JPH0452637A - Silver halide emulsion having high sensitivity and good developability - Google Patents

Abstract

PURPOSE:To enhance the sensitivity and developability of a photosensitive material by incorporating silver halide particles having the specific shapes during the course of the crystal growth of the particles into the emulsion. CONSTITUTION:The silver halide particles in which the central part of at least one face of the 111 faces of an octahedron or 14-faced body in the shape during the course of the crystal growth builds up and this built-up part occupies >=50% of the area of these faces are incorporated into this emulsion. The silver halide particles are grown until the particles have the particle shape having the built-up part in the central part of at least one face of the 111 faces of the octahedron or 14-faced body and further, the particles are grown, by which the emulsion is formed. The formation of the emulsion as a monodisperse emulsion is possible as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a silver halide emulsion, and particularly to a silver halide emulsion with high sensitivity and good developability.

(Prior art) In recent years, demands on silver halide emulsions for photography have become increasingly strict, and demands have been placed on photographic performance such as high sensitivity, excellent graininess, high sharpness, low fog density, and sufficiently high optical density. There are increasing demands for higher standards.Furthermore, good developability is also required.

Among these, various techniques have been proposed in an attempt to provide high-sensitivity emulsions. For example, silver iodobromide emulsions having a silver iodide content of 10 mol % or less are well known. In addition, conventional methods for preparing these emulsions include pH conditions such as the ammonia method, neutral method, and acidic method, PAg
As a method of controlling conditions and a mixing method, a single jet method, a double jet method, etc. are known.

Based on these known techniques, technical means have been elaborately studied and put into practical use for the purpose of achieving high sensitivity, improved graininess, high sharpness, and low fog. In particular, research has been carried out on silver bromide and silver iodobromide emulsions in which not only the crystal phase and grain size distribution but also the concentration distribution of silver iodide within each silver halide grain is controlled.

The means to achieve photographic performance such as high sensitivity, excellent graininess, high sharpness, low capri density, and sufficiently high covering power as described above, especially the most orthodox method for increasing sensitivity, is , to improve the quantum efficiency of silver halide. For this purpose, knowledge of solid state physics is actively incorporated. According to research that theoretically calculated quantum efficiency, narrowing the particle size distribution to create a monodisperse emulsion is effective in improving quantum efficiency.

In addition, it is inferred that monodisperse emulsions are advantageous in order to efficiently achieve high sensitivity while maintaining low fog in a process called chemical sensitization in which silver halide emulsions are sensitized.

For industrial monodisperse emulsion preparation, JP-A-54-4852
After strict control of PAg and pH as described in No. 1, control of the supply rate of silver ions and halide ions to the reaction system based on theoretical civil engineering studies and sufficient stirring conditions are required. . The silver halide emulsions produced under these conditions have a cubic, octahedral, or tetradecahedral shape with various proportions of (100) and (111) planes, so-called Consists of normal crystal grains. It is known that such normal crystal particles can increase sensitivity.

Furthermore, as silver halide grains capable of obtaining high sensitivity, silver iodobromide grains having excellent photographic properties and having (110) planes are disclosed in Japanese Patent Application Laid-open Nos. 61-35440 and 60-222842, respectively. In addition, in Japanese Patent Publication No. 55-42737, there is a rhombus with (110) face as a product with less fog.
Photographic emulsions containing dihedral silver chlorobromide grains are disclosed.

On the other hand, JP-A No. 61-83531 discloses silver bromide and silver iodobromide grains having crystal planes having a ridge line in the center of the (110) plane, and it is possible to achieve even higher sensitivity with this. It is shown. This crystal plane is considered to be a very high-order crystal plane, and its characteristics are described in Japanese Patent Application Laid-Open No. 61-8
No. 3531.

The crystal plane is expressed as (nnl), and examples such as the (331) plane are shown.

Other aspects are described in JP-A Nos. 62-124551, 62-124550, and 62-123447.

On the other hand, silver iodobromide emulsions comprising polydisperse twin crystal grains have been known as silver halide emulsions suitable for high-speed photographic films.

Moreover, silver iodobromide emulsions containing oblate twin grains are disclosed in Japanese Patent Application Laid-open No. 58-113927 and others.

