JPH0789205B2 - Silver halide emulsion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a silver halide (hereinafter referred to as AgX) emulsion useful in the field of photography, and particularly to a dispersion medium and one AgX.
It relates to an AgX emulsion consisting of AgX grains having at least {100} and {111} crystal surfaces on the grain surface.

(Prior Art and its Problems) In general, in order to make highly sensitive photosensitive AgX particles, it is necessary to control the position and number of chemically sensitized nuclei that are the photosensitized centers. As a limiting method, epitaxial particles are grown at the corners or edges of Agx particles with or without adsorbent adsorption by the halogen conversion method or by adding AgNO ₃ and an alkali halide solution to the adsorbent. Is adsorbed and stabilized, and then chemically sensitized to limit the latent image forming position to the epitaxial part.

Regarding this, JP-A-58-108526, 57-133540,
The description in No. 62-32443 can be referred to.

A method in which an additive such as a sensitizing dye is added during grain formation to introduce a defective portion into the grain and preferentially form a chemically sensitized nucleus only in the defective portion.

This method is a method of controlling the number of chemically sensitized nuclei by introducing defects into grains. Regarding these, U.S. Patents 2,735,766, 3,628,960, 4,183,756, and 4,22
5,660, Research Disclosure, Item 1922
Volume 7, 192, P.155 (1980) can be referred to.

By using AgX particles having two or more kinds of crystal planes on one AgX grain and utilizing the difference in reactivity of the sulfur sensitizer to those crystal planes, the chemical sensitization nucleus is present only on one crystal plane. How to form. For example, when an emulsion with pH 6.4 and pAg 8.4 at 40 ° C is used, the reactivity of sulfur sensitization by hypo is
A method of forming chemically sensitized nuclei only on the {111} plane of a tetrahedral grain by utilizing the fact that 1} plane> {100} plane. In this case, the position and number of chemically sensitized nuclei are controlled by using tetradecahedral grains having different {111} area and {100} area and ratio. About this, J.Phot.Sci.23, 249 (197
5) You can refer to Figure 3 of the Journal of the Photographic Society of Japan, Volume 47, P.255 (1984).

There is a method in which an adsorbent (additive such as a sensitizing dye, an antifoggant and a stabilizer) is adsorbed to AgX particles and then a chemical sensitizer is added to perform chemical sensitization. In this method, the number of chemically sensitized nuclei is controlled, but the position is not controlled, because the chemically sensitized nuclei are formed only in the places where the adsorbent is not adsorbed. For this method, for example, JP-A-58-113926,
58-113927, 58-113928, U.S. Patent 4,439,520
Issue 4,435,501, Research Disclosure, Item.17643.
Section III, JP-A-62-6251, JP-A-58-126526, JP-A-62-56949, and JP-A-62-43644.

A having two or more crystal planes on the surface of one AgX particle
Using gX particles, an adsorbent (face-selective adsorbent) that has selectivity for adsorbing on those crystal faces is added, and the crystal face where the adsorbent is adsorbed at a high density and the crystal face where the adsorbent is adsorbed loosely are added. After the formation, a chemical sensitizer is added to perform chemical sensitization, and a chemical sensitization nucleus is formed on the crystal surface where the adsorbent is loosely adsorbed.

Regarding this, JP-A-58-113928 describes that "chemical sensitization is different from that of tabular grains due to preferential adsorption of a spectral sensitizing dye to a crystal surface forming a major surface of tabular grains. It can occur on the crystal surface. "

This method is an attempt to control the number and position of chemically sensitized nuclei.

The present invention relates to improvements in and among these methods.

However, the method has the following problems.

(1) In this case, the adsorbent that can be used is AgX.
It is limited only to the compounds having a large crystal habit-dependent adsorption capacity to the adsorbent, and the selection range of the adsorbent used is largely restricted.

(2) The adsorption of the adsorbent is preferably strong in order to limit the site where the chemically sensitized nuclei are formed, but this is contrary to the fact that the adsorption ability has a crystal habit dependency.

That is, an additive that strongly adsorbs strongly adsorbs strongly on any surface, and thus has little dependence on crystal habit.

Generally, there is a problem that the adsorbing power of a dye or an additive having a large crystal habit-dependent adsorption ability is weak. Therefore, the chemically sensitized nuclei are formed on the crystal plane on which the sensitizing dye or the additive is adsorbed, and the control of the chemically sensitized nucleus forming position is insufficient.

(3) On the other hand, the above method also has the following problems. It is known that the reaction of the sulfur sensitizer also depends on crystal habit, but the difference in reactivity is not sufficient. For example, when ripening was performed using hypo at 50 ° C, pH 6.4, and pAg8.5 emulsion conditions, in the low concentration range of hypo, selective on the {111} plane as compared to the {100} plane. However, when the gold sensitizer is added together, the difference becomes small.

In the opposite case, for example, if triethylthiourea is used to form a chemically sensitized nucleus only on the {100} plane, the difference in reactivity between the {100} and {111} planes is sufficient. Not only that, but also when maturing with a gold sensitizer,
The situation is that the surface selectivity of the reaction is almost lost.

(Object of the Invention) The object of the present invention is to provide a silver halide emulsion in which the position of the chemical sensitizing nuclei and the number / cm ² are sufficiently controlled to obtain sensitivity, gradation, reciprocity characteristic, development progress, It is an object of the present invention to provide a silver halide emulsion capable of improving stability with time, graininess, sharpness and resolution.

4. Disclosure of the Invention The object of the present invention has been achieved by the following 1) or 2).

1) A silver halide emulsion comprising a dispersion medium and silver halide grains, 70% of the projected area of all silver halide grains
The above is at least {10 on one silver halide grain surface.
Halogen characterized by being tetradecahedral grains having 0} and {111} crystal surfaces, the halogen compositions of the surface layers of the crystal surfaces being different from each other, and having the characteristics of a) to c) below. Silver halide emulsion.

a) [area of {111} plane / area of {100} plane] is 20 to 1 /
Twenty.

b) Only on one of the {100} and {111} crystal surfaces, a silver halide having a halogen composition different from the silver halide grain of the substrate is non-epitaxial (the same crystal system layer as the base is placed on the substrate). The halogen compositions differ from each other in iodine content by 2 to 40 mol% or in Cl ⁻ content by 7 to 100 mol%.

c) The chemically sensitized nuclei are preferentially formed on one of the crystal faces, and [(the number of chemically sensitized nuclei on the crystal face where the preferentially chemically sensitized nuclei are formed / cm ² ) / ( The number of chemically sensitized nuclei on the crystal plane where preferentially no chemically sensitized nuclei are formed / cm ² )] is 2.5.
That is all.

2) A silver halide emulsion consisting of a dispersion medium and silver halide grains, which is 70% of the projected area of all silver halide grains.
Above is at least {10 on one silver halide grain surface.
Parallel twin planes having crystal planes of 0} and {111}, having different halogen compositions in the surface layers of the crystal surfaces, and having the characteristics of the following a) to c) and having an aspect ratio of 1.5 or more. A silver halide emulsion having tabular grains.

a) [Area of the {111} crystal surface / area of the {100} crystal surface] is 20 to 1.0.

b) Only on one of the {100} and {111} crystal surfaces, a silver halide having a halogen composition different from that of the silver halide grain of the substrate is non-epitaxial (the same crystal system layer as the substrate is formed on the substrate). The halogen compositions differ from each other in iodine content by 2 to 40 mol% or in Cl ⁻ content by 7 to 100 mol%.

c) The main surface of the tabular grain is a {111} crystal surface, and the {100} crystal surface is present at an edge portion of the tabular grain.

Conventionally, for example, in the case of forming a chemical sensitized nucleus on one crystal face of the {100} face or the {111} face of a tetrahedral grain, simply,
(A) Difference in reactivity of {100} plane and {111} plane of sulfur sensitizer or b (Difference in adsorption ability of {100} plane and {111} plane of adsorbent) + ({100 of sulfur sensitizer } Plane and {111}
In contrast to the method described above, the method of the present invention differs from the above-mentioned a and b in that the halogen composition of the surface layer of the {100} plane is different from that of the {111} plane. Difference in chemical sensitized nucleation ability, which is an effective electron trap,
Alternatively, the difference between the adsorbability of the adsorbent substrate depending on the halogen composition of the adsorbent + the difference of the chemical sensitized nucleation ability of an effective electron trap is used.
By increasing the factor, the position of the chemosensitized nucleus is more sufficiently controlled.

First, the structure of the AgX particles of the present invention will be described in detail.
The method for producing gX particles will be described in detail.

The AgX grain of the present invention is a grain having at least {100} and {111} crystal surfaces on one AgX grain surface, more specifically, a tetrahedral grain and a flat twin plate having parallel twin planes. It is a particle.

It is well known that the outer surface of tetradecahedral grains has {100} and {111} faces, but in the case of tabular AgX grains, TFH
amilton and LEBrady (Journal of Applied Physics,
35, pp. 414-421, 1964), both the parallel main outer surface and the outer surface of the edge part are {111} planes. That is, it can be considered as a structure in which single twin particles whose entire surface is the {111} plane are simply stacked.

However, the tabular grains described in Japanese Patent Application No. 62-203635 by the present inventors have {100} planes at the edges. One of the forms of tabular grains referred to in the present invention is a grain having such a form.

