JPH05216150A - Photosensitive silver halide emulsion - Google Patents

Abstract

PURPOSE:To provide a photosensitive silver halide emulsion excellent in sensitivity, graininess, reducing fogging, and covering power. CONSTITUTION:A silver halide emulsion applied to a base in a monodisperse and oriented fashion contains substantially spherical photosensitive silver iodobromide core/shell particles for which the diffraction line intensity of [220] surface is detected by not less than 8% of the diffraction line intensity of [111] surface in the powder method X-ray diffraction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive silver halide emulsion, and more particularly to improvement of sensitivity, graininess, fog and covering power of the emulsion.

[0002]

BACKGROUND OF THE INVENTION In recent years, the demand for silver halide emulsions for photography has become more and more stringent, and it is increasingly required for photographic performance such as high sensitivity, excellent graininess, high sharpness, low fog density and sufficiently high optical density. High standards are being demanded.

In response to these demands, a silver iodobromide emulsion containing 0 to 10 mol% of iodine is well known as a high-sensitivity emulsion. As a method for preparing these emulsions,
Conventionally, pH conditions such as ammonia method, neutral method, acidic method, pA
As a method for controlling the g condition and a mixing method, a single jet method, a double jet method, etc. are known. Based on these known techniques, further sensitivity enhancement, improvement of graininess,
For the purpose of achieving high sharpness and low fog, precise technical means have been studied and put into practical use. In the silver iodobromide emulsion mainly targeted in the present invention, the crystal habit,
Emulsions having controlled grain size distribution as well as iodine concentration distribution within individual silver halide grains have been studied.

The most legitimate method for achieving photographic performance such as high sensitivity, excellent graininess, high sharpness, low fog density and sufficiently high covering power as described above is the quantum efficiency of silver halide. Is to improve. For this purpose, knowledge of solid state physics, etc. is being actively incorporated. A study that theoretically calculated this quantum efficiency and considered the effect of the particle size distribution is, for example, the 1980 Tokyo Symposium proceedings on the progress of photography, "Interactions".
Between Light and Materials Four
Photographic Applications ”on page 91. This study predicts that narrowing the grain size distribution to produce monodisperse emulsions is effective in improving quantum efficiency. In order to achieve sensitization of a silver halide emulsion, in a process called chemical sensitization described in detail later, in order to efficiently achieve high sensitivity while maintaining low fog, monodispersion The reasoning that emulsions would be advantageous would also make sense.

However, in the actual emulsion system, few monodisperse emulsions are used alone or as a mixture, and it can be said that there is no negative-type high-speed emulsion. The reason for this is that even if a monodisperse emulsion is prepared by a generally known method and subjected to regular chemical sensitization, the sensitization cannot be achieved, and it is inferior to the commonly used polydisperse emulsion. This is because it is widely known in the art to bring about a result.

In order to industrially produce a monodisperse emulsion, the silver ion theoretically determined under the strict control of pAg and pH as described in JP-A-54-48521, Control of the feed rate of halogen ions to the reaction system and sufficient stirring conditions are required. The silver halide emulsion produced under these conditions has a so-called cubic shape, an octahedron shape, or a 14-sided shape having various proportions of (100) planes and (111) planes. Consists of normal crystal grains. We have produced monodisperse emulsions of these shapes and subjected them to the commonly known chemical sensitizations, but certainly equal or rather inferior results to the polydisperse emulsions commonly used in the industry. I only got it.

[0007]

OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide a light-sensitive silver halide emulsion excellent in sensitivity, graininess, fog and covering power.

[0008]

The object of the present invention is to provide a [220] plane diffraction line intensity with respect to a [111] plane diffraction line intensity in powder method Xray diffraction of a silver halide emulsion which is monodisperse and is oriented and coated on a substrate. Of at least 8% is detected, and the light-sensitive silver halide emulsion is characterized by containing light-sensitive silver iodobromide core / shell type grains which are substantially spherical.

[0009] As a result of earnest researches for obtaining a high sensitivity of a monodisperse emulsion, which has been theoretically predicted but the expected result has not been obtained, a substantially spherical monodisperse emulsion was obtained. A method for producing a dispersion emulsion was found, and it was discovered that the spherical monodisperse emulsion exhibits the expected effect and that the sensitivity, graininess, fog performance and covering power are dramatically improved as compared with the polydisperse emulsion. The present invention was completed.

