JPH0812387B2 - Silver halide photographic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to a silver halide photographic light-sensitive material, and in particular, has no loss of sensitivity, enhances optical sharpness, and is obtained in a single emulsion. The present invention relates to an X-ray photographic light-sensitive material having high gradation.

(2) Prior Art Black-and-white silver halide photography relies on developing silver to produce a visible image. With medical radiographs, lesions are diagnosed based on the density of the image silver, but when observing a lesion with a small difference in X-ray transmittance, the gradation is high and the image outline is clear. It is required to be described in. As medical diagnostics have become more sophisticated in recent years and the number of observations of soft tissues such as the breast has increased, the demand for them has become stronger and stronger.

Conventionally, in medical radiography, methods for improving sharpness and increasing gradation are known. As a method of improving the sharpness, there are crossover using a large amount of spectral sensitizing dyes, provision of an anti-halation layer, etc. Examples include utilizing development and monodispersion of silver halide grains.

However, when a large amount of dye is used to improve the sharpness, color contamination is likely to occur after the development processing, and the contrast is likely to decrease. This is particularly noticeable when the amount of coated silver is large. When the antihalation layer is used, there is a large loss of sensitivity and the contrast is reduced.

Further, it is known that when softening and infectious development are used as means for increasing gradation, the graininess of the image contour is roughened and the sharpness is lowered. In addition, if a film or a developing effect is used in addition to the above, the dependency on the processing liquid is large and the performance tends to move.

Even when the silver halide grain size monodispersion is used, the light reaching the grains located near the support is surely reduced as compared with the grains on the surface of the photosensitive material. is there. In particular, it is remarkable when the coated silver amount is large.

Therefore, a technique for simultaneously improving the sharpness without increasing the sensitivity and increasing the gradation is still insufficient.

(3) Object of the Invention It is an object of the present invention to provide a silver halide photographic light-sensitive material capable of improving the sharpness without any loss of sensitivity and simultaneously satisfying the gradation.

The present inventor has paid attention to the fact that no matter how monodisperse emulsion is used, the amount of light reaching near the support is reduced, resulting in desensitization. It was found that the emulsion has a special photographic property by using an emulsion having a layer structure and different sensitivities for each layer.

(4) Disclosure of the Invention The above-mentioned object of the present invention is to provide a photographic light-sensitive material having at least two spectrally sensitized silver halide emulsion layers on one side on a support, in which the emulsion layer in the vicinity of the support is provided. The content of the spectral sensitizing dye is 5 to 100% higher than the content of the spectral sensitizing dye in the upper emulsion layer, and the photosensitivity of the lower emulsion layer after spectral sensitization is 30 to 150% of that of the upper layer. It was achieved by a silver halide photographic light-sensitive material characterized by high sensitivity.

The content of the spectral sensitizing dye in the present invention is characterized in that the content of the lower emulsion layer is 5 to 100% higher than that of the upper emulsion layer, but it is particularly preferably 10 to 80%.

Here, the comparison of the photosensitivity is generally expressed by the reciprocal of the exposure amount required to obtain a constant blackening density, but in the present invention, it can be expressed by the relative sensitivity of the lower layer to the upper layer. .

The characteristics obtained in the present invention are that even if the type of processing solution and the processing temperature are changed, the silver halide emulsion layer can obtain a high gradation without degrading the sensitivity as compared with a single light-sensitive material, and the lower layer. The larger the amount of dye added, the more characteristic is that the anti-halation effect is produced and the optical sharpness is improved. In particular, this is remarkable in a single-sided X-ray sensitive material having a large amount of coated silver on one side. In particular, it is remarkable in a light-sensitive material in which the amount of coated silver on one side is 3 g / m ² or more, particularly 5 g / m ² or more. Thus far, there has never been a radiation sensitive material capable of obtaining such a high gradation and improving the optical sharpness at the same time. The above effects can be obtained for the first time by using the above-mentioned layer structure and using silver halide having different photosensitivity for each layer.

