JPH0675313A - Silver halide photographic sensitive material capable obtaining picture quality and gradation according to purpose of photograph and its image forming method - Google Patents

Abstract

PURPOSE:To silver halide photographic sensitive material that desired characteristics according to the purpose of photograph can be obtd. in one film and that picture images with high sensitivity, high sharpness and good graininess can be obtd. by combination with an intensifying screen. CONSTITUTION:This silver halide photographic sensitive material has emulsion layers on both surfaces of a transparent supporting body. This photographic sensitive material has such a property that when the one surface with higher max. density is exposed to light to give +1.0 fog density to the exposed surface, the back surface having a lower max. density has <=0.20 fog. The sensitivity of the surface having higher max. density is higher than that of the surface having lower max. density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide photographic light-sensitive material for X-rays and a method for forming an image thereof, which enables one type of film to obtain characteristics suited to the purpose of photography.

[0002]

BACKGROUND OF THE INVENTION Currently, many types of X-ray films for direct radiography for medical use are on sale depending on the region and the purpose of radiography. For example, to give an example of Konica Corporation, SR for general use
-G, SR-V for high sensitivity such as contrast photography, SR-H and SR-H for high contrast, low contrast SR-L for digestive organ photography, SR-for wide latitude for chest photography. Numerous varieties such as new-CM are commercially available for C, and for parts that require ultra-high sharpness such as mammography.

[0005] As described above, arranging a large number of film types for each photographing purpose not only makes the user's inventory management very complicated, but also has a risk of using the film type by mistake. This results in serious damage to the diagnosis.

Also, on the film manufacturer side and the sales side, it is not preferable to manufacture and sell such a large variety of products because it increases costs and makes distribution difficult, and improvement thereof has been strongly desired.

[0005]

SUMMARY OF THE INVENTION It is, therefore, a first object of the present invention to provide a silver halide photographic light-sensitive material for X-rays, which can obtain the characteristics suited to the purpose of photographing with one kind of film.

A second object of the present invention is to obtain an image with high sensitivity and high sharpness by changing the combination of two front and back intensifying screens used on both sides of the film. A silver halide photographic light-sensitive material for lines and an image forming method thereof are provided. Other objects will be apparent from the following specification.

[0007]

As a result of intensive studies, the present inventors have found that these objects can be achieved by the following, and have completed the present invention.

(1) In a silver halide photographic light-sensitive material having at least one silver halide emulsion layer having different maximum densities on both sides of a transparent support, the surface having the highest maximum density has a fog density from the side having the highest density. When exposed at an exposure amount of +1.0, it is a silver halide photographic material in which the density of the backside with the lowest maximum density is fog +0.20 or less.
The sensitivity (SH) of the (front side) is the sensitivity (S
Higher sensitivity than (L) and the fog of the characteristic curve of the high sensitivity surface +0.
The contrast that connects the 8 density and the 2 points of the fog +1.3 in a straight line is higher than the contrast that connects the 2 points of the density of fog +0.3 and the fog +0.5 in the characteristic curve of the low sensitivity surface to the straight line. A characteristic silver halide photographic light-sensitive material.

The above-mentioned sensitivities (SH) and (SL) are values obtained as the reciprocal of the exposure amount required to obtain the density of the formula shown below.

[(Maximum density-fog density) × 0.4] + fog density (2) Sensitivity SL 'of the surface having the lowest maximum density when exposed with a fluorescent intensifying screen from the surface having the highest maximum density, and The silver halide photographic light-sensitive material according to item (1), which has a ratio of sensitivity SL (SL '/ SL) of 0.12 or more when exposed by using a fluorescent intensifying screen from the surface having the lowest maximum density.

(3) Sensitivity S of the surface with the highest maximum density when exposed from the surface with the highest maximum density using a fluorescent intensifying screen
L ', and the ratio of the sensitivity SL when exposed with a fluorescent intensifying screen from the surface with the lowest maximum density (SL' / SL), and the exposure with a fluorescent intensifying screen from the surface with the lowest maximum density The ratio (SH '/ SH) between the sensitivity SH' of the surface having the highest maximum density and the sensitivity SH when exposed from the surface having the highest maximum density using a fluorescent intensifying screen is 0.30 or less (1). Silver halide photographic light-sensitive material.

(4) The method for forming an image of a silver halide photographic light-sensitive material according to the item (2), wherein the fluorescent intensifying screen is exposed adjacent to the high sensitivity only.

(5) An image of a silver halide photographic light-sensitive material obtained by exposing one surface of each of the silver halide photographic light-sensitive materials according to the above (1) or (2) to a fluorescent intensifying screen, respectively. Forming method.

