JPS5814829A - Silver halide photosensitive material - Google Patents

Abstract

PURPOSE:To obtain a silver halide photosensitive material small in amount of silver to be used, and superior in graininess and sharpness, by forming silver halide grains in an emulsion layer so that they have >=2 peaks in the grain size distribution curve and the grains of the highest peak have octahedral crystals in a monodispersed emulsion. CONSTITUTION:A silver halide emulsion layer consisting of >=2 kinds of silver halide emulsions different from each other in average grain diameter is formed on a support, the grain diameter distribution curve of the silver halide grains in this emulsion layer has 2 peaks, and the grains of the peak having the maximum average grain diameter have monodispersed octahedral crystals, thus permitting an amount of silver used to be reduced, and the obtained silver halide photosensitive material to be enhanced in graininess, sharpness, and photosensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver halide photographic light-sensitive material, and more specifically, to a silver halide photographic light-sensitive material that uses a small amount of silver and has high sensitivity and excellent graininess and sharpness. Regarding.

Today, the development of highly sensitive silver halide photographic materials having excellent graininess and sharpness is the most important issue in the industry. In particular, in silver halide color sensitive materials for negative-positive print photography, improvements in image quality such as excellent graininess and sharpness are needed to accommodate increasingly smaller cameras, and high sensitivity to accommodate an expanded range of shooting scenes. There is a strong demand for silver 10 genide color sensitive materials having a wide latitude in performance.

Furthermore, there are concerns that silver resources, which are the main raw material for silver halide photographic materials, are being depleted, and the price of silver is becoming increasingly unstable due to the recent rise in oil prices. Therefore, there is a need to reduce the amount of silver used in silver halide photographic materials as much as possible to provide consumers with silver halide photographic materials at stable prices.

Accordingly, a first object of the present invention is to provide a silver halogenide photographic material having excellent graininess and sharpness, high sensitivity, and a wide latitude.

A second object of the present invention is to provide a silver halide photographic material which uses as little silver as possible, has excellent graininess and sharpness, is highly sensitive and has a wide latitude.

The above object of the present invention and other objects described below are to have a silver tetragenide emulsion layer on a support consisting of two or more types of silver halide emulsions having different average grain sizes; The grain size distribution curve of the silver halide grains has two or more peaks, and the silver halide grains at the peak with the largest average grain size among the core peaks are halogen grains consisting essentially of a monodisperse emulsion of octahedral grains. This can be achieved using silver oxide photographic materials.

It is well known in the art that the larger the silver halide grains used in a silver halide photographic light-sensitive material, the higher the sensitivity, while at the same time the graininess deteriorates.

It is also known in the art that graininess can be improved by increasing the amount of coated silver per unit area or decreasing the silver halide grain size, but this also results in a decrease in sensitivity.

Furthermore, methods are known to control particle size and particle size distribution to reduce the influence of light scattering and improve sharpness, but these methods have not yet achieved sufficient effects. Therefore, in order to improve image quality in terms of sharpness and graininess, multilayer color photosensitive materials are currently using development-inhibitor-releasing compounds that utilize the development effect.
r-releasing compounds:
A method using DIR compounds (referred to as DIR compounds) is commonly used.

However, such a method requires a larger amount of silver to be used than conventional methods, resulting in higher product costs.

The present invention overcomes the barriers found in the above general rules.

The present inventors have succeeded in producing a photosensitive material that was completely unimaginable heretofore by efficiently using the minimum necessary amount of silver halide emulsion when producing a silver halide photographic material. Generally, the grain size distribution of silver halide grains in a polydisperse silver halide emulsion has a distribution close to a normal distribution. At this time, the sensitivity of the silver halide photographic light-sensitive material depends on the size and number of silver halide grains with larger grain sizes. Furthermore, in areas where the sensitivity is low but the density is high, it depends on the size and number of smaller silver halide grains.

