenzothiacarbocyanine hydroxide sensitizing dye ■; anhydro-5,5'-diphenyl-9-
Ethyl-3,3'-di(3-sulfopropyl)oxacarbocyanine hydroxide sensitizing dye '-Dipenzoxacarbocyanine hydroxide sensitizing dye ■; Anhydro-3,3'-di(3-sulfopropyl)-4,5-benzo-5'-nodoxythiacyanine anhydroxide 0I+ l c- i H H 01] M-I CM-I V-X V-2 ts-1 Na N^8 [11 Crocodile^-1] Next, in sample 1, the hero 2 of the 9th layer, 11th layer, and 13th layer Em-2 to Em- in place of silver emulsion EII-1
Samples 2 to 7 were prepared using 7.

Each of the samples No. 001 to No. 7 prepared in this manner was exposed to sea urchin light using white light, and then subjected to the following development treatment.

Processing process (38℃) Color development 3 minutes 15 seconds bleaching
Wash with water for 6 minutes and 30 seconds
Fixed for 3 minutes and 15 seconds
Wash with water for 6 minutes and 30 seconds
Stabilized for 3 minutes and 45 seconds
Drying for 1 minute and 30 seconds The composition of the treatment liquid used in each treatment step is as follows.

[Color developer]

4-7 minnow 3-methyl-N-ethyl-N-(β-human C1 quinethyl)-7niline sulfate 4,75° anhydrous sodium sulfite 4.25g hydroxylamine 1/2 sulfate 2,0° anhydrous Charcoal #! Potassium 37.5g Sodium Bromide
1.3g nitrilotriacetic acid trisodium salt (monohydrate) 2.5g potassium hydroxide 1.0g Add water to make 11.

[Bleach solution]

Ethylenediaminetetraacetic acid iron ammonium salt 00g Ethylenediaminetetraacetic acid 11!2 ammonium salt 10, O
g Ammonium bromide 150.0° Glacial acetic acid 10° Add 0wN water to make II, and adjust to pH = 6.0 using aqueous ammonia.

[Fixer]

Ammonium 100sulfate 5.0 g Anhydrous sodium sulfite 8.5° Sodium metasulfite 2.3 g Add water to make 1r, and adjust to 911=6.0 using acetic acid.

[Stabilizing liquid]

Formalin (37% aqueous solution) 1.5-l Konigfuchs (
Konishiroku Photo Industry Co., Ltd.) 7.5 @ 4 Add water to 11
shall be.

Relative sensitivity (S) and granularity (RMS) of each sample obtained were measured using blue light (B), green light (G), and red light (R). The results are shown in Table 8.

Note that the relative sensitivity (S) is the relative value of the reciprocal of the exposure amount that gives the fog density +0.1, and the W sensitivity of sample No. 1 is set to 1.
It is shown as a value of 00.

The RMS value is the density of the minimum density + 0.3 with a gate scanning area of 25
It is expressed as a relative value of the standard deviation of the variation in concentration value that occurs when scanning with a 0μ12 microdensitometer.

The smaller the RMS value, the more effective it is.

Table 8 below: As can be seen from Table 8, samples Nos. 4 and 7 using the silver halide emulsions of the present invention were excellent in both sensitivity and granularity.

Similar results were also obtained for the red-sensitive layer and the blue-sensitive layer.

Claims (1)

[Claims] A silver halide grain having an inner core (core) substantially made of silver iodobromide and an outer shell (shell) made of silver iodobromide provided outside the inner core and having a composition different from that of the inner core. A silver halide photographic light-sensitive material having at least one emulsion layer containing silver iodide, wherein the core of the silver halide grains contains 20 mol% or more of silver iodide, and the surface layer of the silver halide grains contains A silver halide photographic material having a silver iodide content of 0.05-3 mol% and an average silver iodide content of 5 mol% or more.