JPH0473638A - Sheet-like silver halide photographic sensitive material having improved pressure characteristic - Google Patents

Abstract

PURPOSE:To prevent the generation of the pressure fogging along a corner cut by applying silver halide particles in which the silver halide particles have a planar shape of a specific particle diameter/particle thickness ratio or above and having {111} faces and {100} faces occupy half the projecting area of the total silver halide particles or above on the above photosensitive material. CONSTITUTION:The silver halide photographic sensitive material formed by applying at least one kind of the silver halide photographic emulsions in which the silver halide particles having the planar shape of >=3 particle diameter/ particle thickness ratio or above and having the {111} faces and {100} faces occupy 50% the projecting area of the total silver halide particles or above, more preferably 70% or above on a base has >=500cm<2> area and has the corner cut. The ratio of the particle diameter/particle thickness is preferably <=20, more preferably >=3 and <12, more particularly preferably >=4 and <8. The high sensitivity is obtd. in this way and the generation of the pressure fogging along the corner cut is suppressed even if the photosensitive material is subjected to the corner cutting in such a manner that the angle part constitutes an obtuse angle or curved shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sheet-shaped silver halide photographic light-sensitive material. More specifically, it is a sheet-like photosensitive material that has so-called corner cuts with obtuse angles or curves at the corners, and even when the corner cuts are applied, the occurrence of pressure blur that may occur in the process is not suppressed. This invention relates to silver halide photographic materials.

[Foreground of the Invention] When the area of a notebook-shaped photographic material becomes large, bending may occur during handling, and in this case, the bent portion is developed black, making it extremely difficult to see the red image. Therefore, thick supports are often used to strengthen the support so that bending is less likely to occur. However, this makes it stiffer, so if the corners remain at right angles, it can easily injure your hands. For this purpose, the corners of photosensitive materials are made obtuse or curved, so-called corner cuts, to improve handling safety.

In the process of applying corner cants, a large number of sheet-like films are usually stacked on top of each other, and a circular blade, for example, is lowered from above.
- Cutting corners of multiple photosensitive material films. At this time, since the lower film is subjected to pressure from the lower blade stand, fogging occurs along the corner cuts after development, making the image difficult to see, which may significantly reduce the VF and commercial value.

This problem is especially serious with certain types of halide grains, such as tabular silver halide grains.

Emulsions consisting of tabular silver halide grains have high sensitivity;
Therefore, although it is advantageous for obtaining highly sensitive photosensitive materials,
When a photosensitive material using this type of silver halide grains is used in a photosensitive material having a corner cant, the above-mentioned defects are likely to occur.

[Purpose of the invention]

In order to solve the above-mentioned problems, an object of the present invention is to provide high sensitivity and to suppress the occurrence of pressure fog along the corner cant even when a corner cut is made so that the corner part forms an obtuse angle or a curved shape. An object of the present invention is to provide a sheet-like silver halide photographic material.

[Structure of the Invention] The above-mentioned object of the present invention is to completely halogenate 18m halogenated particles having a tabular shape with a particle diameter/grain thickness ratio of 3 or more and having a full plane and a +1001 plane! ! A silver halide photographic emulsion that occupies 50% or more of the projected area of the grains (
A silver halide photographic light-sensitive material formed by coating at least one type of emulsion (hereinafter also referred to as "emulsion of the present invention") on a support, which has an area of 500 cm or more and has a corner This was achieved using a sheet-shaped silver halide photographic material characterized by having cuts.

The present invention will be explained in more detail below.

In the emulsion of the present invention, 50% or more of the projected area is
Tabular silver halide grains having a grain thickness ratio of 3 or more (
This is an emulsion containing such grains (hereinafter sometimes referred to as "silver halide grains according to the present invention"). Preferably 60% or more of the projected area, particularly preferably 70% or more, is an emulsion containing tabular silver halide grains having a grain diameter/grain thickness ratio of 3 or more.

Further, the ratio of particle diameter/particle thickness is preferably 20 or less, more preferably 3 or more and less than 12, and particularly, the ratio of particle diameter is 4 or more and less than 8.