As the silver halide of the photosensitive silver halide emulsion used in the present invention, silver chlorobromide, silver bromide, silver iodobromide and silver chloroiodobromide can be used, but silver iodobromide is preferable. Used. Here, the content of silver iodide is preferably 10
It is preferably in the range of mol% or less, particularly 5 mol% or less. Regarding the silver iodide content in each layer, it is particularly preferable that the silver iodide content in the layer closer to the support is smaller for the color stain after the processing. The distribution of iodine in the silver iodobromide grains may be uniform, or may be different between the inside and the surface. The average particle size is preferably 0.4 μm or more. It is particularly preferably 0.5 to 2.0 μm. The particle size distribution may be narrow or wide.

The silver halide grains in the emulsion may have a regular crystal form such as a cube, an octahedron, a tetrahedron and a rhombohedron, and may also have a spherical shape, a tabular shape, a square or a potato shape. It may consist of a mixture of grains of different crystal forms, which may have irregular crystal forms or composite forms of these forms. Further, tabular grains having a grain size of 5 times the grain thickness or more are preferably used in the present invention (more specifically, RESEARCH DISCLOSUR
E 225, Item 22534, P.20 to P.58, January issue, 1983, and JP-A Nos. 58-127921 and 58-113926).

In the present invention, the photosensitive silver halide emulsion may be a mixture of two or more kinds of silver halide emulsions for each layer. The emulsions to be mixed may differ in grain size, halogen composition, sensitivity, etc. The light-sensitive emulsion may be used as a mixture of a substantially non-light-sensitive emulsion (the surface or inside may or may not be fogged), or it may be divided into different layers ( For details, refer to U.S. Patent No. 2,996,382,
3,397,987 etc.) For example, a light-sensitive silver halide emulsion consisting of a spherical or sword-like light-sensitive emulsion and a tabular grain having a grain diameter of 5 times or more the grain thickness is used in the same layer or as described in JP-A-58-127921. It may be used for different layers. When used in different layers, the light-sensitive silver halide emulsion consisting of tabular grains may be on the side closer to the support or conversely on the side farther from the support. However,
The sensitivity of each layer must be as high as that of the layer closer to the support.

The photographic emulsion used in the present invention is Chimi by P. Glafkides.
e et Physique Photographique (Paul Montel, 196
7 years), Photographic Emulsion Chemist by GF Duffin
ry (The Focal Press, 1966), VLZelikman et a
l Making and Coting Photographic Emulsion (The
Published by Focal Press, 1964), JP-A-58-127921 and 58
-113926 can be used for adjustment. That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and as a method of reacting a soluble silver salt and a soluble halogen salt, any of a one-sided mixing method, a simultaneous mixing method and a combination thereof may be used. .

It is also possible to use a method of forming silver halide grains in the presence of excess silver ions (so-called reverse mixing method).
As one form of the double jet method, a method of keeping pAg constant in a liquid phase in which silver halide is produced, that is, a so-called controlled double jet method can be used. According to this method, a silver halide emulsion comprising silver halide grains having a regular crystal form and a substantially uniform grain size can be obtained.

Even if the crystal structure of the silver halide grains is uniform to the inside, it also has a layered structure in which the inside and the outside are heterogeneous, as described in British Patent 635,841 and U.S. Patent 3,622,318, It may be a so-called conversion type. Further, silver halides having different compositions may be bonded by epitaxial bonding, or may be bonded with a compound other than silver rhodanide and silver oxide, for example.
Further, it may be either a surface latent image type or an internal latent image type. In the process of silver halide grain formation or physical ripening during the production of silver halide, cadmium salt, zinc salt,
A lead salt, a thallium salt, an iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, an iron salt, an iron complex salt or the like may coexist.

During grain formation, so-called silver halide solvents such as ammonia, thioether compounds, thiazolidine-2-thione, tetra-substituted thioureas, rhodancali, rhodammone and amine compounds may be present to control grain growth.

