JP2005321604A - Silver halide emulsion and silver halide photographic sensitive material using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver halide emulsion having high sensitivity, ensuring high-contrast gradation and excellent in graininess, and to provide a silver halide photographic sensitive material using the same. <P>SOLUTION: In the silver halide emulsion comprising a dispersion medium and silver halide grains, ≤50% of the total projected area of the silver halide grains comprised in the silver halide emulsion is occupied by grains satisfying the following conditions (i)-(iii); (i) hexagonal tabular grains having [111] faces as main planes and having a shape with a maximum side to minimum side length ratio of ≤2.0 when seen from a direction perpendicular to the main planes, (ii) the hexagonal tabular grains as hosts have an epitaxial junction on at least one of the corner portions of the hexagon, and (iii) when an equivalent spherical diameter of the epitaxial junctions is represented by d (μm), the expression: 0.60×n≤d≤1.40×n (where n is a constant of double figures below decimal point of 0.10 to 2.00) is satisfied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel silver halide emulsion and a silver halide photographic light-sensitive material using the same.

  While silver halide photographic light-sensitive materials (hereinafter also simply referred to as light-sensitive materials) are said to be extremely mature products, the required performance is high sensitivity, high image quality, and little performance fluctuation due to storage conditions. The required quality has been increasing in recent years. In particular, in terms of higher sensitivity and higher image quality, due to recent technological advances in digital cameras, further performance improvement is necessary to maintain the superiority of silver halide photographic light-sensitive materials.

  On the other hand, in order to achieve higher sensitivity and higher image quality, a technique for improving the sensitivity / grain size ratio per silver halide grain in a silver halide emulsion (hereinafter also simply referred to as an emulsion). Consideration has been ongoing.

  In general, it is known that silver halide grains contained in a silver halide emulsion have various shapes. For example, cubic, octahedral, tetradecahedral normal silver halide grains, tabular silver halide grains having one twin plane or multiple parallel twin planes, non-parallel twin planes There are tetrapotted and rod-shaped silver halide grains. Among these, tabular silver halide grains (hereinafter also simply referred to as tabular grains) are considered to have the following advantages as photographic characteristics.

  1. Since the ratio of the surface area to the particle volume (hereinafter also referred to as specific surface area) is large and a large amount of sensitizing dye can be adsorbed on the surface, the color sensitization sensitivity is relatively high with respect to the intrinsic sensitivity.

  2. When a silver halide emulsion containing tabular grains is applied and dried, the tabular grains are arranged in parallel to the support surface, so that the coating layer can be made thinner, resulting in the sharpness of the photosensitive material. Improvements can be made.

  3. Light scattering by silver halide grains is small, and an image with high resolution can be obtained.

  4). Since the sensitivity (inherent sensitivity) to blue light is low, the yellow filter density can be reduced or eliminated from the structure of the photosensitive material when used in the green photosensitive layer or the red photosensitive layer.

  5). When the same sensitivity as that of general grains is achieved, the amount of coated silver can be reduced due to the characteristics of the grain shape. As a result, the sensitivity / granularity ratio and natural radiation resistance are excellent.

  Examples of conventional techniques related to tabular grains include, for example, U.S. Pat. Nos. 4,434,226, 4,439,520, 4,414,310, 4,433,048, and 4,414. No. 4,306, No. 4,459,353, JP-B-4-36374, JP-A-5-16015, JP-A-6-44132, JP-A-6-43605, JP-A-6-43606, JP-A-6 -214331, 6-222488, 6-230493, 6-258745, etc. disclose their production methods and techniques for use.

  In order to extract the advantages of the tabular grains more effectively, it is effective to use tabular grains having a high aspect ratio. However, as known in the art, as the aspect ratio becomes higher, it becomes difficult to maintain the uniformity of the grain shape. Therefore, many of the conventional tabular grains as described above have a grain size, a grain shape, The silver iodide content, the area ratio of the plane index, and the uniformity among grains having various other grain characteristics deteriorated. As a result, the graininess was deteriorated and the gradation was softened.

  In response to the above problems, particles having a high aspect ratio and an improved equivalent circle diameter or thickness distribution have been disclosed (see, for example, Patent Documents 1 to 4). However, simply improving each of the equivalent circle diameter distribution and the thickness distribution is not sufficient in terms of uniformity of particle shape. Even if both the equivalent circle diameter distribution and the thickness distribution were improved computationally, it was found that the individual quantum sensitivities of the silver halide grains would be non-uniform as a result of the dissimilar shape.

  On the other hand, as a method for sensitizing a tabular grain, there is a method using an epitaxial junction known in the art. As applications to high aspect ratio tabular emulsions, JP-A Nos. 8-69069, 8-101472, 8-101474, 8-101475, 8-171162, 8-171163, 8 -101473, 8-101476, 9-211763, U.S. Pat.Nos. 5,612,176, 5,614,359, 5,629,144, 5,631, 126, 5,691,127, and 5,726,007. However, it is still not sufficient for effective latent image formation.

The reason for this is that even if the tabular grain shape uniformity (eg, grain size, grain shape, silver iodide content, area ratio of surface index, etc.) is improved, the shape and composition uniformity of the epitaxial junction is improved. If not enough, the individual quantum sensitivity of the silver halide grains becomes non-uniform. Japanese Patent Laid-Open No. 2002-278007 discloses a composition uniformity of an epitaxial junction, but it is not intended to make the size and shape of the epitaxial junction uniform. Further, the host grains shown in the examples have an aspect ratio of 11.3, but sufficient effects cannot be obtained in further high aspect ratio tabular grains.
Japanese Patent Publication No. 5-60574 JP 2001-142170 A JP 2001-159799 A JP 2001-255613 A

  An object of the present invention is to provide a silver halide emulsion capable of obtaining a high sensitivity, a high gradation, and excellent in graininess, and a silver halide photographic light-sensitive material using the same.

  The inventors of the present invention have found that by making the size, shape and composition of the epitaxial junction uniform, the latent image formation efficiency is further improved, both sensitivity and graininess are improved, and high contrast is achieved. That is, the above object of the present invention is achieved by the following configuration.

(Claim 1)
In a silver halide emulsion containing a dispersion medium and silver halide grains, 50% or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following conditions i) to iii): Silver halide emulsion.

i) Hexagonal tabular grains having a [111] plane as a main plane and a ratio of the maximum side length to the minimum side length as viewed from a direction perpendicular to the main plane is 2.0 or less
ii) Using the above hexagonal tabular grain as a host, it has an epitaxial junction at at least one of the hexagonal apexes.
iii) When the spherical equivalent particle diameter of the epitaxial junction is d (μm), 0.60 × n ≦ d ≦ 1.40 × n (n is a constant of two digits after the decimal point of 0.10 to 2.00)
(Claim 2)
2. The silver halide emulsion according to claim 1, wherein an inter-grain variation coefficient of a spherical equivalent particle diameter d of the epitaxial junction is 40% or less.

(Claim 3)
In a silver halide emulsion containing a dispersion medium and silver halide grains, 50% or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following conditions i) to iii): Silver halide emulsion.

i) Hexagonal tabular grains having a [111] plane as a main plane and a ratio of the maximum side length to the minimum side length as viewed from a direction perpendicular to the main plane is 2.0 or less
ii) Using the above hexagonal tabular grain as a host, it has an epitaxial junction at at least one of the hexagonal apexes.
iii) The projected area ratio of the epitaxial junction to the host is P, and 0.60 × q ≦ P ≦ 1.40 × q (q is a constant of 3 digits after the decimal point of 0.020 to 0.400)
(Claim 4)
4. The silver halide emulsion according to claim 3, wherein the inter-grain variation coefficient of the projected area ratio P to the host of the epitaxial junction is 40% or less.

(Claim 5)
4 or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following formula, where R is the diameter of the hexagonal tabular grain converted to a circle. The silver halide emulsion as described in the item.

0.75 × m ≦ R ≦ 1.25 × m (m is a constant of two digits after the decimal point of 0.50 to 6.00)
(Claim 6)
6. The silver halide emulsion according to claim 5, wherein the hexagonal tabular grains have an inter-grain variation coefficient of a circle equivalent diameter R of 25% or less.

(Claim 7)
The aspect ratio of the hexagonal tabular grains is A, and 50% or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following formula. A silver halide emulsion described in 1.

0.70 × k ≦ A ≦ 1.30 × k (k is a constant of one digit after the decimal point of 5.0 to 40.0)
(Claim 8)
The silver halide emulsion according to claim 7, wherein the hexagonal tabular grain has an inter-grain variation coefficient of an aspect ratio A of 30% or less.

(Claim 9)
The silver chloride content in the epitaxial junction is _XCl mol%, and 50% or more of the total projected area of silver halide contained in the silver halide emulsion satisfies the following formula: The silver halide emulsion according to any one of the above.

0.70 × l ≦ X _Cl ≦ 1.30 × l (l is a constant of one digit after the decimal point of 7.0 to 95.0)
(Claim 10)
The silver halide emulsion according to claim 9, intergranular variation coefficient of the epitaxial junction silver chloride content in section X _Cl is equal to or less than 30%.

(Claim 11)
The silver iodide content in the epitaxial junction as X _I mol%, claims 1 to 10 or 50 percent of the total projected area of the silver halide contained in the silver halide emulsion is characterized by satisfying the following expression The silver halide emulsion according to any one of the above.

0.60 × j ≦ X _I ≦ 1.40 × j (j is a constant of one decimal place from 1.0 to 40.0)
(Claim 12)
The silver halide emulsion of claim 11, the inter-grain variation coefficient of the silver iodide content X _I in the epitaxial junction portion is equal to or less than 40%.

(Claim 13)
A silver halide emulsion having a silver halide emulsion layer on a support, wherein at least one of the silver halide emulsion layers is a silver halide emulsion according to any one of claims 1 to 12. Silver photographic material.

  According to the present invention, it is possible to provide a silver halide emulsion capable of obtaining a high-sensitivity, high-contrast gradation and excellent in graininess, and a silver halide photographic light-sensitive material using the same.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

  The silver halide grain in the present invention comprises a tabular silver halide host grain part (hereinafter also referred to as tabular host grain) and a silver halide crystal part (hereinafter referred to as epitaxial) joined to the host grain part. .

  The tabular grains in the present invention are classified as twins crystallographically. A twin is a crystal having one or more twin planes in one grain, and the classification of the form of twins in a silver halide grain is a report by Klein and Moiser, “Photographie Korrespondenz”, Vol. 99, p. 99. This is described in detail in Vol. 100, p. 57. The tabular grains in the present invention preferably have two or more twin planes parallel to each other in the grains. These twin planes exist almost in parallel with the plane having the largest area among the planes forming the surface of the tabular grains ([111] plane, which is called the main plane). A particularly preferred form in the present invention is a case having two twin planes parallel to the main plane, and has a hexagonal shape when viewed from the direction perpendicular to the main plane (hereinafter referred to as hexagonal tabular grains).

  The hexasectional tabular grain in the present invention is a replica sample using a sample coated with silver halide grains so that the main plane is oriented parallel to the substrate, and the ratio of the maximum side length to the minimum side length is 2 0.0 or less hexagonal tabular grains, preferably 1.0 to 1.5, and more preferably 1.0 to 1.1. When the hexagonal apex is rounded, the intersection of extending adjacent sides is measured as the apex.

  The silver halide grains having 0 to 1 twin planes and two or more twin planes that are not parallel to each other, as described in the report by Klein and Moiser, are regular hexahedrons, regular octahedrons, triangular pyramids, rods, And an indefinite shape. Since these grains are not tabular grains having a high aspect ratio, they are not only less effective for improving photographic characteristics, but also cause fogging in the chemical sensitization step, so it is preferable to reduce them as much as possible.