In the present invention, the above-mentioned silver halide grains have both [1111 plane and I 100 ) plane. Preferably, 50% or more of the particle surface is an (ill) plane, more preferably 70 to 90% is an (1111 plane), and particularly preferably 75 to 95% is an (1111 plane.
It is preferable that the planes other than the above-mentioned planes are mainly (100) planes.

The present invention↓ Here, the particle size is the diameter when a projected image of the particle is converted into a circular image of the same area.

The projected area of a particle can be determined from the sum of the particle areas.

In either case, the measurement can be performed by observing with an electron microscope a silver halide crystal sample distributed on a sample stage to such an extent that grains do not overlap.

The thickness of the particles can be measured by obliquely observing the sample using an electron microscope.

In the present invention, the emulsion of the present invention is preferably monodisperse. 70% or more of the total silver halide weight, preferably 80% or more, more preferably 90%
That's all.

Here, the average particle size d is the frequency n of particles having particle size d,
The particle size d is defined as the product n,×d,3 of d and 'J. (3 significant digits, the lowest digit is 5 to the nearest 4.) The particle size referred to here is the diameter when the projected image of the particle is converted into a circular image of the same area, as described above.

The particle size can be obtained, for example, by photographing the particles with an electron microscope at a magnification of 10,000 to 50,000 times and actually measuring the particle diameter or projected area on a print. (
The number of particles to be measured is assumed to be 1000 or more indiscriminately. ) Highly monodisperse emulsions particularly preferably used in the present invention have a distribution width defined by: 20% or less, more preferably 15% or less.

Here, the particle size measurement method shall follow the measurement method described above,
The average particle size is a simple average.

Σd1 n Average grain size = Σn4 As a method for obtaining the emulsion of the present invention, a method in which silver halide is precipitated on monodisperse seed crystals is preferably used. Particularly preferably, the method described in JP-A-61-6643 is
One example is a method in which a growth step is provided to enlarge a monodisperse spherical twin seed emulsion. That is, the emulsion of the present invention preferably consists mainly of grains having an even number of parallel twin planes, particularly preferably grains having two twin planes.

The emulsion of the present invention preferably consists of silver iodobromide having an average silver iodide content of 0 to 20 mol%, more preferably 0 to 20 mol%.
．． It is 5 to 15 mol%, particularly preferably 1 to 12 mol%. In that case, silver chloride may be contained within a range that does not impair the effects of the present invention.

In order to obtain the emulsion of the present invention, when using a method of producing a silver halide photographic emulsion by supplying a water-soluble silver salt solution and a water-soluble halide solution in the presence of a protective colloid, (a) containing silver iodide; The pBr of the mother liquor was adjusted to 2.0 for a period of 172 or more from the initial stage of silver halide precipitation with a rate of 0 to 5 mol%.
-047 to -047, and (b) following the core grain generation step, the mother liquor contains 10-5 to 2.0 moles of silver halide solvent per mole of silver halide and substantially A seed particle formation step is provided to form silver halide grains that are monodisperse spherical twins, and (c) a water-soluble silver salt solution, a water-soluble halide solution, and/or silver halide fine particles are then added. Preferably, a method is used in which a growth step is provided in which the heat particles are enlarged.

Here, the mother liquor is a liquid (including silver halide emulsion) used in preparing a silver halide emulsion to produce a finished photographic emulsion.

In the above method, the silver halide grains formed in the core grain generation step are twin grains made of silver iodobromide containing 0 to 5 mol % of silver iodide.

The term "twin" refers to a silver halide crystal that has one or more twin planes within one grain. J (Photography
Korrespondenz) Volume 99, page 99, same 10
It is described in detail in Volume 0, 57. Two or more twin planes of a twin may or may not be parallel to each other.

In addition, the outer wall of the crystal is composed of (111) planes, (10
0) or both surfaces.

In the practice of the present invention, when the above method is used, the twin core particles are produced by increasing the bromide ion concentration in the protective colloid aqueous solution from 0.01 to
5 mol/2 or pBr = 2.0 to -0.7, preferably 0.03 to 5 mol//! (pBr=1.5
-0.7) and adding a water-soluble silver salt or a water-soluble silver salt and a water-soluble halide.

