JPH07152102A - Silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE:To provide the silver halide photographic sensitive material for X-ray photography improved in sharpness and graininess and wide in exposure latitude. CONSTITUTION:This silver halide photographic sensitive material is characterized by containing in a silver halide emulsion layer silver halide grains comprising at least each one kind of flat grains having an aspect ratio of >=3 and a grain diameter of >=0.5mum in terms of a true circle, the grains having an aspect ratio of <=2 and a grain diameter of 0.2-0.5mum in terms of a true sphere, having an average silver iodide content of <=2.0mol% in the total silver halide grains, and having a 0.4-0.7 of gradient (gamma1) of a line joining a point of 0.3 with a point of 0.5 of optical density and a 1.5-2.0 gradient (gamma2) of a line joining a point of 0.5 with a point of 1.5 of optical density and a 2.8-3.5 gradient of a line (gamma3) joining a point of 1.0 with a point of 2.0 of optical density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical silver halide photographic light-sensitive material having excellent diagnostic ability, more specifically, a silver halide photographic light-sensitive material for X-rays having improved sharpness and graininess and a wide exposure latitude. Regarding

[0002]

2. Description of the Related Art In medical silver halide photographic light-sensitive materials for X-rays, an image with good sharpness and excellent graininess is obtained in order to avoid early detection and misdiagnosis of lesions by photographing each part of a living body. Required. Improvement of sharpness and graininess of the light-sensitive material is very important for enhancing the diagnostic ability because it affects the visibility of an image and the amount of information.

[0003] Generally, the trachea of the stomach, chest, limbs, and the like is mentioned as a living body site where X-rays are most frequently taken, but in order to improve the diagnostic ability in these radiographs, it is wide from a low-concentration region to a high-concentration region. There is a need for an image having excellent exposure latitude (latitude) and moderate density, and having excellent sharpness without the image being crushed or skipped.

In general, gamma (γ) is a parameter that determines the exposure latitude of a light-sensitive material, but the commercially available light-sensitive materials for X-ray photography are roughly classified into high γ type, low γ type and moderate γ type. There are three types, each of which is used separately.

However, the high γ type of these films has excellent sharpness, but on the other hand, it has a drawback that the image of the low exposed portion is crushed and the amount of information is reduced, and the low γ type has a wide exposure latitude. Although it has excellent information content, it has a drawback that it lacks in sharpness, and the medium γ type has both advantages and disadvantages in that both sharpness and exposure latitude are moderate and lacking in features.

Further, since the X-ray absorptivity varies depending on the body type of the examiner, it is very difficult to determine the optimum exposure dose for each individual during a mass examination of a large number of people.

A large number of techniques have been proposed in the past for improving and improving photographic performance such as contrast, graininess and sharpness with respect to silver halide emulsions.
No. 214027 proposes a silver halide photographic light-sensitive material for X-rays which defines a gamma (γ) obtained by using a specific developing solution, and further gamma (γ1 to γ3) in a specific range.
Japanese Patent Application Laid-Open No. 61-116346 is disclosed.

However, most of the conventional techniques including these techniques are medical ones capable of improving both sharpness and latitude at the same time, and enhancing the diagnostic ability for any imaging of a living body part as described above. The current situation is that a silver halide photographic light-sensitive material has not yet been obtained.

[0009]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems of the prior art, to improve sharpness and graininess, and to provide a silver halide photographic light-sensitive material for X-ray having a wide exposure latitude. To provide.

[0010]

The objects of the present invention have been achieved by the following.

(1) In a silver halide photographic light-sensitive material having at least one silver halide emulsion layer on a support, the silver halide grains in the emulsion layer have an aspect ratio of 3
Above, tabular grains having an equivalent circle diameter of 0.5 μm or more and one or more grains each having an aspect ratio of 2 or less and a sphere-converted grain size of 0.2 μm or more and 0.5 μm or less are contained, respectively, and the average iodide of all silver halide grains is contained. The silver halide content is 2.0 mol% or less, and the slope (γ1) of the line connecting the points of optical density 0.3 and 0.5 in the characteristic curve of the obtained image is 0.4 to 0.7, the optical density is 0.5.
A silver halide photographic light-sensitive material characterized in that the slope (γ2) of the line connecting points 1.5 and 1.5 is 1.5 to 2.0, and the slope (γ3) of the line connecting optical densities 1.0 and 2.0 is 2.8 to 3.5.

(2) In a silver halide photographic light-sensitive material having at least two silver halide emulsion layers on a support, the silver halide grains in the emulsion layer farthest from the support have an aspect ratio of 3 or more. Is a tabular grain having a circle-equivalent diameter of 0.5 μm or more, and the silver halide grain in any emulsion layer near the support with respect to the emulsion layer has an aspect ratio of 2 or less and a sphere-converted grain size of 0.2 μm or more Particles of 0.5 μm or less,
The average silver iodide content of all silver halide grains is 2.0 mol% or less, and the slope (γ1) of the straight line connecting the optical density points 0.3 and 0.5 in the characteristic curve of the light-sensitive material is 0.4 to
At 0.7, the slope of the line connecting the points of optical density 0.5 and 1.5 (γ
2) The silver halide photographic light-sensitive material is characterized in that the gradient (γ3) of the straight line connecting the optical densities of 1.0 and 2.0 is 2.8 to 3.5. (3) Fluctuation of tabular grains with an aspect ratio of 3 or more and circle equivalent diameter of 0.5 μm or more with a variation coefficient of 25% or more, and with an aspect ratio of 2 or less and a sphere-converted particle size of 0.2 μm or more and 0.5 μm or less The coefficient is less than 20% (1) and
A silver halide photographic light-sensitive material according to the item (2).