  In the present invention, the abundance ratio (number%) of silver halide grains having 0 to 1 twin planes and two or more twin planes not parallel to each other is preferably less than 10%, more preferably less than 3%. Most preferably it is less than 1%.

  The silver halide grains in the present invention have an epitaxial junction at least one of the apexes or sides of the hexagonal shape using the hexagonal tabular grains as a host, but preferably three or more, and all six apexes or all six sides. It is more preferable to have an epitaxial junction. Most preferably, there is no epitaxial junction at a site other than the apex or side. Here, the apex portion means a portion in a circle having a radius of 1/3 of the length of the shorter side of the two sides adjacent to the apex when the tabular grain is viewed in the vertical direction from the main surface. . Even in the case of a rounded circular shape, when a straight side can be identified, the length of each side of a hexagon formed by extending each side is used. In addition, the vertex can be identified as the point having the largest curvature. Here, the term “along the side” means a range of 0.2 μm inward from each side of the hexagon when the tabular grains are viewed in the vertical direction from the main surface.

  The position and occupied area of the epitaxial arrangement are preferably uniform among the grains. More preferably, the positions are uniformly arranged along vertices or sides of 80% or more, and more preferably, the positions are arranged uniformly along vertices or sides of 90% or more. The interparticle variation coefficient of the occupied area of the pitch arrangement is preferably 40% or less, more preferably 30% or less, further preferably 20% or less, and most preferably 10% or less.

  As one of the most preferable embodiments in the case of using a silver halide emulsion containing silver halide grains having silver halide projections on the grain surface, the silver halide projections arranged epitaxially are the apexes or sides of the host grains. It is preferably formed at a limited position along or in the vicinity thereof, and a known method can be applied as a method for achieving this. In the above-mentioned US Pat. No. 4,435,501, a method of adsorbing a spectral sensitizing dye or aminoazaindene as a site director is disclosed, which is preferably applicable also in the present invention.

  The particles according to claim 1 of the present invention have an equivalent spherical particle diameter d (μm) at the apex of the hexagonal tabular grain as a host, and the spherical equivalent particle diameter d is 50% or more of the total projected area. Is (0.60 × n) or more and (1.40 × n) or less (n is a constant of two digits after the decimal point of 0.10 to 2.00). Here, there are a maximum of 12 vertex epitaxials for one host hexagonal tabular grain. This is because there may be two epitaxial points on the two main planes above and below one vertex. All vertex epitaxials existing in one host particle have a particle size d of (0.60 × n) or more and (1.40 × n) or less. Preferably, in grains having 80% or more of the total projected area, the epitaxial sphere equivalent particle diameter d is not less than (0.60 × n) and not more than (1.40 × n), more preferably 90% of the total projected area. In the above particles, the epitaxial sphere equivalent particle diameter d is (0.60 × n) or more and (1.40 × n) or less.

  In the present invention, the interparticle variation coefficient of the epitaxial sphere equivalent particle diameter d is preferably 40% or less, more preferably 30% or less, and still more preferably 20% or less.

  The grain according to claim 3 of the present invention is such that the projected area ratio of the epitaxial junction along the side of the hexagonal tabular grain that is the host to the host is P, and the grain of the host grain is 50% or more of the total projected area. The area ratio P to the projected area is (0.60 × q) or more and (1.40 × q) or less (q is a constant of 3 digits after the decimal point of 0.020 to 0.400). Here, for a hexagonal tabular grain serving as one host, there are a maximum of 12 epitaxials along the side. This is because there may be two epitaxial points on the two main planes above and below one side. The area ratio P of all epitaxials along one side existing in one host particle is (0.60 × q) or more and (1.40 × q) or less. Preferably, particles having an area ratio P of (0.60 × q) or more and (1.40 × q) or less in particles of 80% or more of the total projected area, more preferably 90% or more of particles of the total projected area The area ratio P is (0.60 × q) or more and (1.40 × q) or less.

  In the present invention, the inter-grain variation coefficient of the epitaxial area ratio P with respect to the projected area of the hexagonal tabular grains as the host is preferably 40% or less, more preferably 30% or less, and still more preferably 20% or less.

  The particle according to claim 5 of the present invention has a diameter R of (0.75 × m) in a particle of 50% or more of the total projected area, where R (μm) is the diameter of a hexagonal tabular grain as a host. ) Or more and (1.25 × m) or less (m is a constant of two digits after the decimal point of 0.50 to 6.00). Preferably, in a particle having 80% or more of the total projected area, the circle-converted diameter R of the host particle is (0.75 × m) or more and (1.25 × m) or less, more preferably 90% of the total projected area. % Of the particles, the equivalent diameter R of the host particles is (0.75 × m) or more and (1.25 × m) or less.

  In the present invention, the inter-grain variation coefficient of the circle-converted diameter R of the hexagonal tabular grains serving as the host is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less.

  In the grain according to claim 7 of the present invention, the aspect ratio of the hexagonal tabular grain as a host is A, and the grain having 50% or more of the total projected area has an aspect ratio of (0.70 × k) or more, (1.30 × k) or less (k is a constant value of one digit after the decimal point of 5.0 to 40.0). Preferably, particles having an aspect ratio A of not less than (0.70 × k) and not more than (1.30 × k) in particles having 80% or more of the total projected area, more preferably, particles having 90% or more of the total projected area The aspect ratio A is (0.70 × k) or more and (1.30 × k) or less.

  In the present invention, the hexagonal tabular grains serving as the host preferably have a circle-equivalent diameter R of 0.6 μm or more, more preferably 1.0 μm or more, and 3.0 μm or more and 6.0 μm or less. Most preferred.

  In the present invention, the inter-particle variation coefficient of the aspect ratio A of the hexagonal tabular tabular grains that are hosts is preferably 30% or less, more preferably 20% or less, and even more preferably 15% or less.

The grain according to claim 9 of the present invention is such that the silver chloride content X _Cl is (0.70) in grains having 50% or more of the total projected area, where the silver chloride content in the epitaxial junction is X _Cl mol%. Xk) or more and (1.30 * k) or less (k is a constant of one digit after the decimal point of 5.0 to 40.0). Preferably, in a grain of 80% or more of the total projected area, the silver chloride content X _Cl is (0.70 × k) or more and (1.30 × k) or less, more preferably 90% of the total projected area. In the above grains, the silver chloride content X _Cl is (0.70 × k) or more and (1.30 × k) or less.

In the present invention, the silver chloride content X _Cl is intergranular variation coefficient of preferably 30% or less in the epitaxial junction, and more preferably 20% or less, more preferably 15% or less.

The grain according to the eleventh aspect of the present invention has a silver iodide content X _I of (0) in grains having 50% or more of the total projected area, where the silver iodide content in the epitaxial junction is X _I mol%. .60 × j) or more and (1.40 × j) or less (j is a constant of one digit after the decimal point of 1.0 to 40.0). Preferably, in a grain of 80% or more of the total projected area, the silver iodide content X _I is (0.60 × j) or more and (1.40 × j) or less, more preferably 90% of the total projected area. % Of the grains have a silver iodide content X _I of (0.60 × j) or more and (1.40 × j) or less.

In the present invention, preferably the silver iodide content X _I of 40% coefficient of variation among the particles in the epitaxial junction, and more preferably 30% or less, more preferably 20% or less.

  The ratio of the hexagonal tabular grains contained in the silver halide emulsion of the present invention is 50% or more of the total projected area of the silver halide, preferably 70% or more, more preferably 90% or more.

  In the silver halide grains of the present invention, it is preferable that the silver used for the epitaxial trace contributes efficiently to the epitaxial formation, and the ratio of the silver amount used for the epitaxial formation with respect to the silver amount of the host grain is preferably 1% or more. 1% or more and 15% or less are more preferable, and 2% or more and 10% or less are still more preferable.

  In the present invention, the aspect ratio A is obtained by the following equation.

A = diameter-converted diameter R / particle thickness In the present invention, the average circle-converted diameter is the arithmetic average of the circle-converted diameter R. However, 3 significant figures and minimum digits are rounded off, and the number of measured particles is 1,000 or more indiscriminately. The circle-converted diameter here is the diameter when the projected image of the host tabular grains as viewed from a direction perpendicular to the main plane of the tabular grains is converted into a circle image of the same area. In addition, the diameter in terms of a circle can be obtained by photographing silver halide grains with an electron microscope magnified 5,000 to 70,000 times and measuring the grain diameter on the print or the projected area. The projected area and thickness of individual grains for calculating the circle-equivalent diameter R and aspect ratio of silver halide grains can be determined by the following method.

  A sample is prepared by applying a latex ball with a known particle size as an internal standard on a support and silver halide grains so that the main plane is oriented parallel to the substrate, and shadowing the grains by carbon deposition from a certain angle. After performing the above, a replica sample is prepared by a normal replica method. An electron micrograph of the sample is taken, and the projected area and thickness of each particle are obtained using an image processing apparatus or the like. In this case, the projected area of the particle can be calculated from the projected area of the internal standard, and the thickness of the particle can be calculated from the length of the internal standard and the shadow of the particle.

  In the present invention, the sphere equivalent diameter d of the apex epitaxial portion can be estimated by taking a transmission electron micrograph by the replica method. That is, first, the diameter when the projected image of the apex epitaxial portion when viewed from a direction perpendicular to the main plane of the tabular grain is converted into a circular image of the same area is obtained. Next, the height of the epitaxial portion can be calculated from the length of the shadow of the vertex epitaxial portion.

v (vertical epitaxial portion volume) = π × (equivalent diameter of circle ÷ 2) ² × epitaxial portion height d = 2 × (4 ÷ (3 × π)) 1/3
In the present invention, the projected area ratio P to the host of the epitaxial junction along the side of the host grain can be estimated by taking a transmission electron micrograph in the same manner. That is, first, the projected area of the projected image of the epitaxial portion along each side and the projected area of the host tabular grains when viewed from the direction perpendicular to the main plane of the tabular grains is obtained using an image processing apparatus, etc. The ratio P is calculated. P = projected area of the epitaxial portion ÷ projected area of the host tabular grain P is obtained for each epitaxial junction.

  As a means for making the size, shape and composition of the epitaxial junction more uniform, it is important to make the size, shape and surface composition of the host tabular grains uniform first. The host particles are preferably prepared by the method described in JP-A-2001-183767. If the size, shape, and surface composition of the host tabular grains are uniform, the dye and / or other site director added during epitaxial formation are uniformly coated, and the size, shape, and composition of the epitaxial junction are also made uniform. Further, an epitaxial bonding method by adding silver halide fine grains having a good size distribution is preferable, and it is more preferable to ripen them while controlling the temperature after adding silver halide fine grains.

  As a means of controlling the size of the epitaxial junction, a method of simply increasing or decreasing the amount of silver used for epitaxial formation, or a method of increasing or decreasing the coverage of dyes and / or other site directors added during epitaxial formation, host particles There are a method for controlling the surface silver iodide content, a host grain pAg control, a dye adsorption intensity by adding a cation, and the like, and a method for localizing an epitaxial site by adding silver halide fine particles. In particular, when it is not desired to increase or decrease the amount of silver used or the amount of dye used during epitaxial formation, the size of the epitaxial junction is controlled by controlling the pAg of host grains, controlling the dye adsorption intensity by adding cations, or adding silver halide fine particles. It is preferable. However, in the present invention, it is premised that the uniformity of the size, shape and composition of the epitaxial junction is increased, and the above means (the size, shape and surface composition of the host tabular grains are made uniform. It is preferable to use in combination with the addition of good silver halide fine grains.

