JPH053568B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a silver halide photographic material for X-rays. This type of photosensitive material is used for various diagnostic purposes in the medical field, as part of X-ray flaw detection technology in the industrial field, and for tracing radioactive isotopes in fields such as bioengineering. It is widely used. [Prior Art] X-ray silver halide photographic light-sensitive materials (some have a light-sensitive emulsion layer on both sides of the support and others have a light-sensitive emulsion layer on only one side; hereinafter, both will be included) (referred to simply as "X-ray sensitive material") has high sharpness, a large amount of information, good graininess, is resistant to pressure desensitization (that is, pressure-induced desensitization), and has little deterioration in image quality. required. For example, regarding medical X-ray sensitive materials, the higher the sharpness and the better the graininess, the easier it is to diagnose, the more information there is, the higher the diagnostic ability, which is advantageous, and the less pressure desensitization, the more accurate the information. It is desired that the image can be imaged in a timely manner, and that the image quality will not deteriorate and the storage stability will be good. In this way, when taking X-ray photographs of various parts of the body in the medical field, it is required that the images be sharp, contain a large amount of information, and have high diagnostic ability in order to detect lesions early and prevent misdiagnosis. However, the conventional
Line-sensitive materials are still not always satisfactory. That is, conventional X-ray sensitive materials for direct use are roughly classified into high gamma types shown by a, low gamma types shown by b, and moderate types shown by c in the characteristic curve of FIG. However, in the high gamma type a, the characteristic curve rises steeply as shown in the figure, so although the sharpness is high, the amount of information in the low exposure portion is poor. On the other hand, low gamma type b can be used in the form b′, which adjusts the dose and moves the curve parallel to the left side of the figure.
In this case, since the photographic density D in the low exposure area can be increased, the amount of information in the low exposure area is rich, or the slope of the characteristic curve is gentle and the sharpness is low, making it difficult to diagnose. Furthermore, the moderate type c has only a medium sharpness and a medium amount of information in low density areas. For each type of direct X-ray sensitive material, the gamma at each density is typically shown in the table below.
It becomes as shown in 1. Each gamma shown in the same table is the gamma created by a point with an optical density of 0.05 and a point with an optical density of 0.30 on a characteristic curve on a rectangular coordinate system with the same unit length of the coordinate axes of optical density (D) and exposure dose (logE). Let be gamma 1 (γ ₁ ), and let gamma 2 (γ ₂ ) create the gamma created by a point with an optical density of 0.50 and a point with the same optical density of 1.50, and let the optical density be
The gamma between 2.00 and 3.00 is defined as gamma 3 (γ ₃ ).

[Purpose of the invention]

The purpose of the present invention is to provide high sharpness, wide exposure latitude in low density areas and high density areas, improve diagnostic ability when used for medical purposes, and have good granularity and pressure reduction. It's hard to feel,
It is an object of the present invention to provide an advantageous X-ray sensitive material with little deterioration in image quality. [Structure and operation of the invention] The X-ray sensitive material according to the present invention has a point of optical density 0.05 on a characteristic curve on a rectangular coordinate system with the same unit length of the coordinate axes of optical density (D) and foggy light amount (logE). Same as 0.30
The gamma (γ ₁ ) produced by the point is 0.36 to 0.65, and the gamma (γ ₂ ) produced by the point with an optical density of 0.50 and the same point as 1.50 is 2.7 to 3.3, and the same as the optical density 2.00.
3.00 and a gamma (γ ₃ ) of 1.5 to 2.5, the silver halide photographic material has general formulas [] [] and [] (detailed below). It contains at least one compound selected from the group of compounds represented by
It is characterized by having at least one emulsion layer made of an emulsion that has passed through an atmosphere having a temperature of 10.5 or higher at least once. By adopting this configuration, the X-ray sensitive material of the present invention can achieve the above-mentioned object. In the present invention, each of the above-mentioned configurations of the present invention works together to achieve the above object, but roughly speaking, by setting γ ₁ to the above range, the exposure latitude in the low density area can be widened, It can be said that by setting γ ₂ within the above range, the sharpness can be increased, and by setting γ ₃ within the above range, the exposure latitude in the high density area can be widened. In addition, by having this structure and a layer consisting of an emulsion that contains the compound represented by the above general formula and has passed through a high pAg atmosphere during grain growth as described above, graininess can be improved and pressure desensitization can be achieved. prevention and prevention of image quality deterioration can be achieved. In carrying out the present invention, preferably, in the characteristic curve on the rectangular coordinate system when processed under the following processing conditions, γ ₁ is 0.36 to 0.65, and γ ₂ is 2.7.