The silver halide emulsion used in the present invention may or may not be chemically sensitized. As the chemical sensitization method, known methods such as a sulfur sensitization method, a reduction sensitization method and a gold sensitization method can be used, and they can be used alone or in combination.

Among the noble metal sensitizing methods, the gold sensitizing method is a typical one, which uses a gold compound, mainly a gold complex salt. Noble metals other than gold, for example, complex salts of platinum, palladium, iridium, etc. may be contained.

As the sulfur sensitizer, various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanins and the like can be used in addition to the sulfur compounds contained in gelatin.

As the reduction sensitizer, a primary tin salt, amines, formamidine sulfinic acid, a silane compound or the like can be used.

The photographic emulsion used in the present invention may contain various compounds for the purpose of preventing fog during the production process of the light-sensitive material, during storage or during photographic processing, or stabilizing photographic performance. That is, azoles {eg benzothiazolium salts, nitroimidazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, nitroindazoles, benzotriazoles, aminotriazoles, etc.); mercapto compounds {eg mercapto Tothiazoles,
Mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, mercaptotetrazoles (particularly 1-phenyl-5-mercaptotetrazole), mercaptopyrimidines, mercaptotriazines, etc .; thioketo compounds such as oxadrinethione; azaindene (Eg, triazaindenes, tetraazaindenes (particularly 4-hydroxy-substituted (1,3,3a, 7) tetraazaindenes), pentaazaindenes, etc.); benzenethiosulfonic acid, benzenesulfinic acid, Many compounds known as antifoggants or stabilizers, such as benzene sulfonic acid amide, can be added.

Specifically, RESERCH DISCLOSER Item 17643 VI (1978
December issue, P.24 to P.25), or the documents cited or cited.

Particularly, nitrones and their derivatives described in JP-A-60-76743 and JP-A-60-87322, mercapto compounds described in JP-A-60-80839, and heterocycles described in JP-A-57-164735. A compound, a heterocyclic compound and a silver complex salt (for example, 1-phenyl-5-mercaptotetrazole silver), and the like can be preferably used.

The spectral sensitizing dye used in the present invention may be a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holoholer cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye or the like. it can.

The wavelength region for spectral sensitization may be blue light, green light, red light, or infrared light.

Useful sensitizing dyes used in the present invention are, for example, RESERCH
DISCLOSURE Item 17643 Item IV-A (December 1978 P.23), the same
Item 18431 Item X (P.437, August 1979) or cited.

Here, the sensitizing dye can be used by being present in any step of the production process of the photographic emulsion, or can be present in any stage after production until immediately before coating. Examples of the former include a silver halide grain forming step, a physical ripening step,
For example, the chemical aging process.

 Preferably, it is added before the chemical ripening.

The photographic emulsion layer or other hydrophilic colloid layer of the light-sensitive material prepared by using the present invention may have coating aids, antistatic, slipperiness improvement, emulsification / dispersion, adhesion prevention and photographic property improvement (eg, development acceleration, high contrast For various purposes such as sensitization), various surfactants may be contained.

For example, saponins (steroids), alkylene oxide derivatives (eg polyethylene glycol, polyethylene glycol / polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkylaryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycols). Nonionics such as alkylamines or amides, polyethylene oxide adducts of silicones), glycidol derivatives (eg alkenylsuccinic acid polyglyceride, alkylphenol polyglycide), fatty acid esters of polyhydric alcohols, alkyl esters of sugars, etc. Surfactants; alkyl carboxylates, alkyl sulphonates, alkyl benzene sulphates Acid salts, alkylnaphthalene sulfonates, alkyl sulfates, alkyl phosphates, N-acyl-N-alkyl taurines, sulfosuccinates, sulfoalkyl polyoxyethylene alkyl phenyl ethers, polyoxyethylene Anionic surfactants containing acidic groups such as carboxy groups, sulfo groups, phospho groups, sulfate ester groups, phosphate ester groups such as alkyl phosphates; amino acids, aminoalkyl sulfonates, aminoalkyl sulfates or Amphoteric surfactants such as phosphoric acid esters, alkyl betaines, amine oxides: alkyl amine salts,
Aliphatic or aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts such as pyridinium and imidazolium, and cationic surfactants such as phosphonium or sulfonium salts containing aliphatic or heterocyclic rings can be used.