In the conventional method, the distribution of □ is left to the providence of nature,
Silver halide photographic light-sensitive materials have not necessarily been manufactured to have an effective distribution.

According to the present invention, by controlling the particle size distribution and crystal habit of the silver halide grains, it is possible to provide a silver halide photographic material with high sensitivity, excellent graininess and sharpness, and a wide latitude. The effects of the present invention are completely unexpected and surprising using the conventional techniques described above.

The present invention uses silver halide emulsions having mutually different average grain sizes of at least 2M or more. The average grain size referred to here means the radius in the case of octahedral grains, the diameter in the case of spherical silver halide grains, and the projected image of the same area in the case of grains with shapes other than octahedral, cubic, and spherical. The average value of the diameter when converted into a circular image, where the individual particle size is ri and the number is ni, the average particle size 7 is defined by the following formula.

Σni ri Σni It is preferable that the grain size of the silver halide grains in the silver halide emulsion according to the present invention is at most 3.5 μm or less. When the maximum particle size is larger than 3.5 μm, a sensitizing effect cannot necessarily be obtained, making it difficult to achieve the object of the present invention.

The average grain size of the silver halide grains in the present invention is preferably in the range of 0.2 to 2.0 microns.

The monodisperse emulsion in the present invention refers to one in which the value of the drift deviation S defined by the following formula divided by the average grain size 7 is 0.16 or less.

When Σni -4o,t6 S/〒 exceeds 0.16, it is difficult to reduce the amount of silver used. Preferably, the effect of the present invention is significant in a region where 8/〒 is 0.12 or less.

The silver halide composition of the silver halide emulsion according to the present invention is not particularly limited, and a commonly used range can be applied. For example, when applied to a negative emulsion for general photography, f is a composition whose main component is silver bromide, which contains silver iodide 6- in an amount of 12 moles or less, and may contain silver chloride in a jO mole or less; Examples of emulsions used in prints where relatively low sensitivity is allowed and where priority is given to the above include silver chloride, silver chlorobromide containing silver chloride as a main component, silver chloroiodobromide, and the like. According to the present invention, it is possible to efficiently utilize NOSO silver in various silver halide compositions, and it is possible to obtain photographic materials that are excellent in graininess, sharpness, and amount of silver used in relation to sensitivity.

The composition of silver decagenide in each emulsion having two or more different average grain sizes used in the present invention may be different or the same. In the present invention, a granularity distribution curve combining two or more types of emulsions having different average grain sizes has two or more peaks (maximum), and among the peaks, the maximum peak in the winter peak mode is It is preferable that the interval in grain size between a mode and the mode of the next largest peak is at least 0.3μ, and more preferably the interval is 0.5μ or more. Further, it is desirable that five or more kinds of emulsions having different average grain sizes are used in combination. When there are 6 or more species,
The silver halide grain distribution becomes too large and good control is not always possible. In the present invention, preferably three or less types are used.

In the present invention, "the silver halide grains having the largest average grain size are substantially composed of a monodisperse emulsion of octahedral crystals" means that the silver halide grains contained in the silver halide emulsion according to the present invention are At least 50 silver halogenide grains having a grain size equal to or larger than the point corresponding to the minimum frequency of the valley between the largest peak and the next largest peak in the grain size distribution curve. (in number) means particles consisting essentially of monodisperse octahedral crystals. Here, the term "particles consisting essentially of octahedral crystals" refers to particles in which all or a majority of the surfaces are (111) planes. Preferably, the proportion of particles consisting of substantially octahedral crystals with a monodispersity of 7" is at least 80".

In the present invention, when two or more types of emulsions having different average grain sizes are used together, it is desirable to apply the most suitable chemical sensitization to each emulsion individually.What is chemical sensitization? Known sensitization methods include sulfur sensitization, gold sensitization, selenium sensitization, reduction sensitization, etc., and these can also be carried out in combination.The reaction rate varies depending on the particle size of silver halogenide, and If the above method is applied, or if the method is performed by mixing instead of each individual emulsion, the highest sensitivity of each monodispersed emulsion may not necessarily be obtained.