~3.3, so as to obtain a characteristic curve with _γ3 between 1.5 and 2.5. [Processing conditions] Using the developer-1 below, follow the steps below.
Processed using a roller conveyance type automatic processor. Processing temperature Processing time Development 35℃ 30 seconds fixing 34℃ 20 seconds washing 33℃ 18 seconds drying 45℃ 22 seconds Developer-1 Potassium sulfite 55.0 Hydroquinone 25.5g 1-phenyl-3-pyrazolidone 1.2g Boric acid 10.0g Potassium hydroxide 21.0g Triethylene glycol 17.5g 5-methylbenztriazole 0.04g 5-nitopenzimidazole 0.11g 1-phenyl-5-mercaptotetrazole
0.015g Glutanaldehyde bisulfite 15.0g Glacial acetic acid 16.0g Potassium bromide 40g Add water to make 1. However, among the above conditions, there may be some variation in processing temperature, processing time, amount of developing agent, etc. The characteristic curve referred to in the present invention is obtained by, for example, the following optical sensitometry [A]. That is, in this optical sensitometry [A], the exposure is on both sides (or one side) of the transparent support.
An X-ray sensitive material having a light-sensitive emulsion layer is sandwiched between two engineering wedges whose density gradients are mirror-symmetrically matched, and a light source with a color temperature of 5400 is used to simultaneously illuminate the same amount from both sides at 1/10.
Expose for seconds. The processing is carried out using a roller-conveyed automatic developer according to the steps described above. The fixing solution is not particularly limited as long as it is an acidic dura fixing solution, such as Sakura XF (manufactured by Konishiroku Photo Industries). Gamma in the present invention is determined based on a characteristic curve drawn on a rectangular coordinate system in which the unit lengths of the coordinate axes of optical density (D) and logarithm of exposure (logE) are equal. The γ ₁ is the base (support) on the characteristic curve.
It means the slope of the straight line connecting the density point of density + fog density + 0.05 and the density point of base density + fog density + 0.30, and the above γ ₂ is the density of base density + fog density + 0.50. and the point at the density of base density + fog density + _1.50 .
It means the slope of the straight line connecting the density point of , and the density point of base density + fog density + 3.00. Expressed further numerically, if the angles at which these straight lines intersect with the exposure axis (horizontal axis) are θ ₁ , θ ₂ and θ ₃ , then γ ₁ and γ ₂ are tanθ ₁ , tanθ ₂ and tanθ ₃ respectively. means. The method of obtaining the characteristic curve of the present invention is arbitrary, and may include the use of monodisperse emulsion, polydisperse emulsion, core-shell type monodisperse emulsion, core-shell type polydisperse emulsion alone or in combination of two or more, particle size or Any technique such as controlling particle size distribution, optimizing silver halide crystal habit, adjusting hardness, adding a development accelerator, or adding a development inhibitor may be used in the present invention. By dye-sensitizing the particles obtained by this method using at least one compound selected from the group of compounds represented by the following general formulas [] [] and [], the above characteristic curve of the present invention can be obtained. obtain. In this case, this is preferably achieved by a combination of two or more types of monodisperse or polydisperse particles. Further, these particles can also be chemically sensitized, and in that case, the optimum chemical sensitization may be performed separately for each, or the two may be mixed and then chemically sensitized. For implementation of the present invention, the former is rather preferred. In this way, in the present invention, the general formula []
[] The use of any of the compounds in [] results in ortho-sensitization, resulting in further improvements, particularly with respect to graininess and pressure desensitization. In other words, the regular type had poor graininess and pressure desensitization performance because it used large particles for the legs, which required high sensitivity, but the orthotype had high sensitivity due to dye sensitization. Therefore, the silver halide grains used can be made smaller. As a result, graininess and pressure desensitization performance can be further improved. The general formula [ ] [ ] [ ] is as shown below. General formula [] [In the formula, R ₁ , R ₂ , and R ₃ each represent a substituted or unsubstituted alkyl group, alkenyl group, or aryl group, and at least one of R ₁ and R ₃ is a sulfoalkyl group or a carboxyalkyl group. .
X ^- ₁ is an anion, Z ₁ and Z ₂ are nonmetallic atomic groups necessary to complete the substituted or unsubstituted benzene ring,
n represents 1 or 2. (However, when forming an inner salt, n is 1.) [In the formula, R ₄ and R ₅ each represent a substituted or unsubstituted alkyl group, alkenyl group, or aryl group, and at least one of R ₄ and R ₅ is a sulfoalkyl group or a carboxyalkyl group.