As the antistatic agent, in particular, JP-A-59-74554 and 60-8
0849, Japanese Patent Application Nos. 60-249021, 61-32462, and fluorine-containing surfactants or polymers described in JP-A-60-76742,
No. 60-80846, No. 60-80848, No. 60-80839, No. 60-767
No. 41, No. 58-208743, Japanese Patent Application No. 61-13398, No. 61-16056
No. 61-32462, and the like, or nonionic surfactants described in JP-A-57-204540 and Japanese Patent Application No. 61-
The conductive polymer or latex (nonionic, anionic, cationic, amphoteric) described in No. 32462 can be preferably used. Inorganic antistatic agents include ammonium, alkali metal, and alkaline earth metal halogen salts,
Nitrates, persalts, sulfates, acetates, phosphates, thiocyanates, etc., can be used as conductive tin oxide, zinc oxide or metal oxides thereof as described in JP-A-57-118242. A composite oxide doped with antimony or the like can be preferably used.

In the present invention, a homoponomer of polymethylmethacrylate or a polymer of methylmethacrylate and methacrylic acid, an organic compound such as starch, and fine particles of an inorganic compound such as silica and titanium dioxide can be used as a matting agent. The particle size is 1.0 to 10 μm, especially 2
It is preferably ˜5 μm.

In the surface layer of the photographic light-sensitive material of the present invention as a slip agent U.S. Pat.No. 3,489,576, silicone compounds described in 4,047,958 and the like, in addition to colloidal silica described in Japanese Patent Publication No. 56-23139, Paraffin wax, Higher fatty acid ester, den powder derivative and the like can be used.

Polyols such as trimethylolpropane, pentanediol, butanediol, ethylene glycol and glycerin can be used as a plasticizer in the hydrophilic colloid layer of the photographic light-sensitive material of the present invention. Furthermore, the hydrophilic colloid layer of the photographic light-sensitive material of the present invention preferably contains a polymer latex for the purpose of improving pressure resistance. As the polymer, a homopolymer of an alkyl ester of acrylic acid, a copolymer with acrylic acid, a styrene-butadiene copolymer, or a polymer or copolymer comprising a monomer having an active methylene group can be preferably used.

The photographic emulsion and the non-photosensitive hydrophilic colloid of the present invention may contain an inorganic or organic hardener. For example, chromium salts (chromium alum, etc.), aldehydes (formaldehyde, glitalaldehyde, etc.), active vinyl compounds (1,3,5-triacryloyl-hexahydro-s-triazine, bis (vinylsulfonyl) methyl ether,
N, N′-methylenebis- [β- (vinylsulfonyl) propionamide], etc.), active halogen compounds (2,4-
Dichloro-6-hydroxy-s-triazine etc.), mucohalogen acids (mucochloric acid etc.) and the like can be used alone or in combination. Among them, JP-A-53-4
The active vinyl compounds described in 1220, 53-57257, 59-162546, and 60-80846 and the active halides described in US Pat. No. 3,325,287 are preferable.

When the light-sensitive material of the present invention is used as an X-ray sensitive material, the hydrophilic colloid layer is hardened by these hardeners so that the swelling ratio in water is 200% or less, particularly 150% or less. preferable.

As the binder or protective colloid that can be used in the emulsion layer or intermediate layer of the light-sensitive material of the present invention, it is advantageous to use gelatin, but other hydrophilic colloids can also be used.

For example, 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, sugar derivatives such as dextran and starch derivatives; polyvinyl alcohol, A wide variety of synthetic hydrophilic polymer substances such as polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polyacrylamide, and other single or copolymers can be used.

As the gelatin, besides lime-processed gelatin, acid-processed gelatin or enzyme-processed gelatin may be used, and a hydrolyzate of gelatin may also be used.