Here, the nucleation particle generation process refers not only to the period from the time when the water-soluble silver salt is added to the protective colloid solution until the time when new crystal nuclei are substantially no longer generated, but also the period after which the particles grow. It is defined as a step before the seed particle forming step.

In the practice of the present invention, the size distribution of the core particles is not limited and may be monodisperse or polydisperse. Polydispersity here means that the coefficient of variation of particles (synonymous with the width of the distribution mentioned above) is 2.
5% or more. When the emulsion of the present invention is prepared using core grains, the core grains preferably contain at least 50%, and more preferably 70% or more, of twin grains based on the total number of core grains. , 90% is most preferred.

Next, in the above method, a seed grain forming step will be described in which the core grains obtained in the core grain forming step are ripened in the presence of a silver halide solvent to obtain seed grains consisting of monodisperse spherical grains.

In ripening in the presence of a silver halide solvent (hereinafter simply referred to as ripening), when large grains and small grains coexist, the small grains dissolve and dissolve, and the large grains grow. This seems to be different from Ostwald Jukusei, which is thought to have a wider distribution. The conditions for cultivating seed grains from the core grains obtained in the core grain generation step include the aforementioned core grain generation in which twin core grains are generated using a halogen northern limit with a silver iodide content of 0 to 5 mol%. Substantially monodisperse spherical particles can be obtained by ripening the emulsion mother liquor that has undergone the process in the presence of a silver halide solvent of 10<-5 >to 2.0 mol/wet mol.

Substantially monodisperse means that the width of the distribution defined previously is 25
It means less than %.

Substantially spherical grains are defined as (111) planes or (111) planes or (111) planes or (
100) When a surface such as a plane is rounded to the extent that it cannot be clearly distinguished, and three-dimensional axes that are orthogonal to each other are set at one point near the center of gravity within the particle, the vertical, horizontal, and height of the plane image of the particle The ratio C=□ of the maximum particle diameter L and the minimum particle diameter 2 in the direction is 1.0 to 2.0,! Preferably, it refers to particles having an angle of 1.0 to 1.5 degrees.

Further, when using the above method, it is preferable that the spherical particles account for 60% or more, preferably 80% or more, and more preferably most of the total number of seed particles.

In carrying out the present invention, silver halide solvents used in the seed grain forming step include (a) U.S. Pat.
, No. 157, No. 3,531,289, No. 3,574,
No. 628, JP-A-54-1019, JP-A No. 5445891
Organic thioethers described in No. 7 and Japanese Patent Publication No. 58-30571, (b) JP-A-53-82408 and Japanese Patent Publication No. 53-82408;
Thiourea derivatives described in No. 5-29829 and No. 55-77737, etc., (C) JP-A-53-144319
A silver halide solvent having a thiocarbonyl group sandwiched between an oxygen or sulfur atom and a nitrogen atom, as described in No.
) imidazoles described in JP-A-54-100717, (e) sulfites, (f) thiocyanates, (g
) ammonia, (h) hydroxyalkyl-substituted ethylenediamines described in JP-A No. 57-196228, (i) substituted mercaptotetrazoles described in JP-A-57-202531, (j) water-soluble bromides ,
(k) Examples include benzimidazole derivatives described in JP-A-58-54333.

Next, specific examples of these silver halide solvents (a) to (k) will be given.

The following margin (a) HOCHzCHzSCl (zcHzscHzcHzOH
(b) (c) (CzHs) zNcHzcHJ (CtlzCHzO
H) t(i) (j) N a B r + NHJr.

Br (d) (e) K! 503° Na□503 (f) NIl, SCN.

SCN (g) us (h) (HOCH*GHz) tNcHtcHtN (CIl
xCBgOR) zThese solvents can be used in combination of two or more. Preferred solvents include onythyls, thiocyanates, thioureas, ammonia, and bromides, and particularly preferred is a combination of ammonia and bromide.

These solvents are generally preferably used in an amount of from 10@-5 to 2 moles per mole of silver halide.

In addition, the pH is 3 to 13, and the temperature is 30 to 70.
°C is preferred, particularly preferably pH 6-12, temperature 3
It is in the range of 5 to 50°C.