R ₆ represents a hydrogen atom, a lower alkyl group, or an aryl group. X ^- ₂ represents an anion, Z ₁ and Z ₂ represent a group of nonmetallic atoms necessary to complete a substituted or unsubstituted benzene ring, and n represents 1 or 2. (However, when forming an inner salt, n is 1.)] [In the formula, R ₇ and R ₉ are each substituted or unsubstituted lower alkyl group, R ₈ and R ₁₀ are lower alkyl group, hydroxyalkyl group, sulfoalkyl group,
A carboxyalkyl group, X ^- ₃ is an anion, Z ₁ and Z ₂ are nonmetallic atomic groups necessary to complete a substituted or unsubstituted benzene ring, and n is 1 or 2. (However, when forming an inner salt, n is 1
It is. )] When a compound of the general formula [ ] [ ] [ ] is used in the emulsion forming the X-ray sensitive material of the present invention, the weight or number of silver halide grains contained in the silver halide emulsion is at least as large as that of Preferably, 95% of the particles have a particle size within ±40% of the average particle size. Next, the compound of formula [][][] will be further explained. In the general formula [], specific examples of substituted or unsubstituted alkyl groups for R ₁ , R ₂ , and R ₃ include lower alkyl groups such as methyl, ethyl, n-propyl, and butyl.
Examples of substituted alkyl groups for R ₁ , R ₂ and R ₃ include vinylmethyl, hydroxyalkyl groups such as 2-hydroxyethyl and 4-hydroxybutyl, and acetoxyalkyl groups such as 2-acetoxyethyl, 3-acetoxybutyl group, carboxyalkyl group such as 2-carboxyethyl, 3-carboxypropyl, 2-(2-carboxyethoxy)ethyl, etc., sulfoalkyl group such as 2-sulfoethyl, 3-sulfopropyl,
Examples include 3-sulfobutyl, 4-sulfobutyl, 2-hydroxy-3-sulfopropyl, and the like. Examples of the alkenyl group for R ₁ , R ₂ and R ₃ include allyl, butyryl, octenyl and oleyl. Furthermore, examples of the aryl group for R ₁ , R ₂ , and R ₃ include phenyl, carboxyphenyl, and the like. However, as described above, at least one of R ₁ , R ₂ and R ₃ is a sulfoalkyl group or a carboxyalkyl group. Examples of the anion represented by ^-1 in formula [] include chloride ion, bromide _ion , iodine ion, thiocyanate ion, sulfate ion, perchlorate ion, p-toluenesulfonate ion, ethyl sulfate ion, etc. I can do it. Next, typical examples of the compound represented by this general formula [] will be given, but the present invention is not limited thereto. In formula [ ], R ₆ represents a hydrogen atom, a lower alkyl group, or an aryl group, and examples of the lower alkyl group include methyl, ethyl, propyl, butyl, etc. Examples of the aryl group include, for example, phenyl Examples include groups. As R ₄ and R ₅ , in the explanation of the formula [] above, the formula [] is
Examples of R ₁ and R ₃ can be mentioned. Examples of the anion of X ^- ₂ include those exemplified as X ^- ₁ in the formula []. Next, typical examples of the compound represented by the formula [] will be given, but of course the present invention is not limited to these examples. Next, in formula [], examples of lower alkyl groups for R ₇ and R ₉ include methyl, ethyl, propyl, butyl and the like. Examples of the substituted alkyl group include the groups exemplified for R ₁ to _{R 3} in formula []. Examples of lower alkyl groups for R ₈ and R ₁₀ are the same as those for R ₇ and R ₉ . Also R ₈ ,
Examples of the hydroxyalkyl group, sulfoalkyl group, and carboxyalkyl group for R ₁₀ include the groups exemplified for R ₁ to _{R 3} in formula []. Examples of the anion of X ^- ₃ include those exemplified as X ^- ₁ in the formula. Typical specific examples of the compound represented by the formula [] are listed below. Of course, the present invention is not limited to this example either. The total amount of the compound represented by the above formula [] [] [] is 10 mg to 900 mg per mole of silver halide.