(6) Exposure is performed by adhering a low-sensitivity fluorescent intensifying screen to the high-sensitivity side of the silver halide photographic light-sensitive material described in the above (3) and adjoining the high-sensitivity fluorescent intensifying screen to the low-sensitivity side. A method for forming an image on a silver halide photographic light-sensitive material.

(7) Silver halide in which a high-sensitivity fluorescent intensifying screen is adjacent to the high-sensitivity side of the light-sensitive material described in (3) above, and a low-sensitive fluorescent intensifying screen is adjacent to the low-sensitivity side of the light-sensitive material. Image forming method for photographic light-sensitive material.

(8) On the high-sensitivity surface and the low-sensitivity surface, 50% or more of the projected area has an emulsion layer formed of tabular silver halide grains having an aspect ratio of 3 or more (1), (2) and It is achieved by the silver halide photographic light-sensitive material described in the item (3).

The present invention will be described in detail below. In the method of the present invention, even if one-sided shooting is performed with one type of film (shooting with one intensifying screen), the maximum density is high in order to obtain the characteristics of double-sided shooting (shooting with two intensifying screens). The amount of light [= (SL '/ SL)] that reaches the interface between the surface with the lowest maximum density and the support through the surface is 12%
It is preferably not less than 50% and particularly preferably 14
% To 30% or less.

For single-sided photography only, the larger the transmittance, the more advantageous. On the other hand, when the amount of transmitted light exceeds 30%, when double-sided shooting is performed, sharpness deterioration becomes noticeable due to an increase in crossover light, image quality deteriorates, and the characteristics of the intensifying screen used for each surface are faithfully obtained. It brings about an undesirable effect such as disappearance. Therefore, in order to obtain desired characteristics with high image quality in one-sided and double-sided shooting with one film, which is the object of the present invention, the surface having the highest maximum density is transmitted to reach the interface between the surface having the lowest maximum density and the support. The amount of light to be applied and the amount of light transmitted through the surface having the lowest maximum density and reaching the interface between the surface having the highest maximum density and the support are 50% or less, particularly preferably 30% or less.

When exposing only from the high-sensitivity side with one sheet of fluorescent intensifying screen, if the amount of light transmitted from the high-sensitivity side to the low-sensitivity side becomes less than 12%, the image forming efficiency of the low-sensitivity side becomes very high. become worse. In the case of a film dedicated to using fluorescent intensifying screens on both sides, it is better that the amount of transmitted light is less than 12%. However, as in the present invention, one fluorescent intensifying screen is used for photographing and the conventional one is used. It is preferable that the amount of transmitted light is 12% or more and 30% or less in order to be compatible with both photographing methods using two images.

The light-sensitive material of the present invention is an ordinary double-sided system, for example, SRG film and SRO-250 (both Konica It is preferable that the same gradation as that obtained by combining the above) can be obtained. That is, as a gamma in the characteristic curve, the slope of the straight line connecting (fog + density 0.25) and (fog + density 2.0) has 1.6 to 3.0.

In this case, when the intensifying screen is brought into close contact only with the high-sensitivity surface for photographing, a standard gradation and latitude can be obtained, and it can be used for many purposes. With such gradations, it is possible to produce many sensitivities and gradations in accordance with the purpose of photography by combining fluorescent intensifying screens with various sensitivities on both sides of the photosensitive material.

According to the present invention, the X-ray dose required to obtain the same image can be reduced and high image quality can be obtained as compared with the conventional double-sided photographing system.

If a high-sensitivity (high emission intensity) intensifying screen is used for the high-sensitivity side of the light-sensitive material of the present invention and a low-sensitivity (low emission intensity) intensifying screen is used for the low-sensitivity side, the gradation becomes high. , For example SRH
The same high contrast as (Konica Corporation film) is obtained, and double-sided system (film is SRH and intensifying screen is SRO-250
The same gradation as that of the combination) can be obtained. In this case, there is an advantage that the X-ray dose required to obtain the same image is small and high image quality can be obtained.

The high-sensitivity surface of the light-sensitive material of the present invention has low sensitivity.
Using a (low emission intensity) intensifying screen and a high sensitivity (high emission intensity) intensifying screen on the low sensitivity side is almost the same as shooting with the fluorescent intensifying screen in close contact with only the high sensitivity side. Standard gradation and latitude can be obtained. Also in this case, there is an advantage that the X-ray dose required to obtain the same image quality can be small.

Further, in the present invention, there is an advantage that extremely high sharpness can be obtained as compared with the conventional double-sided system by photographing the fluorescent intensifying screen in close contact with only the high sensitivity surface.
However, since the granularity is slightly deteriorated, the application is limited to bone imaging with low tube voltage and contrast imaging.