On the other hand, there is little research on crystals that have large, clearly defined irregularities on their crystal faces.

As for what is disclosed as a publicly known technique, Japanese Unexamined Patent Publication No. 5
No. 8-106532 describes a silver halide emulsion having a depression in the center of the (111) plane of an octahedral or tetradecahedral crystal. Further, Japanese Patent Application Laid-Open No. 61-75337 discloses a silver halide containing silver halide grains having a hollow conductive portion from the surface toward the inside.

In addition, as tabular grains other than normal crystals, JP-A-63-3
No. 11244 discloses a silver halide emulsion consisting of silver halide grains having a depression or space in the center of the main surface of tabular grains consisting of parallel main planes consisting of (111) planes. There is.

All of these studies from the aspect of crystal morphology of silver halide grains are concerned with the structure of the outermost surface of the grain, and it can be said that there is no research on the crystal morphology within the grain. In this case, grain growth was performed under conditions of an outwardly convex crystal plane with substantially no unevenness on the crystal plane.

On the other hand, many studies have been conducted on the internal composition of silver halide grains, such as JP-A-60-138538;
JP 61-246740, JP 61-27574
There are core/shell type silver halide grains disclosed in publications such as No. 1 and JP-A No. 61-286845.

However, in this type of core/shell type particle, there is no specification regarding the crystal morphology plane inside the crystal, and the environment during particle growth was substantially under octahedral crystal plane conditions.

According to the present inventors' opinion, clear unevenness on the crystal plane during the grain growth process is thought to exert specificity in the concentration of effects in chemical sensitization, exposure, or development. Previously, no research had been conducted in this direction. Against this background, the present inventors have focused on the expectation of technological development from research on crystals that have irregularities on their crystal faces during the grain growth process.

By the way, as silver halide crystal grains that most effectively concentrate the effects in chemical sensitization, exposure, or development as described above, it is preferable to use crystals that have concentration sites at intersections or points of intersection of crystal planes forming concave surfaces. Although possible, this requires precise and novel control of specific crystal structures. Further, it is preferable that the crystal is a normal crystal without any lattice defects or other singular points that would be a substantial hindrance other than the concentrated region of the crystal.

However, in systems in which normal crystals with a predetermined crystal phase, especially monodisperse silver halide grains, are freely suspended, the crystal grains grow surrounded by almost isotropic planes, and there are usually no peculiarities such as crystal habit. Otherwise, there are few opportunities for anisotropy to appear.

On the other hand, under conventional conditions that exhibit isotropy such as twin crystals, it is difficult to precisely control grains, control chemical sensitization associated therewith, and ultimately control photographic properties.

[Purpose of the invention]

The present invention has been made against the above background, and is directed to a silver halide grain having a portion that functions as a concentration site that exerts the effect on photographic performance as described above, and which also does not have any other factors that inhibit it. An object of the present invention is to provide an advantageous silver halide emulsion containing silver halide grains that can be obtained easily and with good controllability.

[Structure of the invention]

As a result of intensive research, the present inventors have found that the above object of the present invention is that the shape of the particles during the crystal growth process is octahedral or unilateral.
A halide containing silver halide grains having a grain shape in which the central part of at least one of the (111) faces of a tetrahedral crystal is raised, and the raised part occupies 50% or more of the area of the face. They discovered that this can be achieved by using a silver emulsion, and completed the present invention.

In the present invention, the center of the r (111) plane is raised.
This means that the surface bulges near the center of the (111) surface (it doesn't have to be exactly at the center, but should be at a position that can almost act as the center), that is, at a position that is not at the edge, resulting in wide shapes of various shapes. This refers to the presence of a protrusion (occupying 50% or more of the area). The raised portion is often rectangular, but it changes depending on the adjustment conditions. The diameter of the raised portion (represented by the diameter of a circle when the projected area of the raised portion is converted into a circle) varies depending on the diameter of the parent octahedral or tetradecahedral particle, but is preferably 0.
005 um to 20 pm, more preferably 0.005 um to 20 pm.
005 μm to 2.0 μm. The height of the protrusion is 0.00 in the 011> direction perpendicular to the +111) plane of the cubic particle.
It is preferably 5 pm or more, more preferably 0.02 μm or more.