It can be used in the mg range. In particular, 60-600
mg is preferred. Examples of chemical sensitization methods applied to growing particles include:
Sulfur sensitization method using sodium thionitrate, thiourea compounds, etc., gold sensitization method using chloraurate, gold trichloride, etc., reduction sensitization method using thiourea dioxide, stannous chloride, silver ripening, etc. Other palladium sensitization methods,
There are selenium sensitization methods, etc., and these can be used alone or in combination of two or more. In this case, it is particularly preferable to use gold sensitization and sulfur sensitization together. In the practice of the present invention, silver halide grains in the silver halide emulsion may have an average grain size of 0.3 to 3 .mu.m. Preferably, such a silver halide grain has a localized portion in which a high concentration of silver iodide of at least 20 mol % is localized inside the grain. In this case, it is preferable that the inside of the particle be as far inward as possible from the outer surface of the particle, and in particular, it is preferable that a localized portion exists at a distance of 0.01 μm or more from the outer surface. Further, the localized portion may exist in a layered manner inside the particle, or may have a so-called core-shell structure, with the entire core serving as the localized portion. In this case, it is preferable that part or all of the grain core excluding the shell portion having a thickness of 0.01 μm or more from the outer surface is a localized portion with a silver iodide concentration of 20 mol % or more. In addition, the concentration of silver iodide in the localized part is 30
It is preferably in the range of ~40 mol%. In the practice of this invention, the silver halide grains used in the silver halide emulsion are, for example, TH
“The Theory of the Photographic” by James
Process” 4th edition, published by Macmillan (1977) 88
Methods such as the neutral method, acid method, ammonia method, forward mixing, back mixing, double jet method, controlled double jet method, convergence method, core/shell method, etc. described in the literature such as pages 104 to 104 are applied. It can be manufactured using As for the silver halide composition, any of silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide, etc. can be used, but the most preferable emulsion is about 10 mol% or less of silver halide. It is a silver iodobromide emulsion containing silver iodide. The grain size of the silver halide grains is not particularly limited, but is preferably 0.1 to 3μ, more preferably 0.3 to 2μ. Further, these silver halide grains or silver halide emulsions may contain an iridium salt and/or a rhodium salt in order to improve flash exposure characteristics. Also preferably
Tl, Pd, or Zn, Ni, Co, U, Th, Sr, W,
It may also contain a Pt salt. The outside of such localized areas is usually coated with silver halide without silver iodide.
That is, in a preferred embodiment, from the outer surface
The shell portion with a thickness of 0.01 .mu.m or more, in particular 0.01 to 1.5 .mu.m, is formed of silver halide (usually silver bromide) without silver iodide. In the present invention, a seed crystal is used as a method for forming a localized portion of high concentration silver iodide of at least 20 mol % inside the grain (preferably inside the grain at a distance of 0.01 μm or more from the outer wall of the grain). A seed crystal is preferably used, but a seed crystal-free one may also be used. When seed crystals are not used, there is no silver halide that can serve as growth nuclei in the reaction liquid phase (hereinafter referred to as mother liquor) containing protected gelatin before the start of ripening, so silver ions and at least 20 mol% or more are first added. Halide ions containing a high concentration of iodine ions are supplied to form growth nuclei. Then, additional supply is continued to grow particles from the growth nuclei. lastly,
A shell layer having a thickness of 0.01 μm or more is formed using silver halide containing no silver iodide. If using seed crystals, at least 20
Silver iodide of mol % or more may be formed and then covered with a shell layer. Alternatively, the amount of silver iodide in the seed crystal is set to 0 or within the range of 10 mol % or less, and at least 20 mol % of silver iodide is formed inside the grain in the step of growing the seed crystal, and then the shell layer is formed. It may be coated with. In this case, in the present invention, the ratio of silver iodide to total silver halide in the entire grain is 0.5 to 10.
If it is within the range of mol %, the former method results in a larger seed crystal particle size than the latter method, resulting in a broader particle size distribution. The latter having a multiple structure is preferable in the present invention. A preferred embodiment of the present invention is to use silver halide grains with regular structure or morphology. i.e. at least 80% by weight or number of silver halide grains
A silver halide emulsion with a regular shape is used. When used in the present invention, silver halide grains with a regular structure or morphology mean grains that grow isotropically without including anisotropic growth such as twin planes, such as cubic or 14-sided grains. ,
It has a shape such as a regular eight-sided pair or a spherical shape. Methods for producing such regular silver halide grains are known, for example, J. Phot. Sci., 5 332 (1961), Ber. Bunsenges.
phys.Chem. 67 949 (1963), Intern.Congress Phot.