Spherical grains and potato-shaped grains of polydisperse emulsions are generally well known. However, monodisperse spherical particles have not been known at all. The reason for this is that in order to obtain the spherical grains, a reaction involving dissolution of silver halide grains, called Ostwald ripening, is necessary, and this reaction conflicts with the conditions for producing a monodisperse emulsion. It is described in, for example, JP-A-54-48521 that it is the direction to do so.

It is predicted from the solid-state physical theory that the surface of silver halide grains has various great influences on photographic performance.
For example, “Basics of Photographic Engineering: Silver Salt Photography” edited by The Photographic Society of Japan
The description is given on page 52. However, no particular mention is made of the optimum surface properties that are effective for photographic performance.

We have produced a normal crystal monodisperse emulsion by the method described in JP-A-54-48521, and then controlled by a suitable silver halide solvent such as rhodan salt, ammonia or tetramethylthiourea. It was found that a spherical monodisperse emulsion can be obtained by processing under the above conditions, and by subjecting the emulsion to generally known sulfur sensitization, gold sensitization, selenium sensitization, etc., an unexpectedly large effect can be obtained. I found that I could get it.

In the present invention, "the diffraction line intensity of the [220] plane is 8% with respect to the diffraction line intensity of the [111] plane in powder method Xray diffraction of a silver halide emulsion which is monodisperse and is oriented and coated on a substrate. The above-mentioned "substantially spherical photosensitive silver halide grain" is a particle group consisting of substantially spherical photosensitive silver halide particles, and the variation in the particle size of the particle group. Has a particle size distribution of a certain ratio or less with respect to the average particle size as shown below. An emulsion composed of a group of photosensitive silver halide grains having uniform grain morphology and a small variation in grain size (hereinafter, referred to as
Since the particle size distribution of (monodisperse emulsion) is almost normal distribution, the standard deviation can be easily obtained, and the size of the distribution can be calculated by the relational expression (standard deviation / average grain size) × 100 = width of distribution (%). By definition, the monodisperse and substantially spherical silver halide grains according to the invention have a broad distribution of 15% or less, preferably 10% or less.

A grain group consisting of substantially spherical photosensitive silver halide grains means that the grains are aligned on a substrate as described in Bretan of the Society of Scientific Photography of Japan, Vol. 13, p. In the powder method Xray diffraction of the emulsion coated by
A group of silver halide grains contained in an emulsion in which the intensity of the diffraction line of the [220] plane is 8% or more, preferably 15% or more, relative to the intensity of the diffraction line of the [111] plane.

To produce the silver halide emulsion of the present invention, a cubic grain formed from the [I00] plane, a regular octahedral grain formed from the [111] plane, or a [I00] plane is prepared by a known method. A normal-crystal monodisperse silver halide emulsion of tetradecahedral grains formed of (111) faces is prepared, and the emulsion is prepared at any time from the time when the silver halide grains of the emulsion are formed to the start of chemical ripening. It is preferable to add a silver halide solvent, for example, a rhodanate salt, ammonia, a thiourea derivative (for example, tetramethylthiourea), a thioether, etc. to the emulsion for processing.

As a method for producing a monodisperse emulsion, a silver halide emulsion in which a core grain is a monodisperse silver halide grain is used, and the shell is coated on the core grain so that the shell has a substantially uniform thickness. A method of obtaining a uniform monodisperse silver halide emulsion is preferred.

The silver halide composition of the monodisperse and substantially spherical photosensitive silver halide grains of the present invention is arbitrary within the range where a monodisperse emulsion can be obtained. By making the dispersed normal crystal particles spherical, the effect of the present invention is imparted as compared with the normal crystal particles as they are.

However, from the viewpoint of high sensitivity, the silver halide composition is silver iodobromide containing 0.1 to 10 mol% of silver iodide, and particularly silver iodobromide containing 2 to 8 mol% of silver iodide. It is preferable that

The photosensitive silver halide emulsion of the present invention may be doped with various metal salts or metal complex salts at the time of silver halide precipitation formation, during grain growth or after grain growth. For example, metal salts or complex salts of gold, platinum, palladium, iridium, rhodium, bismuth, cadmium, copper and the like and combinations thereof can be applied.