Among these, it is preferable to use dextran and polyacrylamide together with gelatin.

The silver halide photographic light-sensitive material of the present invention may have a non-light-sensitive layer such as a surface protective layer, an intermediate layer and an anti-halation layer in addition to the light-sensitive silver halide emulsion layer.

However, the number of silver halide emulsion layers must be two or more on one side, and the closer the layer is to the support, the higher the sensitivity.

Of course, the number of emulsion layers on one side may be three or more, and it is preferable that the emulsion layers closer to the support are provided in the order of higher sensitivity.

A preferable range of the coating silver amount for each layer in such a layer structure is 0.5 to 5.0 g / m ² , and a particularly preferable range is 1.0.
~ 3.0 g / m ² .

The thickness of each layer is preferably 0.1 to less than 5.0 microns, and particularly preferably 0.5 to 3.0 microns.

The gradation of the emulsion used in each layer is not defined, but the gradation of the emulsion in the upper layer is preferably higher than that in the lower layer.

Further, it may have two or more silver halide layers or one or two or more non-photosensitive layers on both sides of the support.

A cellulose triacetate film is preferable as a support for a general light-sensitive material, and either may be colored or may not be colored for antihalation.

A polyethylene terephthalate film or a cellulose triacetate film is preferable as the support for the X-ray photographic light-sensitive material, and particularly preferably colored blue.

The support is preferably a corona discharge treatment, a glow discharge treatment or an ultraviolet irradiation treatment on the surface thereof in order to improve the adhesion with the hydrophilic colloid layer, or a styrene butadiene type latex or a vinylidene chloride type latex. You may provide an undercoat layer,
You may further provide a gelatin layer on it. An undercoat layer using an organic solvent containing a polyester swelling agent and gelatin may be provided. By applying a surface treatment to these undercoat layers, the adhesion with the hydrophilic colloid layer can be further improved.

The present invention can be used in any photographic light-sensitive material which is subjected to ordinary development processing. For example, X
It is used for line photographic light-sensitive materials, lith type photographic light-sensitive materials, black and white negative photographic light-sensitive materials, color negative light-sensitive materials, color reversal light-sensitive materials, color paper light-sensitive materials, black-and-white paper light-sensitive materials.

When used as a photographic material for X-rays,
RESEARCH DISCLOSURE Item 18431 (August 1979 P.433 ~
P.441) Stabilizer, antifoggant and anti-knitting technology (P.433 to P.436), protective layer technology (P.436, IV), crossover control technology (P.436). 436, item V) and the like are preferably used.

To obtain an X-ray photographic image, the exposure may be carried out by using a usual method. That is, it is a method of exposing a photosensitive material having photosensitive layers on both sides with two fluorescent intensifying screens and exposing it to X-rays.

Alternatively, in the case of a photosensitive material having a photosensitive layer on one side, a method of irradiating a fluorescent intensifying screen with X-rays and recording the emitted light on the photosensitive material is used. Of course, the photosensitive material may be brought into contact with the fluorescent intensifying screen to perform X-ray irradiation. As the fluorescent material, fluorescent materials such as blue-emitting calcium tungstate and barium sulfate, and green-emitting rare earth fluorescent materials are used. In addition, after accumulating X-ray exposed materials in the phosphor, various light sources including infrared light such as cathode ray tube flying spot, light emitting diode, laser light (eg gas laser, YAG laser, dye laser, semiconductor laser, etc.) It can also be exposed.

For photographic processing of the light-sensitive material of the present invention, for example, research
Day Disciers No. 176, No. 28 ~
Any known method and known processing solution as described on page 30 (RD-17643) can be applied.
This photographic processing may be either photographic processing for forming a recorded image (black and white photographic processing) or photographic processing for forming a dye image (color photographic processing) depending on the purpose. The treatment temperature is usually selected between 18 ° C and 50 ° C, but 18 ° C
Lower temperatures or temperatures above 50 ° C may be used.