It is described in Sci. Tokyo (1967) and others. Such well-regulated silver halide grains can be obtained by adjusting the reaction conditions when growing silver halide grains using a simultaneous mixing method. In such a simultaneous mixing method, silver halide grains are produced by adding approximately equal amounts of a silver nitrate solution and a halide solution to an aqueous solution of a protective colloid while stirring vigorously. The supply of silver ions and halide ions is necessary and sufficient for the growth of only existing grains, without dissolving the existing crystal grains as the crystal grains grow, and conversely not allowing the generation and growth of new grains. It is preferable to increase the growth rate continuously or stepwise within the critical growth rate for supplying silver halide or within its permissible range. This increasing method is described in Japanese Patent Publication No. 48-36890, Japanese Patent Publication No. 52-16364, and Japanese Patent Application Laid-Open No. 55-142329. This critical growth rate varies depending on the temperature PH, pAg, degree of stirring, composition of halogenated particles, solubility, particle size, interparticle distance, crystal habit, and type and concentration of protective colloid. can be easily determined experimentally by methods such as microscopic observation of emulsion particles suspended in a liquid phase and turbidity measurement. By gradually increasing the addition rate within this limit addition rate or its allowable range, a monodisperse emulsion, that is, one with a coefficient of variation of 20% or less, can be obtained. In order to obtain the above-mentioned monodisperse emulsion, it is particularly preferable to use seed crystals and grow grains by supplying silver ions and halide ions using the seed crystals as growth nuclei. The broader the particle size distribution of this seed crystal, the wider the particle size distribution after particle growth. Therefore, in order to obtain a monodisperse emulsion, it is preferable to use seed crystals with a narrow particle size distribution at the seed crystal stage. The X-ray silver halide photographic material of the present invention has at least one emulsion layer made of an emulsion that has passed through an atmosphere having a pAg of at least 10.5 at least once during the growth of silver halide grains. That is, for example, when carrying out the present invention, an embodiment is preferably adopted in which the pAg of the mother liquor containing the protective colloid is at least 10.5 during particle growth before chemical sensitization as described above, and such pAg atmosphere is maintained. Ventilation can be performed. Particularly preferably, an atmosphere with a very high bromine ion excess of 11.5 or more is passed through at least once. Due to particle growth in such a pAg atmosphere,
By increasing the number of (111) planes of the particles, the particles can be rounded, thereby further enhancing the effects of the present invention. The (111) plane of such a particle is
It is preferable that its proportion to the total surface area is 5% or more. In this case, the increase rate of the (111) plane (the increase rate with respect to that before passing through the pAg atmosphere of 10.5 or more) is preferably 10% or more, more preferably 10 to 20%. Regarding whether the outer surface of silver halide grains is covered with (111) planes or (100) planes, and how to measure the ratio thereof, please refer to the report by Akira Hirata, “Bulletin of the Society of Science”. It is described in "Photography of Japan" No. 13, pages 5-15 (1963). In the present invention, during grain growth before chemical sensitization,
Mother liquor containing protective colloid has a pAg of at least 10.5
By passing the above atmosphere once,
Using Hirata's measurement method, it can be easily confirmed whether the (111) plane has increased by 5% or more. In this case, the above pAg is set before chemical sensitization, but preferably from the time when silver ions are added for the growth of silver halide grains to before the desalting step.