In the following description, silver halide grains in which the intermediate shape during the crystal growth process is an octahedron or a tetradecahedron having such a raised part on at least one of the (111) planes are referred to as silver halide grains. Silver halide grains are referred to as "silver halide grains of the present invention", and emulsions containing these silver halide grains are referred to as "silver halide emulsions of the present invention".

For example, emulsion E, which is an example of the emulsion of the present invention which will be described in detail later,
Regarding the grain structure example shown in the photograph in Figure 1 showing the grain structure of M-1, each face of the (111) face of the octahedron is a triangle (strictly speaking, a triangle with each vertex cut off). It has a structure in which a triangular raised portion, which is approximately concentric with the triangle and slightly smaller than the triangle, is formed on each surface.

The present invention will be explained in more detail below.

In general, the crystal planes of silver halide crystal grains contained in silver halide emulsions have different density, lattice energy, surface energy, or growth conditions of silver ions and halide ions arranged on the plane. , crystal planes with specific Miller indices are dominantly expressed, giving the crystal a specific crystal phase. Furthermore, when there is a difference in the growth conditions surrounding each crystal grain on a grain size scale, the grains will have different crystal habits even though they have the same Miller index.

On the other hand, "the plane that becomes the final crystal plane is the plane with the minimum growth rate in the normal direction of the line plane" (A
, Johnsen, 1910), by selecting the growth conditions, even silver halide crystals belonging to the cubic system can be given a crystal form having a predetermined crystal phase.

For example, in order to give cubic silver halide a hexahedral (cubic) crystalline phase, the growth rate on cubic planes, that is, the deposition of silver ions and halide ions, is slower than on crystal planes with other Miller indices. As long as the conditions are given.

Furthermore, when changing the crystal phase from octahedral silver halide crystal grains surrounded by (111) planes to hexahedral (cubic) host grains, growth conditions are provided to suppress the growth of cubic (100) planes. As silver is further precipitated, a cuboctahedron, that is, a tetradecahedron in which the six vertices of the octahedron have been shaved off, appears in the middle, and the (111) plane gradually degenerates until it becomes a cubic octahedron with only six vertices removed. After that, the cubic crystal grains enlarge as silver halide is added (.

Conversely, cubic crystal grains can also be used as host particles to lead to octahedral crystal grains.

Similarly, cubic crystal grains can also be introduced as host grains, for example trioctahedral crystal grains.

In other words, if silver halide precipitation is continued by selecting growth conditions in which growth in the normal direction of trioctahedral crystal planes is slower than planes of other Miller indices, trioctahedral crystal planes will first be recognized, and then Eventually, the host grains are occupied by trioctahedral crystal faces.

Desired crystal grains can also be obtained with other crystal grains having tetrahexahedral, rhomboid icosahedral, and hippophedral crystal faces by selecting growth conditions that suppress the growth of the faces that give each crystal phase.

The growth conditions for the silver halide grains having various crystal phases are as follows:
Deposition of silver halide on crystal surfaces is influenced by a wide variety of factors such as silver halide composition, density of ions arranged on crystal planes, temperature, lattice or surface energy, adsorbate, silver halide solvent, etc. A growth modifier is added as a factor to retard the process.

Many compounds are already known as growth regulators, and for photographic silver halide, there are photographic dyes such as cyanine dyes that have adsorption properties on the surface, stabilizers such as azaindene and imidazole, and fog suppressants. Some useful agents are known (see the above-mentioned Disclosure Patent Publication, Japanese Patent Application No. 62-159).
No. 280, etc.).

However, at present, there is a lack of theory that relates the various factors that affect crystal growth as described above and the crystal form produced. There is virtually no theoretical support for the unexplored technical field of producing particles with a bulge in the center, and we have no choice but to search for a method to realize the intended crystal shape through trial and error.

The silver halide grains of the present invention have a shape during the crystal growth process of the grains, which is formed by either fewer (111) faces of octahedral or tetradecahedral crystals (preferably all of the <111> faces). ), but it is not necessarily easy to create a particle crystal having such a particle shape in the middle.In order to obtain such a particle crystal, the present inventors Through various trials and errors, it has been discovered that the emulsion of the present invention can be obtained in the following manner.That is, for example, the following manufacturing method can be mentioned.In the following explanation, for the sake of clarity, The first growth is performed until the silver halide grains of the present invention have an intermediate shape (until the grain shape has a raised part in the center of at least one of the (111) faces of an octahedral or 14 tetrahedral crystal). Further, the growth from the particles is defined as the second growth.Of course, the first and second growth may be performed separately or may be performed consecutively.