  As a means for controlling the epitaxial junction site, the type of site director may be selected according to the target site, but the pBr environment at the time of epitaxial junction should be changed in order to avoid influence on the subsequent chemical sensitization. Is preferred. At this time, since the solubility of the reaction system may change due to the change in pBr, for example, in the method of adding silver halide fine particles, the particle size of the silver halide fine particles should be adjusted optimally according to the solubility. Is preferred.

  As a means for controlling the particle size of the silver halide fine particles, it is preferable to control the temperature during nucleation. If nucleation is performed at a low temperature, the particle size of the fine particles becomes small. Nucleation is usually carried out in the presence of gelatin. When nucleation is carried out at a low temperature, it is preferable to use gelatin having a low molecular weight depending on the temperature in order to avoid aggregation due to thickening.

  In order to reduce the particle size distribution of the silver halide fine particles, nucleation is preferably performed in a dilute environment. In that case, it is preferable to concentrate by a method such as ultrafiltration after nucleation so as not to deteriorate the productivity.

  The thickness of the tabular grain in the present invention is preferably 0.25 μm or less, more preferably 0.20 μm or less, and particularly preferably 0.02 to 0.16 μm.

  Further, the variation coefficient of the thickness of the tabular grain in the present invention is preferably 40% or less, more preferably 30% or less, further preferably 20% or less, and more preferably 10% or less. Most preferred.

  In general, the coefficient of variation is a value defined by the following equation.

Coefficient of variation (%) = (standard deviation / average value) × 100
That is, the vertex epitaxial sphere equivalent particle diameter d in the present invention, the epitaxial portion area ratio P along the side with respect to the projected area of the host grain, the circle equivalent diameter R and thickness of the host tabular grain, the aspect ratio A, the epitaxial junction the variation coefficient of the silver chloride content of the X _Cl and iodide content X _I is defined by the following formula.

Coefficient of variation of d (%) = (standard deviation of vertex epitaxial sphere equivalent particle diameter / average sphere equivalent particle diameter) × 100
Coefficient of variation of P (%) = (standard deviation of area ratio of epitaxial portion along side / average area ratio) × 100
Coefficient of variation of R (%) = (standard deviation of circle converted diameter / average circle converted diameter) × 100
Coefficient of variation of thickness (%) = (standard deviation of thickness / average thickness) × 100
A coefficient of variation (%) = (standard deviation of aspect ratio / average aspect ratio) × 100
Variation coefficient of X _Cl (%) = (epitaxial portion standard deviation / average silver chloride content of the silver chloride content) × 100
Variation coefficient of X _I (%) = (standard deviation / average silver iodide content of the epitaxial portion silver iodide content) × 100
In the present invention, the abundance ratio (number%) of rod-like grains contained in the silver halide emulsion is preferably 0.5% or less.

  The rod-like grains not only cause fogging in the chemical sensitization process as well as other grains having 0 to 1 twin planes and two or more twin planes not parallel to each other, but also in the emulsion coating process. Since the filter used for the purpose of removing foreign substances may be clogged, it is preferable that the number is as small as possible.

  In the present invention, the average distance between two or more twin planes parallel to the main plane is preferably 1 nm or more and 30 nm or less, more preferably 1 nm or more and 20 nm or less, and particularly preferably 1 nm or more and 12 nm or less.

  In the present invention, the inter-grain distance distribution of the twin plane distance is preferably 40% or less, and more preferably 30% or less. The twin plane can be observed with a transmission electron microscope. The specific method is as follows.

  First, a sample is prepared by coating a silver halide emulsion so that the tabular grains contained are oriented substantially parallel to the main plane on the support. This is cut using a diamond cutter to obtain a thin slice having a thickness of about 0.1 μm. The existence of twin planes can be confirmed by observing the thin slice with a transmission electron microscope. In the present invention, the average distance between two or more twin planes parallel to the main plane indicates a cross section cut substantially perpendicular to the main plane in the observation of a thin section using the transmission electron microscope. It can be obtained by arbitrarily selecting 100 or more tabular grains, obtaining the distance between twin planes, and averaging them.

  In the present invention, the distance between twin planes is a factor that affects the supersaturation state during nucleation, for example, various factors such as gelatin concentration, temperature, iodine ion concentration, pBr, ion supply speed, stirring rotation speed, and gelatin species. It can be controlled by appropriate selection in combination. In general, the distance between twin planes can be reduced as nucleation is performed in a highly supersaturated state. Details regarding the supersaturation factor can be referred to, for example, the descriptions in JP-A 63-92942 and JP-A 1-213637.

  The average silver iodide content of the silver halide grains contained in the silver halide emulsion of the present invention is preferably 0.1 to 40 mol%, more preferably 0.3 to 30 mol%, and 0 More preferably, it is 5-20 mol%. In order to satisfy main photographic performance such as sensitivity and developability, the content is particularly preferably 2 to 8 mol%.

  The silver iodide content of the silver halide grains is determined by the EPMA method (Electron Probe Micro Analyzer method). Specifically, a sample in which silver halide grains are well dispersed so as not to contact each other is prepared, and irradiated with an electron beam while being cooled to −100 ° C. or lower with liquid nitrogen, and emitted from individual silver halide grains. By obtaining the characteristic X-ray intensity of silver and iodine, the silver iodide content of the individual silver halide grains can be determined.

  By the above method, the silver iodide content of the silver halide grains obtained for each silver halide grain is obtained for 100 or more silver halide grains, and the average is obtained as the average silver iodide content.

Further, when measuring the silver chloride content X _Cl and the silver iodide content X _I of the epitaxial junction, it is necessary to reduce the diameter of the electron beam according to the area of the epitaxial junction.

  The tabular grains in the present invention preferably have a plurality of silver halide phases having different silver iodide contents inside the grains. It is also preferable that the core-shell type silver halide grains have a high or low silver iodide content in the silver halide phase outside the grain interior relative to the silver iodide content in the grain interior. The number of silver halide phases having different silver iodide contents in the grain is arbitrary, but it is preferably 3 or more, more preferably 4 or more, and more preferably 5 or more. Further preferred.

  In the present invention, the average silver iodide content in the outermost layer of the main plane part of the silver halide grains described in JP-A-11-153841 is preferably 8 mol% or more, more preferably 10 mol% or more, and 12 mol. % Or more is more preferable. Further, the average silver iodide content of the outermost surface of the side part is preferably 8 mol% or less, more preferably 5 mol% or less, still more preferably 3 mol% or less.

  In the present invention, the surface silver iodide content of the silver halide grains means the silver iodide content in the silver halide phase including the surface of the silver halide grains and a depth of 5 nm from the surface of the silver halide grains.

  The average silver iodide content (mol%) of the outermost layer of silver halide grains is determined by the following method.

The surface silver iodide content of the silver halide grains is determined by the XPS method (X-ray photoelectron spectroscopy: X-ray photoelectron spectroscopy) as follows. That is, the sample was cooled to −110 ° C. or lower in an ultrahigh vacuum of 1.33 × 10 ⁻⁶ Pa or less, irradiated with MgKα as a probe X-ray at an X-ray source voltage of 15 kV and an X-ray source current of 40 mA, Ag3d5 / 2, Br3d, I3d3 / 2 electrons are measured. The integrated intensity of the measured peak is corrected with a sensitivity factor, and the halide composition of the outermost layer is determined from these intensity ratios.

  The XPS method has been conventionally disclosed in JP-A-2-24188 as a method for determining the silver iodide content on the surface of silver halide grains. However, when the measurement was performed at room temperature, the exact silver iodide content of the outermost layer could not be obtained because the sample accompanying the X-ray irradiation was destroyed. We have succeeded in accurately determining the silver iodide content of the outermost layer by cooling the sample to a temperature at which destruction does not occur. As a result, in particular for particles such as core / shell particles having different surface and internal compositions, and particles having a high and low iodine layer localized on the outermost surface, the measured value at room temperature is X-ray. It was found that the true composition differs greatly due to silver halide decomposition and halide (especially iodine) diffusion upon irradiation.

  Specifically, the XPS method used here is as follows.

  A 0.05% by mass aqueous solution of proteolytic enzyme (pronase) was added to the emulsion and stirred at 45 ° C. for 30 minutes to decompose gelatin. This is centrifuged to settle the emulsion grains and the supernatant is removed. Next, distilled water is added to disperse the emulsion grains in distilled water, and the supernatant is removed by centrifugation. The emulsion grains are re-dispersed in water and thinly coated on a mirror-polished silicon wafer to obtain a measurement sample. Using the sample thus prepared, surface iodine measurement was performed by XPS. In order to prevent destruction of the sample due to X-ray irradiation, the sample is cooled to −110 to −120 ° C. in the XPS measurement chamber.

  As a probe X-ray, MgKα was irradiated at an X-ray source voltage of 15 kV and an X-ray source current of 40 mA, and measurement was performed on Ag3d5 / 2, Br3d, and I3d3 / 2 electrons. The integrated intensity of the measured peak is corrected with a sensitivity factor, and the halide composition of the outermost layer is determined from these intensity ratios.

  The average silver iodide content of the outermost surface layer of the main plane part in the present invention is determined using the XPS method after coating so that the main planes of the tabular grains are oriented in parallel to the silicon wafer. When coating the emulsion grains on a silicon wafer, the grains are prevented from agglomerating or overlapping. A dispersion aid may be used to prevent particle aggregation. The produced measurement sample is preferably confirmed using an optical microscope or SEM.

  The silver halide emulsion of the present invention contains a dispersion medium and tabular grains. Here, the dispersion medium is a compound having a protective colloid property for silver halide grains, and it is preferably present in the emulsion production process from the nucleation process to the grain growth process. Examples of the dispersion medium that can be preferably used in the present invention include gelatin and hydrophilic colloid. Examples of gelatin include alkali-treated gelatin, acid-treated gelatin having a molecular weight of about 100,000, oxidized gelatin, Bull. Soc. Sci. Photo. Japan. No. 16. An enzyme-treated gelatin as described in P30 (1966) can be preferably used. Examples of hydrophilic colloids include gelatin derivatives, graft polymers of gelatin and other polymers, proteins such as albumin and casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, cellulose sulfates, sodium alginate, starch derivatives Sugar derivatives such as: polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinyl pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinyl imidazole, various kinds such as copolymers such as polyvinyl virazole The synthetic hydrophilic polymer substance can be used.

  In the production process of the silver halide emulsion of the present invention, gelatin having a methionine content of 20 μmol or less per gram of gelatin or a gelatin having a methionine content of 20 μmol or less and an average molecular weight of 40,000 or less per gram of gelatin is dispersed. It is preferable to use it as a medium. Here, the methionine content is preferably 10 μmol / g or less, more preferably 5 μmol / g or less, and most preferably 0 to 3 μmol / g. The average molecular weight of gelatin is more preferably 30,000 or less, and even more preferably 1 to 20,000. These gelatins may be added in any process, but are preferably contained during nucleation.

  The tabular grains in the present invention preferably have dislocation lines. The form of dislocation lines can be selected as appropriate. For example, it is possible to select dislocation lines that exist linearly with respect to a specific direction of the crystal orientation of the grains, or curved dislocation lines. Furthermore, it exists throughout the entire particle, or exists only in a specific part of the particle. For example, it is limited to the fringe part (peripheral part) of the particle, the dislocation line exists, or the main plane. It is also possible to select from a form in which dislocation lines exist or a form in which dislocation lines exist in the vicinity of the apex. The tabular grains in the present invention preferably have dislocation lines at least in the fringe part of the grains, and more preferably have dislocation lines in the fringe part and the main plane part. The tabular grains in the present invention preferably have 10 or more dislocation lines in the fringe part, and more preferably 20 or more.

