JPH01154142A - Direct positive type silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE:To obtain the photosensitive material with the high sensitivity and the excellent stability by incorporating an inner latent image type silver halide particle specified in a ratio of the thickness to the length of the particle in the title material. CONSTITUTION:The inner latent image type silver halide particle which is composed of an outermost shell contg. silver chloride and has the ratio of the thickness to the length of the particle of more than (1:8), is incorporated in at least one layer of silver halide emulsion layers. The ratio of the thickness to the length of the inner latent image type silver halide particle is preferable more than (1:8) and less than (1:150), further preferably more than (1:20) and less than (1:150). Thus, the photosensitive material which has the high sensitivity, the less change of the sensitivity against a development processing time and the small min. optical density and the excellent development processing stability, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a direct positive type silver halide photographic light-sensitive material. In particular, the present invention relates to a direct positive type silver halide photographic light-sensitive material that is highly sensitive and has excellent development stability.

[Background of the invention]

Conventionally known techniques for creating positive images using direct positive photosensitive materials can be mainly divided into two types.

One type uses an emulsion containing silver halide grains that have been fogged in advance, and uses solarization or the Burschel effect to create fog nuclei (latent images) in exposed areas.
By destroying the image, a positive image is obtained after development.

The other type uses an emulsion containing internal latent image type silver halide grains that have not been fogged in advance, and performs surface development after image exposure and fogging treatment, or while performing fogging treatment, to create a positive image. It's something you get.

The above-mentioned emulsion containing internal latent image type silver halide grains refers to a silver halide photographic emulsion in which the silver halide grains mainly have photosensitive nuclei inside and a latent image is formed inside the grains upon exposure. say.

Compared to the former type of technology, this latter type of technology is more sensitive and suitable for cases where high sensitivity is required for boat fishing, and the present invention particularly relates to this latter type of technology. .

Various techniques are known to date in this technical field. For example, U.S. Patent No. 2,592.250;
, No. 466.957, No. 2,497,875, No. 2,
No. 588,982, No. 3,761.266, No. 3,7
The main ones are those described in No. 61,276, No. 3,796.577, British Patent No. 1,151,363, etc.

Generally, such direct positive type photographic materials have relatively high sensitivity and good processing properties, but various problems still remain. For example, when a direct positive photosensitive material is constructed using core/shell type silver halide grains containing silver chloride in the outermost shell of the grain, the fluctuation in the maximum density of the resulting positive image is small; Although it is excellent in that there is little variation in m-tone, it tends to be accompanied by an increase in minimum density and sensitivity variation (sometimes a decrease in sensitivity) with respect to variation in development processing time, and there is a problem that development processing stability is poor.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a direct positive type silver halide photographic light-sensitive material having a high degree of anger and excellent stability in development processing.

[Structure and operation of the invention]

The above object of the present invention is to provide a direct positive silver halide photographic material having at least one silver halide emulsion layer on a support, in which at least one of the silver halide emulsion layers has an outermost shell of silver chloride. Core/shell type internal latent image type silver halide grains formed from silver halide containing a core/shell type internal latent image type silver halide grains, and the ratio of the grain thickness to the major axis is 1:?
This is achieved by a direct positive type silver halide photographic light-sensitive material containing internal latent image type silver halide grains of 3 or more.

In order to solve the above-mentioned problems, the present inventors have conducted various studies and have focused on changing the ratio between the thickness and major axis of silver halide grains. Although it was found that it was effective in preventing a decrease in sensitivity against fluctuations, it was not necessarily sufficient to prevent increases in minimum density and fluctuations in sensitivity against fluctuations in development processing time. After further investigation, we obtained the knowledge that the above configuration matches the purpose of the present invention,
This led to the present invention.

The present invention will be explained in detail below.