(1) First Growth Silver halide grains having an octahedral or tetradecahedral crystal shape with an iodine content of 10 mol % or less on the outermost surface are produced and/or grown. Furthermore, the iodine content of the outermost surface of the particles is preferably 10 mol% or more, more preferably 1
A phase with a high iodine content of 5 mol% or more is grown. When the shape is adjusted, the part composed of the original particles is called a low iodine layer, and the phase with a high iodine content formed on it is called a high iodine layer. For the iodide phase,
The volume ratio of the low iodine layer is preferably 20% or more. The pAg during growth of the silver halide grains is preferably 9 or less.

(2) Second growth The second growth following the first growth is preferably performed at a pAg of 7 to 11.5. In addition, the addition rate of silver ions and halogen ions during the crystal growth period is preferably 20 to 100%, more preferably 30 to 100% of the crystal critical growth rate.
It is preferable to set the crystal growth rate to .

In this way, silver halide crystal grains having the preceding crystal planes formed by the first growth inside the grains are obtained.

The silver halide grains of the present invention may be obtained by any of the acid method, neutral method and ammonia method. The particles may be grown continuously or may be grown stepwise while creating seed particles. The method of creating and growing the seed particles may be the same or different.

Although there is no limitation on the silver halide composition of the silver halide emulsion of the present invention, it is preferably substantially silver bromide or silver iodobromide. The emulsion of the present invention preferably contains iodine, but in this case, during grain growth, iodine ions may be added as an ionic solution such as a potassium iodide solution, and the iodine ions may be added as an ionic solution such as a potassium iodide solution, may also be added as particles with a small solubility product. It is more preferable to supply this iodine in the form of silver halide grains (described in detail below) having a small solubility product.

That is, the silver halide grains of the present invention are, during at least one period of the grain growth process, the original silver halide grains of the present invention (in the following description of the grain growth process, for convenience, they are referred to as rAgX grains (1)). In one embodiment, it is preferable that the silver halide grains are grown in the presence of silver halide fine grains (referred to as "rAgX grains (2)") having a solubility product equal to or lower than that of the silver halide grains (rAgX grains (2)).

The solubility product being equal or lower means that the solubility product of AgX particles (2) is equal to or smaller than the solubility product of AgX particles (1). In addition, the solubility product in this specification is
In the ordinary chemical sense.

When adopting such an embodiment, Ag having a solubility product equal to or smaller than that of AgX particles (1)
The X particles (2) are present during at least one period of the growth process of the AgX particles (1), and the growth of the AgX particles (1) is performed in the presence of the AgX particles (2). Here, Ag
The X particles (2) can be used to grow the AgX particles (1) by being present until the supply of grain growth elements (halogen ion liquid, silver ion liquid, etc.) for the AgX particles (1) is finished. .

The average particle size of the AgX particles (2) is generally smaller than the average particle size of the AgX particles (1), but may be larger in some cases. Moreover, the AgX particles (2) generally have substantially no photosensitivity. This Ag
The average particle diameter of the X particles (2) is preferably 0.001 to 0.7 μm, more preferably 0.01 to 0.3 μm, and particularly preferably 0.1 to 0.01 μm.

It is preferable that the AgX particles (2) are allowed to exist in a suspension system (hereinafter referred to as mother liquor) that serves as a place for preparing the AgX particles (1) at the latest by the time the growth of the AgX particles (1) is completed.

When using silver halide seed grains, AgX grains (2
) may be present in the mother liquor before the nuclide particles, or
It may be added to the mother liquor containing seed particles prior to the particle growth composition, it may be added during the addition of particle growth elements, or it may be added at two or more of the above-mentioned addition times. It may be added separately.

When grain growth is performed after the formation of silver halide without using seed grains, it is preferable to add AgX grains (2) after the formation, either before or during the addition of the grain growth element. Often, it can be divided into two or more periods.