One example of a preferred embodiment when the above production method is adopted is pH 10.8 to 11.2, temperature 35 to 45°C.
with ammonia 0.4 to 1.0 mol/2 and potassium bromide 0
．． Using a combination of 03 to 0.5 mol/2, 30 seconds to
By aging for 10 minutes, an emulsion containing suitable seed particles was obtained.

In carrying out the present invention, a water-soluble silver salt may be added during the seed particle formation step for the purpose of adjusting ripening.

The seed grain growth process for enlarging silver halide seed grains involves pAg, p during silver halide precipitation and Ostwald ripening.
This is accomplished by controlling the H1 temperature, the concentration and silver halide composition of the silver halide solvent, and the rate of addition of the silver salt and halide solution.

The conditions for enlarging the obtained seed particles are as follows:
-39027, 55-142329, 5L-1
No. 13928, No. 54-48521 and No. 58-49
As seen in No. 938, a water-soluble silver salt solution and a water-soluble halide solution are added by the double jet method, and the addition rate is adjusted to a range that does not cause new nucleation and Ostwald ripening depending on the enlargement of the particles. One example is a method of gradual change. As another condition for enlarging the seed grains, a method of enlarging the seed grains by adding silver halide fine grains, dissolving and recrystallizing can be used, as shown in Proceedings of the 1981 Annual Conference of the Photographic Society of Japan, 88, but the former The method is preferred.

In producing the emulsion of the present invention, the growth conditions for silver halide grains are pH 6 to 12, temperature 30 to 85°C,
pH 4.0 to 12.0 is preferred. The pH is 5.
0 to 10.0 is particularly preferred. PAg is 6゜0～
9.5 is particularly preferable, and the temperature is particularly preferably 35 to 80°C.

During growth, it is preferable to add a silver nitrate aqueous solution and a halide aqueous solution by a double jet method. Moreover, iodine can also be supplied into the system as silver iodide. The addition rate should be such that new nuclei are not generated and the size distribution does not widen due to Ostwald ripening.
That is, it is preferable to add at a rate of 30 to 100% of the rate at which new nuclei are generated.

In producing the emulsion of the present invention, stirring conditions during production may be extremely important. As the stirring device, the device shown in JP-A-62-160128, in which an additive liquid nozzle is installed in the liquid near the mother liquor inlet of the stirrer, is particularly preferably used. In addition, at this time, the stirring rotation speed is 400 to 1
It is preferable to set it to 20 Orpm.

In the silver halide photographic material of the present invention, at least one emulsion of the present invention may be coated, and it is sufficient that it is contained in at least one silver halide emulsion layer on the support. In addition, in the layer containing the emulsion of the present invention, the content of the emulsion of the present invention is preferably 10% or more by weight, more preferably 30% or more, particularly preferably 5% or more by weight.
It is 0% or more.

That is, in the light-sensitive material of the present invention, the emulsion of the present invention is
Different types of emulsions may be used, or several types of emulsions may be used as a mixture, and other emulsions may also be used as a mixture.

The emulsions of the present invention and emulsions other than the emulsions of the present invention (hereinafter collectively referred to as "emulsions used in the present invention") used in combination as appropriate to constitute the light-sensitive material of the present invention include the following: technology can be used.

That is, in order to remove soluble salts from the emulsion after precipitation or physical ripening, a nude water washing method that involves gelatinization may be used, and inorganic salts, anionic surfactants, and anionic polymers may be removed. (eg, polystyrene sulfonic acid) or a precipitation method (flocculation method) using gelatin derivatives (eg, acylated gelatin, carbamoylated gelatin, etc.) may be used.

The process of removing soluble salts may be omitted.

The emulsion used in the light-sensitive material of the present invention includes gold-sensitized, sulfur-sensitized,
Alternatively, it is preferable to perform reduction sensitization, and it is also preferable to use a combination of these sensitizations.

That is, a sulfur-containing compound (
Sulfur sensitization using reducing substances (e.g., stannous salts, amines, hydrazine derivatives, formamidine sulfinic acid, silane compounds); Reduction sensitization method used; noble metal compounds (e.g., total complex salts, Pt,
Ir.

A noble metal sensitization method using complex salts of metals of group (I) of the periodic table (such as Pd) can be used alone or in combination.