The AgX particles of the present invention have at least {10
It has a 0} plane and a {111} plane, but the area of the {111} plane /
20 to 1/20 when the value of the area of {100} plane is a tetrahedral grain,
It is preferably 10 to 1/10, and 20 to 1 in the case of tabular grains.
It is 0, preferably 15 to 2.0. The area ratio between the {111} plane and the {100} plane is a measurement method using the dependence of the adsorption of the sensitizing dye on the {111} plane and the {100} plane [T. Tani Journal of
Imaging Science, 29 , 165 (1985)].

However, in this method, the value obtained by subtracting about 7% from the calculated {100} area% becomes the actual {100} area%. This is because the formation of J-association body is difficult to occur even in the {111} plane at a place where the adsorption coverage of the dye is low.

However, like the tetradecahedral grain, from its electron micrograph image,
When the area ratio is clear, the area ratio can be obtained from an electron micrograph.

The halogen compositions of the surface layers of the {100} and {111} crystal surfaces of the AgX grains of the present invention are different from each other, but the surface layer of the crystal surface in this case is 5 lattices from the surface, preferably A crystal layer of 20 lattices.

The halogen compositions of the surface layers on the {100} and {111} crystal surfaces of the AgX grains of the present invention are different from each other, but it is preferable that they are different in iodine content and / or Cl content. If the Cl and I contents are determined, the Br content is automatically determined. When the iodide contents are different, it is preferable that they are different from each other by 2 to 40 mol%, preferably 3 to 30 mol%. In this case, the chemically sensitized nuclei are preferably formed preferentially on the crystal surface having the low iodine content surface layer. The iodine content of the surface layer of the crystal surface (hereinafter referred to as A-plane) on which the chemically sensitized nuclei are preferentially formed is preferably 5 mol% or less.

The iodide content of the surface layer of the crystal surface (hereinafter referred to as B surface) on which chemical sensitized nuclei are not preferentially formed is preferably 2 mol% to the solid solution limit, and more preferably 3 to 35 mol%. The reason is that, in general, an adsorbent such as a cyanine dye preferentially and strongly adsorbs on a crystal surface having a high iodine content surface layer.
This is because chemical sensitization nuclei are more difficult to form on the crystal surface having the high iodine content surface layer.

When chemical sensitization is performed on the crystal surface having a high iodine content layer, Ag ₂ S nuclei and Ag-Au-S nuclei are formed, but they are not effective electron traps, and as a result, they are effective. This is because there is an inclination that it is difficult to form a chemically sensitized nucleus.

This is E. Moisar (ICPS Tokyo, 1967) and H. Hirsch
According to the method of [I.Phot.Sci., 20 , 187 (1972)], a monodisperse normal crystal emulsion having the same grain size and varying the iodine content of the surface layer was subjected to sulfur sensitization and gold-ion-sensitization. The results are obtained by measuring the reflection spectrum.

This is because the developing speed of the latent image on the high iodine content layer is usually slower than the developing speed of the latent image on the low iodine content layer, and the development processing time becomes long, which is not preferable.

Further, when the Cl contents are made different, it is preferable that they are made different from each other by 7 to 100 mol%, preferably 10 to 80 mol%.

It is generally known that the adsorption strength of a cyanine dye is AgCl <AgBr <AgBrI. Therefore, in that case, AgBr
It is preferable to form a chemically sensitized nucleus on the priority of I → AgBr → AgCl.

On the other hand, and antifoggants and stabilizers, merocyanine dyes with Ag ⁺ affinity is generally expressed in the form of acid (HL), the solubility product pKsp = -log [Ag ^+] [L ^-] of AgX pKsp When compared with each other, the amount of adsorption increases in the order of AgBrI <AgBr <AgCl, because they are preferentially adsorbed on the AgX particles that are larger than the pksp value of AgX and have a larger difference. Therefore, in that case, the adsorption amount is in the order of AgBrI <AgBr <AgCl. In this case, it is preferable to form a chemically sensitized nucleus on AgCl → AgBr-AgBrI with the priority.

In the AgX particles of the present invention, it is more preferable to adsorb one or more adsorbents on the B surface. As the adsorbent in this case, (a) an adsorbent having different adsorption power depending on the halogen composition of the substrate.

(B) Adsorbents having different adsorption forces for {111} and {100} crystal faces are preferable.

Specifically, 3,3'-bis (4-sulfobutyl) -9-meth
ylthiacarbo cyanine is preferentially adsorbed on the {100} surface and
-3'-dimethyl thiazolino dicarbo cyanine bromid
e and Br ⁻ are preferentially adsorbed on the {111} plane, and 1,1′-diethyl
−2,2′−cyanine chloride, 1,1 ′, 3,3′−tetramethy
-2,2'-cyanine, anionic 9-methylthia carbocya
For nine and the like, the adsorption strength increases as the iodine content of the substrate increases.

As a specific compound example of the antifoggant, 1-phenyl-5-mercaprotetrazole (pksp = 16.2), 5
−Methlben zotriazole (pksp13.6), 5-Bromobenzotri
azole (pksp12.7), 4-Nitro-6-chlorobenzotriazo
le (pksp11.2), 4-Hydroxy-6-methyl-1,3,3a, 7-t
Examples include etraazaindene (pksp10.5).

For the adsorption characteristics of these substrates due to the difference in halogen composition and crystal plane, see TH James, The Theory of the Photogra
phic Process, Fourth Edition, Macmillan, New York, 197
7, Chap.1, Chap.9, Chap.13.

A. Herz and J. Helling, J. Colloid Interface Sci., 22 , 3
91 (1966). SLScrutton, J, Phot.Sci., 22 , 69 (197
Four).

J.Nys, Dye Sensitization, Bressanone Symposium, Focal
Press, London, 1970, P.26-43, 57-65. T.Tani, Journa
l of Imaging Science, 29 , 165 (1985). Japanese Patent Application Sho 62-1977
41, 62-219983, 62-219984, 62-231373, 62-2
The descriptions in Nos. 5137 and 63-269779 can be referred to.

In essence, it can be investigated by measuring Langmuir adsorption isotherms of various adsorbents for cubic particles, octahedral particles, and particles having different halogen compositions, which is described in Chapter 9 of the book by TH James above. Can be referred to.

The halogen compositions of the surface layers of the {100} and {111} crystal surfaces of the AgX particles of the present invention are different from each other.
It can be examined by the ctron Probe Microanalyser (EPMA) method or the like. For this, please refer to the Spring Meeting of the Photographic Society of Japan P.
46 (1987) can be referred to.

In the case of tabular grains as the A face, the {100} face is preferable to the {111} face. This is because in tabular grains, the area ratio of the crystal surface is smaller on the {100} plane, and therefore the number of chemically sensitized nuclei / cm ² and the position of generation can be controlled more.

On the other hand, in the case of tetradecahedral grains, the A faces are {111} faces and {1} faces.
The chemical sensitized nuclei on the {100} plane are generally dot-shaped as compared with the chemical sensitized nuclei on the {111} plane, and the number and position of chemical sensitized nuclei can be increased. From the viewpoint of controlling, the {100} plane is preferable. From the viewpoint of lowering the fogging level, the {111} plane is preferable.

For the difference in the characteristics of the chemically sensitized nuclei formed on the {111} plane and the {100} plane, see, for example, E. Moisar, SPSET.
okyo (1967), E. Moisar, Ber, Bunsenges. Phys. Chem., 72 ,
P.467-474 (1968) and GCFarnell, J, Phot.Sci., 23.249
(1975) can be referred to.

From the viewpoint of the number of A-planes per particle, the first
As shown in the figure, the number of A-faces is 6 in the tetradecahedron which is close to the octahedron, while the number of A-faces is 8 in the cubic basement and the tetradecahedron is cubic. From the viewpoint of reducing the number of A-planes, a tetradecahedral crystal close to an octahedral crystal is preferable.

However, FIG. 1 is a diagram used for explaining the number of A faces, and does not represent the particles of the present invention. The AgX particles of the present invention have at least {10
It is characterized by having crystal planes of 0} and {111} and different halogen compositions, and it is particularly preferable that the chemical sensitization nuclei are preferentially formed on one crystal plane.
In this case, the priority is (the number of chemically sensitized nuclei on the crystal plane where preferentially chemical sensitized nuclei are formed / cm ² ) / (the chemistry on the crystal face where preferentially chemically sensitized nuclei are not formed) Number of sensitized nuclei / c
m ² ) means 2.5 or more, preferably 5 or more.

It is difficult to directly observe this ratio. However, it was exposed to a silver halide emulsifier coating (1 second exposure, the amount of exposure is the amount of exposure at which maximum density is started to 10 times the amount of exposure),
A latent image is formed on the chemically sensitized nuclei (photosensitive nuclei), suppressed development is performed, the suppressed development nuclei are made visible by an electron microscope observation, and then the number of the suppressed development nuclei is counted. The above ratio of nuclei can be determined. DC Birch et al., Journal of Photographic Scien
ce, 23, P.249-256 (1975).

Here, the chemical sensitizing nucleus is a chemical sensitizing nucleus composed of sulfur, selenium, tellurium, gold and a noble metal compound of Group 8 alone or in combination, and most preferably a gold-ion sensitizing nucleus. It is usually called a sulfur sensitized nucleus, a gold sensitized nucleus, a noble metal sensitized nucleus, or a combination thereof, and the details can be referred to the literatures described later.

Further, it is preferable that the inside of these particles is reduction-sensitized. Whether or not it has this reduction-sensitized silver nucleus,
It can be easily judged from the fact that an inverted image of the existing internal fog is observed when wedge exposure is performed, internal development is carried out by a conventional method, and an HD curve is written.