  Dislocation lines possessed by silver halide grains are described in, for example, J.A. F. Hamilton, Photo. Sci. Eng. 11 (1967) 57, and T.W. Shiozawa, J. et al. Soc. Photo. Sci. It can be observed by a direct method using a transmission electron microscope at a low temperature described in Japan 35 (1972) 213. In other words, silver halide grains taken out carefully so as not to apply pressure to the grains from the emulsion are placed on an electron microscope mesh to prevent damage (printout, etc.) due to electron beams. Observation is performed by the transmission method with the sample cooled. At this time, the thicker the particle, the more difficult it is to transmit the electron beam. Therefore, it is possible to observe more clearly using a high acceleration voltage electron microscope. From the particle photograph obtained by such a method, the number and position of dislocation lines in each particle can be known.

  In the silver halide emulsion of the present invention, the silver halide grains corresponding to 50% or more of the projected area of the silver halide grains preferably have 10 or more dislocation lines in the fringe portion.

  In this invention, having a dislocation line in a fringe part means that a dislocation line exists in the vicinity of an outer peripheral part of a tabular grain, a ridge line, or a vertex. Specifically, the fringe part is a line segment connecting the top and the center of the main plane of the tabular grain (the center of gravity when the main plane is regarded as a two-dimensional figure) and the tabular grains are observed perpendicular to the main plane. When the length is L, it refers to the area outside the figure connecting the points whose distance from the center is 0.50 L for each vertex.

  As a method for introducing dislocation lines into silver halide grains, for example, a method of adding an aqueous solution containing iodine ions such as potassium iodide and a water-soluble silver salt solution by a double jet, or a method of adding silver iodide fine particles The dislocation line can be formed at a desired position by using a known method such as a method of adding only a solution containing iodine ions or a method using an iodide ion releasing agent as described in JP-A-6-11781. The origin dislocation can be formed. Among these methods, a method of adding an aqueous solution containing iodine ions and a water-soluble silver salt solution by a double jet, a method of adding silver iodide fine particles, and a method of using an iodine ion releasing agent are preferable. The method of adding is more preferable.

  When introducing dislocation lines into silver halide grains by a method of adding silver iodide fine grains, the average grain diameter of the silver iodide fine grains is preferably 0.08 μm or less, more preferably 0.05 μm or less, and More preferably, it is 03 μm or less. The variation coefficient of the particle diameter of the silver iodide fine particles is preferably 40% or less, more preferably 30% or less, still more preferably 20% or less, and most preferably 10% or less.

  An example of preferable reaction conditions when dislocation lines are introduced into the silver halide emulsion of the present invention by a fine grain emulsion containing silver iodide is shown below. The temperature at which the fine grain emulsion containing silver iodide is added is preferably 30 to 80 ° C, and more preferably 40 to 70 ° C. The amount of the fine grain emulsion containing silver iodide to be added is preferably 1 to 5 mol% with respect to the total silver halide amount after completion of grain growth in terms of silver iodide amount.

  The iodine ion releasing agent referred to in the present invention is a compound that releases iodine ions by a reaction with a base or a nucleophile represented by the following general formula (1).

General formula (1)
R-I
In the general formula (1), R represents a monovalent organic group. R is, for example, an alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, heterocyclic group, acyl group, carbamoyl group, alkyloxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group. It is preferable that R is preferably an organic group having 30 or less carbon atoms, more preferably 20 or less, and still more preferably 10 or less.

  R preferably has a substituent, and the substituent may be further substituted with another substituent. Preferred examples of the substituent include halide, alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, heterocyclic group, acyl group, acyloxy group, carbamoyl group, alkyloxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, Arylsulfonyl group, sulfamoyl group, alkoxy group, aryloxy group, amino group, acylamino group, ureido group, urethane group, sulfonylamino group, sulfinyl group, phosphoric acid amide group, alkylthio group, arylthio group, cyano group, sulfo group, A carboxyl group, a hydroxy group, a nitro group, etc. are mentioned.

  As the iodine ion releasing agent represented by the general formula (1), iodoalkanes, iodoalcohol, iodocarboxylic acid, iodoamide and derivatives thereof are preferable, and iodoamide, iodoalcohol and derivatives thereof are more preferable. More preferred are iodoamides substituted with a (iodoacetamido) benzenesulfonate.

  Specific examples of iodine ion releasing agents that can be preferably used in the present invention are shown below.

  In the present invention, when an iodine ion releasing agent and a nucleophilic reagent are reacted to release iodine ions, examples of the nucleophilic reagent include hydroxide ions, sulfite ions, thiosulfate ions, sulfinates, carboxylates, Ammonia, amines, alcohols, ureas, thioureas, phenols, hydrazines, sulfides, hydroxamic acids, etc. can be used, hydroxide ions, sulfite ions, thiosulfate ions, sulfinates, carboxylates Acid salts, ammonia and amines are preferable, and hydroxide ions and sulfite ions are more preferable.

  An example of preferable reaction conditions when introducing dislocation lines into the silver halide emulsion of the present invention with an iodine ion releasing agent is shown below. The reaction temperature is preferably 30 to 80 ° C, more preferably 40 to 70 ° C. The pAg immediately before dislocation line introduction is preferably 7.0 or more and 10.0 or less, and more preferably 7.5 or more and 9.5 or less. The amount of iodine ion releasing agent to be added is preferably 1 to 5 mol% with respect to the total silver halide amount after the completion of grain growth. The pH during the iodine ion releasing reaction is preferably 7.0 or more and 11.0 or less, and more preferably 8.0 or more and 10.0 or less. When a nucleophilic agent other than hydroxide ions is used, the amount of the nucleophilic agent is preferably 0.25 to 2.0 times the amount of the iodine ion releasing agent, It is more preferable that the ratio is 1.5 times or more and 0.8 times or more and 1.2 times or less.

  The silver halide emulsion of the present invention preferably contains at least one of a polyvalent metal atom ion, a polyvalent metal atom complex or a polyvalent metal atom complex ion inside or on the surface of the silver halide grain.

  Examples of the polyvalent metal atom ions, polyvalent metal atom complexes, or polyvalent metal atom complex ions include Fe, Co, Ni, Ru, Rh, Pd, Re, Os, Ir, Pt, Mg, Al, Ca, and Sc. Ti, V, Cr, Mn, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Mo, Zr, Nb, Cd, In, Sn, Sb, Ba, La, W, Au, Hg, Tl , Pb, Bi, Ce and U, etc., metal atoms, ions, complexes thereof and salts (including complex salts) from the 3rd to 7th periods (most commonly 4th to 6th periods) of the periodic table of elements ) And at least one selected from compounds containing these can be used, but it is preferable to select from a single salt or a metal complex.

When selecting from a metal complex, a 6-coordinate complex, a 5-coordinate complex, a 4-coordinate complex, and a 2-coordinate complex are preferable, and an octahedral 6-coordinate complex and a planar 4-coordinate complex are more preferable. As the ligand constituting the complex, CN ⁻ , CO, NO ₂ ⁻ , 1,10-phenanthroline, 2,2′-bipyridine, SO ₃ ⁻ , ethylenediamine, NH ₃ , pyridine, H ₂ O, NCS ⁻ , NCO ⁻ , O ₃ , SO ₄ ²⁻ , OH ⁻ , N ₃ ⁻ , S ₂ ⁻ , F ⁻ , Cl ⁻ , Br ⁻ , I ^{− and the} like can be used.

  The following known techniques can be applied to incorporate a polyvalent metal into the silver halide emulsion used in the present invention.

  For example, B.I. H. Carroll, "Iridium Sensitization, A Literal Review", Photographic Science and Engineering, Vol. 24, No. 6, November / December 1980, pages 265-267, U.S. Pat. Nos. 1,951,933, 2,628. , 167, 3,687,676, 3,761,267, 3,890,154, 3,901,711, 3,901,713, 4,173,483 No. 4,269,927, No. 4,413,055, No. 4,477,561, No. 4,581,327, No. 4,643,965, No. 4,806,462, 4,828,962, 4,835,093, 4,902,611, 4,981,7 No. 4, No. 4,997,751, No. 5,057,402, No. 5,134,060, No. 5,153,110, No. 5,164,292, No. 5,166,044 5,204,234, 5,166,045, 5,229,263, 5,252,451, 5,252,530, European Patent Application Publication No. 244,184, 488,737, 488,601, 368,304, 405,938, 509,674, 563,946, JP-A-4-125629 The techniques described in Japanese Patent Publication No. WO 93/2390, etc. can be applied. Furthermore, U.S. Pat. Nos. 4,847,191, 4,933,272, 4,981,781, 5,037,732, 937,180, 4,945,035, Nos. 5,112,732, European Patent Application Publication Nos. 509,674 and 513,738, International Publication Nos. 91/10166 and 92/16876, Germany Techniques described in Japanese Patent Nos. 298,320, U.S. Pat. Nos. 5,360,712 and 5,024,931 can be applied.

  Also, Research Disclosure, Volume 367, November 1994, Item 36736, provides an easy-to-understand description of criteria for selecting shallow electron trap dopants. In the present invention, it is preferable to use a hexacoordinate complex ion as shown below among at least one selected from the group consisting of a polyvalent metal atom, its ion and its complex, and its ion.

[ML ₆ ] ⁿ
Where M is a full frontier orbital polyvalent metal ion, preferably Fe ²⁺ , Ru ²⁺ , Os ²⁺ , Co ³⁺ , Rh ³⁺ , Ir ³⁺ , Pd ⁴⁺ or Pt ⁴⁺ ; L ₆ represents a hexacoordinated complex ligand that can be independently selected, provided that at least 4 of the ligands are anionic ligands, and at least 1 of the ligands (preferably at least 3 and optimally at least 4). Is more electronegative than any halide ligand and n represents 2-, 3- or 4-. Specific examples of hexacoordinate complex ions that can provide a shallow electron trap are shown below.

SET-1 [Fe (CN) ₆ ] ^4-
SET-2 [Ru (CN) ₆ ] ^4-
SET-3 [Os (CN) ₆ ] ^4-
SET-4 [Rh (CN) ₆ ] ^3-
SET-5 [Ir (CN) ₆ ] ^3-
SET-6 [Fe (pyrazine) (CN) ₅ ] ^4-
SET-7 [RuCl (CN) ₅ ] ^4-
SET-8 [OsBr (CN) ₅ ] ^4-
SET-9 [RhF (CN) ₅ ] ^3-
SET-10 [IrBr (CN) ₅ ] ^3-
SET-11 [FeCO (CN) ₅ ] ^3-
SET-12 [RuF ₂ (CN) ₄ ] ^4-
SET-13 [OsCl ₂ (CN) ₄ ] ^4-
SET-14 [RhI ₂ (CN) ₄ ] ^3-
SET-15 [IrBr ₂ (CN) ₄ ] ^3-
SET-16 [Ru (CN) ₅ (OCN)] ^4-
SET-17 [Ru (CN) ₅ (N ₃ )] ^4-
SET-18 [Os (CN) ₅ (SCN)] ^4-
SET-19 [Rh (CN) ₅ (SeCN)] ^3-
SET-20 [Ir (CN) ₅ (HOH)] ^2-
SET-21 [Fe (CN) ₃ Cl ₃ ] ^3-
SET-22 [Ru (CO) ₂ (CN) ₄ ] ^3-
SET-23 [Os (CN) Cl ₅ ] ^4-
SET-24 [Co (CN) ₆ ] ^3-
SET-25 [Ir (CN) ₄ (oxalate)] ^3-
SET-26 [In (NCS) ₆ ] ^3-
SET-27 [Ga (NCS) ₆ ] ^3-
In the present invention, when an Ir compound is used, preferred compound examples include K ₂ IrCl ₆ , K ₃ IrCl ₆ , K ₂ IrBr _{6 and the} like.