Specific examples of these include U.S. Patent No. 1.574.944, U.S. Pat. No. 3,410,689, U.S. Pat.
No. 3,656,955, etc., and U.S. Patent Nos. 2,983゜609 and 2,419,97 regarding the reduction aggravation method.
4, U.S. Patent No. 4,054,458, etc., and U.S. Patent No. 2,599,083, U.S. Pat.
It is described in various specifications such as No. 8,060 and British Patent No. 618,061.

In carrying out the present invention, a combination of internal latent image type silver halide grains and surface latent image type silver halide grains described in Japanese Patent Publication No. 41-2086 may be used as an emulsion.

The sheet-shaped silver halide photographic material of the present invention has corner cuts. A corner cut is generally formed so that one corner has an obtuse angle or a curved shape.The photosensitive material of the present invention has high resistance to pressure such as corner cuts.The shape of the corner is Round,
It is preferable to have a curved shape such as an ellipse, or it may be cut in a straight line, but in this case, it is preferable to cut it in two or more straight lines.

When the emulsion of the present invention is used, or when an emulsion layer is formed using other emulsions as necessary, the emulsion layer contains two or more types of halogens having substantially different photographic properties, for example, two to six types of halogens. It can be formed by containing a silver emulsion.

Here, "substantially different photographic characteristics" means at least the photographic characteristics including sensitivity, gradation, color sensitivity, coloration, developability, image sharpness, graininess, etc. It is to have a different tonality.

The emulsions having different photographic properties may be contained in separate emulsion layers.

In terms of graininess and drying properties, the silver halide photographic material of the present invention has silver halide particles when immersed in an aqueous solution of 1.5 weight percent sodium hydroxide at 50.0°C without stirring. The time it takes for the film to separate from the support is 10 minutes or more, more preferably 15 minutes or more,
It is preferable to harden the film by adding a hardening agent.

When the silver halide photographic light-sensitive material of the present invention is processed, for example, in a roller conveyance type automatic processor, it is often processed in a state from development to drying. The water content of the photographic light-sensitive material is preferably in the range of 6.0 to 15.0 g/n, particularly preferably in the range of 9.0 to 14.0 g/m. The water content of a silver halide photographic material is determined by the following measurement method at 25°C and 75% relative humidity. The exposed sample was processed using Konica's automatic processor 5RX-501 (processing speed switch 45 seconds), and the developing solution was Konica's XD-501.
3R with a predetermined amount of starter
-3R (manufactured by the same company) at 32°C, and automatic development was carried out by supplying tap water at 18°C as the washing water at a rate of 32°C per minute. The drying rack of the automatic developing machine was removed, and 101 sheets of the same sample as the sample for moisture content measurement were processed in succession at an interval of 1 sheet/12 seconds, and the 101st sample was used as the sample for moisture content measurement. Take it out and measure the weight 15 seconds later. (At this time, make adjustments in advance so that the power to the drying system does not turn on.) The weight at this time is Ww (g).

Next, after thoroughly drying the sample, the temperature was 25°C for more than 1 hour.
℃, humidity and 55% RH, and its weight is measured. Let this be Wa (g). The water content is calculated from the following formula.

Water content (g/i) = (ww wa) x (10
000 cn/20 cm

The photographic material of the present invention may contain a dispersion of a water-insoluble or sparingly soluble synthetic polymer in the photographic emulsion layer or other hydrophilic colloid layer for the purpose of improving dimensional stability.

For example, alkyl (meth)acrylate, alkoxyalkyl (meth)acrylate, glycidyl (meth)acrylate, (meth)acrylamide, vinyl ester (e.g. vinyl acetate), acrylonitrile, olefin, styrene, etc. alone or in combination, or these and acrylic acid. , methacrylic acid, α,β-unsaturated dicarboxylic acid, hydroxyalkyl (meth)acrylate, sulfoalkyl (meth)acrylate, styrene sulfonic acid, and the like can be used. Note that the term (meth)acrylate mentioned above is an abbreviation for both acrylate and methacrylate.

The silver halide photographic material of the present invention is preferably provided with a protective layer, and this protective layer is a layer made of a hydrophilic colloid, and any hydrophilic colloid such as gelatin can be used.

Further, the protective layer may be a single layer or a multilayer.