The crystal structure inside the grain may be uniform, may have different halogen compositions inside and outside, or may have a layered structure. The change in halogen composition between the layers may be any of gradually increasing type, gradually decreasing type, and steep type, and can be used properly according to the purpose of use, and the crystal structure described in JP-A-63-92942 can also be referred to. .

Further, the halogen composition change between the crystal surface layer and the inside thereof may be any of a gradually increasing type, a gradually decreasing type and a steep type, but from the viewpoint of decreasing the electron trapping property at the interface, a gradually increasing sense or a gradually decreasing type. Is preferred.

The AgX grains in the present invention include silver iodobromide, silver chlorobromide,
It is silver chloroiodobromide, and there is no particular limitation other than the above-mentioned limitation of the halogen composition of the surface layer.

In the AgX particles of the present invention, the particle size distribution of the tetradecahedral particles is preferably narrow, and the coefficient of variation is preferably 20% or less, more preferably 10% or less.

In the AgX grains of the present invention, the tabular grains preferably have a narrow grain size distribution, and the coefficient of variation is preferably 30% or less, more preferably 15% or less. The shape may be triangular or hexagonal, but Japanese Patent Applications Nos. 62-319740 and 63-153722,
Hexagonal tabular grains described in JP-A-63-151618 and Japanese Patent Application No. 62-
The circular tabular grains described in No. 203635 are more preferable.

The tabular grains of the present invention preferably have an aspect ratio of 1.0 or more, more preferably 1.5 to 16.

The AgX emulsion of the present invention has at least {10
0X and {111} crystal surfaces, and the surface layers of the crystal surfaces are composed of AgX grains having different halogen compositions. The projected area ratio of these particles is
70% or more is preferable, 80% or more is more preferable, and 90% or more is further preferable.

Particularly, when an AgX emulsion having a tetrahedral grain and a super-high gradation is preferred, the tetrahedral grain of the present invention has a projected area of 98% of the total grain.
% Or more, more preferably 99% or more, and the coefficient of variation of the particle size distribution is particularly preferably 5% or less.

Next, a method for producing AgX particles of the present invention will be described. First, a method for producing tetradecahedral grains will be described, and then a method for producing tabular grains will be described.

1.14-sided grain It can be made by adding CDJ of AgNO ₃ aqueous solution and alkaline halide aqueous solution in gelatin aqueous solution, but the pBr (or pAg) region of CDJ where tetrahedral crystal is formed is the growing halogen composition and coexisting AgX solvent. , And the degree of supersaturation during growth. For these, see K. Murofushi et al., I.
nternational Congress of Photographic Science, Toky
o (1967) J. Rodgers, Symposium Paper on Growth of Ph
otosensitive crystals, Cambridge (1978) TGBogg
Et al., J.Phot.Sci., 24 , 81 (1976) Akira Sasai, Nissha, 47.
Volume, P. 255 (1984) and Reference Example 2 of Japanese Patent Application No. 62-219982 (hereinafter referred to as Application (A)) can be referred to. For example, the pAg 7.85-7.4 region at a supersaturation level of 50-80% of the critical growth rate with AgBr.

The {111} area and {100} area ratio of this tetradecahedral grain can be changed by the pBr value of CDJ during the crystal growth period.
For example, C. at a potential closer to the pBr value that produces a cubic crystal.
When DJ is added, tetrahedral crystals with a small {111} area ratio are generated.

For the method of preparing an AgX emulsion in which the tetradecahedral grains of the present invention have a projected area of 98% or more, preferably 99% or more, see the description in the same "Application (A)", Japanese Patent Application No. 63-223739. You can In brief, the important point lies in the formation conditions.

That is, the nucleation is preferably carried out under the condition that twin planes are not formed. The frequency of formation of twin planes depends on various supersaturation factors (temperature during nucleation, gelatin concentration, addition rate of silver salt aqueous solution and alkali halide aqueous solution, Br ^- concentration, stirring rotation number, added alkali halide aqueous solution). I ^- content, amount of silver halide solvent, pH, salt concentration (KNO ₃ , NaNO _3, etc.), molecular weight of gelatin, coexistence of an antifoggant, etc. It is shown in the diagram of 238808. Therefore, it is only necessary to move these conditional factors in the direction in which twin planes are not formed while observing these dependencies.

More specifically, while observing the replica image of the finally produced silver halide grain with a transmission electron microscope, the condition of the supersaturation factor at the time of nucleation may be adjusted to a direction in which twin planes are less likely to be formed. .

The pH of the reaction solution during grain formation can be 2 to 10, but when introducing reduction-sensitized silver nuclei, it is preferably 8.0 to 9.5.

The concentration of AgX solvent in the reaction solution is 0 to 1.5 × 10 ^-1 mo
l / l is preferred. As the AgX solvent, those described below can be used.

After forming the dodecahedron grains in this way, the AgX
The following method is used to make the halogen composition of the surface layer of the {100} crystal surface of the grain different from that of the surface layer of the {111} crystal surface.

Generally, when a tetradecahedral crystal is grown under pBr in the cubic crystal formation region and under low supersaturation, only the {111} plane grows.
On the other hand, when tetrahedral crystals are grown at low supersaturation under pAg in the octahedral crystal formation region, only {100} faces grow. Therefore,
Take advantage of this property.

PB of cubic and octahedral crystal formation regions in this case
Regarding the r region, similarly, the description in the above-mentioned documents by K. Murofushi et al. can be referred to.

More specifically, for example, in the case of silver iodobromide grains having different halogen contents, iodide contents of the surface layers are changed as follows.

The entire surface layer forms tetrahedral AgBrI grains with high iodine content, and then pAg in the octahedral region or pAg in the cubic region.
In the Ag region, an AgBrI layer having a low iodine content is grown under low supersaturation.

All surface layers form tetrahedral AgBrI grains with low iodine content, and then pAg in the octahedral region or pAg in the cubic region.
In the Ag region, a high iodine content AgBrI layer is grown under low supersaturation.

In this way, tetradecahedral grains composed of high-iodine content crystal faces and low-iodine content crystal faces are formed.

Further, in the above, the iodine content between the low iodine content layer and the high iodine content layer may be a gradually increasing type. In that case, the iodine content of the halide salt added with crystal growth may be changed with time.

The total surface layer in this case indicates a thickness of 50 lattices, preferably 200 lattices. The degree of low supersaturation in these cases refers to the degree of addition of silver salt and halide salt at an addition rate of 3 to 50%, preferably 5 to 40% of the critical growth rate under the conditions.

More generally, for example, when tetradecahedral grains are placed in a pAg solution in the cubic region, the relationship between the chemical potentials of Ag ⁺ on the {100} face and the {111} face is as shown in FIG. , Ag ⁺ on the {111} plane is lower. In this case, the chemical potential of Ag ⁺ on the {100} plane and the {111} plane
Let E ₁₀₀ and E ₁₁₁ , respectively. Chemical po of Ag ⁺ in solution when silver salt and halide salt are added to this system
Let tential be E _Ag ⁺ . When the addition rate of silver salt and halide salt is increased, the supersaturation ratio (S) of the solution increases, and E _Ag ⁺ is Δ
E _Ag ⁺ = kTlnS (where k = Boltzmann constant, T = absolute temperature)
Follow ascend. The driving force of crystal growth is this c
This is the difference in hemical potential. Focusing only on this driving force, it is preferable to add the silver salt and the halide salt at a supersaturation ratio satisfying E ₁₀₀ > E _Ag ⁺ > E ₁₁₁ .
Specifically, it corresponds to the above-mentioned addition rate.

Further, when the surface layers having different halogen compositions are formed, it is not preferable that Ostwald ripening occurs between the layers, so that the temperature at that time is preferably low. In this case, the preferred temperature range is 15 to 65 ° C, more preferably 20
~ 60 ° C.

It is also preferable that the above-mentioned adsorbent is adsorbed immediately after crystal growth to prevent Ostwald ripening due to mutual layer feeling.

Incidentally, there is AgX particle described in JP-A-55-124139 as a particle having AgX surface of different halogen composition in one AgX particle. The AgX particles are particles having a cubic crystal formed by precipitating AgX having a halogen composition different from that of the main body at the corners of the tetradecahedron, and are particles having only the outer surface of {100}. Different from AgX particles.

As a method for producing the AgX particles of the present invention, in addition, after adsorbing an adsorbent that preferentially adsorbs on one crystal face, a silver salt and a silver halide are added, and on the other crystal face, different from the main body part. A method of precipitating AgX having a halogen composition is also effective.

2. Tabular Grain For the conventional tabular grain forming method, see JP-A-58-113926.
No. 58-113927 and No. 58-113928 can be referred to.

One method, a method for forming tabular grains having good monodispersity is disclosed in JP-A-55-142329, JP-A-61-48950, 61-299155,
Reference can be made to the descriptions in 61-238808 and 62-319740.

Usually, the tabular grains thus prepared have, as described above, both the main planes and most of the edge faces are {111} faces, and the main surface has a hexagonal shape (hereinafter referred to as hexagonal tabular grains). ), The particle size distribution is narrow.

However, after making hexagonal tabular grains, the cubic or tetradecahedral region (more specifically, in the case of AgBr,
When the crystal is grown with pAg 8.0 or less), the grains grow while increasing the thickness, and the main surface is the {111} plane, but the {100} plane appears at the edge part. Reference example 1
Can be used as a reference. At this time, the coexistence of the AgX solvent further promotes this change.