In the direct positive silver halide photographic light-sensitive material of the present invention, at least one of the silver halide emulsion layers is of a core/shell type internal cavity in which the outermost shell is formed of silver halide containing silver chloride. Image-shaped silver halide grains,
and contains internal latent image type silver halide grains (hereinafter appropriately referred to as "internal latent image type silver halide grains according to the present invention") having a ratio of grain thickness to major axis of 1:8 or more. There is. The ratio of the thickness to the major axis of the internal latent image type silver halide grains according to the present invention is preferably 1:8 or more and less than 1:150, more preferably 1:20 or more and less than 1:150. The thickness here is determined appropriately depending on the shape of the silver halide grains, and when the silver halide grains are normal crystals (octahedral, tetradecahedral, etc.) and irregular shapes (non-tabular), they have the same volume. It is the length of one side when converted into a cube, and in the case of tabular grains, it is the distance between the surfaces having the maximum projected area.

In addition, the long axis is determined appropriately depending on the shape of the silver halide grain, and the shape of the silver halide grain is normal crystal (8
For silver halide grains (hedron, tetradecahedron, etc.) and irregular shapes, the definition is the same as thickness, which is the length of one side when converted to a cube with the same volume, and for tabular grains, the projected area of the silver halide grain is the same area. This is the diameter value when converted to a circle with .

The outermost shell of the internal latent image type silver halide grains according to the present invention contains at least silver chloride. Preferably, the silver chloride content is from 30 mol% to 100 mol%, more preferably from 35 mol% to 100 mol%. Any silver halide composition can be used as long as the shell substantially contains silver chloride. Examples include silver chloride, silver chlorobromide, silver chloroiodobromide, and silver chloroiodide.

The outermost shell layer of the internal latent image type silver halide grains according to the present invention can completely cover the silver halide grain surface, or can selectively cover a part of the surface. . In the present invention, the shell surface layer containing silver chloride preferably occupies 10% or more of the grain surface.

The shell in the internal latent image type silver halide grains may be a single monolayer in terms of silver halide composition, or may be a single layer of silver halide composition.
It may be a multilayer shell having more than one layer.

In the case of a multi-layer shell, it consists of at least an outermost layer and a layer adjacent thereto, but it may also have a structure in which layers having mutually different silver halide compositions are laminated.

Further, the multilayer shell layer may have a structure in which the silver halide composition changes continuously in the radial direction of the silver halide grains.

In the case of the above-mentioned multilayer shell, as long as silver chloride is contained in the outermost shell (or its surface), the entire grain or the inner layer may have any silver halide composition. Good too. Examples include silver iodobromide, silver bromide, silver chlorobromide, silver chloroiodide, and silver chlorobromoiodide.

It is preferable that the shell covers 50% or more of the surface area of the core, and it is particularly preferable that the shell completely covers the core.

The core preferably consists primarily of silver bromide and may further contain silver chloride and/or silver iodobromide. The silver halide grains forming the core may have any shape; for example, they may be cubic, octahedral, dodecahedral, tetradecahedral, or a mixture thereof; they may also be spherical, tabular, irregular, etc. Particles having a regular shape (for example, including a hexagonal bipyramid structure) or a mixture thereof may be used as appropriate. Amorphous particles are preferred. In carrying out the present invention, the average particle size and particle size distribution of the silver halide grains constituting the core can be varied over a wide range depending on the desired photographic performance, but a narrower particle size distribution is more preferable.

That is, the silver halide grains constituting the core are preferably substantially monodisperse.

Herein, silver halide grains with a heavily dispersed core are defined as silver halide grains in which the weight of the silver halide grains included in the grain size range of ±20% around the average grain size 7 in the silver halide grains constituting the core. It is 60% or more of the total silver halide weight, preferably 70% or more, particularly preferably 80% or more.

Here, the average particle size 7 is the frequency n8 of particles having particle size ri.
The particle diameter r is the maximum value of the product n1Xri'' of xr and 3 (3 significant figures, minimum number of digits is 4 to 5).

In addition, the grain size here refers to the diameter in the case of spherical silver halide grains, and in the case of grains with shapes other than spherical, the diameter when the projected image is converted into a circular image with the same area. It is.