A capping agent and/or a smoothing agent may be added to the emulsion layer or protective layer of the silver halide photographic material of the present invention, preferably to the protective layer. Although known matting agents can be used, polymer matting agents are more preferred, and their average particle size is preferably in the range of 0.3 μm to 12 μm, particularly preferably in the range of 3 μm to 9 μm.

Specific examples of polymer capping agents used in the practice of the present invention include water-dispersible vinyl polymers such as polymethyl methacrylate, cellulose acetate propionate, starch, and the like. In particular, matting agents of water-dispersible vinyl polymers such as homopolymers of acrylic esters such as methyl methacrylate, glycidyl acrylate, and glycidyl methacrylate, or copolymers of these acrylic esters with each other or with other vinyl monomers are used. Among these, a spherical matting agent of polymethyl methacrylate having an average particle diameter of 3 μm to 9 μm is particularly preferred.

The matting agent is usually added, for example, to the protective layer above the emulsion layer or to the protective layer on the back side, but the above polymer matting agent is added to the protective layer on the emulsion layer side. It is more preferable to add it, and for example, when processing a photographic material containing a polymer matting agent with a roller conveyor type automatic developer, the photosensitive material will not slip.

Smoothing agents help prevent adhesion failure similar to matting agents, and
It is particularly good for improving the frictional properties related to the projection of motion picture films or camera compatibility during projection. Hydrocarbons or derivatives thereof, silicones such as polyalkylpolysiloxanes, polyarylpolysiloxanes, polyalkylarylpolysiloxanes, or alkylene oxide addition derivatives thereof, and the like can be preferably used.

It is preferable to use a plasticizer in the light-sensitive material of the present invention in order to prevent fogging during coating and drying, and to prevent capri, loss, etc. due to bending under low humidity conditions. Examples of plasticizers include JP-A No. 48-63715 and JP-A No. 43-4
No. 939, No. 47-8745, U.S. Patent No. 306, 4
No. 70, No. 2,960,404, No. 3,412.15
No. 9.

3,791,857 and the like can be used, but it is preferable to contain at least one polyhydric alcohol compound having at least two or more hydroxyl groups and having a melting point of 40° C. or higher. Such compounds include alcohols that have 2 to 12 hydroxyl groups and 2 to 20 carbon atoms, and in which the hydroxyl groups are not conjugated with a conjugated chain, that is, an oxidized form cannot be written. is preferred. Further, the melting point is preferably 50°C or higher and 300°C or lower. Examples of compounds include JP-A-62-147
There is one described in No. 449.

In carrying out the present invention, surfactants can be used in the photosensitive material for various purposes.

〔Example] Hereinafter, the present invention will be explained in detail by giving Examples.

However, it goes without saying that the present invention is not limited to the following examples.

Example 1 (Preparation of spherical seed emulsion) A monodisperse spherical seed emulsion was prepared by the method described in JP-A-61-6643. That is, seed emulsions were obtained using the following four types of liquids in the following manner.

Dl Ammonia water (28%)? 05
Liquid B1 and liquid 01 were added in 30 seconds to liquid A1, which was vigorously stirred at 1140°C, by a double jet method to generate nuclei. pBr at this time is 1.09 to 1.15
Met.

After 1 minute and 30 seconds, liquid C3 was added for 20 seconds and aged for 5 minutes. The KBr concentration during aging was 0.071 mol/2, and the ammonia concentration was 0.63 mol/2.

Thereafter, the pH was adjusted to 6.0, and the mixture was immediately desalted and washed with water. When this seed emulsion was observed under an electron microscope, it was found to be a monodisperse spherical emulsion with an average grain size of 0.36 μm and a distribution width of 18%.

A photograph (20,000 times magnification) of the grains of the obtained emulsion is shown in FIG.

Comparative Example 1 (Preparation of a tabular comparative emulsion consisting of 1111 planes) Using a seed emulsion (emulsion obtained in Example 1) and the three types of solutions shown below, halogenation of a comparative emulsion consisting mainly of tabular twins was carried out. Silver emulsion Em-1 was prepared.

- Add water and waste to make it 6248 m.