As another method, the excess halogen present in the solution is changed to Cl ⁻ (the excess Br ⁻ is reduced by washing the emulsion with water or adding AgNO ₃ and then NaCl is added), and the silver halide salt is used. The {100} plane can also be formed at the edge portion by adding the double jet of the above aqueous solution. In this case, the excess Cl ⁻ concentration is preferably pCl = 0.7 to 2.5.

After making hexagonal tabular grains, when they are aged under pAg in cubic or tetradecahedral regions, edge {100} faces appear. The aging progress at this time depends on the grain size of the tabular grains, the pBr of the solution, and the concentration of the AgX solvent, and the dependency can be referred to FIG. 7 of Japanese Patent Application No. 62-203635. Tabular grains having {100} faces are generated on the shaded side of the curve in the figure.

The obtuse angle of the edge portion of the tabular grain thus prepared has an angle of 125 °, whereas that of the conventional tabular grain is 109.5 ° when the edge portion is completely made into {100} faces.

In this way, after forming tabular grains having {100} faces at the edges, halogens different from the substrate on the {111} faces of these grains were produced under low supersaturation under pBr in the cubic crystal region. By laminating AgX having the composition, the tabular grains of the present invention are produced.

The degree of low supersaturation in this case is the same as in the case of the above-mentioned tetradecahedral grains, and the silver salt and halide are added at 3 to 50%, preferably 5 to 40% of the critical growth rate of AgX grains under the conditions. Refers to the degree to which salt is added.

In the above tetradecahedral grains and tabular grains, only on one crystal face, the selective growth property is not perfect when laminating AgX having a halogen composition different from the substrate, and when laminated on the other crystal face as well. , Followed by aging in the cubic crystal region or the octahedral crystal region, resulting in an accidentally stacked Ag
The X layer melts and is deposited on one crystal face to obtain the AgX particles of the present invention. At this time, if the AgX solvent is present, the aging is further promoted.

In the present invention, only on one crystal plane, AgX having a halogen composition different from that of the substrate is laminated, but this is because the same crystal system layer as the substrate is laminated as a simple extension layer on the substrate,
Therefore, it is different from epitaxial growth.

As a method of adding silver ions and halogen ions to be added during the crystal growth period, a method of adding an aqueous solution of silver salt, which is prepared in advance.
Ultrafine grain emulsion with a size of 1 μm or less (AgCl, AgBr, AgI
And / or a mixed crystal thereof and a method of superposing them. Further, a method of increasing the addition rate of silver ions and halogen ions during crystal growth can be used. Regarding these, the description in Japanese Patent Application No. 63-223739 can be referred to.

Thus at least {100} on one AgX particle surface
Chemical sensitization is performed after forming AgX grains having a {111} crystal surface and having different halogen compositions in the surface layer of the crystal surface, and preferentially chemical sensitizing on one crystal surface. It is preferable to form nuclei. The two typical processes of the chemical sensitization are as follows.

Grain formation → Adsorption of an adsorbent on a specific crystal plane → (sulfur + gold) sensitization Grain formation → (sulfur + gold) sensitization However, in the above process, the emulsion washing process may be performed anywhere after grain formation. Good. That is, it may be after grain formation, after adsorbing an adsorbent, between sulfur sensitization and gold sensitization, or after gold sensitization. Even one washing step, 2
It may be times.

First, the process of will be described.

It is preferable to add an adsorbent immediately after the grain formation or after washing the emulsion with water to adsorb the adsorbent on the AgX grains. It is also preferable from the viewpoint of preventing Ostwald ripening between crystal planes having different halogen compositions.

As described above, the adsorbent is preferably (a) an adsorbent having a different adsorbing power depending on the halogen composition of the substrate, and (b) an adsorbent having a different adsorbing power with respect to {111} and {100} crystal faces.

Specifically, such an adsorbent is obtained by examining adsorption isotherms of various adsorbents for various AgX emulsion grains having different halogen compositions or crystal habits in the same grain surface area,
You can choose.

In this way, by utilizing the selective adsorption property of the adsorbent of (a) or (a) + (b), the adsorbent is selectively adsorbed on the crystal plane where the chemical sensitized nuclei are not preferentially formed. .

Further, generally, the stronger the adsorption force, the more
Aggregates are easily formed, and J aggregates are preferable because they can more sufficiently prevent the formation of chemically sensitized nuclei.

For the adsorption characteristics of adsorbents due to differences in halogen composition and crystal plane of these substrates, see TH James, The Theory of the
Photographic Process, Fourth Edition, Macmillan, New
York, 1977, Chap.9, Chap.1, Chap.13.

A. Herz and J. Helling, J. Colloid Interface Sci., 22 , 3
91 (1966).

SLScrutton, J.Phot.Sci., 22 .69 ( 1974).

J.Nys, Dye Sensitization, Bressanone Symposium, Focal
Press, London, 1970, P.26-43, 57-65.

T. Tani, Journal of Imaging Science, 29 , 165 (198
Five).

Also, the above-mentioned “Application (A)” and Japanese Patent Application No. 63-223739 can be referred to.

Also, the adsorption power of sensitizing dyes and additives to silver halide is
It is known that in addition to the crystal habit and halogen composition of the substrate, it depends on various atmospheres of the emulsion (emulsion pH, pAg, coexistence of adsorption promoter, etc.). Therefore, using that knowledge,
The adsorption strength of sensitizing dyes and additives can be adjusted.

About these, for example TH James, The Theory of th
e Photographic Process, Fourth Edition, Macmillan, Ne
The description of w York, 1977, Chap.9, Chap.1, Chap.13 can be referred to.

As adsorbents, in addition to sensitizing dyes, antifoggants, stabilizers,
The pendant dyes (compounds chemically bonded to the sensitizing dyes and the antifoggants or stabilizers) described in the above "Application (A)" are also effective.

As a method of adding these adsorbents, only one kind of sensitizing dye, antifoggant, stabilizer, and pendant dye may be added, or two or more kinds of additives may be mixed and added,
You may add separately.

Further, the whole amount may be added before adding the chemical sensitizer, or 1 part may be added and the rest may be added later. One part is 1/10 to 1 of the total amount.

The amount of the adsorbent added is not particularly limited, but is usually 0 to 120%, preferably 0 to 100% of the saturated adsorption amount of AgX particles.

In this way, after the adsorbent is selectively adsorbed on one of the crystal faces, the chemical sensitizer is added and aged to preferentially form the chemical sensitized nuclei on the other crystal face.

As the chemical sensitization method in this case, the following two chemical sensitization methods can be used.

[1] Commonly used chemical sensitization method (
Even if chemical sensitization is carried out at a temperature of 40 ° to 75 ° C, a sulfur sensitizer is added, and then a gold sensitizer is added 2 to 5 minutes later and aging is performed for 20 to 80 minutes. Since the adsorbent is preferentially adsorbed on the surface, almost no chemically sensitized nuclei are formed on the crystal face, and chemically sensitized nuclei are preferentially formed on the other crystal face. It

[2] As the chemical sensitizer, a plane-selective chemical sensitizer that selectively reacts on a specific crystal plane is used. Specifically, a face-selective sulfur sensitizer that selectively reacts on a specific crystal face is used as the sulfur sensitizer. In the above case, it is preferable to use a sulfur sensitizer that selectively reacts on the crystal plane where the adsorbent is not preferentially adsorbed. Regarding the surface-selective reactivity of this sulfur sensitizer, the description in the above-mentioned “Application (A)” and its Reference Example 1 can be referred to.

For example, when the emulsion conditions are pH 6.5, pAg8.5, 50 ° C., and ripening for 60 minutes, hypo reacts very well selectively on the {111} plane as compared to the {100} plane, and sulfur sensitization is performed. Form a nucleus.

Triethyl thiourea reacts very selectively on the {100} plane as compared with the {111} plane, and selectively forms sulfur sensitized nuclei on the {100} plane.

However, under other conditions such as (pH6.5, pAg8.5 ℃, 65 ℃, 6 ℃,
Under the conditions of aging (0 minutes) and aging (pH 6.5, pAg 7.7, 50 ° C, 60 minutes), the selectivity is low, which is not preferable. The area selectivity of the compound including other sulfur sensitizers is generally high under low temperature and high pAg conditions.

Further, in this case, when the gold sensitizer is added at the same time and chemically sensitized, the area-selective reactivity thereof becomes small. Therefore, the method of the above-mentioned “Application (A)” (after sulfur sensitization, washing with water, residual It is preferable to use a method of adding the gold sensitizer after removing the sulfur sensitizer, or a method of adding the gold sensitizer after 80% or more of the added sulfur sensitizer has reacted.

In this way, the effective chemical sensitization nuclei are preferentially formed on one of the crystal faces to form the AgX grains of the present invention.

Further, in the present invention, when AgBrI having a high iodine content is used as the halogen composition of the surface layer on the B side, the chemical sensitized nuclei formed on the crystal face are difficult to be an effective electron trap as described above. In this case, discrimi in the degree of chemical sensitization
As the nation factor, (difference in crystal plane + difference in halogen composition) can be used, and more effectively discrimina
It is particularly preferable because it has the merit of being able to perform an optional treatment.