The present invention will be described in detail below. One of the two kinds of silver halide grains used in the present invention has an aspect ratio (ratio of equivalent circle diameter / grain thickness) of 3
Above, preferably 5-8 particles, equivalent circle diameter 0.5μm
As described above, tabular grains having a size of 0.8 μm to 2.0 μm are preferable.

The other one is a particle having an aspect ratio of 2 or less, preferably 1 to 1.5, and a sphere-converted particle diameter of 0.2 μm or more and 0.5 μm or less, preferably 0.3 μm or more and 0.4 μm or less.

In the present invention, the equivalent circle diameter means a diameter when a projected image of a grain is converted into a circular image having the same area, and the grain thickness means a distance between two principal planes of tabular grains facing each other. Say The projected area of a grain can be calculated from the sum of the grain areas.

The total projected area and the projected area for obtaining the grain diameter are 10,000 times to 50,000 times with an electron microscope for a silver halide crystal sample distributed on the sample stage to the extent that grains do not overlap. It can be obtained by taking a magnified image twice and measuring the particle diameter on the print or the area at the time of projection (the number of measurement is indiscriminately 1000 or more).

The thickness of the particles can be obtained by observing the sample obliquely with an electron microscope. In the present invention, the sphere-converted particle diameter is a diameter when each particle is converted into a sphere having the same volume. The grain volume can be determined from the grain projected area and grain thickness obtained by the above method.

In a particularly preferred embodiment of the present invention, the variation coefficient of tabular grains having an aspect ratio of 3 or more and a circle equivalent diameter of 0.5 μm or more is 25% or more, preferably 25% to 35%, and an aspect ratio of 2 or less. The variation coefficient of particles having a sphere-converted particle size of 0.2 μm or more and 0.5 μm or less is 20% or less, preferably 10% to 15%.

In the present invention, the coefficient of variation is expressed by the following equation.

(Particle size standard deviation) / (average particle size) × 100 = (coefficient of variation) (%) Here, the particle size measurement method is based on the above circle equivalent diameter measurement method, and the average particle size is a simple average. To do.

(Average particle size) = Σdini / Σni As a method for obtaining the emulsion used in the present invention, a gelatin solution containing seed particles is treated with a water-soluble silver salt solution and a water-soluble halide solution under the control of pAg and pH. There is a method of obtaining by the double jet method, and such means can be used.

In determining the addition rate, Japanese Patent Laid-Open No. 54-485
21 and 58-49938 can be referred to.

The silver halide composition of the silver halide emulsion used in the present invention may be silver iodobromide or silver iodochlorobromide containing 2.0 mol% or less of silver iodide, preferably 2.0 to 0.05 mol%. Silver halide may be used.

Regarding the halogen distribution in the grains, it may have a uniform structure or a layered structure (core / shell structure).

The silver halide photographic emulsion which can be used in the present invention may take any method such as an acidic method, a neutral method and an ammonia method, but a double jet method is used as a method of reacting a soluble silver salt and a soluble halogen salt. (Simultaneous mixing method)
Is preferably used.

As one form of the simultaneous mixing method, a method of keeping pAg in a liquid phase where silver halide is formed constant, that is, a so-called controlled double jet method can be used. According to this method, a silver halide emulsion having a regular crystal form and a substantially uniform grain size can be obtained.

Further, the present invention may have a grain forming step by supplying fine silver iodide grains (hereinafter referred to as "fine grains"). Since the grain size of fine grains controls the supply rate of iodine ions, the preferable grain size varies depending on the size of the silver halide grains of the host and the halogen composition, but those having an average equivalent spherical diameter of 0.3 μm or less are used. More preferably, it is 0.1 μm or less. In order for the fine particles to be laminated on the host particles by recrystallization, the particle size of the fine particles is preferably smaller than the equivalent spherical diameter of the host particles, and more preferably,
It is 1/10 or less of the equivalent diameter of this sphere. The halogen composition of the fine grains has a silver iodide content of 95 mol% or more, and is preferably pure silver iodide.

In the silver halide emulsion according to the present invention, various hydrophilic colloids for wrapping silver halide are used as a binder. For this purpose, gelatin as well as synthetic polymers such as polyvinyl alcohol and polyacrylamide, and photographic binders such as colloidal albumin, polysaccharides and cellulose derivatives may be used.

The silver halide emulsion used in the practice of the present invention has a pA suitable for chemical sensitization by removing soluble salts by an appropriate method after the growth of silver halide grains is completed.
Can be g-ion concentration. The coagulation method and the noodle washing method for removing soluble salts may be the method described in Research Disclosure (RD) .17643, and a preferable washing method is, for example, a sulfonic acid group described in JP-B-35-16086. And a desalting method using a polymer flocculant such as Exemplified G-3 and G-8 described in JP-A-63-158644.

The present invention relates to the optical density (D) of the obtained image.
And the characteristic curve on the rectangular coordinate system with the same unit length of the coordinate axis of the exposure dose (logE), the slope (γ1) of the line connecting the points of optical density 0.3 and 0.5 is 0.4 to 0.7, and the point of optical density 0.5 and 1.5 is connected. The slope of the straight line (γ2) is 1.5 to 2.0 and the optical density is 1.0
It is characterized in that the slope (γ3) of the straight line connecting 2.0 is 2.8 to 3.5.

In the present invention, the point of the density of the base (support) density + 0.3 on the characteristic curve, and the base (support)
The slope of the line connecting the density points of density +0.5 is expressed as (γ1), and similarly, the point of the density of base (support) +0.5 and the point of the density of base (support) +1.5 The slope of the straight line connecting the two is expressed as (γ2), and the slope of the straight line connecting the base (support) density +1.0 density point and the base (support) density +2.0 density point is expressed as (γ3). .

If the angle at which these straight lines intersect the exposure (logE) axis is θ, then γ = tan θ.