Furthermore, the AgX particles (2) and the particle growth element may be added all at once, continuously, or intermittently.

AgX particles (2) and particle growth elements can be added to the mother liquor by a multi-jet method such as a double jet method under conditions where p) f, pA, g, temperature, etc. are controlled at a rate suitable for particle growth. preferable.

The AgX grains (2) and silver halide seed particles may be prepared in the mother liquor, or may be prepared outside the mother liquor and then added to the mother liquor.

As the water-soluble silver salt solution used for preparing the AgX particles (2), an ammoniacal silver salt solution is preferable.

The halogen composition of the AgX particles (2) is, for example, Ag
When the X grains (1) are silver iodobromide, silver iodobromide having a higher iodine content than silver iodide or growing silver iodobromide grains is preferable; for example, if the AgX grains (1) are When silver bromide is used, silver chlorobromide having a higher bromine content than silver bromide or growing silver chlorobromide is preferred. When the AgX grains (1) are silver iodobromide, it is particularly preferable that the AgX grains (2) are silver iodide.

When the AgX grains (1) are silver iodobromide or silver chloroiobromide, all the iodine used for grain growth is absorbed by the AgX grains (1).
Although it is preferable to supply it as 2), a part of it may be supplied as a halide aqueous solution to the extent that the effects of the present invention are not impaired.

Further, during the growth of silver halide grains, a known silver halide solvent such as ammonia, 1,000-onythyl, thiourea, etc. can be present.

Silver halide grains contain at least one selected from cadmium salts, zinc salts, lead salts, thallium salts, iridium salts, rhodium salts, iron salts, and complex salts thereof during the process of forming and/or growing the grains. These metal elements can be added inside the particles and/or on the surface of the particles by adding metal ions, and by placing them in an appropriate reducing atmosphere, reduction sensitizing nuclei can be added inside the particles and/or on the surface of the particles. can be granted.

In the silver halide emulsion of the present invention, unnecessary soluble salts may be removed after the growth of silver halide grains is completed, or they may be left contained. When removing the salts, Research Disclosure (Research Disclosure)
Disclosure (hereinafter abbreviated as RD) No. 17643 ■
It can be carried out based on the method described in Section.

Further, the average grain size of the silver halide grains of the present invention is 0.0
5-30 micrometers are preferable, and 0.1-3.0 micrometers are more preferable.

The silver halide emulsion of the present invention can have any configuration, such as a polydisperse emulsion with a wide grain size distribution or a monodisperse emulsion with a narrow grain size distribution.

The silver halide emulsion of the present invention may be composed of a single emulsion or a mixture of several types of emulsions.

When carrying out the present invention, it is preferable to use a monodispersed emulsion. The silver halide emulsion of the present invention can be stably obtained as an emulsion with good monodispersity.

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

Here, the average particle size t, the frequency ni of particles with particle size ri
The particle size r when the product n1Xri' of
Define i (3 significant digits, minimum digit is 4 to 5 digits).

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

Particularly preferred highly monodispersed emulsions are those with a distribution width of 20% or less, more preferably 15% or less, when the width of the distribution is defined as follows.

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

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

In determining the addition rate, refer to JP-A-54-48521.
No. 58-49938 can be referred to.

As a method for obtaining a more advanced monodispersed emulsion, JP-A-60-1
The growth method in the presence of tetrazaindene disclosed in No. 22935 can be used.

Further, in the silver halide emulsion of the present invention, it is preferable that most of the grains be comprised of silver halide grains in which each grain grows while maintaining the same shape.

Each particle maintains the same shape in its shape, which means that when the shape of the particle is observed using a scanning electron micrograph at a magnification of at least 10,000 times, at least the crystal habit and particle size are the same for each individual particle of interest. say something. In particular, in order to observe the fine structure of the surface, it is preferable to use a low acceleration voltage of 2 kV or less.

For example, taking normal crystal grains as an example, the individual grains: (1) have the same hemostasis rate such as (111), (100), (331)', etc., and (2) have silver halide grains with core/shell. If it is a particle, the particle must not have any part where a shell is not formed during shell formation, ■The flatness such as surface irregularities must be the same, ■It must not contain twin grains, and the particle size must be 0. When all individual particles are the same, they do not contain clearly different microscopic or coarse particles, or aggregate particles made up of two or more particles attached (these can be seen by microscopic observation), etc. This is an example of maintaining the same shape.