The particle size can be obtained, for example, by magnifying the particle 10,000 to 50,000 times with an electron microscope and projecting it, and actually measuring the particle diameter or area at the time of projection on the print (the number of particles measured is (Assume there are more than 1000 items indiscriminately.)

Examples of methods for producing the monodisperse core emulsion include, for example, Japanese Patent Publication No. 4B-36890, Japanese Patent Application Laid-open No. 48520/1986,
The double jet method disclosed in various publications such as No. 54-65521 can be used. In addition, JP-A-54-15
A premix method described in Japanese Patent No. 8220 and the like can also be used.

The core of the internal latent image type silver halide grains according to the present invention is chemically sensitized, doped with metal ions, or both, or not at all. It may be something.

As the chemical sensitization, sulfur sensitization, gold sensitization, reduction sensitization, noble metal sensitization, and a combination of these sensitization methods can be employed. As the sulfur sensitizer, thiosulfates, thioureas, thiazoles, rhodanines, and other compounds can be used.

Such methods are described, for example, in U.S. Pat. No. 1,574,944.
No. 1,623,499, No. 2,410,689, No. 3,656,955, etc.

The core of the internal latent image type silver halide grains according to the present invention is disclosed in, for example, U.S. Pat.
As described in No. 56, No. 2,642,361, etc., sensitization can be carried out with a water-soluble gold compound or with a reduction sensitizer. Regarding such methods, reference can be made to, for example, US Pat. No. 2,487,850, US Pat. No. 2,518.698, US Pat.

Furthermore, noble metal sensitization can also be carried out using noble metal compounds such as platinum, iridium, palladium, and the like. Such methods are described, for example, in U.S. Pat.
8.060 and British Patent No. 618,061.

Further, the core of the internal latent image type silver halide grains can be doped with metal ions. To dope the core with metal ions, the metal ions can be added as water-soluble salts, for example, during any process of forming the core particles. Preferred specific examples of metal ions include iridium, lead, antimony, bismuth, gold, osmium,
There are metal ions such as rhodium. These metal ions are preferably present in an amount of lXl0-3 to 1x10 per mole of silver.
- used at a concentration of 4 molar.

However, the material used as the core of the internal latent image type silver halide grains according to the present invention may not be subjected to the above-mentioned chemical sensitization treatment or metal ion doping.

In this case, it is thought that the photosensitive center is generated by forming crystal strain at the interface between the core and shell during the process of covering the core particle with the shell, and in this regard, US Pat. No. 3,935. No. 014, No. 3.
Reference may be made to the description in No. 957.488.

A double jet method or a premix method can be used to form the shell on the core described above. It is also possible to form the core emulsion by mixing fine grains of silver halide and performing Ostwald ripening.

The internal latent image type silver halide grains according to the present invention can be produced by an acid method,
It may be obtained by either the neutral method or the ammonia method. The particles may be grown all at once, or may be grown after seed particles are created. The method of creating and growing the seed particles may be the same or different. A silver halide emulsion containing the silver halide grains may be prepared by simultaneously mixing halide ions and silver ions, or by mixing one of them in a solution in which the other is present. In addition, while considering the critical growth rate of silver halide crystals, the pH and p
It may be produced by sequentially and simultaneously adding Ag while controlling it.

By this method, silver halide grains having a regular crystal shape and a nearly uniform grain size can be obtained. Conversion methods can also be used to change the halogen composition of the particles after growth. The silver halide emulsion thus obtained may have any grain size distribution. Therefore, an emulsion with a wide grain size distribution (referred to as a polydisperse emulsion) may be used, or an emulsion with a narrow grain size distribution (referred to as a monodisperse emulsion) may be used alone or in combination. A mixture of emulsions may be used. Preferably, a monodisperse emulsion is used.

Here, the monodispersity of a monodisperse emulsion refers to an emulsion in which the coefficient of variation in the grain size distribution of silver halide grains contained in the emulsion is 22% or less, preferably 15% or less.