In the above chemical sensitization in the present invention, the sulfur sensitization is
For example, it can be carried out by using sodium thiosulfate, thiourea, allylthiourea, etc., and metal sensitization can be carried out by using, for example, chloroauric acid, IJum, gold thiocyanate potassium, etc. Furthermore, for gold-sulfur sensitization, chemical sensitization can be carried out using at least one of the above-mentioned sensitizers in combination. In this case, ammonium thiocyanate, etc. may be further added for chemical sensitization. You can also do it.

In addition to the above-mentioned sulfur sensitization method, selenium sensitization method can also be used for the silver 10 genide emulsion used in the present invention. For example, U.S. Patent No. 1,574,944 using selenourea, N,N'-dimethylce9-lenourea, etc.
No. 3,591,385. The method described in Japanese Patent Publication No. 43-13849 and Japanese Patent Publication No. 44-15748 can be employed.

Furthermore, conventionally known methods can be applied to reduction sensitization. For example, aging can be carried out using a low pAg atmosphere, using a suitable reducing agent, or using electromagnetic waves such as light and γ rays.

In the silver halide photographic material according to the present invention, two or more types of emulsions having different average grain sizes can be coated on the support separately in layers, or they can be coated as a mixture. You can also.

The supports used at this time include all known ones, such as polyester films such as polyethylene terephthalate, polyamide films, polycarbonate films, styrene films, baryta paper, paper coated with synthetic polymers, and the like.

The present invention is applicable to all silver halogenide photographic materials. For example, it is suitable for high-sensitivity black-and-white photosensitive materials or color negative photosensitive materials.

In the present invention, gelatin is the most preferred hydrophilic colloid for dispersing silver halide grains, but in order to further improve the physical properties of the binder, for example, gelatin derivatives,
Other natural hydrophilic colloids such as albumin, casein,
agar, gum arabic, alginic acid and its derivatives such as salts, amides and esters, starch and its derivatives, cellulose derivatives such as cellulose ether, partially hydrolyzed cellulose acetate, carboxymethyl cellulose etc., or synthetic hydrophilic resins such as polyvinyl alcohol. , polyvinyl bitetraridone, acrylic acid and methacrylic acid or their derivatives, such as homo- and copolymers of esters, amides and nitriles, vinyl polymers such as vinyl ethers and vinyl esters can be used.

The silver halide grains other than the octahedral grains used in the silver halide photographic light-sensitive material according to the present invention may be so-called twin crystals having irregular shapes such as spherical or plate-like, or cubic,
It may have a regular shape such as an octahedron or a tetradecahedron, but the latter is more preferred.

Further, regular and irregular types can be used in combination with each other.

The silver halide grains used in the silver halide photographic light-sensitive material according to the present invention may be obtained by any of the acid method, neutral method, and ammonia method. Alternatively, for example, a method may be used in which seed particles are produced by an acidic method and then grown by an ammonia method, which has a faster growth rate, to grow to a predetermined size. When growing silver halide grains, the PH and BAg in the reaction vessel
For example, JP-A-54-48521
As described in the above publication, it is desirable to simultaneously implant and mix silver ions and halide ions in amounts appropriate to the growth rate of silver halide grains.

The silver halide grains of the present invention have I
Noble metal ions such as r, Rh, Pt, and Au can be added and included inside the particles, and reduction-sensitized nuclei can be added inside the particles using a low pAg atmosphere or an appropriate reducing agent. .

The silver halide emulsion of the present invention is prepared by adding a pAg suitable for chemical sensitization by an appropriate method after the growth of silver halide grains is completed.
or ion concentration. Research Disclosure 17643, such as flocculation method and noodle washing method.
No. (Re5earch Disclosure 1764
This can be done using the method described in item 3).