As an embodiment of the present invention, (γ1) is 0.4 to 0.7, (γ) in the characteristic curve on the rectangular coordinate obtained when processed under the following development processing conditions.
A silver halide photographic light-sensitive material having 2) of 1.5 to 2.0 and (γ3) of 2.8 to 3.5 is obtained.

<Processing conditions> The following developer-1 and fixer-1
Is processed in a roller-conveying type automatic developing machine according to the following steps.

Developer-1 Part-A (12 liter finish) Potassium hydroxide 450 g Potassium sulfite (50% solution) 2280 g Diethylenetetraamine pentaacetic acid 120 g Sodium hydrogencarbonate 132 g 5-Methylbenzotriazole 1.2 g 1-phenyl-5 -Mercaptotetrazole 0.2g Hydroquinone 340g Add water to finish to 5000ml Part-B (for finishing 12 liters) Glacial acetic acid 170g Triethylene glycol 185g 1-Phenyl-3-pyrazolidone 22g 5-Nitroindazole 0.4g Part-C (12 liters) For finishing) Glutaraldehyde bisulfite 180g Starter Glacial acetic acid 120g Potassium bromide 225g Add water to finish to 1000ml. Prepare the developer with approximately 5 liters of water Part-A, Part-B, Part-
C is added at the same time, water is added while stirring and dissolving to make 12 liter, and pH is adjusted to 10.40 with glacial acetic acid. This is used as a development replenisher, and 20 ml / l of the above starter is added to the development replenisher to adjust the pH to 10.26 to obtain a working solution.

Fixer-1 Part-A (for 18 liter finish) Ammonium thiosulfate (70wt / vol%) 6000g Sodium sulfite 110g Sodium acetate ・ trihydrate 450g Sodium citrate 50g Gluconic acid 70g 1- (N, N-dimethyl) Amino) -ethyl-5-mercaptotetrazole 18g Add water to make 6000ml Part-B Aluminum sulphate 800g Add water to make 1000ml To prepare a fixer, add about 5 liters of Part-A and Part-B at the same time. Then, while stirring and dissolving, water is added to make 18 liter, and then the pH is adjusted to 4.4 using sulfuric acid and NaOH. This is the fixing replenisher.

Processing step Development temperature 35 ° C. Fixing temperature 33 ° C. Washing temperature 20 ° C. Drying temperature 50 ° C. Dry to Dr using an automatic processor SRX-501 (manufactured by Konica Corporation)
Process for 45 seconds with y.

Under the above conditions, the composition of the processing solution, the processing temperature and the time may vary to some extent.
All the characteristic curves may be obtained by treating under the same conditions as above except that SR (manufactured by Konica Corporation) is replaced with Developer-1.

As the exposure conditions, the silver halide photographic light-sensitive material according to the present invention having emulsion layers provided on both sides of a transparent support is sandwiched between two optical wedges whose density gradients are mirror-symmetrically aligned, and the color temperature is 5.400 °. It was exposed from both sides of the light source of K at the same time and in the same amount for 1/10 seconds. However, the exposure conditions for sensitometry used for silver halide photographic light-sensitive materials for X-rays can be used without being limited to these conditions.

In the silver halide photographic emulsion according to the present invention, various photographic additives can be used in the steps before and after physical ripening or chemical ripening.

Examples of the compound that can be used in such a step include Research Disclosure (RD) 17643, (R
D) 18716 (November 1979) and (RD) 308119 (December 1989). These three
The types of compounds described in (RD) and their locations are listed below.

Additive RD-17643 RD-18716 RD-308119 Page Classification Page Page Classification Chemical sensitizer 23 III 648 Upper right 996 III Sensitizing dye 23 IV 648-649 996-8 IVA Desensitizing dye 23 IV 998 IVB Dye 25 ~ 26 VIII 649 ~ 650 1003 VIII Development accelerator 29 XXI 648 Upper right fog inhibitor / stabilizer 24 IV 649 Upper right 1006-7 VI Whitening agent 24 V 998 V Hardener 26 X 651 Left 1004-5 X Surfactant 26-27 XI 650 Right 1005-6 XI Plasticizer 27 XII 650 Right 1006 XII Sliding Agent 27 XII Matting Agent 28 XVI 650 Right 1008-9 XVI Binder 26 XXII 1003-4 IX Support 28 XVII 1009 XVII Halogenation of the Invention Examples of the support used in the silver photographic light-sensitive material include those described in the above RD, and a suitable support is a plastic film or the like, and the support surface improves the adhesiveness of the coating layer. May be provided with an undercoat layer, or may be subjected to corona discharge or ultraviolet irradiation. The silver halide emulsion of the present invention can be coated on one side or both sides of the support thus treated.

The silver halide photographic light-sensitive material of the present invention comprises
If necessary, an antihalation layer, an intermediate layer, a filter layer, etc. can be provided.

When the present invention is applied to medical X-ray radiography, for example, a fluorescent intensifying screen containing a phosphor as a main component, which emits near-ultraviolet light or visible light upon exposure to penetrating radiation, is used. It is desirable that this intensifying screen is brought into close contact with both sides of a light-sensitive material obtained by coating the emulsion of the present invention on both sides and exposed.

The penetrating radiation referred to here is an electromagnetic wave of high energy and means X-rays and gamma rays.

The fluorescent intensifying screen refers to, for example, an intensifying screen mainly containing calcium tungstate as a fluorescent component or a fluorescent intensifying screen mainly containing a rare earth compound activated by terbium. As the fluorescent intensifying screen, a fluorescent component uniformly coated on a support or a cylindrical or conical coating can be used. German Karman Karlsruhe N presented at Session 868C of the '92 RSNA (Radiological Society of America) when using particularly low-sensitivity light-sensitive materials.
By increasing the thickness of the fluorescent component and applying it in a conical shape like the microstructured intensifying screen of uclear reserch, a fluorescent intensifying screen with improved sensitivity and at the same time reduced quantum mottle and improved graininess Preference is given to using.