Here, the particle diameter of the particles for obtaining the above particle size distribution is the same as that described for the core particle.

As the internal latent image type silver halide grains according to the present invention, internal latent image type silver halide grains whose surfaces are not fogged in advance can be used. Here, the meaning that the surface of the internal latent image type silver halide grains is not fogged in advance means that such an emulsion is coated on a transparent film support with 35 mgAg/
It means that the density obtained when a test piece coated to give cnf is developed with the following surface developer A at 20° C. for 10 minutes without exposure to light does not exceed 0.6, preferably 0.4.

Surface developer A Metol 2.5g! -Ascorbic acid 10 gNaBO2・4t
h0 35 gKBr
Add 1g water
11 Furthermore, the emulsion containing the internal latent image type silver halide grains according to the present invention has a sufficient density when the test piece prepared as described above is exposed and then developed with internal developer B having the following formulation. It is preferable to use what is given.

Internal developer B Metol 2g Sodium sulfite (
anhydrous) 90 g hydroquinone
8g Soda carbonate (-water salt)
52.5gKBr
5 gKI
Add 0.5g water 11
To be more specific, a portion of each test piece was
When exposed to a light intensity scale for a defined time up to seconds and developed in internal developer B for 10 minutes at 20°C, another portion of each specimen exposed under the same conditions was exposed in surface developer A. It is preferred to use those which exhibit a maximum density of at least 5 times, preferably at least 10 times, that obtained when developed for 10 minutes at 20°C.

Silver halide emulsions can be optically enhanced with commonly used sensitizing dyes. Combinations of enhancing dyes used for supersensitization of internal latent image type silver halide emulsions, negative type silver halide emulsions, etc. are also useful for the silver halide emulsions used in the present invention. Research on aggravating pigments
Discology 11- (Research Dis
closure)llkL15162 and 17643
can be referred to.

The silver halide photographic material of the present invention can be easily produced by subjecting it to image exposure (so-called photography, in which light is applied to a photosensitive material to form an image) in a conventional manner, and then surface-developing it. A positive image can be obtained directly. Surface development here means developing latent image nuclei formed on the surface of silver halide grains. The main process for forming a direct positive image is generally to process a photographic material having an internal latent image type silver halide emulsion layer, after image exposure, to generate fog nuclei by chemical or photochemical action (hereinafter referred to as fog processing). The method consists of performing surface development after applying (referred to as ``fogging'') and/or while performing fogging treatment. Here, the fogging treatment can be carried out using a compound (hereinafter referred to as a fogging agent) that provides full exposure or generates capri nuclei.

For example, full-surface exposure is performed by immersing or moistening the image-exposed photosensitive material in a developer or other aqueous solution, and then exposing the entire surface uniformly to light. The light source used here may be any light within the sensitive wavelength range of the photographic light-sensitive material, and it may be a short-term exposure to high-intensity light such as a flash light, or a long-term exposure to weak light. . Further, the overall exposure time can be varied over a wide range depending on the photographic material, processing conditions, type of light source used, etc. so as to ultimately obtain the best positive image.

Further, it is most preferable that the exposure amount of the entire surface exposure is within a certain range in combination with the photosensitive material.

In addition, when fogging treatment is used, a wide variety of compounds can be used as the fogging agent, and it is sufficient that the fogging agent is present during the development process. Among these, the silver halide emulsion layer is particularly preferred), or it may be contained in a developer or a processing solution prior to development. Moreover, the amount used can vary widely depending on the purpose.

The direct positive silver halide photographic material according to the present invention includes:
The light-sensitive material of the present invention having at least one silver halide emulsion layer can be used as a black-and-white and color light-sensitive material. It can also be preferably implemented as a full-color photographic material, in which case it usually comprises a green-sensitive silver halide emulsion layer containing a magenta coupler, a blue-sensitive silver halide emulsion layer containing a yellow coupler, and a cyan coupler. A photographic light-sensitive material is formed having a red-sensitive silver halide emulsion layer containing the red color-sensitive silver halide emulsion layer.