Specifically, it is preferable that 70% or more of the number of grains in the emulsion are grains that maintain the same identity in the above shape, more preferably 80% or more, still more preferably 9.
It is preferable that 0% or more of the particles maintain the same identity in the above shape.

Further, it is preferable that the silver halide emulsion of the present invention maintains the same silver iodide content of its individual silver halide grains.

The silver iodide content of individual silver halide grains and the average silver iodide content in the emulsion of the present invention are determined by the EPMA method (Ele
ctron Probe Micro Analyze
r'' method).

This method is a technique in which a well-dispersed sample is prepared so that the emulsion grains do not come into contact with each other, and elemental analysis of extremely small portions is performed by X-ray analysis using electron beam excitation by irradiating the sample with an electron beam.

By this method, the halogen composition of each grain can be determined by determining the characteristic X-ray intensities of silver and iodine emitted from each grain.

If the silver iodide content of at least 50 grains is determined by the EPMA method, the average silver iodide content can be determined from the average thereof.

The equipment used for measurement does not require any special specifications, but
In the examples of the present invention described later, the silver iodide content of the emulsion was measured using an X-ray microanalyzer JXA-8621 manufactured by JEOL Ltd. The measurements were performed while cooling to a low temperature to eliminate electron beam damage.

The relative standard deviation of the silver iodide content of individual grains is the standard deviation of the silver iodide content when measuring the silver iodide content of at least 50 emulsion grains in the above measurement. This value is obtained by multiplying the value divided by the content rate by 100.

The emulsion of the present invention is preferably one in which the relative standard deviation of the silver iodide content of each individual silver iodobromide grain is 20% or less. In the emulsion of the present invention, it is preferable that the iodine content among the grains is even more uniform. That is, when the distribution of iodine content among particles was measured by the EPMA method, the relative standard deviation was 20.
% or less, more preferably 15% or less, particularly 10% or less.

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 using dyes known as sensitizing dyes in the photographic industry. Sensitizing dyes may be used alone, but
2[! The above may be used in combination.

Antifoggants, stabilizers, etc. can be added to the silver halide emulsion. It is advantageous to use gelatin as the binder for the emulsion.

When a light-sensitive material is formed using the silver halide emulsion of the present invention, the emulsion layer and other hydrophilic colloid layers of the light-sensitive material can be hardened, and plasticizers, water-insoluble or poorly soluble synthetic polymers, etc. can contain a dispersion (latex) of

The silver halide emulsion of the present invention can be effectively used to form a light-sensitive material for color photography, and when used in the emulsion layer, it is generally used in the form of a color-forming coupler.

Furthermore, various fragments such as development accelerators, bleaching accelerators, developing agents, silver halide solvents, and toning agents can be produced by coupling with colored couplers, competing couplers, and oxidized products of developing agents, which have the effect of color correction. , hardener, fogging agent,
Compounds that release photographically useful fragments such as antifoggants, chemical sensitizers, spectral enhancers, and desensitizers can be used.

When a photosensitive material is formed using the silver halide emulsion of the present invention, the photosensitive material can be provided with auxiliary layers such as a filter layer, an antihalation layer, and an antiirradiation layer. These layers and/or the emulsion layers may contain dyes that are leached or bleached from the light-sensitive material during the development process.

Photosensitive materials include formalin scavengers, optical brighteners,
A matting agent, a lubricant, an image stabilizer, a surfactant, a color antifoggant, a development accelerator, a development retarder, and a bleach accelerator can be added.

As the support for the photosensitive material, any material can be used, such as paper laminated with polyethylene or the like, polyethylene terephthalate film, baryta paper, cellulose trisaucetate, or the like.

A dye image can be obtained using the light-sensitive material of the present invention by performing a commonly known color photographic process after exposure.

〔Example〕

Next, the present invention will be explained by examples. However, it goes without saying that the present invention is not limited to the following examples.

Example-1 (Preparation of silver iodide fine grain emulsion Al-1) An aqueous solution containing 5% by weight of ossein gelatin was added to a reaction vessel, and while stirring at 40"C, 3.5N silver nitrate aqueous solution and 3.5N iodine gelatin were added. 1 mol of each aqueous solution was added at a constant rate over a period of 30 minutes.