Specific examples of other polyvalent metal compounds preferably used in the present invention include InCl ₃ , K ₄ Fe (CN) ₆ , K ₃ Fe (CN) ₆ , K ₄ Ru (CN) ₆ , Pb (NO _{3). 2} ) and hydrates thereof.

  In the present invention, at least one selected from the group consisting of polyvalent metal atoms, ions thereof and complexes thereof is used. Ir, Ru, Os, Fe, Rh, Co, In, Ga, Ge, Pd or Pt And the like, and their ions and complexes thereof are particularly preferably used.

  In the present invention, in order for silver halide emulsion to contain at least one selected from the group consisting of polyvalent metal atoms, ions and complexes thereof, and ions, doping is performed during physical ripening of silver halide grains. Alternatively, doping may be performed during the formation process of the silver halide grains (generally during the addition of the water-soluble silver salt and the water-soluble alkali halide), or doping is performed while the silver halide grain formation is temporarily stopped. And then further particle formation may be continued. Further, doping may be performed after the formation of silver halide grains, and at least one selected from the group consisting of polyvalent metal atoms, ions and complexes thereof, and ions may be introduced on the surface of the silver halide grains. Introduction of at least one selected from the group consisting of a polyvalent metal atom, its ion and its complex, and its ion is nucleation and physical ripening in the presence of the polyvalent metal atom, its ion and its complex and its ion, It can be carried out by forming particles.

The concentration of at least one selected from the group consisting of polyvalent metal atoms, ions and complexes thereof, and ions used in the present invention is generally 1 × 10 ⁻⁷ to 1 × 10 6 per mol of silver halide. The range of ^-2 mol is appropriate, more preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mol, and particularly preferably in the range of 2 × 10 ⁻⁶ to 1 × 10 ⁻⁴ mol.

  In the present invention, in order to contain polyvalent metals in the silver halide emulsion, they may be directly dispersed in the emulsion, or those dissolved in a solvent such as water, methanol, ethanol or the like alone or in a mixed solvent. A method of adding an additive to a silver halide emulsion is generally applicable in the art. In addition, at least one selected from the group consisting of polyvalent metal atoms, ions and complexes thereof, and ions may be added to the silver halide emulsion together with the silver halide fine particles, or the polyvalent metal may be added to the silver halide fine particles. A silver halide emulsion containing at least one selected from the group consisting of atoms, ions and complexes thereof, and ions can also be added to the silver halide emulsion.

  Regarding the production method of adding silver halide fine particles containing at least one selected from the group consisting of polyvalent metal atoms, ions and complexes thereof, and ions, a method described in JP-A-11-212201 Can be referred to.

  The silver halide emulsion of the present invention is preferably silver bromide, silver iodobromide or silver iodobromochloride, and particularly preferably silver iodobromide or silver iodobromochloride. The silver chloride content of the host tabular grains is preferably 0 to 50 mol%, more preferably 0 to 30 mol%, and still more preferably 0 to 10 mol%. The host tabular grains in the present invention preferably contain a silver halide emulsion having a plurality of silver halide phases having different silver iodide contents inside the silver halide grains, and the tabular grains have a plurality of phases having different halide compositions. Core-shell type particles made of The core-shell particles preferably have three or more phases with different halide composition ratios, more preferably have four or more phases, and more preferably have five or more phases. The halide composition ratio of adjacent phases is preferably different by 1 mol%, more preferably 3 mol% or more. The silver halide emulsion of the present invention can have an arbitrary halide composition, but is preferably silver iodobromide or silver iodochlorobromide. The adjacent phases of the core-shell type grains preferably differ in silver iodide content by 1 mol% or more, and preferably differ by 3 mol% or more. Further, the volume ratio of each phase of the core-shell type particles to the whole particles is 1% or more, preferably 3% or more, and more preferably 5% or more. The core-shell type particle may have a lower iodine content or a higher iodine content, and may alternately have a phase having a high iodine composition and a phase having a low iodine composition. The outermost layer of the core-shell type grain is preferably a low iodide phase having a silver iodide content of less than 3 mol%, more preferably less than 1 mol%, and particularly preferably no silver iodide. is there.

  In order to avoid structural breakdown of the host grain, it is preferable that the total solubility of the epitaxial portion according to the present invention is higher than the total solubility of silver halide forming the host grain. Therefore, it is preferable that the silver chloride content of the epitaxial portion is higher. Specifically, it is preferably 20% or more, more preferably 50% or more, and still more preferably 80% or more. Since silver chloride forms a face-centered cubic lattice structure like silver bromide, it facilitates epitaxial deposition.

  The silver halide emulsion of the present invention may be reduction sensitized. The reduction sensitization may be carried out by adding a reducing agent to a protective colloid aqueous solution in which silver halide milk grain growth is performed, or by using a protective colloid aqueous solution in which silver halide grain growth is performed under a low pAg condition of pAg 7.0 or less. Or under high pH conditions of pH 7.0 or higher by ripening or grain growth of silver halide grains. These methods may be performed in combination.

  When a reducing agent is used in the present invention, thiourea dioxide, ascorbic acid and its derivatives, stannous salts, borane compounds, hydrazine derivatives, formamidine sulfinic acid, silane compounds, amines and polyamines, sulfites and the like may be used. Preferably, thiourea dioxide, ascorbic acid and its derivatives, and stannous salts are preferably used.

When a reducing agent is used, the addition amount is preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻² mol per mol of silver halide, but more preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻³ mol.

In the present invention, when reduction sensitization is carried out under a low pAg condition where the silver halide grain growth is carried out under a low pAg condition of pAg 7.0 or less, a silver salt is added to the protective colloid aqueous solution. After the appropriate pAg, the silver halide grains are preferably ripened or grown. The silver salt is preferably a water-soluble silver salt, particularly preferably an aqueous solution of silver nitrate. The pAg at the time of aging is suitably 7.0 or less, preferably 2.0 to 5.0 (here, the pAg value is a common logarithm of the reciprocal of Ag ⁺ concentration).

  In the present invention, when reduction sensitization is performed by setting the protective colloid aqueous solution in which silver halide grain growth is performed to a high pH condition of pH 7.0 or higher, an alkaline compound is added to the protective colloid aqueous solution. After a suitable pH, the silver halide grains are ripened or grown. As the alkaline compound, for example, sodium hydroxide, potassium hydroxide, ammonia and the like can be used, but other than ammonium compounds are preferable.

  As a method for adding a reducing agent, a silver salt for reduction ripening, and an alkaline compound, rush addition may be used, or addition over a certain period of time. In this case, constant rate addition or function addition may be performed. Further, the necessary amount may be added in several divided portions. Prior to addition of the soluble silver salt and / or soluble halide into the reaction vessel, it may be present in the reaction vessel, or may be mixed in the soluble halide solution and added together with the halide. Further, the addition may be performed separately from the soluble silver salt and the soluble halide.

In the present invention, an oxidizing agent can be used for deactivation of the reducing agent and other purposes. For example, hydrogen peroxide (water) and its adducts: H ₂ O ₂ , NaBO ₂ , H ₂ O ₂ -3H ₂ O 2NaCO ₃ -3H ₂ O ₂ , Na ₄ P ₂ O ₇ -2H ₂ O ₂ , 2Na ₂ SO ₄ -H ₂ O ₂ -2H ₂ O, etc., peroxy acid salts: K ₂ S ₂ O ₃ , K ₂ C ₂ O ₃ , K ₄ P ₂ O ₃ , K ₂ [Ti (O ₂ ) C ₂ O ₄ ] -3H ₂ O, peracetic acid, ozone, I ₂ , thiosulfonic acid and the like.

In the present invention, the above oxidizing agent can be used for purposes other than deactivation of the reducing agent. The addition amount of the oxidizing agent is affected by the amount of the reducing agent, reduction sensitization conditions, addition timing of the oxidizing agent, addition conditions of the oxidizing agent, etc., but 1 × 10 ⁻³ per mole of the reducing agent used. ˜1 × 10 ⁵ mol is preferred.

  The oxidant may be added anywhere during the silver halide emulsion production process. It can also be added prior to the addition of the reducing agent. As a method for adding an oxidizing agent, a method in which an additive is generally added to a silver halide emulsion can be applied in the art. For example, it can be dissolved in an appropriate organic solvent typified by alcohols or added as an aqueous solution.

Moreover, after adding an oxidizing agent, in order to neutralize an excess oxidizing agent, a reducing substance can also be newly added. These reducing substances are substances that can reduce the oxidizing agent, sulfinic acids, di- and trihydroxybenzenes, chromans, hydrazine and hydrazides, p-phenylenediamines, aldehydes, aminophenols, Examples include enediols, oximes, reducing sugars, phenidones, sulfites, and ascorbic acid derivatives. The amount of the reducing substance ^{is, 1 × 10 -3 ~1 × 10} 3 mol amount per mol of the oxidizing agent to be used is preferred.

  Various methods well known in the art can be used to form silver halide grains in the production of the silver halide emulsion of the present invention. That is, a single jet method, a double jet method, a triple jet method, a silver halide fine particle supply method, or the like can be used in any combination. A method of controlling the pH and pAg in the liquid phase in which silver halide is produced in accordance with the growth rate of silver halide can also be used. The formation of silver halide grains is preferably performed under conditions close to the critical growth rate.

  A seed emulsion can also be used in the production of the silver halide emulsion of the present invention. When a seed emulsion is used, the silver halide grains in the seed emulsion may have a regular crystal structure such as a cube, octahedron, or tetradecahedron, or may have a spherical or plate shape. It may have an irregular crystal form. Any ratio of the [100] plane and the [111] plane can be used in these particles. Further, a composite of these crystal forms or a mixture of grains having various crystal forms may be used. Grains are preferred, with twin silver halide grains having two opposing parallel twin planes being particularly preferred.

  In the present invention, a method known in the art can be applied as a condition for silver halide nucleation and ripening regardless of whether a seed emulsion is used or a seed emulsion is not used.

  In the production of the silver halide emulsion of the present invention, a silver halide solvent known in the art can be used. If possible, the use of the silver halide solvent is preferably used after the nucleation. Should be avoided except for aging.

  For the production of the silver halide emulsion of the present invention, any of an acidic method, a neutral method and an ammonia method can be used, but an acidic method or a neutral method is preferred.

  In the production of the silver halide emulsion of the present invention, halide ions and silver ions may be mixed at the same time, or the other may be mixed while either one is present. Further, in consideration of the critical growth rate of silver halide crystals, halide ions and silver ions can be added sequentially or simultaneously by controlling the pAg and pH in the mixing vessel. You may change the halogen composition of a silver halide grain using the conversion method in the arbitrary steps of silver halide formation.