The following process will be described. In this case, since there is no adsorbent that preferentially adsorbs on one of the crystal planes, the control of the effective chemical sensitization nucleus generation position is controlled by the reactivity of the chemical sensitizer (difference in crystal plane + surface layer). Difference in halogen composition)). Therefore, its discrimination is inferior to that of.

However, compared to the conventional method (difference in crystal plane), the difference in halogen composition of the surface layer is also included as a discrimination factor, so there is a merit that the position of chemically sensitized nuclei can be controlled more effectively than the conventional method. Hold. Also,
As described in 63-26979, it is more preferable to use the adsorbent in a function-separated type.

As the chemical sensitization method of AgX grains of the present invention, other Japanese Patent Application No.
The description in the amendment of 1-299155 can be referred to.

The silver halide grain of the present invention can be used as an emulsion by the above-mentioned silver halide grain itself, but a core / shell type direct inversion emulsion can be formed by using the grain as a core and used. Regarding this, Example 1 of Japanese Patent Application No. 61-299155
3, and U.S. Patent Nos. 3,761,276, 4,269,927, and
You can refer to No. 3,367,778.

Further, a shallow inner latent emulsion may be formed and used by using the grains as a core. For this, reference can be made to JP-A-59-133542, US Pat. Nos. 3,206,313, and 3,317,322.

Alternatively, the particles may be used as host particles to form epitaxial particles. Regarding this, JP-A-58-108526
No. 59-133540 and Japanese Patent Application No. 60-172966 can be referred to.

Further, the particles may be used as substrate particles to form ruffled particles. U.S. Patent
You can refer to issue No. 4643966.

The tabular grains can also be used in a highly hardened system. Regarding this, JP-A-58-11392 Research Disclosure, Volume 184, 197
August 18th, Item 18431, Item K can be referred to.

Further, a method of adding an oxidizing agent such as H ₂ O ₂ or peroxy acid before the gold-sensitized ripening of the grains is completed, and then adding a reducing substance, or a method in which the sensitized material is free after the gold-sensitized ripening is performed. A method of reducing gold ions can be used. Regarding this, Japanese Patent Application Nos. 59-122981, 59-122984, 60-96237, and
60-61429, 60-61430, 61-184890, 61-183
You can refer to No. 949. The tabular grains may be spectrally sensitized with an antenna dye. About this, Japanese Patent Application 61-5
Reference can be made to the descriptions of 1396, 61-284271, and 61-284272.

Regarding the utilization of the optical coherence of the tabular grains, and the details of the above matters and other matters, Japanese Patent Application No. 61-2
You can refer to issue No. 99155.

In the aging process of the present invention, in order to promote aging,
A silver halide solvent may be used to promote crystal growth during the crystal growth period after ripening.

Examples of the silver halide solvent often used include thiocyanate, ammonia, thioether, thioureas and the like.

For example, thiocyanate (U.S. Pat.
2,448,534, 3,320,069, etc.), ammonia, thioether compounds (e.g., U.S. Pat.Nos. 3,271,157, 3,574,628, 3,704,130, 4,297,439,
No. 4,276,347, etc.), thione compounds (for example, JP-A-5
No. 3-144319, No. 53-82408, No. 55-77737, etc.), amine compounds (for example, JP-A No. 54-100717, etc.) and the like can be used.

Examples of the sensitizing dye used as the adsorbent and the spectral sensitizing dye of the present invention include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, hemioxonol dyes, and oxo dyes. Mention may be made of polymethine dyes containing normerostyryl and streptocyanin.

Specifically, 1,1'-diethyl-2,2'-cyanine chlorid
e, 1,1 ', 3,3'-tetramethyl-2,2'-cyanine, anionic 9-methylthiacarbocyanine 3,3'-dimethylthi
azolinodicar-bocyanine bromide etc.
Reference can be made to Japanese Patent Application Nos. 62-197741, 62-219983, 62-231373, and the below-mentioned documents.

In addition, the pendant dye (a compound in which a sensitizing dye and an antifoggant or stabilizer are chemically bonded during the substitution period) described in the above “Application (A)” can also be used.

Further, the adsorbent and the antifoggant, the antifoggant used as a stabilizer, the stabilizer, for example, tetrazaindenes, azoles, for example, benzothiazolium salt,
Nitroindazoles, nitrobenzimidazoles,
Chlorobenzimidazoles, promobenzimidazoles, mercaptothiazoles, mercaptobenzimidazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (especially 1-phenyl-5-mercaptotetrazole), etc., and mercapto Examples include pyrimidines, mercaptotriazines, thioketo compounds such as oxazolithion, and further benzenethiosulfinic acid, benzenesulfinic acid, benzenesulfonic acid amide, hydroquinone derivatives, aminophenol derivatives, gallic acid derivatives, and ascorbic acid derivatives. it can.

As the sulfur sensitizer used in the present invention, in addition to the sulfur sensitizer of Reference Example 1, US Patent Nos. 1,574,944 and 2,27
No. 8,947, No. 2,410,689, No. 3,189,458, No. 3,5
The compounds described in 01,313, French Patent 2,059,245 and the like, or active gelatin can be used.

The other constitution of the emulsion layer of the silver halide photographic light-sensitive material of the present invention is not particularly limited, and various additives can be used if necessary.

Chemical sensitizers, spectral sensitizing dyes, antifoggants, metal ion dopes, silver halide solvents, stabilizers, dyes, color couplers, DIR couplers, binders, hardening agents, coating aids, sensitizers that can be added. Sticky agent, emulsion precipitation agent, plasticizer,
Dimension stability improver, antistatic agent, optical brightener, lubricant, matting agent, surfactant, ultraviolet absorber, scattering or absorbing material,
Hardening agents, anti-adhesion agents, photographic property improving agents (for example, development accelerators, contrast enhancers, etc.), developers, and other photographically useful fragments (development inhibitors or accelerators, bleaching accelerators, developers,
Silver halide solvents, toners, hardeners, antifoggants, competitive couplers, couplers that release chemical or spectral sensitizers and desensitizers, image dye stabilizers, self-inhibiting developers, and their use, In addition, supersensitization in spectral sensitization, halogen acceptor effect and electron acceptor effect of spectral sensitizing dye, action of antifoggant, stabilizer, development accelerator or inhibitor, and others, in the production of the emulsion of the present invention. Manufacturing equipment used, reaction equipment, stirring equipment, coating, drying method, exposure method (light source, exposure atmosphere, exposure method), photographic support, microporous support, undercoat layer, surface protective layer, matting agent, intermediate layer , Antihalation layer, photographic processing agent, and photographic processing method, Research Disclosure Magazine, Volume 176, December 1978, December issue (item 17643), Volume 184, August 1979 issue (item 18
No. 431), Vol. 134, June 1975 (Item 13452), Product Licensing Index, Vol. 92, 107-110.
(December 1971), JP-A-58-113926, JP-A-58-113927,
58-113928, 61-3134, 62-6251 JCIA Monthly Report 1
984, December issue, P.118-27 T.H.James, The Theory of th
e Photographic Process, Fourth Edition, Macmillan, Ne
w York, 1977, VLEelikman et al., Making and Coa
ting Photographic Emulsion (The Focal Press, 196
4 years) can be referred to.

If necessary, the silver halide emulsion of the present invention can be provided on the support together with other emulsions, protective layers, intermediate layers and filter layers in one or more layers (for example, two layers or three layers).
Further, it is not limited to one side of the support, and may be provided on both sides. It is also possible to superimpose emulsions having different color sensitivities.

Regarding the layer structure, the descriptions in JP-A-61-3134 and Japanese Patent Application No. 61-299155 can be referred to.

In addition, the AgX emulsion of the present invention can be used in any combination with conventional known techniques.

With respect to this conventional known technique and other constitutions of the AgX emulsion of the present invention, the description of Japanese Patent Application No. 63-153722 and its amendment can be referred to.

The silver halide emulsion of the present invention is a black-and-white silver halide photographic light-sensitive material [eg, X-ray sensitive material, printing sensitizer, photographic paper, negative film, microfilm, direct positive sensitive material], color photographic light-sensitive material (eg, (Negative film, photographic paper, reversal film, direct positive color photosensitive material, silver dye bleaching method photo, etc.)
Can be used for. Further, a light-sensitive material for diffusion transfer (for example, a color diffusion transfer element, a silver salt diffusion transfer element), a photothermographic material (black and white, color), a high-density digital recording photosensitive material,
It can also be used as a sensitive material for holographic materials.

The emulsion of the present invention is described in Examples 1 and 62-14 of JP-A-62-269958.
1112, 63-151618, Examples 13, 14, 60-95533
No. 59-142539, No. 62-253159, Japanese Patent Application No. 62-203635, Example 9, No. 61-109773, No. 62-54640, No. 62-208241.
No. 62-263319, and can be preferably used as the constituent emulsions of Examples.

(Effect of the present invention) The thus obtained AgX particles of the present invention in which the position and the number of chemically sensitized nuclei on one AgX particle are controlled have the following characteristics.

1. The formation of chemically sensitized nuclei is well limited on one crystal plane. Therefore, a silver halide emulsion with less latent image dispersion and high sensitivity and good development progress can be obtained. This effect is particularly great with AgX particles having a particle size of 1.0 μm or more, which tends to cause latent image dispersion.

2. It has the following advantages over the method of controlling the formation position of chemically sensitized nuclei only by the crystal plane dependence of the adsorption power of the adsorbent.