The processing of the light-sensitive material of the present invention is carried out by, for example,
RD-17643 XX-XXI, pages 29-30 or 308119 XX-XX
Treatment with a treatment solution as described in I, pages 1011-1010 may be performed.

Developers for black and white photographic processing include dihydroxybenzenes (eg hydroquinone), 3-pyrazolidones (eg 1-phenyl-3-pyrazolidone), aminophenols (eg N-methyl-aminophenol).
Etc. can be used alone or in combination.
It should be noted that the developer may be a known one such as preservative, alkaline agent, p
An H buffer, an antifoggant, a film hardener, a development accelerator, a surfactant, an antifoaming agent, a toning agent, a water softener, a dissolution aid, a viscosity imparting agent and the like may be used as necessary.

A fixing agent such as thiosulfate or thiocyanate is used in the fixing solution and may further contain a water-soluble aluminum salt such as aluminum sulfate or potassium alum as a hardening agent. Other preservatives, pH adjusters,
It may contain a water softener and the like.

In the photographic light-sensitive material of the present invention, the photographic emulsion layer and other hydrophilic colloid layers can be coated on the support or other layers by various coating methods. For the coating, a dip coating method, a roller coating method, a curtain coating method, an extrusion coating method, a slide hopper method, or the like can be used.
For details, see (RD) Volume 176. P.27-28 `` Coating procedure
The method described in the section "s" can be used. In carrying out the present invention, various techniques known in other photographic techniques can be applied.

[0051]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 (Preparation of hexagonal tabular seed emulsion EM-A) A hexagonal tabular seed emulsion was prepared by the following method. _(N + _m = 5~7) <solution A> ossein gelatin 60.2g Distilled water _{20.0l HO- (CH 2 CH 2 O} ) n- [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) _m H ( _n + _m = 5 to 7) 10% methanol aqueous solution 5.6 ml KBr 26.8 g 10% H ₂ SO ₄ 144 ml <Solution B> Silver nitrate 1487.5 g Distilled water to 3500 ml <Solution C> KBr 1029 g KI 29.3 g Distilled water to 3500 ml <Solution D> 1.75N KBr aqueous solution At the following silver potential control amount of 35 ° C, use a mixing stirrer described in JP-B-58-58288 and 58-58289 to prepare a solution A. 64.1 ml of each of solution B and solution C was added by the simultaneous mixing method over a period of 2 minutes to perform nucleation.

After stopping the addition of Solution B and Solution C, 60
The temperature of solution A was raised to 60 ° C. over a period of time, and solution B and solution C were again added by the simultaneous mixing method at a flow rate of 68.5 ml / min for 50 minutes. During this period, the silver potential (measured with a silver ion selective electrode using a saturated silver-silver chloride electrode as a reference electrode) was controlled to be +6 mV using the solution D.

After the addition was completed, the pH was adjusted to 6.0 with 3% KOH, immediately desalted and washed with water to obtain a seed emulsion EM-A.

In the seed emulsion EM-A thus prepared, 90% or more of the total projected area of silver halide grains consisted of hexagonal tabular grains having a maximum adjacent side ratio of 1.0 to 2.0, and the average thickness of the hexagonal tabular plate was 0.07. It was found by electron microscope observation that the average diameter (circle diameter conversion) was 0.5 μm, and the coefficient of variation was 25%.

(Preparation of Hexagonal Tabular Seed Emulsion EM-B) Solution A
A seed emulsion EM-B was obtained in the same manner as the seed emulsion EM-A except that the temperature was raised to 60 ° C. for 30 minutes. In the seed emulsion EM-B thus prepared, 90% or more of the total projected area of silver halide grains consisted of hexagonal tabular grains having a maximum adjacent side ratio of 1.0 to 2.0, and the average thickness of the hexagonal tabular plate was 0.07 μm, and the average thickness was 0.07 μm. diameter
It was found by electron microscope observation that the (circle diameter conversion) was 0.5 μm and the coefficient of variation was 32%.

(Preparation of Twin Crystal Emulsion EM-1) A monodispersed twin silver iodobromide emulsion EM-1 of the present invention containing 1.53 mol% AgI was prepared using the following four kinds of solutions.

[0058] <solution A> ossein gelatin _{29.4g HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) mH (n + m = 5~ 7) 10% methanol aqueous solution 2.5ml seed emulsion EM-A 0.588mol equivalent Distilled water to 4800ml <Solution B> Silver nitrate 1404.2g Distilled water to 2360ml <Solution C> KBr 968g KI 20.6g Distilled water to 2360ml <Solution D> 1.75N KBr aqueous solution At the following silver potential control amount of 60 ° C., all the amounts of Solution B and Solution C were simultaneously added to Solution A using the mixing stirrer described in JP-B-58-58288 and 58-58289. Addition growth was performed by the mixing method at a flow rate of 21.26 ml / min for 111 minutes.

During this period, the silver potential was controlled to be +25 mV by using the solution D.

After the addition was completed, the following spectral sensitizing dye (A) and
After adding (B) 300 mg and 15 mg, respectively, per mol of silver halide, precipitation desalting was carried out using an aqueous solution of Demol N (manufactured by Kao Atlas) and an aqueous solution of magnesium sulfate to remove excess salts, and ossein gelatin was added. An aqueous gelatin solution containing 92.2 g was added to 2500 ml, and the mixture was redispersed with stirring.

Spectral sensitizing dye (A): 5,5'-dichloro-9-ethyl-3,3'-di- (3-sulfopropyl) oxacarbocyanine sodium salt anhydride Spectral sensitizing dye (B) : 5,5'-di- (butoxycarbonyl) -1,1 '
-Diethyl-3,3'-di- (4-sulfobutyl) benzimidazolocarbocyanine sodium salt anhydrous About 3000 particles of EM-1 were observed and measured by an electron microscope, and the shape was analyzed. Average particle diameter 1.05
The average particle thickness was 0.25 μm, the equivalent spherical diameter was 0.59 μm, and the coefficient of variation was 18%.