As the yellow coupler, known acylacetanilide couplers can be preferably used, and among these, benzoylacetanilide and pivaloylacetanilide compounds are preferred.

As the magenta coupler, pyrazoloazole type magenta couplers, 5-pyrazolone type couplers, pyrazolobenzimidazole type couplers, open chain acylacetonitrile type couplers, etc. can be used arbitrarily.

As the cyan coupler, naphthol couplers and phenol couplers can be preferably used.

In addition to having at least one photosensitive silver halide emulsion layer on the support, the photographic light-sensitive material described above also has various layers such as a filter layer, an intermediate layer, a protective layer, a subbing layer, a backing layer, and an antihalation layer. It is possible to provide a large number of photographic constituent layers. As these coating methods, a dip coating method, an air doctor coating method, an extrusion coating method, a slide hopper coating method, a curtain flow coating method, etc. can be applied.

The support may be opaque or transparent,
It can be selected depending on the intended photosensitive material.

Examples of the support include polyethylene terephthalate film, polycarbonate film, polystyrene film, polypropylene film, cellulose acetate film, glass, baryta paper, polyethylene laminate paper, etc., which have been subbed as necessary.

In carrying out the present invention, various photographic additives such as wetting agents, film property improvers, coating aids, etc. may be added to the silver halide emulsion of the light-sensitive material depending on the purpose. Furthermore, other photographic additives include gelatin plasticizers, surfactants, ultraviolet absorbers, pH adjusters, antioxidants, antistatic agents, thickeners, graininess improvers, dyes, mordants, brighteners, A development speed regulator, matting agent, etc. may also be used.

Furthermore, it is useful to use ultraviolet absorbers, such as thiazolidone, benzotriazole, acrylonitrile, and benzophenone compounds, to prevent fading of dye images due to short-wavelength actinic rays.

In addition to gelatin, suitable gelatin derivatives can be used as protective colloids or binders in the silver halide emulsion layer used in the above-mentioned light-sensitive materials. A binder may be included. The above-mentioned photographic light-sensitive material can be added to photographic constituent layers such as an emulsion layer, an intermediate layer, a protective layer, a filter layer, and a backing layer depending on the purpose.
Furthermore, the hydrophilic binder may contain a suitable plasticizer, wetting agent, etc. depending on the purpose.

Further, the constituent layers of the photographic material can be hardened with any suitable hardening agent.

When carrying out the present invention, an As agent (antistine agent) can be used. , and Developing Section (Examples) Specific examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

Example 1 (Preparation of AgBr seed grain emulsion) An AgBr seed grain emulsion was prepared by a double jet precipitation method at pBr 2.85.35°C.0.12
To prepare a 5 molar emulsion, 60 g of deionized bone gelatin was dissolved in 2.51 molar water of a 5.0 molar silver nitrate solution and a 5.0 molar potassium bromide solution for 3.5 minutes. was added to the containing reaction vessel. AgB generated
The r-seed emulsion had an average grain size of 0.31 μm and the crystals had a hexagonal bipyramid structure.

Hereinafter, using this AgBr seed grain emulsion, emulsions (a) to
(h) was produced.

Preparation of emulsion (a)) Emulsion (al) was prepared using the AgBr seed grain emulsion. That is, 60 g of deionized bone gelatin in which the AgBr seed grain emulsion was dissolved in 2.5 g of water was contained. After adding to the reaction vessel, add silver nitrate aqueous solution and sodium chloride/potassium bromide mixed aqueous solution (the sum of the moles of sodium chloride and potassium bromide is the same number of moles as the silver nitrate solution). ) were simultaneously added by a double jet method to form a core/shell type cubic AgBrCl with an average particle size of 1.0 μm (in terms of the length of one side of a cube).
An emulsion was obtained.