For example, the developing solution used for black and white photographic processing can contain a known developing agent. Examples of developing agents include dihydroxybenzenes (for example, hydroquinone) and 3-pyrazolidones (for example, 1-phenyl-3).
-Pyrazolidone), aminophenols (for example, N-methyl-p-aminophenol) and the like can be used alone or in combination. For the photographic processing of the light-sensitive material of the present invention, it is also possible to perform processing with a developing solution containing imidazoles as a silver halide solvent described in JP-A-57-78535. Further, it can be processed with a developer containing a silver halide solvent described in JP-A-58-37643 and an additive such as indazole or triazole. Generally, other known preservatives, alkaline agents, pH buffers,
Including antifoggants, etc., if necessary, dissolution aids,
A color tone agent, a development accelerator, a surfactant, a defoaming agent, a water softener, a hardener (eg glutaraldehyde), a viscosity imparting agent and the like may be contained.

As the fixer, one having a commonly used composition can be used. As the fixing agent, in addition to thiosulfates and thiocyanates, organic sulfur compounds known to be effective as a fixing agent can be used. The fixing solution may contain a water-soluble aluminum salt as a hardening agent.

(Example-1) In a gelatin solution containing potassium iodide and potassium bromide in advance, a potassium bromide solution and an ammoniacal silver nitrate solution were sequentially mixed by a double jet method to obtain an iodide content of 2.
8 mol% of silver iodobromide twin polydisperse grains were prepared. (Average particle size 0.65 micron) After washing with water, after adding 43gGel to 100g of AgNO ₃ p
After adjusting to H6.8, an unripened emulsion (E-1) was obtained.

This unripened emulsion (E-1) was prepared according to US Pat. No. 1,574,944.
And a sulfur compound as described in No. 5, and are chemically sensitized with potassium dihydrogen auronate, and anhydro-5,
5-Di-chloro-9-ethyl-3,3-di (3-sulfopropyl) oxacarbocyanine hydroxide sodium salt was added to prepare 5 types of emulsions having different sensitivities shown in Table 1.

The emulsion thus obtained contains 3-
Sodium (5-mercaptotetrazolyl) benzenesulfonate and the like and a coating aid were added to prepare a coating liquid for the emulsion layer.

Further, as a protective layer, a coating aid of bis-type polyethylene oxide, a fluorocarbon-based surfactant and an anionic surfactant and a matting agent of polymethylmethacrylate, a polysiloxane-based sliding agent, a hardener (2,4- Dichlor-6-
A gelatin solution containing (hydroxy-s-triazine) was prepared.

The emulsion layers are composed of the combination shown in Table 2 (the upper layer is O
3) together with the protective layer on the PET support on which the anti-halation layer had been previously coated on BACK so that the amount of silver coated on one side was 4.0 g / m ² in multiple layers. The amount of silver in each layer was 2.0 g / m ² .

The relative sensitivities in Tables 1 and 2 were obtained by determining the exposure amount at the point where the optical density was at the point where Fog was 1.0, and the reciprocal thereof was used as an index of sensitivity, and the relative sensitivity was obtained from this value.

(Treatment and Evaluation Method) The coated sample was exposed to FILM on a continuous wedge for 1/2 second using a green filter. This sample was subjected to the automatic processing shown below.

That is, photographic processing was performed with a trademark Fuji FPM4000, which is a conventional commercial radiographic photo processor. Development time is 35C
21 ″. As the developing solution, Fuji FILM RD-V was used,
After fixing, washing with water and drying, sensitometry was carried out by a usual method.

The sharpness was evaluated by contacting the CTF measurement chart with a rectangular wave of 0.8-10 line / mm with a rectangular wave made of lead on the back side of the front side of the fluorescent screen and measuring the density of the area not shielded by the rectangular wave of lead. Was irradiated with X-rays so as to be 1.0, and after treatment, scanning measurement was performed in the direction perpendicular to the rectangular wave using a Fuji microdensitometer. At this time, the aperture size is 230 μm in the parallel direction of the rectangular wave and 25 in the perpendicular direction.
Micrometer, magnification is 100 times. As in the case of Strips, the processing was carried out using a developing machine FPM4000 with a development time of 35 ° 21 ″.