(I) The adsorbents (especially sensitizing dyes) that can be used are limited to the surface-selective adsorbents, but since the difference in the adsorption force due to the difference in the halogen composition of the surface layer is used, The selection range of adsorbents that can be formed is widened.

(Ii) In order to suppress the formation of chemically sensitized nuclei, an adsorbent that strongly adsorbs is more preferable, but in general, a surface-selective adsorbent is
The adsorptive power was weak, and both requirements were contradictory. In the present invention, since the difference in the adsorption force due to the difference in the halogen composition of the surface layer is also utilized, the adsorbent can be strongly adsorbed on the intended crystal plane, and the above problems have been solved. For example, a high iodine content AgBrI layer is used for the crystal surface layer and AgBI layer is used for other crystal surface layers.
When the r or AgBrCl layer is used, the adsorbent is strongly adsorbed on the surface of the AgBrI crystal.

(Iii) Since the chemical aging is performed in a state where the adsorbent is strongly adsorbed, the particle deformation during the chemical aging is small.

3. Separation of Latent Image Forming Site and Color Sensitizing Site Generally, when a large amount of an adsorbent (sensitizing dye) is adsorbed, the development suppressing action becomes strong, but in the case of AgX particles of the present invention, the latent image serving as a development starting point is formed. Since the nuclei are formed on the crystal surface on which the sensitizing dye is loosely adsorbed, the development suppressing effect is small.

On the other hand, up to now, it was not possible to adsorb a large amount of the sensitizing dye from the viewpoint of development suppression, but since there are almost no latent image nuclei on the crystal faces that adsorb a large amount of the sensitizing dye, development suppression It is possible to adsorb a large amount of the sensitizing dye onto the crystal surface without increasing the concern that the minus blue sensitivity can be increased.

That is, the adsorption distribution of the sensitizing dye on the surface of the AgX particles is such that the necessary amount of the sensitizing dye is adsorbed to the necessary place, and only a small amount of the sensitizing dye is adsorbed to the harmful place. Therefore, it is possible to obtain a photographic property with high sensitivity and good development progress.

4. Photosensitization process, effects on the development process Further, as a preferred embodiment of the present invention, one crystal plane has a high iodine content AgBrI as a surface layer, the other crystal plane low iodine content AgBrI or AgBr, AgBrCl When it is used as a surface layer, it has the following features.

(I) Sensitization effect due to dye holes When exposed to minus blue, excited electrons of the dye are injected into the conduction band of AgX and trapped in the chemical sensitized nuclei on the low-iodine content crystal face to form a latent image. , And the charge is spatially separated from the dye holes.

On the other hand, the dye holes are injected into the high iodine content layer and react with the reduction sensitized nuclei in the high iodine content layer as follows to emit electrons.

Ag ₂ + hole → Ag ⁺ + Ag → 2Ag ⁺ + e This electron is trapped in the latent image nucleus and acts to enhance photographic sensitivity.

Since the valence band of the high iodine content layer is located at a higher position, this dye hole injection is more efficiently injected into AgX, the above reaction is further promoted, and the sensitivity is enhanced.

That is, the effect of preventing recombination due to the separation of latent image nuclei from the dye holes and the effect of increasing the sensitivity due to the high efficiency of conversion from dye holes to conduction electrons can be obtained. The energy level diagram of AgX and dye is shown in Fig. 3.

(Ii) Effect of having a low-iodine content crystal face and a high-iodine content crystal face on one AgX grain Until now, with respect to the iodine content of the AgX grain surface, from the viewpoint of accelerating the initial development rate, low iodine The content AgX is preferred, on the other hand, the adsorption of the sensitizing dye, the color sensitization efficiency (when strongly adsorbed, the wave function overlap between the conduction band of AgX and the excited level of the dye becomes larger, and The high iodine content layer is preferred from the viewpoint of the efficiency of electron injection into AgX) and the efficiency of hole injection into AgX.

In the AgX particles of the present invention, in order to accelerate the initial development speed, the development starting point (latent image nucleation position) is on the low iodine content crystal face, and a large amount of dye is strongly adsorbed to improve the color sensitization efficiency. For the sake of improvement, the dye-adsorbed crystal face has a high iodine content of AgX, which satisfies both of these conflicting requirements.

5. Blue light absorption and development activity Generally, the magnitude of blue light absorption of AgX emulsion particles is AgCl <AgB.
r <AgI, while development progress is AgCl <AgBr <AgI
And satisfying both is a conflicting requirement. However, in the AgX grains of the present invention, the latent image nuclei that are the development starting point are on the low iodine content crystal plane, and there is no problem in terms of development rate, while regarding the point of light absorption, inside the grain, and other Since the crystal plane can be made to have a high iodine content AgBrI, there is no problem and both requirements can be satisfied.

The thus obtained light-sensitive material comprising AgX grains of the present invention provides a silver halide emulsion excellent in sensitivity, development progress, graininess, reciprocity law property, sharpness, resolution, gradation and image quality.

Preferred embodiments of the present invention are as follows.

1) 70% or more of the projected area of all AgX grains, preferably 80
% Or more, and more preferably 90% or more is composed of AgX particles according to claim 1 or 2.
gX emulsion.

2) (Number of chemically sensitized nuclei on the crystal plane where preferentially chemical sensitized nuclei are formed / cm ² ) / (Number of chemically sensitized nuclei on the crystal faces where preferentially chemically sensitized nuclei are not formed) / Cm ² ) is 2.5 or more, the silver halide emulsion according to claims 2 to 3 3) The average value of {111} plane area / {100} plane area is 20
AgX according to claims 1 and 2, characterized in that it consists of tetradecahedral grains of -1/20, preferably 10-1 / 10.
emulsion.

4) Average value of {111} plane area / {100} plane area is 20
Claims 1, characterized in that they consist of tabular grains having parallel twin planes of ~ 1.0, preferably 15-2.0.
The AgX emulsion according to item 2.

5) The halogen composition of the surface layers on the {100} and {111} crystal surfaces is 2 to 40 mol%, preferably 3 to 40% in terms of iodine content.
The AgX emulsion according to claim 2, wherein the chemical sensitized nuclei differ by 30 mol% and are preferentially formed on the crystal surface having the low iodine content surface layer.

6) The AgX emulsion according to claim 2, wherein the iodine content of the surface layer on the crystal surface where the chemically sensitized nuclei are preferentially formed is 5 mol% or less.

7) The halogen composition of the surface layers on the {100} and {111} crystal surfaces is 7 to 100 mol%, preferably 10 to 8 in terms of Cl content.
Claims characterized in that the chemical sensitized nuclei differ by 0 mol% and are preferentially formed on the crystal surface having the high Cl content layer or on the crystal surface having the low Cl content layer. The AgX emulsion according to item 2.

8) By utilizing the difference in effective chemical sensitized nucleation ability due to (difference in crystal plane + difference in halogen composition of surface layer), the AgX emulsion grains produced by the method of claim 4 A method for producing an AgX emulsion, which comprises forming preferentially effective chemically sensitized nuclei on a crystal plane.

9) In the AgX emulsion produced by the method of claim 4, on the crystal plane of which the chemical sensitization nucleus is not preferentially formed,
A method for producing an AgX emulsion, which comprises chemically sensitizing after adsorbing an adsorbent that preferentially adsorbs by utilizing (difference in crystal plane + difference in halogen composition of surface layer).

The present invention will be further described below with reference to Reference Examples and Examples, but the embodiments of the present invention are not limited thereto.

Reference Example 1 An aqueous solution of gelatin [water 1000
ml, gelatin 7g, KBr4.5g, pH8.0)
25ml of AgNO ₃ solution (including AgNO ₃ 8.0g) while keeping at 30 ℃
And 25 ml of KBr aqueous solution (including 5.8 g of KBr) were added simultaneously over 1 minute (flow rate 25 ml / min), and after stirring for 1 minute, 350 ml of the solution was used as a seed crystal and the gelatin aqueous solution (water 650 m
l, gelatin 20g, KBr0.5g, pH8.0), and the temperature is 75 ℃.
Raise to. After raising the temperature and aging for 45 minutes, the AgNO ₃ aqueous solution (1
30 ml AgNO ₃ in 00 ml) and an aqueous KBr solution, using pBr1.at 7 ml / min for the first 10 minutes and 13 ml / min for the next 20 minutes.
8 (However, this was Br adsorbed on the AgX grains ^-.., Including also excess KBr present in the AgX emulsion indicates that the 1.6 g / l silver potential showed -15 mV) in the following CDJ was added at 20 ml / min for 20 minutes. A is (-4m
V), B +10 mV, C +40 mV, D +70 mV, E +100
mV of CDJ was added. The area ratio of {100} planes of the obtained AgBr tabular grains was calculated by the method of T. Tani mentioned above, and A (2%), B (2.6%), C (8.5%), D (18%) , E
(51%), and the {100} area ratio of tabular grains increased as the CDJ potential increased.

Example 1 A gelatin aqueous solution [water 1000
ml, deionized alkali treated gelatin 30g, KBr0.5g, NH
₄ NO ₃ 1 g, NH ₃ (25 wt%) 2 ml] and put the solution temperature at 60 ° C.
While maintaining the above, the AgNO ₃ aqueous solution and the halide aqueous solution were added. AgNO ₃ addition rate is 3.3 × 10 ^-4 M / for the first 10 minutes.
At min., double jet addition of AgNO ₃ aqueous solution and KBr aqueous solution was performed. The pBr value during the addition was 2.53. Next addition speed
After adding AgNO ₃ aqueous solution and KBr aqueous solution at 6.0 × 10 ^-4 M / min for 7 minutes, the initial addition rate is 6.0 × 10 ^-4 M / min. And the final addition rate is 8 × 10 ^-3 M / min. PAg by the 85-minute linear acceleration addition method
7.7 CDJ additions were made. The distance between the {111} plane pairs of the tetradecahedral grains (hereinafter referred to as E1) obtained at this point is 0.90 μm,
The {111} area was 17%.