Further, excess halogen compounds generated during the preparation of the emulsion of the present invention, or salts and compounds of by-produced or unnecessary nitrates, ammonia and the like may be removed. As a removing method, a Nudel water washing method, a dialysis method, a coagulation precipitation method or the like which is commonly used in general emulsions can be appropriately used.

The emulsion of the present invention can be subjected to various chemical sensitization methods which are applied to general emulsions. That is, a noble metal sensitizer such as active gelatin, water-soluble gold salt, water-soluble platinum salt, water-soluble palladium salt, water-soluble rhodium salt, water-soluble iridium salt; sulfur sensitizer; selenium sensitizer; polyamine,
The chemical sensitization can be performed alone or in combination with a chemical sensitizer such as a reduction sensitizer such as stannous chloride. Further, this silver halide can be optically sensitized to a desired wavelength range. The optical sensitizing method of the emulsion of the present invention is not particularly limited, and examples thereof include a cyanine dye such as a zeromethine dye, a monomethine dye, a dimethine dye, and a trimethine dye, or an optical sensitizer such as a merocyanine dye alone or in combination (for example, super (Color sensitization) Optical sensitization is possible. For these technologies, U.S. Pat.Nos. 2,688,545 and 2,912,3
No. 29, No. 3,397,060, No. 3,615,635, No. 3,628,964
No., British Patents 1,195,302, 1,242,588, 1,293,86
No. 2, West German patent (OLS) 2,030,326, 2,121,780
No. 43-4936 and 44-14030. The selection can be arbitrarily determined depending on the wavelength region to be sensitized, sensitivity, etc., according to the purpose and application of the light-sensitive material.

The monodisperse silver halide emulsion of the present invention comprises
Even if the particle size distribution is used as it is, or two or more kinds of monodisperse emulsions having different average particle sizes are blended at any time after the grain formation to prepare a predetermined gradation, and then used. May be. However, in addition to the above, those containing silver halide grains other than those of the present invention are included to the extent that the effects of the present invention are not impaired.

The emulsion of the present invention may contain various additives usually used depending on the purpose. Examples of these additives include azaindenes, triazoles, tetrazoles, imidazolium salts, tetrazolium salts,
Stabilizers such as polyhydroxy compounds and antifoggants; aldehyde-based, aziridine-based, isoxazole-based, vinylsulfone-based, acryloyl-based, arpegimide-based, maleimide-based, methanesulfonic acid ester-based, triazine-based hardening agents; benzyl Development accelerators such as alcohols and polyoxyethylene compounds; image stabilizers of chroman type, clamane type, bisphenol type and phosphite type; lubricants such as wax, glyceride of higher fatty acid, higher alcohol ester of higher fatty acid, etc. Is mentioned. Also,
Anionic, cationic, nonionic or amphoteric materials such as coating aids as surfactants, improvers of permeability to processing solutions, defoamers or materials for controlling various physical properties of photosensitive materials. Various types can be used. As antistatic agent, diacetyl cellulose, styrene perfluoroalkylridium maleate copolymer,
Alkaline salts of the reaction product of styrene-maleic anhydride copolymer and p-aminobenzenesulfonic acid are effective. Examples of matting agents include methyl polymethacrylate, polystyrene, and alkali-soluble polymers. It is also possible to use colloidal silicon oxide. Examples of the latex added to improve the physical properties of the film include copolymers of acrylic acid ester, vinyl ester and the like with other monomers having an ethylene group. Examples of the gelatin plasticizer include glycerin and glycol compounds, and examples of the thickener include styrene-sodium maleate copolymer and alkyl vinyl ether-maleic acid copolymer.

The support of the light-sensitive material prepared by using the emulsion of the present invention prepared as described above includes, for example, baryta paper, polyethylene-coated paper, polypropylene synthetic paper, glass paper, cellulose acetate, cellulose nitrate. , Polyvinyl acetal, polypropylene, polyester films such as polyethylene terephthalate, polystyrene, etc., and these supports are appropriately selected according to the intended use of each silver halide photographic light-sensitive material.

These supports are subjected to undercoating processing if necessary.

The emulsion of the present invention is used for general black and white, X ray,
It can be effectively applied to light-sensitive materials for various uses such as color, infrared, micro, silver dye bleaching, reversal, and diffusion transfer.