The silver halide emulsion used in the silver halide photographic light-sensitive material of the present invention is a stabilizer and a capri inhibitor, for example, US Pat. No. 2,444,607 and US Pat.
No. 62, No. 3,512,982, No. 3,342,
596, German Patent No. 1,189,380, German Patent No. 20
Specifications of No. 5,862 and No. 211.841, Japanese Patent Publication No. 43-4183, Japanese Patent Publication No. 39-2825, and Japanese Patent Application Laid-open No. 1973
Methods using stabilizers and antifoggants described in Publications No. 22626 and No. 50-25218 may be applied, and particularly preferred compounds include 5.6-)rimethylene-7-hydroxy-8-triazolo (1,5-a)
Pyrimidine, 5,6-titramethylene-7-hydroxy-8-)riazolo(1,5-8)pyrimidine, 5-methyl-7-hydroxy-8-)riazo"(1,5")
Pyrimidine, 7-hydroxy-8-)riazolo (1°1
3-5-a) Pyrimidine, gallic acid ester (e.g. isoamyl gallate, dodecyl gallate, propyl gallate,
sodium gallate), mercaptans (e.g.!
-7enyl-5-mercaptotetrazole, 2-mercaptopentthiazole, etc.), penztriazoles (
Examples include 5-brompenztriazole, 4-methylpenztriazole, etc.), penzimidazoles (e.g., 6-nidrobenzimidazole, etc.), and the like.

The silver halide emulsion of the present invention can be spectrally sensitized with cyanine dyes, merocyanine dyes, etc. For example, in the regular area, JP-A Nos. 55-2756 and 55-14
No. 743, and in the ortho region, JP-A-48-
No. 56425, No. 51-31228, Special Publication No. 1977-2
As described in Japanese Patent No. 5379, they can be used alone or in combination. Furthermore, spectral sensitization on the longer wavelength side can be carried out using, for example, a cyanine dye with a longer methine chain described in JP-A-51-126140, and supersensitization using a combination of dyes can also be carried out. It can be done arbitrarily.

The silver halide photosensitive material according to the present invention can be prepared by using photographic hardeners commonly used in the coating solution, such as aldehyde-based and aziridine-based hardeners (for example, PB Report, 19.921, U.S. Pat. No. 2,950,197, Same No. 2,964,404
No. 2,983,611, No. 3,271,17
Specifications of No. 5, Special Publication No. 46-40898, 41ii
, 1985-91315), isoxazole-based (e.g., described in U.S. Pat. No. 331,609), epoxy-based (e.g., U.S. Pat. No. 3,047,394, West German Patent No. 1.085,663
No. 1,033,518, those described in Japanese Patent Publication No. 48-35495), vinyl sulfone type (e.g. PB Revo) 19,920, West German Patent No. 1,100,942 British Patent No. 1,251,
No. 091, Japanese Patent Application No. 45-54236, No. 48-110
996, U.S. Pat. No. 353.964, U.S. Patent No. 3,49
No. 0,911), acryloyl type (e.g., Japanese Patent Application No. 48-27949, U.S. Patent No. 3,
640,720), carbodiimides (e.g., U.S. Pat. No. 2,938,892, Japanese Patent Publication No. 46-38715, Japanese Patent Application No. 1987-15)
095), other maleimides,
Acetylene-based, methanesulfonic acid ester-based, triazine-based, and polymer-based hardeners can be used. In addition, thickeners such as those described in U.S. Pat.
, 960,404 specification, Japanese Patent Publication No. 43-4939,
JP-A No. 48-63715 (Japanese Patent Publication No. 48-63715), as latexes, US Pat.
-43125, and as a matting agent, those described in British Patent No. 1,221,980 can be used.