Next, KBr was added to make pAg 8.6, and then the initial addition rate was 1.5 × 10
^-3 M / min., Final addition acceleration 2 × 10 ^-3 M / min, addition time 20
Minute aqueous solution of AgNO ₃ and 6 mol% KI content (KBr + KI) aqueous solution
CDJ of pAg8.6 was added. The {111} face-to-face distance of the tetradecahedral grains obtained at this time was 0.90 μm, which is the same as above.
It is shown that the added AgBrI (6 mol%) is laminated only on the {100} plane of the tetradecahedron.

Lower the temperature of this emulsion to 30 ° C, wash with water, redisperse,
pAg8.6, pH6.5, temperature 40 ℃, 3,3'-bis (4-sulfo
butyl) -9-methtylthiacarbocyanine dye after adsorbing 75% of the saturated adsorption amount, the emulsion conditions were pAg8.6, pH6.5,
The temperature _{50 ℃, Na 2 S 2 O} 3 · 5H 2 O of 0.9 × 10 ^-5 mol / mol AgB
r was added, and after a delay of 3 minutes, a gold sensitizer (gold thiocyanate complex) was added in an amount of 0.3 × 10 ⁻⁵ mol / mol AgBr, followed by aging for 70 minutes.

The temperature was raised to 40 ° C and the antifoggant {TAI (4-hydroxy-6
-Methyl-1,3,3a, 7-tetraazaindene) 3 g / mol Ag)
A coating aid was added and silver 1.5 g / m ² was coated on the transparent base.

Example 2 In Example 1, the dye was adsorbed on the tetradecahedral grains and the emulsion conditions were adjusted to pA.
It is the same until g8.6, pH6.5 and temperature 50 ℃. Then _{Na 2 S 2 O 3 · 5H} 2 O of 0.9 × 10 ^-5 mol / mol AgBr only addition, 4
After aging for 0 minutes, 0.3 × 10 ⁻⁵ mol / mol AgBr of the above-mentioned gold sensitizer was added and aging was continued for 40 minutes. Then set the temperature to 40
The temperature was lowered to ℃, antifoggants and coating aids were added, and silver was coated on the transparent base at 1.5 g / m ² .

Comparative Example 1 The procedure is the same as in Example 1 until E1 AgX particles are prepared. Next, KBr was added to make pAg 8.6, and then the initial addition rate was 1.5 × 10 ^-3
M / min. Final addition rate 2 × 10 ^-3 M / min, addition time 20 minutes AgN
An aqueous solution of O ₃ and an aqueous solution of KBr were added to pJg8.6 of CDJ. The distance between the {111} faces of the tetradecahedral grains obtained at this time is 0.9 μm.
In addition, it is shown that the added AgBr was laminated only on the {100} face of the tetradecahedron. After that, the same steps as in Example 1 were performed.

The emulsion coatings of Examples 1, 2 and Comparative Example 1 were exposed to blue light 1
Second exposure (exposure is 10 times the exposure that gives maximum density)
Then, after development was carried out at 20 ° C. for 6 minutes with the above-mentioned suppression developing solution of Birch et al., Gelatin was removed, and TEM images of the particles were observed by the replica method. The proportion of the development starting points of the grains existing on the {111} faces of the tetradecahedral grains was as shown in Table 1.

The emulsion coatings of Examples 1 and 2 and Comparative Example 1 were subjected to wedge exposure through a blue filter for 10 ^-3 seconds and developed with MAA-1 developer at 20 ° C for 10 minutes. The obtained characteristic curve and AgX
The relative quantum sensitivities obtained from the light absorptance of the particles are shown in Table 1, and the effect of the present invention on Comparative Example 1 was confirmed.

Example 3 An aqueous solution of gelatin (water 1000
ml, gelatin 7g, KBr4.5g, pH8.0)
25ml of AgNO ₃ solution (including AgNO ₃ 8.0g) while keeping at 30 ℃
Then, 25 ml of KBr aqueous solution (containing 5.8 g of KBr) was added simultaneously over 1 minute (flow rate 25 ml / min) and stirred for 1 minute, 300 ml of which was used as a seed crystal, and the gelatin aqueous solution (water 650 m
l, gelatin 20g, KBr0.6g, pH8.0), and the temperature is 75 ℃.
Raise to. After raising the temperature and aging for 45 minutes, the AgNO ₃ aqueous solution (1
Using KBr aqueous solution containing) the AgNO ₃ 40g of in 100 ml, the first 10 minutes at 6 ml / min, following 20 min at 12 ml / min, pBr
1.7 CDJ was added. Then C at 6 ml / min for 7 minutes with pAg6.8.
DJ added. The tabular grains obtained at this point were treated as described above.
The {100} area ratio obtained by the method of T. Tani was 13%. The average particle size was 1.1 μm.

Next, an aqueous solution of AgNO ₃ with pAg 6.5 and an aqueous solution of (KBr + KI) having an iodine content of 6 mol% were added at 6 ml / min for 7 minutes. The average particle size of the finally obtained tabular grains was 1.1 μm, which was not the same as the above. Therefore, AgBrI (6 mol%) is {111}
It can be seen that the layers are stacked only on the main plane. The tabular grains had an average aspect ratio of 6 and the variation coefficient of the projected grain size of the tabular grains was 15%.

The AgX emulsion thus obtained was washed with water, redispersed,
The emulsion was adjusted to pH 6.5, pAg 8.0, and temperature 40 ° C, and 3,3'-dimethyl was added.
Saturated adsorption amount of thiazolinodicarbocyanine bromide dye
The added amount of 80% was added to adjust the pAg to 8.0. After aging for 20 minutes, pAg8.5 temperature was raised to 50 ℃ and methanol solution of Triethyl-thiourea (0.005% by weight) was added at 1.0 × 10 ^-5 mol / mol Ag.
Add Br only, delay 3 minutes, then add the above gold sensitizer to 0.4
Only × 10 ^-5 mol / mol AgBr was added, and the mixture was aged for 40 minutes. The temperature was lowered to 40 ° C., an antifoggant and a coating aid were added, and the mixture was coated on a transparent base.

Comparative Example 2 In Example 3, an AgX emulsion was prepared in which the AgBrI layer to be laminated later was replaced by AgBr and all other conditions including chemical sensitization were the same, and an antifoggant and a coating aid were added. It was coated on a transparent base.

Next, the emulsion coatings of Example 3 and Comparative Example 2 were compared in the same manner as in Table 1, and the results are shown in Table 2. The effect of the present invention on Comparative Example 2 was confirmed.

Example 4 A gelatin aqueous solution (water 1, gelatin 20 g, KBr 0.3 g) containing 0.22 mol of the emulsion A of Reference Example 1 (average projected grain size 1.35 μm).
, PH 6.0) into a 4 liter reaction vessel and the temperature at 75 ° C.
And add 3 g of NH4NO3 and 6 ml of NH3 water (25% by weight),
Minutes later AgNO3 solution (containing 100g of 10g AgNO3 in 100ml) and KB
The rJ aqueous solution was added with CDJ for 40 minutes at a silver potential of +40 mV. The initial flow rate is 3.9 ml / min and the final flow rate is 13 ml / min. One minute after the addition was completed, 28 ml of HNO ₃ (3N) solution was added. The average projected grain size of tabular grains at this point is 1.
It was 45 μm.

Then, an AgNO ₃ aqueous solution (containing 100 g of AgNO ₃ in 100 ml) and an aqueous solution of (KBr + KI) having a KI content of 6 mol% were added at 2.5 ml / min for 30 minutes at a silver potential of 120 mV. The temperature was lowered to 30 ° C., the emulsion was washed with water and redispersed. The average projected grain size of the tabular grains at this time was 1.45 μm. Therefore, it is shown that the finally added AgBrI did not deposit on the edge of the average particle but was laminated on the {111} major surface. The edge shape of these particles is shown in FIG. (Magnification 21,000 times).
It is shown that they are tabular grains having {100} edge faces having an obtuse angle of 125 ° with respect to the (111) main surface. The average {100} area ratio was 23%. 1,1 'in the AgX emulsion
-Diethyl-2,2'-cyanine chloride dye was adsorbed at 65% of the saturated adsorption amount, and then triethyl-thiourea was added at 0.6 × 10 ^-5.
Only 20 mol / mol Ag was added, and after 20 minutes, 0.2 × 10 ⁻⁵ mol / mol Ag of gold-thiocyanate complex was added, and the mixture was aged at 50 ° for 40 minutes. The temperature was lowered to 40 ° C., an antifoggant and a coating aid were added, and the mixture was coated on a transparent base. When exposed and developed, it showed excellent reciprocity law photographic properties.