Preparation of Emulsions (b) to (h)> Emulsion (b) was prepared using the hegBr seed grain emulsion described above. That is, after adding the AgBr seed grain emulsion to a reaction vessel containing 60 g of deionized bone gelatin dissolved in 2.5 g of water, an aqueous silver nitrate solution and odor were added into the reaction vessel by a double jet method. A mixed aqueous solution of potassium chloride and sodium chloride (the sum of moles of sodium chloride and potassium bromide is the same as the aqueous silver nitrate solution) at an accelerated flow rate (6 times from beginning to end),
Added over 15 minutes at 0°C. pBr is the first 5
minutes was maintained at 1.3, adjusted to 2.2 over the next 3 minutes, and maintained at 2.2 for the remainder of the precipitation period.

Emulsions (C) to (h) were prepared in the same manner by changing the mixing ratio of potassium bromide and sodium chloride (core/sodium chloride).
shell-shaped cubic AgBrC12 emulsion).

Table 1 shows the side length of each emulsion when converted to a cube, the ratio of the thickness to the major axis of each emulsion, and the AgC of the outermost shell of each emulsion.
The fi content is shown. The thickness and major axis mentioned here are those described in the detailed description.

Table 1> * The major axis indicates the diameter value when the projected area of the silver halide grain is converted into a circle having the same area.

(Single layer coating conditions) After adding a commonly used spreading agent and hardening agent to each of the emulsions (a) to (h) obtained above, the silver amount was 35n+g/100a& on a resin-coated paper support. Eight types of direct positive photosensitive material samples A, B, C, and D were coated and dried.

E, F, G, and H were created.

(Processing solution and processing conditions) The obtained sample was exposed to light through a sensitometric wedge using a photosensitive needle, and was incubated at 20°C with a developer having the following formulation.
Developed for 30 seconds.

1-phenyl-3-pyrazolidone 0.4 g Sodium sulfite (anhydrous) 75 g Hydroquinone 12 g Sodium carbonate (monohydrate) 40 g Sodium hydroxide 4 g Potassium bromide 4 g 5-Methylbenzotriazole 10 mg Add water
However, the entire surface was uniformly exposed to white light of 1 lux for 10 seconds 20 seconds after the start of development.

Next, it was bleach-fixed, washed with water, and dried.

Table 2 shows the relative comparative sensitivity results of each sample.

・Sensitivity comparison Table 2> *3%1 indicates the relative value of the reciprocal of the exposure amount required to give the minimum density (Dn+in) + 0.3, and 8
2'2 represents the relative value of the reciprocal of the exposure amount required to provide a density of minimum density (Dmin) + 1.0.

As is clear from the results in Table 2, samples D~ according to the present invention
It can be seen that H has higher sensitivity than comparative samples A-C.

Example 2 Samples (A) to (H) were prepared in the same manner as in Example 1 using similar emulsions (al to (hl). Development times were 1 minute 50 seconds, 2 minutes 10 seconds, and 2 minutes. 30 seconds, 2 minutes and 50 seconds.As is clear from the results in Table 3, Sample D-
H has small sensitivity fluctuations and minimum density with respect to development processing time, and is excellent in development processing stability.

In particular, samples G and H are excellent.

On the other hand, comparative samples A, B, and C other than those according to the present invention have large sensitivity fluctuations with respect to the development processing time and have a high minimum density, and do not have good development processing stability like the samples according to the present invention. I can't get sex.

Example 3 Monolayer coating and processing conditions for magenta> The sensitizing dye anhydro-9-ethyl-3,31-di(3-sulfobutyl)-5 was added to each of the emulsions (a) to (h) used in Example 1. , 5''-diphenyloxacarbocyanine hydroxide was added for spectral sensitization.

Separately, as a magenta coupler, 1-(2,4,6-)lichlorophenyl)-3-(2-10rho5-t'19decylsuccinimidoanilino)-5-pyrazolone was dissolved in a mixed solvent of dibutyl phthalate and ethyl acetate. An emulsion was prepared by dispersing it in an aqueous gelatin solution, and the emulsion was added to each of the above spectrally sensitized emulsions and mixed. After adding a hardener to this emulsion, a silver f
Samples 1 to 8 were prepared by coating and drying to give fi 5 mg/100 cm.