The pAg during addition was 13.5 using conventional PAg control means.
I kept it.

The produced silver iodide is βAgl with an average grain size of 0.06 μm.
and r-AgI.

This emulsion will hereinafter be referred to as emulsion Al-1.

(Creation of emulsion EM-1) Using the four types of solutions shown below, make the first growth emulsion EM-1.
1 was created.

Aqueous solution (a-1) Compound (1) H3 HO(CHzCHzO) m(CHCHzO) + t(
CHzCHzO)nH (average molecular weight ~1300) Aqueous solution (a-2) Aqueous solution (a-3) Emulsion solution containing silver iodide fine grains (a-4) [(hereinafter sometimes abbreviated as TAI) 2.77 g Add water 1
Finished at 206m/.

A seed emulsion (average particle size 0.27 μm, average AgI content 2 mol %) which becomes a core equivalent to 0.407 mol was added to the aqueous solution (a-1) having the above composition which was vigorously stirred at a temperature of 60°C.
) was added, and the pH and PAg were adjusted using acetic acid and KBr aqueous solution.

Thereafter, while controlling the pH and PAg as shown in Table 1, the aqueous solutions (a-2), (a-3) and (a
-4) were added by the triple jet method at the flow rates shown in Tables 22, 3 and 4, respectively.

According to electron microscopy, this emulsion has an average grain size of 0.46.
It was found that the emulsion was a highly monodisperse emulsion in which 92% of all silver halide grains were composed of octahedral grains having protrusions on the (111) plane, and the coefficient of variation in grain size distribution was 11.2%. Therefore, emulsion EM that can be used as this type of emulsion
-1 corresponds to one containing grains at the end of the first growth for forming silver halide grains of the present invention. Table 5 shows the prescription grain structure and volume ratio of each phase of this first growth emulsion EM-1.

FIG. 1 is an electron microscope photograph of silver halide grains in this emulsion after the first growth.

Table 1 → indicates that the pH and II)Ag are kept constant, - indicates that it is continuously decreased, and ↓ indicates that it is decreased rapidly (the same applies below).

(a Table-2 2) Addition pattern table-3 (a-3) Addition pattern table-4 (a-4) Addition pattern table-5 (Preparation of emulsion EM-2) JP-A-61-246740 , Japanese Patent Publication No. 61-27574
No. 1, by the method shown in JP-A-61-286845, emulsion EM-1 has the same halogen composition, grain size distribution, and average grain size, and the final grain shape is (111).
A comparative emulsion EM-2 was prepared consisting of silver halide grains which are octahedral grains having no raised surfaces. This emulsion EM-2 is a comparative seed emulsion that does not have the above-mentioned protrusions at the end of the first growth, compared to the first growth emulsion EM-1 which can be used as a seed emulsion for obtaining silver halide grains of the present invention. This corresponds to emulsion. Therefore, the emulsion grown from this emulsion EM-2 serves as a comparative emulsion.

(Preparation of Emulsion EM-3) Emulsion EM-3, which corresponds to the emulsion of the present invention, was prepared using the three types of solutions shown below.

Aqueous solution (b-1) AgN0・1452・9g ■Add water to -C2443m/, then remove.

Aqueous solution (b-2) Roselatin 34.9g (b-
2) were added by the triple agent method at the flow rates shown in Tables 7 and 8, respectively.

After the addition is complete, add a phenylcarbamyl gelatin aqueous solution and adjust the pH of the mixed solution to sediment the particles.
It was coagulated and washed with demineralized water. Thereafter, the temperature was adjusted to pH 5.80 and pA g 8.06 at 40°C.

Thus, the average grain size is 0.8 μm and the average silver iodide content is 4.3.
A monodisperse silver iodobromide emulsion with a mol% and coefficient of variation of grain size distribution of 11.2% was obtained. This emulsion is called EM-3.

Table 9 shows the grain structure of emulsion EM-3 and the volume ratio of each phase.