As a basic method, by using fluorescent intensifying screens on both sides of the light-sensitive material of the present invention, the sharpness is slightly reduced, but the graininess is further improved, and it is also useful for chest imaging. I found that it could be expanded.

The emulsion used in the silver halide photographic light-sensitive material of the present invention may be any silver halide such as silver iodobromide, silver iodochloride and silver iodochlorobromide, but is particularly sensitive. Silver iodobromide is preferred from the standpoint of obtaining

The silver halide grains in the photographic emulsion were all isotropically grown such as cubes, octahedrons and tetrahedra, or were polyhedral crystals such as spheres and had plane defects. It may be composed of twins, or a mixed type or a composite type thereof. The grain size of these silver halide grains may be from fine grains of 0.1 μm or less to large grains of 20 μm.

The emulsion used in the silver halide photographic light-sensitive material of the present invention can be produced by a known method. For example, Research Disclosure (RD) No.17643 (December 1978)
・ Pages 22-23, 1 ・ Emulsion Preparation an
d types) and RD No. 18716 (November, 1979) -Page 648.

The emulsion of the silver halide photographic light-sensitive material according to the present invention is described, for example, in "The theory of the phot" by TH James.
ographic process ”4th edition, published by Macmillan (1977) 38
~ 104, "Photographic emulsion Chemistry" by GF Daufin, Focal pre
Published by ss (1966), P. Glafkides “Physics and Chemistry of Photography“ Chimie et physique photographique ”Paul Montel
Published by VL Zelikman et al. "Making and Coating photographic Emulsion" (1967)
It is prepared by the method described in Focal press (1964).

That is, a solution method such as a neutral method, an acid method or an ammonia method is mixed under conditions such as a forward mixing method, a back mixing method, a double jet method, a controlled double jet method or the like, a conversion method, a core / shell method. It can be produced using the particle preparation conditions such as and the like and a combination method thereof.

One of the preferred embodiments of the present invention is a monodisperse emulsion in which silver iodide is localized inside the grains.

The silver halide emulsions preferably used in the present invention are, for example, JP-A-59-177535 and 61-802237.
No. 61-132943, No. 63-49751, and the like, high internal iodine type monodisperse particles are disclosed. The crystal habits are cubic, tetradecahedron, octahedron, and {111} faces and {1} in the middle.
00} planes may be arbitrarily mixed.

The definition of monodispersity given here is as follows:
It is described in JP-A-60-162244 and has a coefficient of variation of particle size of 0.20 or less.

The crystal structure of silver halide may be composed of different silver halide compositions inside and outside. A preferred embodiment of the emulsion is a core / shell type monodisperse emulsion having a two-layer structure comprising a high iodine core portion and a low iodine shell layer.

The silver iodide content in the high iodine portion is 20 to 40 mol%, particularly preferably 20 to 30 mol%. A method for producing such a monodisperse emulsion is known, and for example, J. Phot. Sic.12.242 to 251 (1
963), JP-A-48-36890, 52-16364, 55-14232.
9, 58-49938, British Patent 1,413,748, U.S. Patent 3,57
It is described in gazettes such as 4,628 and 3,655,394.

A seed crystal is used as the monodisperse emulsion, and an emulsion in which grains are grown by supplying silver ions and halide ions with the seed crystal as a growth nucleus is particularly preferable. The core / shell emulsion can be obtained by, for example, British Patent 1,027,146, U.S. Patents 3,505,068, 4,44.
It is described in detail in the publications such as 4,877 and JP-A-60-14331.

The silver halide emulsion as another grain form used in the present invention is preferably tabular grains having an average aspect ratio of 3 or more.

The advantage of such tabular grains is that the spectral sensitization efficiency can be improved and the graininess and sharpness of images can be improved. For example, British Patent 2,112,157 and US Pat.
No. 20, 4,433,048, 4,414,310, 4,434,226
No. 58-113927, No. 58-127921, No. 63-138342
No. 63-284272, No. 63-305343, etc., and the emulsion can be prepared by the method described in these publications.

The above-mentioned emulsion is either a surface latent image type that forms a latent image on the surface of the grain, an internal latent image type that forms a latent image inside the grain, or a type that forms a latent image on the surface and inside. May be. In these emulsions, a cadmium salt, a lead salt, a zinc salt, a thallium salt, an iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, an iron salt or a complex salt thereof, or the like may be used at the stage of physical ripening or grain preparation. The emulsion may be subjected to a water washing method such as a Noudel water washing method or a flocculation sedimentation method in order to remove soluble salts. As a preferred washing method, for example, a method using an aromatic hydrocarbon aldehyde resin containing a sulfo group described in JP-B-35-16086, or an aggregating polymer agent Ex. G described in JP-A-63-158644
A particularly preferred desalting method is a method using 3, G8 or the like. The emulsion according to the present invention can use various photographic additives in the steps before and after physical ripening or chemical ripening. Known additives include, for example, Research Disclosure (RD) No. 17643 (December 1978).
No. 18716 (November 1979) and No. 308119 (198)
The compound described in December, 9) is mentioned. The types of compounds and the places where they are described in these three Research Disclosures are listed below.