(Preparation of Twin Crystal Emulsion EM-2) Twin crystal emulsion EM-2 was prepared by the same method as EM-1, except that seed emulsion EM-A was changed to EM-B. Approximately 3000 particles of EM-2 were observed and measured by an electron microscope, and the shape was analyzed. The average particle diameter was 1.05 μm, the average particle thickness was 0.25 μm, and the sphere-equivalent particle diameter was 0.
The coefficient of variation was 59 μm and the coefficient of variation was 26%.

(Preparation of Twin Crystal Emulsion EM-3) The monodisperse twin silver iodobromide emulsion EM-3 of the present invention containing 1.53 mol% AgI was prepared using the following four kinds of solutions.

[0064] <solution A> ossein gelatin _{29.4g HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) m H (n + m = 5 ~ 7) 10% methanol aqueous solution 2.5 ml seed emulsion EM-A 1.906 mol equivalent Distilled water to 6250 ml <Solution B> Silver nitrate 1176 g Distilled water to 1976 ml <Solution C> KBr 811 g KI 17.2 g Distilled water to 1976 ml <Solution D> 1.75N KBr aqueous solution Simultaneous mixing of all amounts of Solution B and Solution C into Solution A using the mixing stirrer described in JP-B Nos. 58-58288 and 58-58289 at the following silver potential control amount of 60 ° C. Thus, additional growth was performed at a flow rate of 21.26 ml / min for 111 minutes. During this period, the silver potential was controlled to be +40 mV by using the solution D.

After the completion of addition, the above-mentioned spectral sensitizing dye (A) and
After adding (B) 450 mg and 20 mg, respectively, per mol of silver halide, remove excess salts by the same method as in EM-1 above, and add an aqueous gelatin solution containing 92.2 g of ossein gelatin to make 2500 ml. Redispersed with stirring.

Approximately 3000 particles of EM-3 were observed and measured by an electron microscope, and the shape was analyzed.
The average particle thickness was 70 μm, the average particle thickness was 0.17 μm, the sphere-equivalent particle size was 0.40 μm, and the coefficient of variation was 20%.

(Preparation of Twin Emulsion EM-4) EM-A was replaced with EM-
Twin crystal emulsion EM-4 was prepared in the same manner as in EM-3 except that B was used. About 3000 particles of the obtained EM-4 were observed and measured by an electron microscope, and the shape was analyzed. The average particle diameter was 0.70 μm, the average particle thickness was 0.17 μm, and the sphere-equivalent particle diameter was 0.59 μ.
m, the coefficient of variation was 30%.

(Preparation of Spherical Twin Crystal Emulsion EM-C) A spherical twin seed emulsion EM-C was prepared by the following method.

<Solution A> Ossein gelatin 150 g KBr 53.1 g KI 24 g Distilled water to 7200 ml <Solution B> Silver nitrate 1500 g Distilled water to 6000 ml <Solution C> KBr 1327 g 1-phenyl-5-mercaptotetrazole (methanol 1.2 g Distilled water to 3000 ml <Solution D> Ammonia water (28%) 705 ml Nuclei were generated in solution A which was vigorously stirred at 40 ° C. The pBr at this time was 1.09 to 1.15. 20 minutes in 60 minutes
After the temperature was lowered to 0 ° C., Solution D was added in 20 seconds and aging was carried out for 5 minutes. The KBr concentration during aging was 0.071 mol / liter, and the ammonia concentration was 0.63 mol / liter.

Thereafter, the pH was adjusted to 6.0, and immediately desalted and washed with water to obtain EM-C. Observation of the seed emulsion with an electron microscope revealed that it was a monodisperse spherical emulsion having an average grain size of 0.24 μm and a coefficient of variation of 18%.

(Preparation of Spherical Twin Crystal Seed Emulsion EM-D) A spherical twin seed emulsion EM-C was prepared in the same manner as EM-C except that the ripening after addition of the solution D was conducted for 2 minutes. E
MD was prepared.

About 3000 particles of the obtained EM-D were observed and measured by an electron microscope, and the shape was analyzed. As a result, the average particle diameter was 0.24 μm and the coefficient of variation was 26%.

(Preparation of Twin Crystal Emulsion EM-5) A silver halide emulsion EM-5 consisting mainly of tabular twin crystals was prepared using a seed emulsion and the following three kinds of solutions.

<Solution A> Ocein gelatin 37 g HO- (CH ₂ CH ₂ O) _n- [CH (CH ₃ ) CH ₂ O] _17- (CH ₂ CH ₂ O) _m H ( _n + _m = 5 ~ 7) 10% methanol aqueous solution 10 ml Emulsion EM-C 0.475 mol equivalent Make up to 4000 ml with distilled water <Solution B> Ocein gelatin 109 g KBr 772 g KI 16.4 g Make up 4390 ml with distilled water <Solution C> Silver nitrate 1119 g 6269 ml with distilled water Solution B and solution C are added to solution A that is vigorously stirred at 65 ° C.
It was added by the double jet method in minutes. During this time, the pH is 5.8
In addition, pAg was kept at 8.8 throughout. The addition rates of solution B and solution C were linearly increased to 6.4 times in the initial and final stages.

After the addition was completed, a sensitizing dye was prepared in the same manner as in EM-1.
After the addition of (A) and (B), desalting was carried out in the same manner, and then an aqueous gelatin solution containing 92.2 g of ossein gelatin was added and the mixture was redispersed with stirring to 2500 ml.

Approximately 3000 particles of EM-5 were observed and measured by an electron microscope, and the shape was analyzed.
The average particle thickness was 78 μm, the average particle thickness was 0.43 μm, the sphere-equivalent particle size was 0.59 μm, and the coefficient of variation was 16%.