In order to obtain a broad latitude characteristic with the emulsion of the present invention, at least two monodisperse emulsions having different average particle diameters or different sensitivities are mixed, or multilayer coating is performed. As a result, it is possible to obtain a light-sensitive material having a large latitude, a small coating amount of silver due to the characteristics of the emulsion of the present invention, and a high covering power, that is, a high optical density.

In order to apply the emulsion of the present invention to a color light-sensitive material, the emulsion of the present invention adjusted to have a red-sensitivity, a green-sensitivity and a blue-sensitivity may contain a combination of cyan, magenta and yellow couplers. The method and material used for the light-sensitive material for use may be applied, and as the yellow coupler, a known closed ketomethylene type coupler can be used. Among these, benzoylacetanilide compounds and pivaloylacetanilide compounds are effective.

Examples of magenta couplers include pyrazolone compounds, indazolone compounds, cyanoacetyl compounds,
As the cyan coupler, a phenol compound, a naphthol compound or the like can be used.

The light-sensitive material prepared by using the emulsion of the present invention can be subjected to development processing by a known method usually used after exposure.

The black-and-white developing solution is an alkaline solution containing a developing agent such as hydroxybenzenes, aminophenols and aminobenzenes, and other alkali metal sulfites, carbonates, bisulfites, bromides and iodides. Can be included. When the light-sensitive material is for color, color development can be carried out by a commonly used color development method. In the reversal method, it is first developed with a black-and-white negative developing solution and then exposed to white light, or treated with a bath containing a fog agent,
Further, color development is performed with an alkali developing solution containing a color developing agent. The processing method is not particularly limited and any processing method can be applied. For example, as a typical example, after color development, a bleach-fixing process is carried out, followed by washing with water, if necessary, a stabilizing process, or after color development. ,
It is possible to apply a system in which bleaching and fixing are performed separately, and if necessary, further washing with water and stabilizing treatment are performed.

[0032]

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

Example 1 The following three types of monodisperse cubic emulsions a and b having an average particle size of 1.2 μ and consisting of silver iodobromide containing 1.5 mol% of silver iodide, and the method described in JP-A-54-48521. A monodisperse cubic crystal emulsion c made of pure silver bromide having an average grain size of 1.2 μ was prepared. Here, a is a silver iodobromide emulsion having a silver bromide shell (having a thickness of 0.2 μ), and b is a silver iodobromide emulsion having no silver bromide shell. After that, each emulsion was divided into two, and one of them was subjected to desalting operation to remove excess salt to obtain a comparative emulsion. This emulsion is named a, b and c. To the other emulsion, 100 mg / l of rhodammone was added, and the mixture was stirred at 60 ° C. for 30 minutes and processed, and then desalted in the same manner as the comparative emulsion. This emulsion is a spherical monodisperse emulsion and is named A, B and C, respectively. Each of the above 6 emulsions was subjected to gold sensitization and sulfur sensitization, which were considered to be optimal, and after the ripening was completed, 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added thereto. After adding general photographic additives such as extenders, thickeners, hardeners, etc. to the emulsion, double-sided so that the Ag amount becomes 50 mg / 100 cm ² on the subbed polyethylene terephthalate film base. Sample Nos. 1 to 6 were prepared by coating and drying.

Sensitometry of these samples was performed as follows. The exposure was carried out using a light source having a color temperature of 5,400 ° K for 1/50 seconds through an optical wedge. The exposure was 3.2 CMS on each side. Development was carried out at 35 ° C. for 30 seconds with the following developer.

Developer: Anhydrous sodium sulfite 70 g Hydroquinone 10 g Boric anhydride 1 g Sodium carbonate monohydrate 20 g 1-Phenyl-3-pyrazolidone 0.35 g Sodium hydroxide 5 g 5-Methyl-benzotriazole 0.05 g Potassium bromide 5 g Glutaraldehyde bisulfite 15g Glacial acetic acid 8g Add water to make 1 liter.

The results are shown in Table 1. Sensitivity is the sensitivity of sample 1
It was expressed as relative sensitivity as 100.

[0037]

[Table 1]

As is apparent from the above results, the spherical monodisperse emulsion A of the present invention is a comparative monodisperse emulsion a, b, c, respectively.
Excellent in sensitizing effect for B and C.

Example 2 An octahedral monodisperse emulsion was prepared in the same manner as in Example 1 while keeping pAg at 9.5. The mol% of silver iodide was a 4 mol% silver iodobromide emulsion, and the shell thickness of silver bromide was 0.2 μm, similar to the emulsion a in Example 1. This emulsion is designated as d.