Additives RD-17643 RD-18716 RD-308119 Page Classification Page Classification Page Classification Chemical sensitizer 23 III 648 Upper right 996 III Sensitizing dye 23 IV 648-649 996-8 IV Desensitizing dye 23 IV 998 B 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 Agent 26-7 XI 650 Right 1005-6 XI Antistatic agent 27 XII 650 Right 1006-7 XIII 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 XXII support 28 XVII 1009 XVII Supports that can be used in the light-sensitive material of the present invention include, for example, RD-17643, page 28 and RD-308119, 100.
Examples include those described on page 9.

A suitable support is a plastic film or the like, and the surface of these supports may be provided with an undercoat layer, corona discharge or ultraviolet irradiation in order to improve the adhesion of the coating layer.

[0043]

EXAMPLES Examples of the present invention will be described below. However, as a matter of course, the present invention is not limited to the examples described below.

Example 1 Preparation of Silver Halide Emulsion Silver halide grains (A) were composed of iodine of 1.3 mol% and bromine of 98.7.
Average particle size consisting of mol% 2.0μm, average particle thickness 0.4μm
The particle size dispersibility was 0.20 in terms of coefficient of variation.

The particles (B) are 0.3 mol% iodine and 98.7 bromine.
Average particle size consisting of mol% 1.7μm, average particle thickness 0.34μ
The particle size dispersibility was 0.21 in terms of coefficient of variation.

In both grains (A) and (B), tabular grains accounted for 90% or more of the total projected area.

(Variation coefficient: according to the method described in JP-A-60-162244) Preparation, processing and evaluation of samples Per mol of silver in each silver halide emulsion of the obtained emulsions (A) and (B) To 50 ° C after adding pure water so that the volume becomes 500 ml, and add the spectral sensitizing dyes A and B shown below to 10 ml.
The total amount was added in a weight ratio of 0: 1 so that (A) was 600 mg and (B) was 250 mg per mol of silver halide.

[0048] 10 minutes per mol of silver of ammonium thiocyanate after (A) is 4 × 10 ^-3 mol, (B) added is 2 × 10 ^-3 mol, more appropriate amount of addition of the hypo chloroauric acid Then the chemical ripening was started.

At this time, the pH was 6.15 and the silver potential was 80 mv.

15 minutes before the end of chemical ripening (70 minutes from the start of chemical ripening
(After a minute), 300 mg of potassium iodide is added per mol of silver, and 5
After 10 minutes, 10% (wt / vol) acetic acid was added to lower the pH to 5.6 and maintain the pH value for 5 minutes.
Add 0.5% (wt / vol) solution to return pH to 6.15, then
2-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene
The chemical ripening was completed by adding 500 mg.

The following additives for emulsion were added to (A) and (B) of the obtained emulsion to prepare a preparation liquid.

The pH after preparation of the photographic emulsion coating solution was 6.2.
0, the silver potential was adjusted to 80 mV (35 ℃) using sodium carbonate and potassium bromide solution.

A sample was prepared as follows using this emulsion coating solution. That is, the photographic emulsion layer has a gelatin amount of 2.1 g / m ² on both the high-speed emulsion layer side and the low-speed emulsion layer side.
The amount of silver halide was adjusted to the amount shown in Table 1 in terms of silver.

A protective layer solution was prepared using the additives described below. The protective layer performs a simultaneous double side coated on the support at a speed per minute 86m using two slide hopper type coater with the the prepared emulsion layer such that the 1.15 g / m ² as a weight with gelatin, 2 A sample was obtained by drying in 20 minutes.
As a support, glycidyl methacrylate 50 wt%, methyl acrylate 10 wt%, butyl methacrylate 40 wt%
The copolymer aqueous dispersion obtained by diluting the copolymer consisting of the three types of monomers described above to a concentration of 10 wt% was applied as an undercoating liquid and was colored blue with a concentration of 0.15 for a 175 μm X-ray film. A polyethylene terephthalate film base was used.

The spectral sensitizing dyes used for sample preparation are as follows.

<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,
Additives used in 3'-di- (4-sulfobutyl) benzimidazolocarbocyanine sodium salt anhydride and emulsion (light-sensitive silver halide coating solution) are as follows. The addition amount is indicated by the amount per mol of silver halide.