Liquid B2 and liquid 02 were added to liquid A2, which was vigorously stirred at 65°C, over a period of 112 minutes using a double jet method. During this time the pH
was maintained at 2.0 with nitric acid, and pAg was maintained at 9.0 throughout. B
The addition rate of liquid 2 and liquid 02 was linearly increased to 6.4 times between the initial and final values.

After the addition, in order to adjust the pH to 6.0 and remove excess salts, precipitation desalination was performed using an aqueous solution of Demol (manufactured by Kao Atlas Co., Ltd.) and an aqueous solution of magnesium sulfate, and the pH was adjusted to 6.0.
8.5. An emulsion with a pH of 5.85 was obtained at 40°C.

When the obtained emulsion was observed with an electron microscope, it was found that it was a monodisperse emulsion with an average grain size of 1.6 μm and a distribution width of 19%, with 88% of the projected area of all grains in this emulsion being 100% (11
1) They were tabular silver halide grains consisting of planes.

In addition, the average grain diameter of the tabular silver halide grains/
The particle thickness ratio was 4.9, and the particle distribution width was 12%.

A photograph of the grains of the obtained emulsion Em-1 is shown in FIG. FIG. 2(a) is a photograph taken at a magnification of 9,000 times, and FIG. 2(b) is a photograph taken at a magnification of 35,000 times. Since the photograph is not necessarily clear, FIG. 4 shows a plan view of the particles based on the photograph of FIG. 2(b).

Example 2 Emulsion E of the present invention was prepared in exactly the same manner as Comparative Emulsion Em-1 except that the pH during mixing was changed to 5.8 in Comparative Example 1.
m-2 was created.

When the obtained emulsion was observed under an electron microscope, it was found that the average grain size was 1
．． In a monodispersed emulsion with a diameter of 5 μm and a distribution width of 15%, 85% of the projected area of all grains in this emulsion are composed of (111) and (10) planes.
They were tabular silver halide grains consisting of 0) faces.

The (111) plane and (1
00) plane ratio was 94:6 on average.

Further, the average grain diameter/grain thickness ratio of the tabular silver halide grains was 4.7, and the width of grain distribution was 11%.

Example 3 Emulsion E of the present invention was prepared in exactly the same manner as in Example 2, except that the PAg during mixing was changed to 8.8.
m-3 was created.

When the obtained emulsion was observed under an electron microscope, it was found that the average grain size was 1
．． In a monodispersed emulsion with a diameter of 45 μm and a distribution width of 14%, 83% of the projected area of all grains in the emulsion are (1111 planes and (100
) planes were tabular silver halide grains.

The (1111 plane and (1
00) plane ratio was 79:21.

In addition, the width of the distribution of tabular silver halide grains is 11%,
The average particle diameter/particle thickness ratio was 4.6.

A photograph (20,000 times magnification) of the grains of the obtained emulsion Em-3 is shown in FIG. Photos are not always clear, so
The figure shows a plan view of the particles based on the photograph.

Example 4 Emulsion E of the present invention was prepared in exactly the same manner as in Example 2, except that the PAg during mixing was changed to 8.3.
m-4 was created.

When the obtained emulsion was observed with an electron microscope, it was found that it was a monodisperse emulsion with an average grain size of 1.35 μm and a distribution width of 13%, with 81% of the projected area of all the grains of the emulsion having (111) planes and (10) planes.
They were tabular silver halide grains consisting of 0) faces.

The (1111 plane and (1
00) plane ratio was 65:35.

In addition, the width of the distribution of tabular silver halide grains is 11%,
The average particle diameter/particle thickness ratio was 3.5.

Example 5 Next, the silver halide emulsions Em-1, Em-2, Em-3 and Em-4 obtained in Comparative Example 1 and Examples 2 to 4 were each subjected to appropriate gold-sulfur sensitization. . Immediately before the end of this chemical sensitization, the following sensitizing dye was added to dye A: dye B = 20:1.
Add 1000 1 mol Ag in the ratio of 4-hydroxy-
6-methyl-1,3,3a,7-chitrazaindene2.
5g 1 mol^g was added.

Spectral sensitizing dye A Spectral sensitizing dye B C,H.