  In the present invention, when silver halide fine particles are used, the silver halide fine particles may be prepared in advance prior to the preparation of the silver halide grains in the present invention, or prepared in parallel with the preparation of the silver halide grains. May be. When the latter is prepared in parallel, silver halide grains are formed into silver halide grains in the present invention as disclosed in JP-A-1-183417 and 2-44335. Although it can be produced by using a mixer provided outside the reaction vessel, a preparation vessel is provided separately from the mixer, and the silver halide fine particles once prepared in the mixer are used for the halogenation. It is preferable that the silver particles are prepared arbitrarily so as to be suitable for the growth environment in the reaction vessel in which the silver particles are prepared, and then supplied to the reaction vessel.

  As a method for preparing the silver halide fine particles, an acidic and neutral environment (pH ≦ 7) is preferable when the reduction-sensitized fine particles are not intended to be prepared. When preparation of reduction sensitized fine particles is intended, silver halide fine particles may be prepared by appropriately combining the above reduction sensitization techniques.

  In order to produce the silver halide fine particles, a water-soluble silver salt containing silver ions and an aqueous solution containing halide ions may be mixed while appropriately controlling the supersaturation factor. Regarding the control of the supersaturation factor, descriptions in JP-A-63-92942 and JP-A-63-111244 can be referred to.

  The pAg for producing the silver halide fine particles is preferably 3.0 or more, more preferably 5.0 or more, in order to suppress the generation of reduced silver nuclei in the silver halide fine particles themselves. Preferably it is 8.0 or more. The temperature for producing the silver halide fine grains is preferably 50 ° C. or lower, more preferably 40 ° C. or lower, and most preferably 35 ° C. or lower.

  In addition, as the protective colloid used in producing the silver halide fine particles, the above-mentioned protective colloid-forming substances used in the production of silver halide grains in the present invention can be used.

  When the silver halide fine particles are formed at a low temperature, coarsening of the grain size due to Ostwald ripening after the formation of the silver halide fine particles can be suppressed. However, since gelatin tends to coagulate at a low temperature, JP-A-2-166422. It is preferable to use low molecular weight gelatin, a synthetic molecular compound having a protective colloid action on silver halide grains, or a natural polymer compound other than gelatin. The concentration of the protective colloid is preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 3% by mass or more.

  The grain size of the silver halide fine particles is preferably 0.1 μm or less, more preferably 0.05 μm or less.

  The silver halide fine particles can contain the above-described reduction sensitization and optionally metal ions as required.

  In the production of the silver halide emulsion of the present invention, it is preferable that at least a part of the growth process is performed by concentrating the silver halide emulsion by ultrafiltration. When producing a tabular grain-containing emulsion having a high aspect ratio, such as the silver halide emulsion of the present invention, the dilution environment is preferred, and therefore, the ultrafiltration method is preferably applied in order to improve productivity. When a silver halide emulsion is concentrated using an ultrafiltration method, a silver halide emulsion production facility disclosed in JP-A-10-339923 can be preferably used.

  In the present invention, the ultrafiltration concentration mechanism is connected to the reaction vessel with a pipe or the like, and the reaction solution solution is circulated between the reaction vessel and the concentration mechanism at an arbitrary flow rate by the reaction solution circulation mechanism such as a pump. It has a mechanism that can be stopped and further has a device that detects the volume of an aqueous solution containing a salt extracted from the reactant solution by the concentration mechanism, and that can arbitrarily control the amount thereof. Equipment. In addition, other functions can be added as necessary.

  In the present invention, the concentration by ultrafiltration can be preferably applied in the following (1), (2) or a combination of (1) and (2).

  (1) In the step of forming silver halide grains, the volume of the reaction solution is reduced using the above-described concentration mechanism.

  (2) Using the concentration mechanism in the step of forming silver halide grains, an aqueous solution containing a soluble material in an amount equal to or less than the amount of the additive solution for silver halide formation is removed from the reactant solution. Removing, keeping the volume of the reactant solution substantially constant, or inhibiting the increase in volume.

  Further, reducing the volume of the reactant solution by the method (1) before the dislocation line introducing step leads to an improvement in the dislocation line particle ratio, which is a preferable embodiment.

  The ultrafiltration may be performed by interrupting silver halide grain growth at an arbitrary point in the silver halide grain formation process, or may be performed over an arbitrary period while continuing silver halide grain growth, Although it may be carried out a plurality of times in the process of forming silver halide grains, it is preferably carried out before the completion of silver halide grain formation, more preferably during the growth of silver halide grains, or during the growth of silver halide grains. It is preferable.

  Using the ultrafiltration, unnecessary water-soluble salts can be removed and desalted in the process of forming silver halide grains. Further, a reducing agent, an oxidizing agent, a halogen ion releasing compound, a silver halide solvent, a polyvalent metal atom, a polyvalent metal atom ion, a polyvalent metal atom complex or a polyvalent metal atom complex ion added at the time of forming silver halide grains It is possible to remove and deactivate the unreacted materials such as unreacted materials and undoped residues. Furthermore, control of the distance between silver halide grains, control of the growth conditions of silver halide grains used for controlling the pH and pBr of silver halide grains, control of the volume of the reaction solution during the formation of silver halide grains, concentration, etc. Can be implemented.

  Regarding ultrafiltration using membrane separation, Chemical Engineering Handbook, Revised 5th Edition (Chemical Engineering Association, Maruzen), pages 924-954, RD 102, 10208 and 131, 13122, or Japanese Examined Publication No. 59-43727, the same JP-A-62-27008, JP-A-62-113137, JP-A-57-209823, JP-A-59-43727, JP-A-62-113137, JP-A-61-219948, JP-A-62-23035, JP-A-63-40137, Reference can also be made to the methods described in JP-A-63-40039, JP-A-3-140946, JP-A-2-172816, JP-A-2-172817 and JP-A-4-22942. In the present invention, it is preferable to use an apparatus or a method described in JP-A-11-339923 or JP-A-11-231448 for ultrafiltration.

  In the production of the silver halide emulsion of the present invention, the temperature at the time of low-temperature nucleation of the silver halide grains is preferably 40 ° C. or less, more preferably 30 ° C. or less, and further preferably 25 ° C. or less. . The high temperature ripening temperature of the silver halide emulsion of the present invention is preferably 55 ° C. or higher, more preferably 58 ° C. or higher and 90 ° C. or lower, still more preferably 62 ° C. or higher and lower than 77 ° C.

  In the production of the silver halide emulsion of the present invention, one or more desalting steps can be provided during grain formation. The desalting step here refers to washing the silver halide emulsion with water to remove soluble salts. Regarding the desalting step, reference can be made to RD17643, Item II, which is preferably carried out by a flocculation method using an inorganic salt, an anionic surfactant or an anionic polymer (for example, polystyrene sulfonic acid). Can do. The desalting step is preferably performed at a time of less than 10% by volume, and more preferably performed at a time of less than 5% by volume with respect to the volume after the growth of silver halide grains. In the production of the silver halide emulsion of the present invention, desalting is preferably performed after completion of the grain growth step.

  More specifically, in order to remove unnecessary soluble salts from the precipitated product or the emulsion after physical ripening, a noodle water washing method in which gelatin is gelled may be used, and inorganic salts and anionic surfactants may be used. A precipitation method using an anionic polymer (for example, polystyrene sulfonic acid) or a gelatin derivative (for example, acylated gelatin or carbamoylated gelatin) can be used. Moreover, the ultrafiltration using the above-mentioned membrane separation can be preferably used for desalting.

  In nucleation and / or silver halide grain formation using supply of silver halide fine grains in the silver halide emulsion of the present invention, the nucleation and / or silver halide is prepared using a mixer provided outside the reaction vessel. It is preferable to form fine particles. A mixer provided outside the reaction vessel continuously forms the nuclei and / or silver halide fine particles, and continuously supplies the nuclei and / or silver halide fine particles to the reaction vessel. It is preferable that Regarding the continuous process nucleation facility, refer to the descriptions in JP-A-11-338087, JP-A-11-38659, JP-A-2000-75431, JP-A-2000-29155, JP-A-2000-112049, etc. be able to.

  The capacity of the continuous process nucleation facility is preferably small, and it is preferable to simultaneously generate nuclei by connecting a plurality of devices in parallel according to the desired production amount.

  In the present invention, it is preferable to use polyalkylene oxide compounds described in US Pat. No. 5,252,453.

  In the present invention, silver halide grains described in US Pat. Nos. 4,680,256, 4,684,607, 4,680,254, and 4,680,255, etc. It is also possible to use a surface index control agent in

  In the present invention, the [111] face and [100] face ratio on the side surfaces of the tabular grains can be arbitrarily selected, but the [100] face on all side faces is preferably 20% or more, preferably 30% or more. More preferably.

  In the present invention, when reduction sensitization is performed during the formation of silver halide grains, a radical scavenger or other additive that controls the oxidation of silver nuclei can be used.

  In the production of the silver halide emulsion of the present invention, the conditions other than those described above are described in JP-A Nos. 61-6643, 61-14630, 61-112142, 62-157024, and 62-18556. 63-29442, 63-151618, 63-163451, 63-220238, 63-31244, RD38957 I and III, RD40145 XV, etc. Thus, an appropriate condition can be selected.

  When a color light-sensitive material is constituted using the silver halide emulsion of the present invention, a silver halide emulsion that has been subjected to physical ripening, chemical ripening and spectral sensitization is used. Additives used in such a process are described in the IV and V terms of RD38957, the XV term of RD40145, and the like.

  As the known photographic additive that can be used in the present invention, those of RD38957, items II to X, and RD40145, items I to XIII can also be used.

  The silver halide photographic light-sensitive material of the present invention can be provided with red, green and blue light-sensitive silver halide emulsion layers, and each layer can contain a coupler. The coloring dye formed from the coupler contained in each of these layers preferably has a spectral absorption maximum at least 20 nm apart. As the coupler, a cyan coupler, a magenta coupler, or a yellow coupler is preferably used. As a combination of each emulsion layer and a coupler, a yellow coupler and a blue photosensitive layer, a magenta coupler and a green photosensitive layer, and a combination of a cyan coupler and a red photosensitive layer are usually used, but are not limited to these combinations. Other combinations may be used.

  In the present invention, a DIR compound can be used. Specific examples of the DIR compound that can be used include D-1 to D-34 described in JP-A-4-114153. In the present invention, these compounds can be preferably used. Specific examples of DIR compounds that can be used in the present invention include, in addition to the above, for example, U.S. Pat. Nos. 4,234,678, 3,227,554, 3,647,291, and 3,958. , 993, 4,419,886, 3,933,500, JP-A 57-56837, 51-13239, US Pat. No. 2,072,363 , No. 2,070,266, the XIV term of RD40145, and the like.

  Specific examples of couplers that can be used in the present invention are described in Section II of RD40145.

  The additive used in the present invention can be added by the dispersion method described in VIII of paragraph RD40145.

  In the present invention, a known support described in the above-mentioned RD38957 item XV can be used.

  In the silver halide photographic light-sensitive material of the present invention, auxiliary layers such as a filter layer and an intermediate layer described in the item XI of RD38957 can be provided. The silver halide photographic light-sensitive material of the present invention can have various layer configurations such as a normal layer, a reverse layer, and a unit configuration described in RD38957, item XI.

  The silver halide emulsions of the present invention are various silver halide colors of the present invention represented by color negative films for general use or movies, color reversal films for slides or television, color papers, color positive films and color reversal papers. It can be preferably applied to a photographic material.

  In order to develop these silver halide color photographic light-sensitive materials, for example, T.W. H. Theory of the Photographic Process, 4th edition by James, pages 291-334, Journal of the American Chemical Society, Vol. 100, Journal 1 of the American 73rd. Developers known per se described on page (1951) can be used, and development is carried out by the usual methods described in the above-mentioned paragraphs XVII to XX of RD38957 and XXIII of RD40145. be able to.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<< Preparation of Host Tabular Emulsion Em-1 >>
Host tabular emulsion Em-1 was prepared by the following procedure.