1,1-Dimethylol-1-bromo-1-nitromethane 70 mg t-butyl-catechol 400 mg Polyvinylpyrrolidone (molecular weight 10,000) 1.0 g Styrene-maleic anhydride copolymer 2.5 g Nitrophenyl-triphenylphosphonium chloride 50 mg 2 -Anilino-4,6-dimercaptotriazine 60 mg 1,3-dihydroxybenzene-4-ammonium sulfonate 4 g 2-mercaptobenzimidazole-5-sodium sulfonate 1.5 mg C ₄ H ₉ OCH ₂ CH (OH) CH ₂ N (CH ₂ COOH) ₂ 1g 1-phenyl-5-mercaptotetrazole 15mg

[0058]

[Chemical 1]

* (Dye emulsion dispersion) 1.2 g The additives used in the protective layer liquid are as follows. The added amount is shown as an amount per 1 l of the coating liquid.

Lime-treated inert gelatin 68 g Acid-treated gelatin 2 g Sodium-i-amyl-n-decylsulfosuccinate 0.3 g Polymethylmethacrylate (matting agent having an area average particle size of 3.5 μm) 1.1 g Silicon dioxide particles (area average particle size 1.2 μm matting agent) 0.5 g Ludox AM (DuPont) (colloidal silica) 30 g 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt 2% aqueous solution (hardener) 10 ml Glyoxal 40% aqueous solution (hardener) 1.5 ml (CH ₂ = CHSO ₂ CH ₂ ) ₂ O (hardener) 300 mg C ₁₂ H ₂₅ CONH (CH ₂ CH ₂ O) ₅ H 2.0 g

[0061]

[Chemical 2]

* The dye emulsion dispersion was prepared as follows.

10 kg of each of the following dyes was weighed and dissolved in a solvent consisting of 28 l of tricresyl phosphate and 85 l of ethyl acetate at 55 ° C. This is called an oil-based solution. On the other hand, 1.35k of anionic surfactant (AS below)
270 ml of a 9.3% aqueous gelatin solution dissolved at 45 ° C was prepared. This is called an aqueous solution.

The above oil-based and water-based solutions were placed in a dispersion pot and dispersed while controlling the liquid temperature to 40 ° C.

To the obtained dispersion, 8 g of the following additive C, 16 l of a 2.5% aqueous solution of phenol and water were added to make 240 kg, and then the mixture was cooled and solidified.

[0066]

[Chemical 3]

The area average particle diameters of the obtained dispersions are all 0.
It was within the range of 12 to 0.14 μm.

The sensitivity of the obtained sample No. 1 was measured by using the fluorescent intensifying screen SRO-250 for the back (manufactured by Konica Corporation).
And a low-sensitivity emulsion layer side, in which the fluorescent-sensitizer screen was brought into contact with the high-sensitivity emulsion layer side (H side) by a single back method (using the intensifying screen only on one side). Samples (I-H) and (I-L) were obtained by developing together the ones that were photographed by contacting with (L-side).

At this time, a black coating having a high light absorption rate was applied to the front side of the cassette where the intensifying screen did not exist.

For the photographing, a tube voltage of 60 KVP and 20 mA was irradiated with X-ray for 0.05 seconds, and a sensitometric curve was prepared by a distance method to determine the sensitivity, maximum density and gamma.

For the development, an automatic developing machine SRX-502 (manufactured by Konica Corporation) was used with a developing solution and a fixing solution having the following compositions. The developing temperature was 35 ° C., the fixing temperature was 33 ° C., and the washing water was at a temperature of 18 ° C. The entire process was processed in a 45 second mode, supplying 5 liters per minute at ° C.

The sensitivity of the H surface was obtained by removing the photosensitive layer on the L surface side of the sample (I-H) with a protease, and the photosensitive layer on the H surface side was similarly removed from the sample (I-L). Therefore, the sensitivity of the L surface is required.

The sensitivity value was obtained as the reciprocal of the X-ray dose required to obtain the density obtained by multiplying the maximum density minus fog by 0.4 and then adding the fog. In Table 2, sample No.
It is represented by relative sensitivity when the sensitivity of 1 is 100.

However, since Sample No. 1 had the same emulsion constitutional layer as a normal double-sided X-ray film, it was subjected to normal exposure using both sides of a fluorescent intensifying screen.

The gamma in the table is shown by the reciprocal of the difference of the logarithm of the reciprocal of the X-ray dose that gives the densities of 1.0 and 2.0.

As the evaluation of the image quality of each sample No. 1 to 20, sharpness is evaluated by the following Funk chart photography.