These samples were wedge-exposed through a yellow filter and developed with a developer having the following formulation at 38° C. for 2 minutes and 30 seconds.

4-Amino-3-methyl-N-ethyl-N-(β-methanesulfonamidoethyl)aniline sulfate 5g Sodium sulfite (anhydrous) 2g Sodium carbonate (monohydrate) 15g Sodium bromide 1g Benzyl alcohol 10m I! 11 (pH adjusted to 10.2 with potassium hydroxide) However, the entire surface was uniformly exposed to white light for 10 seconds starting 20 seconds after the start of development. Then, it was bleach-fixed, washed with water, and dried in a conventional manner.

Table 4 shows the sensitivity results of the obtained magenta positive image.

<Table 4> As is clear from the results in Table 4, similar to the results in Table 2 of Example 1, the samples according to the present invention are found to have higher sensitivity than the comparative samples.

Further, Table 5 shows the sensitivity and minimum density (Dmin) results of magenta positive images obtained by processing the samples in the same manner except that the development processing time was changed.

As is clear from the results in Table 5, the samples according to the present invention have small sensitivity fluctuations due to changes in development processing time, small increase in minimum density, and are found to have excellent development processing stability.

Example 4 Single-layer coating and processing conditions for oxidant> The emulsions used in the examples (al to (hl) each contained the sensitizing dye anhydro-9-ethyl-3,3°-di(3-sulfopropyl)-5, Spectral sensitization was performed by adding 5'-dichlorothiacarbocyanine hydroxide.Separately, 2,4-dichloro-3-methyl-6-C2-(
2,4-di-t-amylphenoxy)butyramide]phenol was dissolved in a mixed solvent of dibutyl phthalate and ethyl acetate, and dispersed in an aqueous gelatin solution to prepare an emulsion, and added to each of the above spectrally sensitized emulsions. , mixed. A hardener was added to these emulsions, and then coated on a resin-coated paper support at a silver content of 4 mg/100 cat and dried to prepare sample fish 9 to 16.

These samples were wedge-exposed through a red filter and developed with a developer having the following formulation at 38° C. for 2 minutes and 30 seconds.

4-Amino-3-methyl-N-ethyl-N-(β-methanesulfonamidoethyl)aniline sulfate 5 g Sodium sulfite (anhydrous) 0.3 g Sodium carbonate (monohydrate) 15 g Potassium bromide 0.3 g Water 11 (adjusted to pH 10.2β with sodium hydroxide) However, at the start of development 20
After a few seconds, the entire surface was uniformly exposed to white light for 10 seconds. Then, it was bleach-fixed, washed with water, and dried in a conventional manner.

The sensitivity results of the obtained cyan positive images are shown in Table 6. As is clear from the results in Table 6, the samples according to the present invention have higher sensitivity than the comparative samples.

In addition, the sensitivity and minimum density (
Dmin) results are shown in Table 7.

As is clear from the results in Table 7, the samples according to the present invention have small sensitivity fluctuations due to changes in development processing time, small increase in minimum density, and are found to have excellent development processing stability.

Example 5 <Single layer coating and processing conditions for yellow> The yellow coupler α-(4-(1-benzyl-2-
Phenyl-3,5-dioxo-1,2,4-)riazolidinyl)]-]α-pivalyl-2-chloro5-γ-(
An emulsion of 2,4-di-t-amylphenoxy)butyramide]acetanilide dispersed in oil protection was added and mixed, and a hardener was further added to prepare an emulsion.

Next, the emulsion was deposited on a resin-coated paper support in an amount of 5 mg/silver.
Samples Nos. 17 to 24 were prepared by applying the coating to 1100 cr.

These samples were wedge-exposed to white light and developed with the developer used in the examples at 38° C. for 2 minutes and 30 seconds.