[Low temperature nucleation process]
In a reaction vessel, 10.47 L of an aqueous gelatin solution of pBr2.0 containing 70.7 g of gelatin A (alkali-treated inert gelatin, average molecular weight 100,000, methionine content 55 μmol / g gelatin) was kept at 35 ° C. The pH was adjusted to 1.90 using 0.5 mol / L sulfuric acid while stirring at high speed using the mixing stirrer described in JP-A-62-160128. Then, using the double jet method, the following S-1 solution and X-1 solution were added at a constant flow rate over 1 minute to perform nucleation.

Solution S-1: 88.75 ml of 1.25 mol / L silver nitrate aqueous solution
Solution X-1: 88.75 ml of 1.25 mol / L potassium bromide aqueous solution
[Temperature raising process]
After completion of the nucleation step, the following G-1 solution using gelatin A as gelatin was added, and the temperature was raised to 75 ° C. at a rate of 0.6 ° C. per minute. The pBr was continuously controlled from 2.5 to 1.9 using a 1.75 mol / L potassium bromide aqueous solution immediately after the start of temperature increase.

Solution G-1: 1260 ml of an aqueous solution containing 52.0 g of gelatin A and 3.78 ml of a 10% by weight methanol solution of the following surfactant A Surfactant A: [CH (CH ₃ ) CH ₂ O] ₁₇ [ (CH ₂ CH ₂ O) _n COCH ₂ CH ₂ COONa] (n = 5.7 / 2)
[High temperature aging process]
After reaching a temperature rise of 75 ° C., the pH was adjusted to 10.3 and held for 6 minutes and 30 seconds, and then the pH was adjusted to 6.1 using a 56% aqueous acetic acid solution.

[Growth process-1]
After completion of the high temperature ripening step, while maintaining the temperature at 65 ° C., the pH is 6.1 using a 56% aqueous acetic acid solution and the pBr is controlled to 1.8 using a 1.75 mol / L potassium bromide aqueous solution. While using the double jet method, the following S-2 solution and X-2 solution were added while accelerating the flow rate.

Solution S-2: 1.25 mol / L silver nitrate aqueous solution 1130 ml
Solution X-2: 1130 ml of 1.25 mol / L potassium bromide aqueous solution
After the addition of each of the above solutions, desalting and washing with a flocculation method using demol (Kao Atlas) aqueous solution and magnesium sulfate aqueous solution, adding gelatin A, and dispersing well to prepare a seed emulsion did.

[Growth process-2]
Further grain growth was performed using the seed emulsion prepared in the growth step-1. As the stirring device, a mixing stirring device described in JP-A-2-160128 was used. Moreover, when removing a soluble component from a reaction liquid by ultrafiltration, the apparatus of Unexamined-Japanese-Patent No. 10-339923 was used.

  The reaction mother liquor having a volume of 24.0 L by adding 345.8 g of the gelatin A to 0.270 mol of the seed emulsion, 0.12 ml of a 10% by weight methanol solution of the surfactant A and pure water, While maintaining the pAg at 9.4 with a 1.75 mol / L potassium bromide aqueous solution at 60 ° C., the following S-3 solution and the following X-3 solution were added using the double jet method while accelerating the flow rate. At this time, the soluble component of the reaction solution was removed by ultrafiltration to keep the volume of the reaction solution constant.

S-3 solution: 3730 ml of 1.75 mol / L silver nitrate aqueous solution
Solution X-3: 3730 ml of 1.75 mol / L potassium bromide aqueous solution
Subsequently, the following S-4 solution and the following X-5 solution were added while accelerating the addition flow rate.

S-4 solution: 303 ml of 1.75 mol / L silver nitrate aqueous solution
Solution X-4: 303 ml of an aqueous solution containing 1.698 mol / L potassium bromide and 0.053 mol / L potassium iodide
Next, 6.0 L of the soluble component of the reaction solution was removed by ultrafiltration over 25 minutes.

  Subsequently, the following N-3 solution was added over 8 minutes and held for 2 minutes, and then the pAg was adjusted to 9.4 with a 1.75 mol / L potassium bromide aqueous solution.

Liquid N-3: 1733 ml of an aqueous solution containing 0.350 mol of silver iodide fine grain emulsion having an average grain diameter of 0.03 μm and a coefficient of variation of 20% and 51.98 g of gelatin
Subsequently, the following S-5 solution and the following X-5 solution were added while accelerating the addition flow rate.

S-5 solution: 1011 ml of 1.75 mol / L silver nitrate aqueous solution
Solution X-5: aqueous solution 1011 ml containing 1.663 mol / L potassium bromide and 0.088 mol / L potassium iodide
Subsequently, the following S-6 solution and the following X-6 solution were added while accelerating the flow rate.

S-6 solution: 605 ml of 1.75 mol / L silver nitrate aqueous solution
X-6 solution: 605 ml of 1.75 mol / L potassium bromide aqueous solution
After completion of the addition, according to the method described in JP-A-5-72658, an aqueous solution containing 360 g of chemically modified gelatin having a phenylcarbamoylated amino group (modification rate: 95%) was added, and the pH was adjusted to desalinate. Then, an additional gelatin A was added and well dispersed, and the pH was adjusted to 5.8 and the pAg to 8.9 at 40 ° C. Tabular emulsion Em-1 was prepared as described above.

<< Preparation of Host Tabular Emulsion Em-2 >>
In the preparation of the host tabular emulsion Em-1, the temperature was raised to 65 ° C. at a rate of 0.6 ° C. per minute in the temperature raising step, and after reaching the temperature raised to 65 ° C. in the high temperature ripening step, The host tabular emulsion Em-2 was prepared in the same manner except that an aqueous solution containing ammonium nitrate was added so that the ammonium concentration was 0.0129 mol / L, and then adjusted to pH 11.3 by adding an aqueous potassium hydroxide solution. Prepared.

<< Preparation of Host Tabular Emulsion Em-3 >>
A host tabular emulsion Em-3 was prepared in the same manner as in the preparation of the host tabular emulsion Em-2 except that the temperature in the reaction vessel was kept at 20 ° C. in the nucleation step.

<< Preparation of Host Tabular Emulsion Em-4 >>
In the preparation of the above-mentioned host tabular emulsion Em-3, gelatin B (oxidized gelatin, average molecular weight 100,000, methionine content 5 μmol / g in place of gelatin A in the low temperature nucleation step, temperature rise step and growth step −1 In the same manner except that the pAg was kept at 8.8 during the addition of the S-3 solution and the X-3 solution in the growth step-2 using gelatin and calcium content of 41 ppm / g gelatin). Emulsion Em-4 was prepared.

<< Preparation of Host Tabular Emulsion Em-5 >>
In the preparation of the tabular emulsion Em-4, the tabular emulsion Em-5 was prepared in the same manner except that the pAg was maintained at 9.3 during the addition of the S-3 solution and the X-3 solution in the growth step-2. Was prepared.

<< Preparation of Host Tabular Emulsion Em-6 >>
In the preparation of tabular emulsion Em-4, tabular emulsion Em-6 was prepared in the same manner except that pAg was maintained at 9.54 during the addition of S-3 solution and X-3 solution in the growth step-2. Was prepared.

<< Preparation of Host Tabular Emulsion Em-7 >>
In the preparation of the host tabular emulsion Em-4, gelatin E (oxidized gelatin, average molecular weight 15,000, methionine content 5 μmol / g gelatin, calcium content was used instead of gelatin B used in the low-temperature nucleation process. Host tabular emulsion Em-7 was prepared in the same manner except that 41 ppm / g gelatin) was used.

<< Preparation of Host Tabular Emulsion Em-8 >>
In the preparation of the tabular emulsion Em-7, tabular emulsion Em-8 was prepared in the same manner except that the pAg was maintained at 9.3 during the addition of the S-3 solution and the X-3 solution in the growth step-2. Was prepared.

<< Preparation of Host Tabular Emulsion Em-9 >>
In the preparation of the tabular emulsion Em-7, tabular emulsion Em-9 was prepared in the same manner except that the pAg was maintained at 9.54 during the addition of the S-3 solution and the X-3 solution in the growth step-2. Was prepared.

  The host tabular emulsions Em-1 to Em-9 were epitaxially deposited by the following methods a to c.

<< Epitaxial deposition method a >>
Epitaxial deposition was performed by the following method. The addition amount of each material and solution is shown as a ratio with respect to 1 mol of silver in the host tabular grains.

After dissolving the host tabular grain emulsion at 30 ° C. and adding 0.18 mol of an aqueous KI solution, a sensitizing dye described in the ninth layer of the color photosensitive material sample described later was added at a ratio of 85% of the saturated coating amount. Next, silver iodide fine grain emulsion-1 (average of equivalent circle diameter is 0.0088 μm and variation coefficient of equivalent circle diameter distribution is 24%) prepared immediately before addition by a known method such as JP-A-2002-278007. 1.4 mol was added. One minute later, 4.7 mol of an AgNO ₃ aqueous solution and an aqueous halogen solution (containing 2.2 mol of KBr and 7.0 mol of NaCl) were added by a double jet method over 1 minute. Finally, an aqueous KBr solution was added to adjust the silver potential to +40 mV with respect to the saturated calomel electrode.

<< Epitaxial deposition method b >>
Epitaxial deposition was performed by the following method. The addition amount of each material and solution is shown as a ratio with respect to 1 mol of silver in the host tabular grains.

After dissolving the host tabular grain emulsion at 40 ° C. and adding an aqueous silver nitrate solution to adjust the silver potential to +100 mV with respect to the saturated calomel electrode, silver iodide fine grain emulsion-2 (average grain size 0.03 μm, grain size variation coefficient of 20%, silver iodide concentration of 0.3 mol / L, 3% by weight gelatin concentration) was 3 × 10 ^-3 mol per mol. Next, a sensitizing dye described in the ninth layer of the color light-sensitive material sample described later is added at a ratio of 95% of the saturated coating amount, and then 1.5 × 10 ⁻² mol of KBr aqueous solution is added, and then a silver chloride fine grain emulsion -1 (average particle diameter 0.03 μm, coefficient of variation of particle diameter 20%, silver chloride concentration 0.3 mol / L, gelatin concentration 3% by mass), and ripened for 30 minutes. After completion of aging, an aqueous KBr solution was added to adjust the silver potential to +50 mV with respect to the saturated calomel electrode.

<< Epitaxial deposition method c >>
Epitaxial deposition was performed by the following method. The addition amount of each material and solution is shown as a ratio with respect to 1 mol of silver in the host tabular grains.

After the host tabular grain emulsion was dissolved at 30 ° C. and an aqueous silver nitrate solution was added to adjust the silver potential to +88 mV with respect to the saturated calomel electrode, the silver iodide fine grain emulsion-3 (average grain size 0.03 μm, grain size A variation coefficient of 15%, a silver iodide concentration of 0.3 mol / L, and a gelatin concentration of 3% by mass were added at 3 × 10 ⁻³ mol, and ripened for 10 minutes. Next, a sensitizing dye described in the ninth layer of the color light-sensitive material sample described later is added at a ratio of 95% of the saturated coating amount, and then 1.5 × 10 ⁻² mol of KBr aqueous solution is added, and then a silver chloride fine grain emulsion -2 (average particle size 0.03 μm, particle size variation coefficient 15%, silver chloride concentration 0.3 mol / L, gelatin concentration 3 mass%). After raising the temperature to 40 ° C. over 10 minutes, the mixture was aged for 20 minutes. After completion of aging, an aqueous KBr solution was added to adjust the silver potential to +50 mV with respect to the saturated calomel electrode.