The fluorescent intensifying screens shown in Table 1 were combined by the single back method and photographed at a tube voltage of 90 KVP. The treatment was the same as the above-mentioned sensitometry (treatment with the same automatic developing machine, treating agent, treating temperature and treating time).

Sharpness is Funk test chart SMS5853
Photographs were taken with a combination of intensifying screens and films as shown in Table 2 using (Konica Medical Co., Ltd.) and processed under the above processing conditions.

As for the exposure amount, each sample was exposed so that the average density of light and shade formed by the Funk test chart was 0.8 ± 0.02.

[Developer composition] Developer potassium sulfite 60.0 g hydroquinone 25.0 g 1-phenyl-3-pyrazolidone 1.5 g boric acid 10.0 g potassium hydroxide 23.0 g triethylene glycol 17.5 g 5-methylbenztriazole 0.04 g 5-nitro Benzimidazole 0.11g 1-Phenyl-5-mercaptotetrazole 0.015g Glacial acetic acid 16.0g Potassium bromide 4.0g Add water to make 1 liter.

[Fixing solution] Sodium thiosulfate 45g Ethylenediaminetetraacetic acid disodium 0.5g Ammonium thiosulfate 150g Anhydrous sodium sulfite 8g Potassium acetate 16g Aluminum sulfate 10-hydrate 27g Sulfuric acid (50wt%) 6g Citric acid 1g Boric acid 7g Glacial acetic acid 3g 1l The pH of the solution was adjusted to 4.6 (25 ° C) with glacial acetic acid. The developing solution and the fixing solution were put into an automatic developing machine 24 hours after preparation and used.

Evaluation of Sharpness A: A loupe can identify up to 10 LP / mm B: A loupe can identify up to 8 LP / mm C: A loupe can identify up to 6 LP / mm D: A loupe can identify up to 5 LP / mm E: Loupe Can identify up to 4 LP / mm.

Granularity was determined by sticking acrylic beads with a diameter of 3 mm and aluminum balls with a diameter of 3 mm to a penetrometer made of aluminum having a thickness of 20 steps, and applying a tube voltage.
The image was taken at 90 KVP and developed under the same processing conditions as in the above sensitometry. The obtained sample was visually evaluated for graininess in a density range of 0.5 to 1.2 in which the graininess was noticeable.

A: Same as sample No. 1 in Table 2 and very good in graininess. B: Some deterioration is observed with respect to sample No. 1, but no problem in practical use. C: High contrast double-sided film. It is equivalent to sample No. 5 used, and the deterioration of graininess is clearly observed. D: The deterioration of graininess is remarkable, making it difficult to identify acrylic beads with a small concentration difference, but the concentration of aluminum There is no effect on image discrimination with a large difference E: Graininess is remarkably deteriorated, which also hinders image discrimination of aluminum balls and is not practical.

The above shows that A is the best and E is not the best. The results obtained are shown in Table 2 below.

Table 1 shows the details and characteristics of the applied film.

Fluorescent intensifying screen SRO- sold by Konica Corporation
The 125, SRO-250 and SRO-500 are a set for the front and back. In Table 1, the film Nos. I and II having the same identity on both sides of the support used the front side for the front side and the back side for the back side. Film Nos. III to VII having different properties on both sides of the support were all used for the back.

[0088]

[Table 1]

The coated seven kinds of films had the following photographic properties.

* Coated film No. I has the same emulsion surface characteristics on both sides of the support, and relative sensitivity on both SH and SL surfaces.
It was 68.

The contrast _GH connecting the density of fog +0.8 and the density of fog +1.3 is 1.30 the contrast _GL connecting the density of fog +0.3 and the density of fog +0.5 is 1.15 the density after development on the SH surface. The density of the SL surface when the exposure amount was such that the density was fog +1.0 was fog +0.32.

* Coating film No. II has the same characteristics on the emulsion side on both sides of the support, and the relative sensitivity on both SH side and SL side.
It was 75.

SH surface: Fog +0.8 density and fog +1.3
Contrast H _G is 1.62 SH surface connecting the concentrations: Contrast L _G connecting the density of the density and fog +0.5 fog +0.3 is the concentration after development in 1.45 SH surface a density of fog + 1.0 exposure The density of the SL surface when exposed to light was fog +0.22.

* Coated film No. III had different emulsion surface characteristics on both sides of the support, and the SH surface had a relative sensitivity of 98 and the SL surface had a relative sensitivity of 67.

SH surface: Contrast connecting density of fog 0.8, density of fog +0.8 and density of fog +1.3 H _G is 2.30 SL surface: Contrast of density of fog +0.3 and density of fog +0.5 L _G had a density of fog +0.06 on the SL surface when exposed to an exposure amount such that the density after development was a density of fog +1.0 on the 1.10 SH surface.