C,ll5 (C11,) 450. In addition, each emulsion contains, as emulsion layer additives, L-butyl-catechol 400 μm per mole of silver halide, polyvinylpyrrolidone (molecular weight 10,000) 1.0 g, and styrene/maleic anhydride. Copolymer 2.5g, trimethylolpropane 10g.

Diethylene glycol 5g.

Nitrophenyl-triphenylphosphonium chloride 50■, 1.3-
Dihydroxybenzene 4-ammonium sulfonate 4g12-Mercaptobenzimidazole-5-sulfonic acid sodium 15■, 2-mercaptobenzothiazole 10■, Ul'1 1.1-dimethylol-1-bromo-1-nitromethane 10■, also protected The following compounds were added as layer additives. That is, per 1 g of gelatin, C9F, "MCHzCHzO:h-7f-CHzCH
A protective layer solution was prepared by adding zOHCeF+tsOJ 2■, 3■, a matting agent 7■ consisting of polymethyl methacrylate having an average particle size of 5 μm, and 70■ colloidal silica having an average particle size of 0.013 μm.

Furthermore, as a hardening agent, the following compound was added at 7% per 1g of gelatin.
■Added.

CHI=CHS(hOcHzsOzc)l=CH
z Thickness 1 of the obtained emulsion and protective film solution colored blue
It was coated on both sides of 80 μm subbed polyethylene terephthalate to obtain a double-sided emulsion sheet-like photosensitive material. At this time, the amount of silver per side was 1.98/n (with 2 g/rrf as gelatin in the emulsion and Ig/rr as gelatin in the protective film).
It was applied so that it became f.

The obtained sample was evaluated as follows.

(Sensitometric evaluation) The obtained sample was sandwiched between X-ray photographic intensifying screens KC)-250 (manufactured by Konica Corporation) and irradiated with X-rays through a penetrometer type B (manufactured by Konica Medical Corporation). after that,
Using Konica Corporation's 5RX-501 automatic processor,
Processing was performed for 45 seconds using a D-3R developing solution.

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

The results obtained are shown in Table-1.

(Preparation of corner cut) Cut the coated sample into the size shown in Table 1, randomly stack 1000 pieces of each type of sample of the same size, including dummies, and cut into a round with a radius of curvature of 1ai using a round blade. Corner cuts were made by cutting off the corners. These samples were developed using the above-mentioned developing machine, and the degree of blackening of the corner cut portions was visually evaluated. 1 is black and cannot be put to practical use, 2 is better than 1 but still not practical, 3 is usable, 4 is a little blackening, and 5 is no blackening at all. Table -
1 shows the average value of 10 sheets.

(Comprehensive evaluation) As shown in Table 1, the samples of the present invention have high sensitivity and a good corner cut evaluation of 3 or more, indicating that pressure force blur accompanying corner cuts is suppressed.

Margins below -: et al. 4 [Effects of the Invention] As described above, the silver halide photographic material of the present invention has a high degree of anger, and has corners cut so that the corners are obtuse or curved. This has the effect of suppressing the occurrence of pressure burr along the corner cut even in the case of a corner cut.

[Brief explanation of the drawing]

1 to 3 are electron micrographs showing the grain/grain structures of silver halide grains in emulsions used in Examples or Comparative Examples of the present invention. Photograph of the grain structure of the prepared monodisperse spherical seed emulsion (20000
Figure 2 is a photograph of the grain structure of emulsion Em-1 prepared in Comparative Example 1 (a: 9,000 times, b: 35,000 times).
FIG. 3 is a photograph (20,000 times magnification) of the grain structure of emulsion Em-3 prepared in Example 3. 4 is a plan view of the particles in the photograph of FIG. 2(b), and FIG. 5 is a plan view of the particles in the photograph of FIG. 3. ＜-1・sun'' Figure 2 ('b)/) Flat face of the odor ÷ 4 Figure 5

Claims (1)

[Claims] 1. Silver halide grains having a tabular shape with a grain diameter/grain thickness ratio of 3 or more and having {111} planes and {100} planes account for 50% or more of the projected area of all silver halide grains. A silver halide photographic light-sensitive material formed by coating on a support at least one silver halide emulsion that accounts for
A sheet-shaped silver halide photographic material having an area of 500 cm^2 or more and having corner cuts.