  Tables 1 and 2 show the characteristics of the tabular emulsions prepared by epitaxially depositing the host tabular emulsions Em-1 to Em-9 by the methods a to c described above.

<< Chemical sensitization of tabular emulsion >>
Each of the tabular emulsions Em-1a to Em-9c prepared above was heated to 57 ° C., and then the sensitizing dye and trimethyl compound described in the ninth layer of the color light-sensitive material sample described later at a silver potential of 50 mV and pH 6.5. Furylphosphine selenide, chloroauric acid, potassium thiocyanate, sodium thiosulfate pentahydrate are added to ripen for optimum sensitivity, and at the end of ripening 6-methyl-4-hydroxy-1,3,3a , 7-tetrazaindene, compound (1-6) described in JP-A-2002-90957, silver iodide fine particles were added, the temperature was lowered, and the mixture was cooled and solidified to effect color sensitization and chemical sensitization. .

<< Preparation of silver halide photographic material >>
Samples 101 to 111, which are silver halide photographic light-sensitive materials, are formed by sequentially forming each layer having the composition shown in Tables 2 to 4 on the triacetyl cellulose film support having a thickness of 120 μm with an undercoat layer from the support side. Was made. In addition, unless otherwise indicated, the addition amount of each raw material described in the table is expressed in grams per 1 m ² . Silver halide and colloidal silver are shown in terms of silver amount, and sensitizing dye (shown as SD) is shown in moles per mole of silver.

  Here, as the silver iodobromide emulsion G described in the ninth layer below, the above-prepared color sensitized and chemically sensitized tabular emulsions Em-1a to Em-9c were used, respectively, to prepare samples 101 to 111. did. The coating liquid for each constituent layer was applied within 1 hour after the addition of each additive listed in the table was completed.

  Table 6 shows the characteristics of the silver iodobromide emulsion used in the preparation of the above samples.

  Each emulsion other than Emulsion M listed in Table 6 was subjected to chemical sensitization so that the fog and sensitivity relationship would be optimized according to a conventional method after sensitizing dyes listed in Tables 3 to 5 were added and ripened. What was done was used.

  In addition to the above-mentioned compositions in the preparation of each sample, OIL-3, coating aids SU-1, SU-2, SU-3, dispersion aid SU-4, viscosity modifier V-1, stable Agent ST-1, two types of polyvinylpyrrolidone (AF-1, AF-2), weight average molecular weight: 10,000 and weight average molecular weight: 100,000, calcium chloride, inhibitors AF-3, AF-4, AF -5, AF-6, AF-7, hardener H-1 and preservative Ase-1 were added. The structure of the compound used for the sample is shown below.

<< Exposure and development process >>
Each sample prepared as described above was subjected to the following exposure and development processing. Exposure is performed for 1/200 second using a light source with a color temperature of 5400 ° K., and wedge exposure is performed via an optical wedge, and then the development processing steps described in paragraphs [0220] to [0227] of JP-A-10-123651 The color development processing was performed according to the above.

<Each characteristic evaluation>
(Measurement of sensitivity)
Next, each developed sample is measured for magenta density with a densitometer manufactured by X-rite, a characteristic curve consisting of density D-exposure amount LogE is created, and the exposure dose giving an optical density of minimum density of magenta density + 0.20. Was defined as sensitivity, and relative sensitivity with the sensitivity of sample 101 as 100 was determined.

(Measurement of gradation)
In the above characteristic curve, S1 is the reciprocal of the exposure amount giving the minimum density of magenta density + 0.10 and S2, and S2 is the reciprocal of the exposure amount giving the optical density of minimum density + 0.30. .20 / (S1-S2) is defined as the gradation, and is shown as a relative gradation where the gradation of the sample 101 is 100.

(Evaluation of graininess)
The RMS value at a position giving an optical density of the minimum magenta density + 0.20 of each sample was measured using green light, and the RMS value of the sample 101 was expressed as a relative value of 100. The RMS value was measured by scanning the measurement target portion of each sample with a microdensitometer (slit width 10 μm, slit length 180 μm) equipped with Eastman Kodak's Latten filter (W-99). It was determined as a standard deviation of density values of several thousand or more.

  Table 7 shows the evaluation results obtained as described above.

  As is apparent from Table 7, it can be seen that the sample using the silver halide emulsion of the present invention is excellent in all the characteristics of sensitivity, gradation and graininess as compared with the comparative example. In particular, the improvement in graininess is remarkable as compared with the emulsion of Example 2 described later.

Example 2
The host tabular emulsions Em-1 to Em-9 described in Example 1 were epitaxially deposited by the method a described in Example 1 and the following methods d and e.

<< Epitaxial deposition method d >>
Epitaxial deposition was performed by the following method. The amount of each material and solution added is the ratio of the host tabular grain to the silver amount of 1 mol of the host tabular grain. The host tabular grain emulsion is dissolved at 40 ° C. After adjusting to −50 mV, 3 × silver iodide fine grain emulsion-4 (average grain size 0.07 μm, grain size variation coefficient 20%, silver iodide concentration 0.3 mol / L, gelatin concentration 3 mass%) ^10-3 mol was added and aged for 10 minutes. Next, an aqueous silver nitrate solution was added to adjust the silver potential to +50 mV with respect to the saturated calomel electrode, and then a sensitizing dye described in the ninth layer of the color photosensitive material sample described later was added at a ratio of 85% of the saturated coating amount, Thereafter, silver chloride fine grain emulsion-1 (average grain size 0.03 μm, grain size variation coefficient 20%, silver chloride concentration 0.3 mol / L, gelatin concentration 3 mass%) was added and ripened for 30 minutes. After completion of ripening, an aqueous KBr solution or an aqueous silver nitrate solution was added again to adjust the silver potential to +50 mV with respect to the saturated calomel electrode.

<Epitaxial deposition method e>
Epitaxial deposition was performed by the following method. The addition amount of each material and solution is shown as a ratio with respect to 1 mol of silver in the host tabular grains.

After dissolving the host tabular grain emulsion at 30 ° C. and adding an aqueous KBr solution to adjust the silver potential to −57 mV with respect to the saturated calomel electrode, silver iodide fine grain emulsion-5 (average grain size 0.07 μm, grain size) 3 × 10 ⁻³ mol) was added and the mixture was aged for 30 minutes. Next, after adding an aqueous silver nitrate solution to adjust the silver potential to +40 mV with respect to the saturated calomel electrode, a sensitizing dye described in the ninth layer of the color photosensitive material sample described later is added at a ratio of 85% of the saturated coating amount, Thereafter, silver chloride fine grain emulsion-2 (average grain size 0.03 μm, grain size variation coefficient 15%, silver chloride concentration 0.3 mol / L, gelatin concentration 3 mass%) was added. After raising the temperature to 40 ° C. over 10 minutes, the mixture was aged for 20 minutes. After completion of ripening, an aqueous KBr solution or an aqueous silver nitrate solution was added again to adjust the silver potential to +50 mV with respect to the saturated calomel electrode.

  Tables 8 and 9 show the characteristics of tabular emulsions prepared by epitaxially depositing the host tabular emulsions Em-1 to Em-9 by the methods a and d and e described above in Example 1.

  The above prepared tabular emulsions Em-1a to Em-9e are chemically sensitized by the method described in Example 1 to produce silver halide photographic materials (samples 101 and 201 to 210). Development processing was performed. Table 10 shows the evaluation results thus obtained. Note that the RMS value indicating sensitivity, gradation, and graininess is a relative value with the sample 101 as 100.

  As can be seen from Table 10, the sample using the silver halide emulsion of the present invention is excellent in all characteristics of sensitivity, gradation and graininess as compared with the comparative example. In particular, the improvement in sensitivity is remarkable as compared with the emulsion of Example 1.

Claims (13)

In a silver halide emulsion containing a dispersion medium and silver halide grains, 50% or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following conditions i) to iii): Silver halide emulsion.
i) Hexagonal tabular grains having a [111] plane as a main plane and a ratio of the maximum side length to the minimum side length as viewed from a direction perpendicular to the main plane is 2.0 or less
ii) Using the above hexagonal tabular grain as a host, it has an epitaxial junction at at least one of the hexagonal apexes.
iii) When the spherical equivalent particle diameter of the epitaxial junction is d (μm), 0.60 × n ≦ d ≦ 1.40 × n (n is a constant of two digits after the decimal point of 0.10 to 2.00) 2. The silver halide emulsion according to claim 1, wherein an inter-grain variation coefficient of a spherical equivalent particle diameter d of the epitaxial junction is 40% or less. In a silver halide emulsion containing a dispersion medium and silver halide grains, 50% or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following conditions i) to iii): Silver halide emulsion.
i) Hexagonal tabular grains having a [111] plane as a main plane and a ratio of the maximum side length to the minimum side length as viewed from a direction perpendicular to the main plane is 2.0 or less
ii) Using the above hexagonal tabular grain as a host, it has an epitaxial junction at at least one of the hexagonal apexes.
iii) The projected area ratio of the epitaxial junction to the host is P, and 0.60 × q ≦ P ≦ 1.40 × q (q is a constant of 3 digits after the decimal point of 0.020 to 0.400) 4. The silver halide emulsion according to claim 3, wherein the inter-grain variation coefficient of the projected area ratio P to the host of the epitaxial junction is 40% or less. 4 or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following formula, where R is the diameter of the hexagonal tabular grain converted to a circle. The silver halide emulsion as described in the item.
0.75 × m ≦ R ≦ 1.25 × m (m is a constant of two digits after the decimal point of 0.50 to 6.00) 6. The silver halide emulsion according to claim 5, wherein the hexagonal tabular grains have an inter-grain variation coefficient of a circle equivalent diameter R of 25% or less. The aspect ratio of the hexagonal tabular grains is A, and 50% or more of the total projected area of the silver halide contained in the silver halide emulsion satisfies the following formula. A silver halide emulsion described in 1.
0.70 × k ≦ A ≦ 1.30 × k (k is a constant of one digit after the decimal point of 5.0 to 40.0) The silver halide emulsion according to claim 7, wherein the hexagonal tabular grain has an inter-grain variation coefficient of an aspect ratio A of 30% or less. The silver chloride content in the epitaxial junction is _XCl mol%, and 50% or more of the total projected area of silver halide contained in the silver halide emulsion satisfies the following formula: The silver halide emulsion according to any one of the above.
0.70 × l ≦ X _Cl ≦ 1.30 × l (l is a constant of one digit after the decimal point of 7.0 to 95.0) The silver halide emulsion according to claim 9, intergranular variation coefficient of the epitaxial junction silver chloride content in section X _Cl is equal to or less than 30%. The silver iodide content in the epitaxial junction as X _I mol%, claims 1 to 10 or 50 percent of the total projected area of the silver halide contained in the silver halide emulsion is characterized by satisfying the following expression The silver halide emulsion according to any one of the above.
0.60 × j ≦ X _I ≦ 1.40 × j (j is a constant of one decimal place from 1.0 to 40.0) The silver halide emulsion of claim 11, the inter-grain variation coefficient of the silver iodide content X _I in the epitaxial junction portion is equal to or less than 40%. A silver halide emulsion having a silver halide emulsion layer on a support, wherein at least one of the silver halide emulsion layers is a silver halide emulsion according to any one of claims 1 to 12. Silver photographic material.