* Coated film No. IV had different emulsion surface characteristics on both sides of the support, the SH surface had a relative sensitivity of 91, and the SL surface had a relative sensitivity of 68.

SH surface: Fog +0.8 density and fog +1.3
Contrast H _G is 1.80 SL surface connecting the concentration contrast LG connecting density of the density of fog + 0.3 and fog +0.5 concentration after development in 1.15 SH surface exposure amount of a density of fog + 1.0 The density of the SL surface when exposed was fog +0.12.

* The coating film No. V had different emulsion surface characteristics on both sides of the support, and the SH surface had a relative sensitivity of 99 and the SL surface had a relative sensitivity of 60.

SH surface: Fog +0.8 density and fog +1.3
Contrast H _G is 2.35 SL surface connecting the concentrations: Contrast L _G connecting the density of the density and fog +0.5 fog +0.3 is the concentration after development in 0.90 SH surface a density of fog + 1.0 exposure The density of the SL surface when exposed to light was fog +0.05.

* Coated film No. VI had different emulsion surface characteristics on both sides of the support, the SH surface had a relative sensitivity of 99, and the SL surface had a relative sensitivity of 70.

SH surface: Fog +0.8 density and fog +1.3
Contrast H _G is 2.35 SL surface connecting the concentration of: the contrast L _G connecting the concentration and density of fog + 0.5 of fog +0.3 concentration after development in 1.35 SH surface a density of fog + 1.0 When the exposure amount was exposed, the density on the SL surface was fog +0.05.

* Coated film No. VII had different emulsion surface characteristics on both sides of the support, the SH surface had a relative sensitivity of 87, and the SL surface had a relative sensitivity of 70.

SH surface: Fog +0.8 density and fog +1.3
Contrast H _G is 1.35 SL surface connecting the concentration contrast L _G connecting the density of the density and fog +0.5 fog +0.3 is the concentration after development in 1.35 SH surface exposure amount of a density of fog + 1.0 The density of the SL surface when exposed was fog +0.05.

Using these films, the sensitivity and contrast were determined by using a fluorescent intensifying screen as shown in Table 2 below.

<How to Obtain System Sensitivity and Contrast>
For the sensitivity measurement of the obtained sample, exposure was performed by combining intensifying screens having different sensitivities (luminance) on one side and both sides of the sample. The relative sensitivity of the obtained sample was obtained as the reciprocal of the X-ray dose required to obtain the fog + 1.0 density. The sensitivity of Sample 1 in Table 2
It is represented by relative sensitivity when 100 is set. Also, the contrast (gamma) is shown by the logarithm of the reciprocal of the X-ray dose that gives the densities of 1.0 and 2.0.

<How to obtain SL ', SL, SH' and SH> Sensitivity SB 'of the surface with the lowest maximum density when exposed with a fluorescent intensifying screen from the surface with the highest maximum density, and the lower maximum density. The sensitivity SB when exposed from the surface using a fluorescent intensifying screen was determined by removing the photosensitive layer on the surface having the highest maximum density with a protease. Further, the sensitivity SH of the surface having the highest maximum density when exposed using the fluorescent intensifying screen from the surface having the lowest maximum density and the sensitivity SH of the surface using the fluorescent intensifying screen exposing from the surface having the highest maximum density are , The highest concentration of the light-sensitive layer on the lower side was removed by proteolytic enzyme.

SL ', SL, and SH were obtained as the reciprocal of the X-ray dose required to obtain the density obtained by multiplying the value obtained by subtracting the fog density from the maximum density by 0.4 and further adding the fog density.

<How to Obtain Contrast on Each Surface> Above S
A sample for which L and SH were obtained was used.

On the high sensitivity side, the difference in logarithm of the reciprocal of the X-ray dose which gives (fog + 0.80) and (fog + 1.30) of the characteristic curve is 2
It is shown as the reciprocal of the multiplied value.

On the low sensitivity side, the difference in logarithm of the reciprocal of the X-ray dose which gives (fog + 0.30) and (fog + 0.50) of the characteristic curve is 5
It is shown as the reciprocal of the multiplied value.

However, for the conventional type films I and II coated with the same emulsion on both sides, the reciprocal of the X-ray dose that gives (fog + 0.80) and (fog + 1.30) of the characteristic curve, as with the high-sensitivity surface. It is shown by the reciprocal of the numerical value obtained by doubling the difference in logarithm.

The obtained results are shown in Tables 2 and 3.