A portion of d was divided, tetramethylthiourea was added so as to have a concentration of 50 mg / l, and the mixture was stirred at 60 ° C. for 30 minutes and then subjected to ordinary desalting treatment. This emulsion was a spherical monodisperse emulsion. This emulsion is designated as D. Optimal sulfur sensitization and gold sensitization were respectively applied to these two emulsions, and the ortho sensitizing dye was used to make them green-sensitive. Then as a coupler, 1- (2,4,6-trichlorophenyl) -3- [3- (2,4-di-t-
Amylphenoxyacetamido) benzamide] -5-pyrazolone 15 g ethyl acetate 30 ml and dibutyl phthalate 15
It was dissolved in 10 ml of 10% aqueous solution of alkanol B (alkylnaphthalene sulfonate, manufactured by DuPont) and 200 ml of 5% gelatin aqueous solution, and the mixture was emulsified and dispersed by a colloid mill. Samples No. 7 and No. 8 applied on the base were prepared.

[0041]

[Table 2]

The samples shown in Table 2 above were subjected to wedge exposure, color development was carried out at 38 ° C. for 3 minutes using a color developer having the following composition, bleach-fixing was carried out, and then washed with water to measure sensitivity and fogging. The results are shown in Table 3.

(Color developer composition) 4-amino-3-methyl-N-ethyl-N- (β-hydroxyethyl) -aniline / sulfate 4.75 g anhydrous sodium sulfite 4.25 g hydroxylamine 1/2 sulfate 2.0 g Anhydrous potassium carbonate 37.5 g Sodium bromide 1.3 g Nitriloacetic acid trisodium (monohydrate) 2.5 g Potassium hydroxide 1.0 g Water is added to make 1 liter and the pH is adjusted to 10.0 with potassium hydroxide.

[0044]

[Table 3]

As is clear from Table 3, the spherical monodisperse emulsion of the present invention is remarkably excellent in sensitizing effect as compared with the octahedral monodisperse emulsion. The effect of subjecting the octahedral emulsion to the surface treatment of the present invention is greater than the effect of the surface treatment of the cubic emulsion shown in Example 1.

Example 3 An emulsion having core / shell type grains consisting of a core made of silver iodobromide containing 2 mol% of silver iodide and a shell made of silver bromide was prepared according to the conventional method described in JP-B-51-1417. Created by law. The average grain size was 1.2μ and the distribution was 35% (this emulsion is designated as E). The grain type of this emulsion was a potato type polydisperse emulsion.

This emulsion was subjected to ripening, addition of additives, coating and drying in the same manner as in Example 1 to prepare Sample 9.

On the other hand, a core of silver iodobromide containing 2 mol of silver iodide and an average thickness of 0.
Two types of cubic monodisperse emulsions having an average grain size of 1.0μ and 0.5μ having a 03μ silver bromide shell were prepared, and the distribution of each was 8% by the method of Example 1. Rhodan Ammon was processed. As a result, average particle size 1.0
Monodisperse spherical emulsions F and G with μ, 0.5μ distribution of 8% and 8.5%
After obtaining the above two kinds, each emulsion was subjected to optimum chemical ripening. These F and G emulsions are mixed in a silver halide weight ratio of F: G.
= Emulsion H prepared by mixing at a ratio of 7: 3 was prepared in the same manner as described in Example 1 and coated to prepare a sample.
Got 10.

Sensitometry and development processing were carried out in the same manner as in Example 1. The results are shown in Table 4.

[0050]

[Table 4]

As is clear from Table 4, among the two samples having almost the same sensitivity and latitude, the sample No. 10 of the present invention is significantly superior in covering power and graininess.

[0052]

According to the present invention, a photosensitive silver halide emulsion having excellent sensitivity, graininess, fog and covering power is provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masatoshi Iwata 1st Sakura-cho, Hino City, Tokyo Konica Stock Company In-house

Claims (1)

[Claims] 1. A [111] in a powder method Xray diffraction of a silver halide emulsion which is monodispersed and orientated and coated on a substrate.
Diffraction line intensity of [220] plane is 8% of diffraction line intensity of plane
A light-sensitive silver halide emulsion containing the substantially spherical light-sensitive silver iodobromide core / shell type particles detected as described above.