FIG. 1 shows the change in gradation of the sensitivity difference between the O layer and the U layer. In the case of a single layer, it is possible to obtain a high gradation that cannot be achieved.

Figure 2 shows the difference in CTF between the A-1 emulsion alone and the A / B combination. Clearly the A / B combination is better.

It should be noted that the gradation is such that the optical density becomes Fog + 0.25 and Fog +
It was calculated from the tan θ by connecting the points to 2.0.

(Example-2) 30 g of gelatin, 5 g of potassium bromide and 0.0 g of potassium iodide in 1 water.
5 g was added, and an aqueous solution of silver nitrate (5 g as silver nitrate) and an aqueous solution of potassium bromide containing 0.75 g of potassium iodide were added to the container kept at 75 C by a double jet method over 1 minute. Further, an aqueous silver nitrate solution (145 g as silver nitrate) and an aqueous potassium bromide solution were added by the double jet method. At this time, the addition rate was accelerated so that the flow rate at the end of the addition was 8 times that at the start of the addition. Then add potassium iodide aqueous solution 0.37
g was added. (Average particle size 0.65μ) Similar to (Example-1), after washing with water, 150g of AgNO ₃ and 6
After adding 5 g of Gel, the pH was adjusted to 6.8 and the unripened emulsion (E-
I got 2). This emulsion was chemically sensitized in the same manner as in Example 1,
Five kinds of emulsions having different sensitivities were prepared and coated with the same formulation as in Example-1. Table 3 shows the amount of dye added and the difference in sensitivity, and Table 4 shows the combinations of coating. The results are shown in Figures 3 and 4. As in Example-1, the gradation became harder and the sharpness improved. The processing and evaluation methods are the same as those in Example-1.

(Example-3) For the O layer, the unripened emulsion (E-) prepared in Example-1 was used.
The emulsion (A-1) chemically sensitized in 1) was used, and in the U layer,
Emulsions (B-1 to B-4) obtained by chemically sensitizing the unripened emulsion (E-2) prepared in Example-2 were used.

Emulsion No., dye addition amount and relative sensitivity are shown in Table-5.

The combinations of the above emulsions are shown in Table-6. The application was performed with the same formulation as in Example 1 and Example 2.

The samples (1) to (5) described above are used in Example-1 and Example-
Treatment and evaluation according to 2. Figure-5 shows photographic characteristics and Figure-6
Shows the results of sharpness. Even with a combination of silver halides having different compositions, the gradation becomes hard and the sharpness is improved as in Examples 1 and 2. In addition, this embodiment-
In No. 3, although the amount of the dye used is larger than that in Example-1, the iodine content of the silver halide in the lowermost layer is small, and thus the color contamination after the processing is small, which is preferable.

[Brief description of drawings]

FIG. 1 shows the relationship between relative sensitivity difference and gradation in Example-1, where the horizontal axis represents relative sensitivity difference (%) and the vertical axis represents gradation. FIG. 2 shows the sharpness of each sample (-) of Example-1, the horizontal axis represents the spatial frequency, and the vertical axis represents the CTF value. FIG. 3 shows the relationship between the relative sensitivity and the gradation in the example, and FIG. 4 shows the comparison of the sharpness of the sample of example-2 and the sharpness of the samples. FIG. 5 shows the relationship between the relative sensitivity difference and the gradation in Example-3, and FIG. 6 shows the comparison of the sharpness of each sample in Example-3.

Claims (1)

[Claims] 1. A photographic light-sensitive material having at least two spectrally sensitized silver halide emulsion layers on one side of a support, the content of the spectral sensitizing dye in the emulsion layer adjacent to the support. Is higher than the content of the spectral sensitizing dye in the upper emulsion layer by 5
The silver halide photographic light-sensitive material is characterized in that the light sensitivity after spectral sensitization of the lower emulsion layer is higher than that of the upper layer by 30 to 150%.