[0113]

[Table 2]

[0114]

[Table 3]

As is clear from Tables 2 and 3, a conventional system using a fluorescent intensifying screen having almost the same emission intensity (within 40%) with respect to the film having the same photographic characteristics on both sides of the support. Compared with the sample, the sample according to the present invention had excellent balance in sensitivity, granularity and sharpness, and was comparable to the sample. Further, Sample No. 6 obtained by photographing the film III according to the present invention by the single back method has a better balance of sensitivity, graininess and sharpness than the double-sided system samples of Comparative Samples No. 1, 2, 3, and 5. Has improved. Samples taken with a combination of a high-sensitivity fluorescent intensifying screen on the low-sensitivity emulsion side and a low-sensitivity fluorescent intensifying screen on the high-sensitivity emulsion side have higher maximum densities on the low-sensitivity side than those on the high-sensitivity side. Sample No. 18 according to the present invention is superior in both graininess and sharpness to No. 14.
As described above, according to the present invention, it is possible to obtain images having various contrasts by selecting fluorescent intensifying screens having different emission intensities with one type of film according to the purpose and photographing. Therefore, it is no longer necessary to own many types of film according to the shooting site and purpose, as in the past.
Inventory management has become easier, and misuse of film types can be avoided.

[0116]

Industrial Applicability According to the present invention, a silver halide photographic light-sensitive material for X-ray can be obtained which can obtain the characteristics suitable for the purpose of photographing with one film. Further, according to the present invention, by changing the combination of each of the front and back intensifying screens used on both sides of the film, high sensitivity, high sharpness,
Further, it was possible to provide a silver halide photographic light-sensitive material for X-ray and an image forming method thereof, which can obtain an image having excellent graininess.

Claims (8)

[Claims] 1. In a silver halide photographic light-sensitive material having at least one silver halide emulsion layer having different maximum densities on both sides of a transparent support, the surface having the highest maximum density has a fog density of +1.0. When exposed at an exposure amount that gives a density of, the density of the surface with the lowest maximum density on the back surface is a fog +0.20 or less, and it is a silver halide photographic material, and the sensitivity of the surface with the highest density (the surface) ( SH) has a higher sensitivity than the sensitivity (SL) of the surface with the lowest maximum density (back surface), and the contrast that connects the two points of fog +0.8 and fog +1.3 of the characteristic curve of the high-sensitivity surface to a straight line However, the fog of the characteristic curve of the low-sensitivity surface +0.
A silver halide photographic light-sensitive material characterized by having a density higher than that of a straight line connecting the density of 3 and the density of fog +0.5. 2. The sensitivity SL 'of the surface with the lowest maximum density when exposed using a fluorescent intensifying screen from the surface with the highest maximum density.
2. The silver halide photographic light-sensitive material according to claim 1, wherein the ratio (SL '/ SL) of the sensitivity SL when exposed by using a fluorescent intensifying screen from the surface of the lowest maximum density is 0.12 or more. material. 3. The sensitivity SL 'of the surface having the lowest maximum density when exposed from the surface having the highest maximum density using a fluorescent intensifying screen.
And the ratio of the sensitivity SL when exposed using a fluorescent intensifying screen from the surface with the lowest maximum density (SL '/ SL) and the maximum when exposed using a fluorescent intensifying screen from the surface with the lowest maximum density. The ratio of the sensitivity SH 'of the high density surface to the sensitivity SH when exposed with a fluorescent intensifying screen from the surface of the highest density (S
2. The silver halide photographic light-sensitive material according to claim 1, wherein H '/ SH) is 0.30 or less. 4. The method for forming an image on a silver halide photographic light-sensitive material according to claim 2, wherein the fluorescent intensifying screen is exposed adjacent to only the high sensitivity. 5. A silver halide photographic light-sensitive material, characterized in that one surface of each of the silver halide photographic light-sensitive materials according to claim 1 or 2 is exposed so as to be adjacent to each other. Image forming method. 6. Exposure is carried out by adhering a low-sensitivity fluorescent intensifying screen to the high-sensitivity side of the silver halide photographic light-sensitive material according to claim 3 and adjoining the high-sensitivity fluorescent intensifying screen to the low-sensitivity side. An image forming method for a silver halide photographic light-sensitive material, comprising: 7. The light-sensitive material according to claim 3, wherein the high-sensitivity surface is adjacent to a high-sensitivity fluorescent intensifying screen, and the low-sensitivity surface is adjacent to a low-sensitivity fluorescent intensifying screen for exposure. Image forming method for silver halide photographic light-sensitive material. 8. A projected area of 50 on the high-sensitivity surface and the low-sensitivity surface.
4. The silver halide photographic light-sensitive material according to claim 1, 2 or 3, characterized in that at least% has an emulsion layer formed of tabular silver halide grains having an aspect ratio of 3 or more.