Desired coating aids can be used in the constituent layers of the silver halide photographic material according to the present invention, such as saponin or sulfosuccinic acid surfactants, such as those described in British Patent No. 548,532 and Japanese Patent Application No. 47-89630, or anionic surfactants such as Japanese Patent Publication No. 43-18166 and U.S. Patent No. 3.
, 514,293, French Patent No. 2.025,68
Those described in each specification of No. 8, Japanese Patent Publication No. 4.3-10247, etc. can be used.

In the silver halide photographic light-sensitive material according to the present invention, a dye can be used in the layer below the emulsion layer of the present invention and in contact with the support, and it is also possible to improve the sharpness of images or reduce fog caused by safe light. For mitigation, dyes can be added to the protective layer and/or the emulsion layer of the invention and/or the non-light-sensitive layer adjoining the emulsion layer of the invention. As the dye, any known dye for the above purpose can be used.

17- In addition, in order to apply the emulsion of the present invention to color light-sensitive materials, the emulsion of the present invention adjusted to have red sensitivity, green sensitivity, and blue sensitivity may be combined with cyan, magenta, and yellow couplers, etc. The method and material used for the false color light-sensitive material described in "Photosensitive Materials for Use and Imaging A 18-19" (1976) may be applied.

Useful couplers include open-chain methylene yellow couplers, pyrazolone magenta couplers, and phenolic or 7-tole cyan couplers. couplers with a split-off group having an azo group as a bonding group), osazone-type compounds, development-diffusive dye-releasing couplers, and development inhibitor-releasing compounds (couplers that react with oxidized forms of aromatic primary amine developing agents). So-called DIR couplers, which release development-inhibiting compounds and react with oxidized aromatic primary amine developing agents to form colored dyes, as well as so-called DIR couplers, which form colorless compounds. It is also possible to use (including both). In order to incorporate these couplers into a silver halide color photographic light-sensitive material, various known techniques conventionally used for couplers can be applied.

The silver halide photographic material according to the present invention can be developed by a commonly used known method. The black and white developer is a commonly used developer, such as hydroquinone, 1-7er-3-pyrazolidone, N-methyl-p-
Those containing aminophenol or p-phenyl diamine alone or in combination of two or more thereof are used, and other commonly used additives can be used.

Further, when the light-sensitive material is for color use, color development can be carried out by a commonly used color development method.

Developers containing aldehyde hardeners can also be used in the silver halide photosensitive materials of the present invention, such as dialdehydes such as maleic dialdehyde or glutaraldehyde and their sodium bisulfite salts. The present invention will be illustrated by examples, but the embodiments of the present invention are not limited thereto.

Example 1 Emulsion 1. II and ■ were prepared.

[Preparation of emulsion ■]

A disc-shaped polydisperse silver iodobromide emulsion containing 2 mol % of silver iodide and having an average grain size of 1.02 μm was prepared. Ammoniacal silver nitrate and aqueous alkali halide solution were allowed to fall naturally into a reaction vessel to which an aqueous gelatin solution and excess halide had been added in advance, and were obtained by simultaneous addition at 60° C. for 20 minutes. The standard deviation of this emulsion grain is 0.336 μm, s/r=o, 2g
Met. Desalting was then carried out using benzenesulfonyl chloride, gelatin was added, and PAg 7.8
+ An emulsion with a pH of 6.0 was obtained. Furthermore, sodium thiosulfate, chloroauric acid and ammonium bromide were added, and chemical ripening was performed at 52□°C for 70 minutes to form 4-hydroxy-6-methyl-1,3,3a, 7-titrazaindene and 1-phenyl-5-. Emulsion I was obtained by adding mercaptotetrazole and gelatin.

[Preparation of emulsion ■]

A monodisperse silver iodobromide emulsion containing 2 mol % of silver iodobromide and having an average grain size of 1° and 15 μm was prepared. Potassium iodide and gelatin aqueous solution were charged in advance into a reaction vessel, and while maintaining the pAg in the reaction vessel at 8.6, an ammoniacal silver nitrate aqueous solution and a potassium bromide aqueous solution were added in proportion to the increase in surface area during particle growth. and added.