However, the entire surface was uniformly exposed to white light for 10 seconds from 20 seconds after the start of development. Then, it was bleach-fixed, washed with water, and dried in a conventional manner.

Table 8 shows the sensitivity results of the yellow positive image obtained.

As is clear from the results in Table 8, it can be seen that the samples according to the present invention have higher sensitivity than the comparative samples.

Table 9 shows the results of the sensitivity and minimum density (Dmin) of the yellow positive images obtained by processing the samples in the same manner except that the development processing time was changed.

As is clear from the results in Table 9, the samples according to the present invention have small sensitivity fluctuations due to changes in development processing time, small increases in minimum density, and are found to have excellent development processing stability.

Example 6 Multilayer coating and processing conditions> The emulsion (C) used in the example was divided into three parts, and a part of the sensitizing dye anhydro-9-ethyl-3,3°-di(3-sulfopropyl)- A red-sensitive emulsion was prepared by spectrally sensitizing using 5,5-dichlorothiacarbocyanine hydroxide.

Another part of the sensitizing dye anhydro-9-ethyl-3,3'
A green-sensitive emulsion was prepared by spectrally sensitizing using -di(3-sulfopropyl)-5,5'-diphenyloxacarbocyanine hydroxide. Still another part is the sensitizing dye anhydro-3-sulfopropyl)-31-carboxymethyl-5
A blue-sensitive emulsion was prepared by spectrally sensitizing using 5g-dichlorothiacarbocyanine hydroxide.

Sample area 25 was prepared by sequentially applying the following layers onto a resin-coated paper support from the support side. In addition, the emulsion prepared in Example 1 (except for changing the emulsion using phantom),
A sample plate 26 was prepared in exactly the same manner.

(1) Red-sensitive emulsion layer The above-mentioned red-sensitive emulsion (5 mg/100a in terms of silver)
and an oil-protected dispersed cyan coupler (same as the cyan coupler used in Example 2, 0.45 mol per mol of silver halide).

(2) Intermediate layer oil protection Contains dispersed 2,5-di-t-octylhydroquinone.

(3) Green-sensitive emulsion layer The above-mentioned green-sensitive emulsion (5 mg/100cj in terms of silver)
) and oil-protected dispersed magenta coupler (same as the magenta coupler used in the example, silver halide 1)
0.25 mole per mole).

(4) Yellow filter layer yellow colloidal silver and oil protection dispersed 2
, 5-di-t-octylhydroquinone.

(5) Blue-sensitive emulsion layer The above-mentioned blue-sensitive emulsion (6 mg/100 cd in terms of silver)
) and an oil-protected dispersed yellow coupler (same as the yellow coupler used in Example 3, 0.45 mol per mol of silver halide).

(6) Protective layer gelatin layer.

After drying, sample areas 25 and 26 were exposed to a wedge of white light and developed with the developer used in the example at 38° C. for 2 minutes and 50 seconds. However, from 10 seconds after the start of development, the entire surface was uniformly fog-exposed to white light for 10 seconds. Then, it was bleach-fixed, washed with water, and dried.

After drying, 11 m25.26 of the sample was treated in the same manner as in Example 3.

The results of the positive images obtained are shown in Table IO.

Table 10 is shown below in the margin. As is clear from the results in Table 10, the samples according to the present invention are found to have high sensitivity and excellent development processing stability.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a direct positive type silver halide photographic light-sensitive material which is highly sensitive and has excellent development stability with small sensitivity fluctuations and minimum density with respect to development processing time.

Claims (1)

[Scope of Claims] 1. In a direct positive silver halide photographic light-sensitive material having at least one silver halide emulsion layer on a support, at least one of the silver halide emulsion layers is an outermost shell. is a core/shell type internal latent image type silver halide grain formed from silver halide containing silver chloride, and the ratio of the grain thickness to the major axis is 1:8 or more. A direct positive silver halide photographic material containing silver halide grains.