Example 5 Reference Example gelatin aqueous solution containing 0.26 moles of Emulsion A in 1 (water 1, NaCl 5 g, containing gelatin 20 g) were placed in a reaction vessel 4l, the temperature was brought to 75 ° C., AgNO ₃ in aqueous AgNO ₃ solution (100ml 1
(Including 0 g) and an aqueous solution of (KBr + NaCl) having a NaCl content of 25 mol% were added while maintaining pCl = 1.07 by linear acceleration addition of an initial flow rate of 4.0 ml / min and a final flow rate of 20 ml / min. Temperature 3
The temperature was lowered to 0 ° C., the emulsion was washed with water and redispersed. The average projected grain size of the tabular grains at this time was 1.30 μm, indicating that the added AgBrCl was laminated only on the {111} main surface of the tabular grains. The shape of these particles is shown in FIG.
(Magnification 19,000 times). It is shown that the grains are tabular grains having {100} edge faces having an obtuse angle of 125 ° C. with respect to the {111} main surface. The average {100} area ratio was 43%.
A saturated adsorption amount of 5-Bromobenzotriazole of 65 was added to the AgX emulsion.
%, Then triethyl-thiourea was added at 0.6 × 10 ^-5 mol / mol Ag, and after 20 minutes, the gold-thiocyanate complex was added.
Only 0.2 × 10 ⁻⁵ mol / mol Ag was added, and the mixture was aged at 50 ° C. for 40 minutes. The temperature was lowered to 40 ° C., an antifoggant and a coating aid were added, and the mixture was coated on a transparent base. When exposed and developed, it showed excellent reciprocity law photographic properties.

Example 6 In a reaction vessel having a volume of 4 l, an aqueous gelatin solution [water 1000
ml, gelatin 30 g, KBr 0.5 g, NH ₃ (25 wt%) 2 ml, NH
₄ NO ₃ (50 wt%) 2 ml] was added, and an aqueous solution of AgNO ₃ (containing 0.93 g of AgNO ₃ in 1000 ml) and an aqueous solution of a halide salt were added while keeping the solution temperature at 60 ° C.

The addition rate of AgNO ₃ was 3.3 × 10 ^-4 M / min for the first 10 minutes, and 8.9 × 10 ^-4 M / min for the next 9 minutes with AgNO ₃ solution (KBr + K
I) Aqueous solution (KI content 6 mol%) was added by double jet. The pBr value during the addition was 2.4.

Next, the initial addition rate of 9.0 × 10 ^-4 M / min, the final addition rate of 7.8 × 10
CD with silver potential of 125 mV by linear acceleration addition method at ^-3 M / min for 60 minutes
J. added. The tetradecahedral grains obtained at this point were the tetrahedral grains as shown in FIG. 6a.

Then, the silver potential to + 170 mV, AgNO ₃ in AgNO ₃ solution (100ml
(Including 10 g) and KBr solution, initial addition rate 1.8 × 10 ^-3 M /
Minute, final 3.25 × 10 ^-3 M / min, 20 minutes linear acceleration addition method,
CDJ with a silver potential of 180 mV was added. 1 obtained at this point
The tetrahedral grains were tetrahedral grains as shown in Figure 6b.

The edge lengths of both dodecahedron grains were both 0.63 μm, indicating that AgBr added last was precipitated only at the corners of the dodecahedron. The {100} area: {111} area = 15: 85 of this grain obtained from the TEM image.

To this emulsion was added 3,3'-bis (4-sulfobutyl) -9-methyt.
After adsorbing 75% of the saturated adsorption amount of hiacarbocyanine dye, the emulsion conditions were adjusted to pAg 8.6, pH 6.5, and temperature 50 ° C, and Na ₂ S ₂ O ₃ was added.
5H ₂ O was added only at 0.9 × 10 ^-5 mol / mol AgBr, and after 3 minutes, the gold sensitizer [gold-thiocyanate complex] was added at 0.3 × 10 ^-5 mol / mol.
Mole AgBr alone was added and aged for 70 minutes. The temperature was lowered to 35 ° C, the emulsion was washed with water and redispersed, and the emulsion was adjusted to pH 6.5, pAg8.5
Adjusted to.

Bring the temperature to 40 ° C, add antifoggants and coating aids, and
1.5g / m ^{2 It} was applied on a transparent base.

Comparative Example 3 The procedure is the same as in Example 6 until the AgX particles shown in FIG. Next, the silver potential was set to +90 mV, and AgNO ₃ solution (AgNO
₃ including 10 g) and using the KBr solution, the initial addition rate 1.8 × 10 ^-3 M /
CDJ with a silver potential of 90 mV was added by the linear acceleration addition method for 20 minutes at a final addition rate of 3.25 × 10 ⁻³ M / min. The shape of the tetradecahedral grains obtained at this point is almost similar to that of the tetradecahedral grains of FIG. 6a, and AgBr added last is uniformly laminated on almost all surfaces of the tetradecahedral grains, so-called internal It is shown that they are high-iodity type double-structured grains.

This emulsion was washed with water and redispersed to obtain 3,3'-bis (4-sulf
Obutyl) a -9-methylthiacarbocyanine dye After 75% adsorption of the saturation adsorption amount, the emulsion conditions PAg8.6, pH 6.5, to a concentration _{50 ℃, Na 2 S 2 O} 3 · 5H 2 O of 1.5 × 10 ^{- 5} mol / mol AgBr
Then, after a delay of 3 minutes, 0.5 × 10 ⁻⁵ mol / mol AgBr of the above-mentioned gold sensitizer was added, followed by aging for 60 minutes.

Next, the temperature was lowered to 40 ° C., an antifoggant and a coating aid were added, and silver 1.5 g / m ² was coated on a transparent base.

Next, the emulsions of Example 6 and Comparative Example 3 were compared in the same manner as in Table 1, and the results are shown in Table 3. The effect of the present invention on Comparative Example 3 was confirmed.

[Brief description of drawings]

FIG. 1 schematically shows the positions where chemically sensitized nuclei are generated. (A) shows the case of tetradecahedral grains close to a cube,
(B) shows a case of tetradecahedral grains close to an octahedron. FIG. 2 is a schematic diagram showing the relationship between the chemical potentials of the (100) plane and the (111) plane in the cubic crystal atmosphere in the method for producing AgX particles of the present invention and the chemical potential of silver ions in the solution. FIG. 3 shows a band structure of AgX particles which is particularly preferable in the present invention. The vertical axis represents potential and the horizontal axis represents geometrical coordinates. Black circles represent electrons and white circles represent holes. 4 and 5 are electron micrographs showing the crystal structure of the silver halide grains prepared in Examples 4 and 5. The magnification is 21,000 times and 19,000 times, respectively. FIG. 6 schematically shows the structure of AgX of Example-6. (A) shows tetradecahedral grains of host grains, (b) shows
Indicates tetradecahedral grains obtained by growing AgX having different halogen compositions on the host grains.

Claims (5)

[Claims] 1. A silver halide emulsion comprising a dispersion medium and silver halide grains, wherein 70% or more of the projected area of all silver halide grains is at least {100} on the surface of one silver halide grain. Have a {111} crystal surface, the halogen compositions of the surface layers of the crystal surface are different from each other, and the following a) to
A silver halide emulsion which is a tetradecahedral grain having the characteristics of c). a) [area of {111} plane / area of {100} plane] is 20 to 1 /
Twenty. b) Only on one of the {100} and {111} crystal surfaces, a silver halide having a halogen composition different from that of the silver halide grain of the substrate is non-epitaxial (the same crystal system layer as the substrate is formed on the substrate). The halogen compositions differ from each other in iodine content by 2 to 40 mol% or in Cl ⁻ content by 7 to 100 mol%. c) Chemically sensitized nuclei are preferentially formed on one of the crystal faces, and [(number of chemically sensitized nuclei on the crystal face where preferentially chemically sensitized nuclei are formed / cm ² ) / ( The number of chemically sensitized nuclei on the crystal plane where preferentially no chemically sensitized nuclei are formed / cm ² )] is 2.5 or more. 2. The [area of {111} plane / area of {100} plane]
The silver halide emulsion according to claim 1, wherein the value of is 10 to 1/10. 3. A silver halide emulsion comprising a dispersion medium and silver halide grains, wherein 70% or more of the projected area of all silver halide grains is at least {100} on the surface of one silver halide grain. And a {111} crystal surface, the halogen compositions of the surface layers of the crystal surface are different from each other, and a) to
A silver halide emulsion characterized in that it is a tabular grain having parallel twin planes having an aspect ratio of 1.5 or more and having the characteristic of c). a) [Area of the {111} crystal surface / area of the {100} crystal surface] is 20 to 1.0. b) Only on one of the {100} and {111} crystal surfaces, a silver halide having a halogen composition different from that of the silver halide grain of the substrate is non-epitaxial (the same crystal system layer as the substrate is formed on the substrate). The halogen compositions differ from each other in iodine content by 2 to 40 mol% or in Cl ⁻ content by 7 to 100 mol%. c) The main surface of the tabular grain is a {111} crystal surface, and the {100} crystal surface is present at an edge portion of the tabular grain. 4. Chemically sensitized nuclei are preferentially formed on one of the crystal faces, and [(number of chemically sensitized nuclei on the crystal face where preferentially chemically sensitized nuclei are formed / cm ² ) / (Number of chemically sensitized nuclei on the crystal plane where preferentially no chemically sensitized nuclei are formed / cm ² )]
Is 2.5 or more, Claim 3
A silver halide emulsion as described in the above item. 5. The tabular grain according to claim 3, wherein the main plane of the tabular grain is hexagonal, and the variation coefficient of grain size distribution of the grain is 30% or less. Silver halide emulsion.