The standard deviation of the cubic emulsion grains was 0.104μ and S/r = 0.09. Thereafter, chemical ripening was carried out in the same manner as in Emulsion I above to obtain Emulsion II.

[Preparation of emulsion ■]

A monodisperse silver iodobromide emulsion containing 2 mol % of silver iodide and having an average grain size of 1.15 μm was prepared. To a reaction vessel containing potassium iodide and gelatin aqueous solution in advance, while maintaining the pAg in the reaction vessel at 9°0, add an ammoniacal silver nitrate aqueous solution and a potassium bromide aqueous solution in proportion to the increase in surface area of particle growth. did. The standard deviation of the octahedral crystal emulsion grains was 0.106μ, 21-8/〒=0.09. Thereafter, chemical ripening was carried out in the same manner as Emulsion I to obtain Emulsion II.

[Preparation of emulsion ■]

A silver iodobromide emulsion containing 2 mol % of silver iodide and having an average grain size of 0.62 μm was prepared. The preparation method is the same as emulsion ■,
S/〒=0.36. Furthermore, chemical ripening was carried out in the same manner as Emulsion I to obtain Emulsion II.

[Preparation of emulsion V]

A monodisperse silver iodobromide emulsion containing 2 mol % of silver iodide and having an average grain size of 0.62 μm was prepared. The preparation method was the same as that of emulsion ①, and S/r was 0.07. Furthermore, chemical ripening was carried out in the same manner as Emulsion I to obtain Emulsion II.

Further 1 was added to the prepared emulsions I, n, III, IV and V.
-(2,4,6-)lichlorophenyl)-3-(3-(
A coupler dispersion of α-(2,4-di-tsrt-amylphenoxyacetamide)-benzamide-5-pyrazolone dissolved and dispersed in tricresyl phosphate, conventional coating aids and hardeners, and a polyethylene terephthalate support. Sample A1 was applied on the body in multiple layers as shown in Table 1.
-5 was obtained.

Table 1 These samples were exposed to white light through a wedge and then developed using a CNK-4 color processing solution manufactured by Konishiroku Photo Industry Co., Ltd. The photographic properties obtained are shown in Table 2.

The improvement effect of image sharpness is detected using MTF (Modu
Transfer Function)
This was done by comparing the magnitude of MTF at 40 spatial frequencies.

Further, graininess (RMS) was determined by comparing 1000 times the standard deviation of density value fluctuations that occur when scanning with a microdensitometer having a circular scanning aperture of 5 μm.

Table 2 From Table 2, sample 3.5 of the present invention has sensitivity and graininess of 1
It can be seen that the sharpness is significantly improved.

This effect was an unexpected result. ◇Example-2 Emulsions I, m, IV, and V prepared in Example 1 were further added with commonly used coating aids and hardeners, and polyethylene terephthalate was added. Coated on a support. In addition,
In this sample, a large grain emulsion and a small grain emulsion were separately chemically ripened and mixed before coating, and then coated. The contents of the coating sample are shown in Table 3.

Table 3 After these samples were exposed to white light through a wedge,
It was developed for 5 minutes at 20'C using a Condor super developer manufactured by Roku Konishi Photo Industry Co., Ltd. The fourth photographic performance obtained
Shown in the table.

Table 4 It is clear from Table 4 that the effects of the present invention are remarkable even in systems in which two types of silver halide emulsions having different average grain sizes are mixed in the same layer.

-ga-

Claims (1)

[Claims] A silver halide emulsion layer consisting of two or more types of silver halide emulsions having different average grain sizes is provided on a support, and the grain size distribution curve of the silver halide grains in the emulsion layer has two or more peaks. 1. A silver halide photographic light-sensitive material having a silver halide grain having a maximum average grain size among the winter grains, wherein the silver halide grains having the largest average grain size substantially consist of a monodispersed emulsion of octahedral crystals.