(Preparation of twinned emulsion EM-6) EM-C was replaced with EM-
Twin emulsion EM-6 is performed in the same manner as EM-5 except that D is used.
Was prepared. About 3000 particles of the obtained EM-6 were observed and measured by an electron microscope, and the shape was analyzed. As a result, the average particle diameter was 0.78 μm, the average particle thickness was 0.43 μm, and the sphere-equivalent particle diameter was 0.59.
μm, the coefficient of variation was 22%.

(Preparation of Twin Crystal Emulsion EM-7) Using the seed emulsion and the following three kinds of solutions, a silver halide emulsion EM-7 mainly composed of tabular twin crystals was prepared.

<Solution A> Ocein gelatin 37 g HO- (CH ₂ CH ₂ O) _n- [CH (CH ₃ ) CH ₂ O] _17- (CH ₂ CH ₂ O) _m H ( _n + _m = 5 ~ 7) 10% methanol aqueous solution 10 ml seed emulsion EM-C equivalent to 1.525 mol Distilled water to 6000 ml <Solution B> Ocein gelatin 109 g KBr 649 g KI 13.8 g Distilled water to 3694 ml <Solution C> Silver nitrate 941 g Distilled water 5272 ml Solution B and solution C are added to solution A that is vigorously stirred at 65 ° C.
It was added by the double jet method in minutes. During this time, the pH is 5.8
In addition, pAg was kept at 8.8 throughout. The addition rates of solution B and solution C were linearly increased to 6.4 times in the initial and final stages.

After completion of the addition, the spectral sensitizing dyes (A) and (B) were added in the same manner as in EM-3, desalting was performed in the same manner, and then an aqueous gelatin solution containing 92.2 g of ossein gelatin was added. The mixture was redispersed with stirring as 2500 ml.

Approximately 3000 particles of EM-7 were observed and measured by an electron microscope, and the shape was analyzed. The average particle diameter was 0.52.
The average particle thickness was 7 μm, the average particle thickness was 0.29 μm, the sphere-equivalent particle size was 0.40 μm, and the coefficient of variation was 17%.

(Preparation of Twin Emulsion EM-8) EM-C was replaced with EM-
A twinned crystal emulsion EM-8 was prepared in the same manner as in EM-7 except that D was used. About 3000 particles of the obtained EM-8 were observed and measured by an electron microscope, and the shape was analyzed. As a result, the average particle diameter was 0.527 μm, the average particle thickness was 0.29 μm, and the equivalent spherical diameter was 0.40.
μm, coefficient of variation 24%.

(Preparation of Monodisperse Cubic Seed Emulsion EM-E) <Solution A> Ocein gelatin 30 g KBr 1.25 g Nitric acid (0.1 N) 150 ml Distilled water to 7700 ml <Solution B> KBr 6 g KI 0.16 g Distilled water <Solution C> KBr 680g KI 20g Distilled water to 2480ml <Solution D> Silver nitrate 8.4g Nitric acid (0.1N) 32ml Distilled water to 740ml <Solution E> Silver nitrate 91.6g Nitric acid (0.1N) 80ml Solution B and solution D were added by the double jet method over 10 minutes to solution A that was vigorously stirred at 60 ° C. with distilled water to 2480 ml. Then, the solution C and the solution E were added by the double jet method over 140 minutes. At this time, the initial addition flow rate is 1/8 of the final addition flow rate.
So, it increased linearly with time. While these liquids were being added, the pH was adjusted to 2 and the pH was adjusted to 8 so that the pH was kept constant. After the addition was completed, the pH was raised to 6 with sodium carbonate, 150 g of KBr was added, and immediately thereafter desalting and washing were carried out to obtain a monodisperse cubic crystal of silver iodobromide containing 2 mol% of silver iodide having an average grain size of 0.3 μm. Emulsion EM-E was obtained. According to an electron microscope observation, the occurrence of twins in this emulsion was 1% or less in number.

(Preparation of Normal Crystal Core / Shell Emulsion EM-9) A normal crystal emulsion EM-9 containing 2.0 mol% of AgI was prepared using the following 5 kinds of solutions.

<Solution A> Ossein gelatin 75.5 g HO- (CH ₂ CH ₂ O) _n- [CH (CH ₃ ) CH ₂ O] _17- (CH ₂ CH ₂ O) _m H ( _n + _m = 5 ~ 7) 10% methanol aqueous solution 15 ml seed emulsion EM-E 0.928 mol equivalent Make up to 4000 ml with distilled water <Solution B> AgNO ₃ 151.3 g AgNO ₃ and an equivalent amount of ammonia solution and distilled water to make 848 ml <Solution C ＞ AgNO ₃ 890.9g Add the same amount of ammonia solution as AgNO ₃ and distilled water to make 1497ml <Solution D> KBr 74.1g KI 44.3g Make distilled water 848ml <Solution E> KBr 623.6g Make 1497ml with distilled water Solution A was kept at 40 ° C. in the reaction kettle, and ammonia water and acetic acid were further added to adjust the pH to 9.5.

After adjusting the pAg to 7.3 with an ammoniacal silver ion solution, the solution B and the solution D were added by the double jet method while keeping the pH and pAg constant, and silver iodobromide containing 30 mol% of silver iodide was added. The layers were allowed to form.

After adjusting pH to 9.0 and pAg to 9.0 using acetic acid and KBr, solution C and solution E were added at the same time and grown, and then grown to 90% of the grain size. The pH at this time is 9.0
From 8.20 down gradually.

After KBr solution was added to adjust pAg to 11, solution C and solution E were further added to grow while gradually lowering pH to 8 to obtain a silver iodobromide emulsion containing 2 mol% of silver iodide.