The first growth emulsion EM-1 was used as a seed emulsion, that is, 2.03 mol of the above-mentioned seed emulsion EM-1 was vigorously stirred at a temperature of 60°C, and then the pH was adjusted using acetic acid and a KBr aqueous solution. While controlling and PAg as shown in Table-6, the aqueous solution (b-1), Table-6 Table-7 (b-1) addition pattern Table-8 (b-2) addition pattern Table-9 ( Preparation of Emulsion EM-4) Next, comparative emulsion EM-4 was prepared. EM- as a seed emulsion
Comparative emulsion E
M-4 was created.

Example 2 The emulsions EM-3 and EM-4 prepared in Example 1 were optimally gold-sulfur sensitized, and 120 μ of the following sensitizing dye (1) and sensitizing dye ( 80 μm of n) was added to spectral sensitize to green sensitivity. TAI and 1-phenyl-5-mercaptotetrazole were then added for stabilization. (AgX represents silver halide).

Furthermore, the following magenta coupler (M-1) at 5X10-3 moles per mole of AgX, the following magenta coupler (M-2) at 6.2 Xl0-3 moles, and 4. OXl0
-'mol of the following colored magenta coupler (CM-1)
was dissolved in di-t-nonyl phthalate and emulsified and dispersed in an aqueous solution containing gelatin.The obtained dispersion was added to each emulsion, and then general photographic additives such as a spreading agent and a hardening agent were added. In addition, a coating solution was prepared, coated on the undercoated film base by a conventional method, and dried to obtain sample No. 101.
, 102 was created.

M~1 M-1 Sensitizing dye (■) Aggravating dye (■) Wedge exposure was performed on each of sample seeds 101 and 102 through a yellow filter according to a conventional method. Next, the following processing steps (I) and (II) were performed using the following developing solution to determine the sensitivity.

Processing step N) (38”C) Color development bleaching water Washing Water landing Washing, stabilization, drying Drying processing step (n) (38°C) Color development bleaching water Washing Water landing Washing, stabilization, drying Used in each processing step The processing solution composition is below 2 minutes 30 minutes.
Seconds 6 minutes 30 seconds 3 minutes 15 seconds 6 minutes 30 seconds 3 minutes 15 seconds 1 minute 30 seconds 3 minutes 15 seconds 6 minutes 30 seconds 3 minutes 15 seconds 6 minutes 30 seconds 3 minutes 15 seconds 1 minute 30 seconds .

<Color developer> 4-amino-3-methyl-N-ethyl-N-β-hydroxyethylaniline sulfate 4.75g anhydrous sodium sulfite 4.25g hydroxylamine 1/2 sulfate 2.0g anhydrous potassium carbonate 37.5 g Sodium bromide 1.3 g Nitrilotriacetic acid trisodium salt (monohydrate) 2.5 g Potassium hydroxide 1.0 g Add water and 1! and adjust the pH to 10.1.

Bleaching solution> Ethylenediaminetetraacetic acid iron ammonium salt 100.0
g Ethylenediaminetetraacetic acid diammonium salt 10.0 g Ammonium bromide 150.0 g
Glacial acetic acid 10.0af Add water to make 11, and use ammonia water to adjust pH to e, o
Adjust to.

<Fixer> Ammonium thiosulfate 175.0g Anhydrous ammonium sulfite 8.5g Sodium metasulfite 2.3g Add water and 1
1 and adjust the pH to 6.0 using acetic acid.

<Stabilizer> Formalin (37% aqueous solution) 1.5m
/ Konidax (manufactured by Konica Corporation) 7.5d
Add water to make 12.

The magenta density of the obtained processed sample was measured using green light.

The results are shown in Table-10. Sensitivity is minimum density (fog) +
It is expressed as the reciprocal of the exposure amount giving 0.3, and expressed as a relative value when the sensitivity of processing step (1) of sample 102 is set to 100.

table

[Brief explanation of drawings]

FIG. 1 is an electron micrograph showing the grain structure of silver halide grains of emulsion EM-1, which is an emulsion of the present invention used as a seed emulsion in Example-1.

Claims (1)

[Claims] 1. The shape of the particles during the crystal growth process is octahedral or 1
A halide containing silver halide grains having a grain shape in which the central part of at least one of the (111) faces of a tetrahedral crystal is raised, and the raised part occupies 50% or more of the area of the face. silver emulsion.