After the completion of the addition, the spectral sensitizing dyes (A) and (B) were added in the same manner as in EM-1, followed by desalting in the same manner, and then an aqueous gelatin solution containing 92.2 g of ossein gelatin was added. The amount was 2500 ml and the mixture was stirred and redispersed to obtain EM-9.

Approximately 3000 particles of EM-9 were observed and measured by an electron microscope, and the shape was analyzed.
It was a monodisperse spherical particle having a distribution of 59% and a width of 12%.

(Preparation of Normal Crystal Core / Shell Emulsion EM-10)
A normal crystal emulsion EM-10 containing 2.0 mol% AgI was prepared using the following 5 kinds of solutions.

[0092] <solution A> ossein gelatin _{94.4g HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) m H (n + m = 5 ~ 7) 10% methanol aqueous solution 15 ml seed emulsion EM-E 2.09 mol equivalent Distilled water to make 5000 ml <Solution B> AgNO ₃ 146.6 g AgNO ₃ and an equivalent amount of ammonia solution and distilled water to make 822 ml <Solution C ＞ AgNO ₃ 698.1g Add ammonia solution equivalent to AgNO ₃ and distilled water to make 1173ml <Solution D> KBr 71.8g KI 42.9g Make 822ml with distilled water <Solution E> KBr 488.7g Make 1765ml with distilled water Solution A was kept at 40 ° C. in the reaction kettle, and ammonia water and acetic acid were further added to adjust the pH to 9.5.

After adjusting the pAg to 7.3 with an ammoniacal silver ion solution, the solution B and the solution D were added by the double jet method while keeping the pH and the pAg constant, and silver iodobromide containing 30 mol% of silver iodide was added. The layers were allowed to form.

After adjusting the pH to 9.0 and the pAg to 9.0 using acetic acid and KBr, solution C and solution E were added at the same time to grow,
It was grown to 90% of the grain size. The pH at this time is
Gradually lowered from 9.0 to 8.20.

After adding the KBr solution to adjust the pAg to 11, the solution C and the solution E were further added to grow while gradually lowering the pH to 8 to obtain a silver iodobromide emulsion containing 2 mol% of silver iodide.

After completion of the addition, spectral sensitizing dyes (A) and (B) were added in an amount of 400 mg and 20 mg per mol of silver halide, respectively, and then desalted in the same manner as in EM-1 and then ossein gelatin 92.2 Add gelatin aqueous solution containing g to make 2500 ml,
Redispersion with stirring gave EM-10.

Approximately 3000 particles of EM-10 were observed and measured by an electron microscope, and the shape was analyzed.
The particles were monodisperse spherical particles having a size of 45 μm and a distribution of 13%.

(Preparation of Normal Crystal Core / Shell Emulsion EM-11)
A normal crystal emulsion EM-11 containing 2.0 mol% AgI was prepared using the following 5 kinds of solutions.

[0099] <solution A> ossein gelatin _{94.4g HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) m H (n + m = 5 〜7) 10% methanol aqueous solution 15 ml seed emulsion EM-E 3.47 mol equivalent Distilled water to make 5000 ml <Solution B> AgNO ₃ 141.1 g AgNO ₃ and an equivalent amount of ammonia solution and distilled water to make 790 ml <Solution C ＞ AgNO ₃ 469.0g Add ammonia solution equivalent to AgNO ₃ and distilled water to make 788ml <Solution D> KBr 69.1g KI 41.3g Make 790ml with distilled water <Solution E> KBr 328.3g Make 788ml with distilled water Solution A was kept at 40 ° C. in the reaction kettle, and ammonia water and acetic acid were further added to adjust the pH to 9.5.

After adjusting the pAg to 7.3 with an ammoniacal silver ion solution, the solution B and the solution D were added by the double jet method while keeping the pH and the pAg constant, and silver iodobromide containing 30 mol% of silver iodide was added. The layers were allowed to form.

After adjusting pH to 9.0 and pAg to 9.0 using acetic acid and KBr, solution C and solution E were added at the same time and grown, and then grown to 90% of the grain size. The pH at this time is 9.0
From 8.20 down gradually.

The KBr solution was added to adjust the pAg to 11, and the solutions C and E were further added to grow while gradually lowering the pH to 8 to obtain a silver iodobromide emulsion containing 2 mol% of silver iodide.

After the completion of the addition, spectral sensitizing dyes (A) and (B) were added at 450 mg and 20 mg, respectively, per mol of silver halide, desalted in the same manner as in EM-1, and then ossein gelatin was used. An aqueous gelatin solution containing 92.2 g was added to 2500 ml with stirring and redispersion to obtain EM-11.

Approximately 3000 particles of EM-10 were observed and measured by an electron microscope, and the shape was analyzed.
The particles were monodisperse spherical particles having a width of 0.38 μm and a distribution of 15%.

(Preparation of Sample) Spectral sensitizing dyes (A) and (B) were added to each emulsion per mol of silver halide.
After adding 140 mg and 1.4 mg, ammonium thiocyanate salt was chemically ripened by adding 7.0 × 10 ^-4 mol per mol of silver, and an appropriate amount of chloroauric acid and hypo, and then 6 μm.
After adding 6 × 10 ⁻⁴ mol / Ag 1 mol of AgI fine grain emulsion of
Hydroxy-6-methyl-1,3,3a, 7-tetrazaindene 3
Stabilized at × 10 ^-2 mol.

The respective emulsions were mixed at the ratios shown in Table 1 and various additives described below were added to prepare emulsion coating solutions. The amount of each additive added is indicated by the amount per mol of silver halide.

T-Butyl-catechol 150 mg Polyvinylpyrrolidone (molecular weight 10,000) 1.0 g Styrene-maleic anhydride copolymer 2.5 g Trimethylolpropane 10 g Diethylene glycol 5 g Nitrophenyl-triphenyl-phosphonium chloride 50 mg 1,3-Dihydroxybenzene-4 -Ammonium sulfonate 4g 2-Mercaptobenzimidazole-5-sodium sulfonate 1.5mg

[0108]

[Chemical 1]

NC ₄ H ₉ OCH ₂ CH (OH) CH ₂ N (CH ₂ COOH) ₂ 1 g The additives used in the protective layer liquid are as follows. The added amount is shown as an amount per 1 g of gelatin.

Matting agent composed of polymethylmethacrylate having an area average particle size of 7 μm 7 mg Colloidal silica (average particle size 0.013 μm) 70 mg 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt 30 mg (CH ₂ = CHSO ₂ -CH _2- ) ₂ O 36mg Sodium isoamyldecyl sulfosuccinate 7mg

[0111]

[Chemical 2]

The above coating solution was uniformly applied to both surfaces of a blue-colored polyethylene terephthalate film base having a thickness of 180 μm and subjected to undercoating treatment, and dried to prepare samples 1 to 20 as shown in Table 1.

Further, all the samples were adjusted so that the coated gelatin was 3.0 g / m ² on both sides. The amount of silver coated on each sample was adjusted to 2.0 g / m ² on one side.

<Evaluation of sensitometry (sensitivity, γ)>
The obtained sample is sandwiched between two optical wedges whose density gradients are mirror-symmetrically aligned, exposed at the same time from both sides by a light source with a color temperature of 5,400 ° K, and after an equal amount of 1/10 second exposure, SRX-501 automatic processor
(Manufactured by Konica Corp.) was processed with Developer-1 and Fixer-1 at a developing temperature of 35 ° C. for 45 seconds.

The sensitivity of each sample developed as described above was evaluated. The sensitivity was shown as a relative value with the reciprocal of the amount of bombardment energy required for Sample 1 to give a density of fog +1.0 as 100. At this time, the sensitivity of the X-ray film SR-G for direct photography (manufactured by Konica Corporation, product number 2014A) was 98.

<Evaluation of MTF> A rectangular wave chart was photographed for each sample, and MTF was measured by the contrast method. In addition, MTF showed the value of spatial frequency of 2.0 lines / mm.

<Evaluation of Diagnostic Properties (Sharpness, Granularity)> Each sample was sandwiched between X-ray fluorescent intensifying screens SRO-250, and the highest concentration in the lung field through the chest phantom as shown in Table 2. X-ray photography was performed while changing the exposure time so that the temperature was 35 ° C with the XD-SR development processing solution (manufactured by Konica Corporation) using the SRX-501 automatic processor.
For 45 seconds.

With respect to the mediastinum and lung field of the obtained image, the visual sharpness and graininess were evaluated by the following 5 grades.

1. Very inferior 2. Inferior 3. Normal 4. Good 5. Very good results obtained above are shown below.

[0120]

[Table 1]

[0121]

[Table 2]

Example 2 The emulsion of Example 1 was coated in two layers in the combinations shown in Table 3 to prepare a sample, and the same evaluation as in Example 1 was carried out.

The coating conditions were the same as in Example 1, and the first layer and the second layer were coated in this order from the side closer to the support so that the coated silver amount was 2 g / m ^{2 on each} side. The results obtained are shown below.

[0124]

[Table 3]

[0125]

[Table 4]

As is apparent from the table, the sample of the present invention is excellent in sharpness and graininess in the lung field and mediastinum, and is excellent in image sharpness.

[0127]

According to the present invention, it is possible to obtain a silver halide photographic light-sensitive material having a wide exposure latitude which is excellent in image graininess and sharpness and has little change in diagnostic ability due to exposure variations.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Iwa ▲ Saki ▼ Kazuhiro Konica Co., Ltd. 1 Sakura-cho, Hino City, Tokyo

Claims (3)

[Claims] 1. A silver halide photographic light-sensitive material having at least one silver halide emulsion layer on a support,
The silver halide grains in the emulsion layer are tabular grains having an aspect ratio of 3 or more and a circle equivalent diameter of 0.5 μm or more, and grains having an aspect ratio of 2 or less and a sphere-converted grain size of 0.2 μm or more and 0.5 μm or less. More than one kind, the average silver iodide content of all silver halide grains is 2.0 mol% or less, and the slope of the straight line connecting the optical density points 0.3 and 0.5 in the characteristic curve of the obtained image (γ1) 0.4 to 0.7, optical density 0.5 and 1.5
The slope (γ2) of the line connecting the points is 1.5 to 2.0, and the optical density is 1.
A silver halide photographic light-sensitive material characterized in that the slope (γ3) of a straight line connecting 0 and 2.0 is 2.8 to 3.5. 2. A silver halide photographic light-sensitive material having at least two silver halide emulsion layers on a support, wherein the silver halide grains in the emulsion layer farthest from the support have an aspect ratio of 3 or more. It is a tabular grain having a circle-equivalent diameter of 0.5 μm or more, and silver halide grains in any emulsion layer near the support with respect to the emulsion layer have an aspect ratio of 2 or less and a sphere-converted grain size of 0.2 μm or more and 0.5 The average silver iodide content of all silver halide grains is 2.0 mol%
And the slope (γ1) of the line connecting the optical density points 0.3 and 0.5 in the characteristic curve of the light-sensitive material is 0.4 to 0.7.
Then, the slope (γ2) of the straight line connecting the points of optical density 0.5 and 1.5 is
1.5-2.0, slope of the straight line connecting optical density 1.0 and 2.0 (γ3)
Is 2.8 to 3.5, and a silver halide photographic light-sensitive material. 3. A circle equivalent diameter of 0.5 μm with an aspect ratio of 3 or more.
The coefficient of variation of the above tabular grains is 25% or more, and the coefficient of variation of particles having an aspect ratio of 2 or less and a sphere-converted particle size of 0.2 μm or more and 0.5 μm or less is 20% or less. The silver halide photographic light-sensitive material according to claim 1 and claim 2.