In particular, it is desirable to carry out the process after the addition of silver ions is completed, but before the so-called desalting step which is usually carried out before chemical sensitization. This is because it is easy to obtain a monodispersed emulsion with a narrow particle size distribution. Note that aging in an atmosphere where pAg is 10.5 or more is preferably performed for 2 minutes or more. Such pAg control increases the number of (111) planes by 5% or more, resulting in a rounded shape. As a result, it is possible to obtain a preferable particle in which the (111) plane accounts for 5% or more of the total surface area of the particle. A stabilizer can be added to the silver halide emulsion thus prepared after completion of chemical sensitization. For example, 4-hydroxy-6-methyl-
Any stabilizer known in the art can be used, including 1,3,3a,7-tetrazyden, 5-mercapto-1-phenyltetrazole, 2-mercaptobenzothiazole, and the like. The silver halide photographic emulsion of the present invention uses gelatin, gelatin derivatives,
Synthetic hydrophilic polymers and the like can be used, and various photographic additives can also be included. As the hardening agent, aldehyde compounds, S-triazine compounds, ketone compounds, halogen-substituted acids such as mucochloric acid, ethyleneimine compounds, vinylsulfophane compounds, etc. can be used. As the spreading agent, saponin, lauryl or oleyl monoether of polyethylene glycol, etc. are used. The development accelerator is not particularly limited, but compounds such as thioether compounds, benzimidazole compounds (for example, those described in JP-A-49-24427), quaternary ammonium salts, polyethylene glycol, etc. can be used. As physical property improvers, alkyl acrylate,
Polymer lacquers made of homo- or copolymers of alkyl methacrylate, acrylic acid, etc. can be contained. The silver halide photographic emulsion of the present invention includes a compound obtained by addition copolymerizing glycidol and ethylene oxide to a phenolaldehyde condensate (for example, the one described in JP-A-51-56220), a lanolin-based ethylene oxide addition body, alkali metal salts and/or alkaline earth metals (such as those described in JP-A-53-145022), water-soluble inorganic chlorides and matting agents (Japanese Patent Application No. 1983-145022),
69242), an addition condensate obtained by addition-condensing glycidol and ethylene oxide to a phenolaldehyde condensate, and a fluorine-containing succinic acid compound (patent application
An antistatic agent such as No. 52-104940) can be added. Furthermore, it may contain a PH adjuster, a thickener, a graininess improver, a matting agent for improving the film surface, and the like. As a support for obtaining the light-sensitive material of the present invention, a film made of polyethylene terephthalate, polycarbonate, polystyrene, polypropylene, cellulose acetate, etc. can be used. In addition, as a support, JP-A-52-
104913, JP-A-5-19941, JP-A-59-19940, and JP-A-59-18949 are preferred. [Embodiments of the Invention] Specific embodiments of the present invention will be described below.
However, the following examples are illustrative of the present invention, and the present invention is not limited thereto. Example 1 Six types of emulsions -1 to -6 as described below
was prepared. First, a silver iodobromide polydisperse emulsion (-1) containing 2.0 mol % of silver iodide was obtained by a forward mixing method. Emulsion-2 was prepared by the following method. Potassium iodide 2.0 mol% in gelatin aqueous solution
A potassium bromide solution containing . Further, an ammoniacal silver nitrate solution and a potassium bromide solution were added by a double jet method, and a shell of pure silver bromide was covered. During this period, pAg was maintained at 10.0, and PH was gradually lowered from 9.0 to 8.0. As a result, a cubic crystal monodisperse emulsion-2-2 having an average grain size of 1.25 μm was obtained. Moreover, this emulsion-2-
By the same method as 2, cubic monodispersed emulsion-2-1 with an average grain size of 1.65 μm and an average grain size of 0.65 μm were prepared.
A cubic monodispersant-3-1 was obtained. This emulsion-2-1 and the above emulsion-2-2 were mixed at a mixing ratio of 10:90 as shown in the table below to obtain emulsion-2 as a sample. Further, Emulsion-2-2 and Emulsion-3-1 were mixed at a mixing ratio of 75:25 as shown in the table below to obtain Emulsion-3 as a sample. Next, emulsions -4 to -6 were obtained as described below. A monodisperse cubic emulsion of silver iodobromide containing 2.0 mol% of silver iodide and having an average grain size of 0.3 μm was obtained by a double jet method while controlling the temperature at 60° C., pAg=8, and pH=2.0. An electron micrograph of this emulsion showed that the incidence of twin grains was 1% or less in number. A portion of this emulsion was used as a seed crystal and grown as follows. That is, the seed crystals were dissolved in a solution 8.5 containing protected gelatin and optionally ammonia kept at 40°C, and the pH was further adjusted with glacial acetic acid. Using this solution as a mother liquid, a 3.2N ammoniacal silver ion aqueous solution and a halide aqueous solution were added by a double jet method in a flow pattern as shown in FIG. 2, followed by stirring and mixing. In this case, the ammonia concentration of this mother liquor is 0.6N,
By setting PH9.7 and pAg7.6, internally,
30 mol% silver iodide was localized. Next, the pAg was kept constant at 9.0, and the pH was changed from 9 to 8 in proportion to the amount of ammoniacal silver ion added to form a shell of pure silver bromide. Furthermore, after the completion of grain growth, ripening was performed at pAG of 11.5 for 3 minutes, and the grains were rounded. In this way, seven types of monodisperse emulsions -4-1 to -6-3 shown in Table 2 were prepared. Three of emulsions -4 to -6 were the same as the emulsion -1.
It was obtained by mixing three types of internally high iodine type monodispersed emulsions, each having a different average grain size, prepared in the same manner as above. In other words, emulsions -4 and -5 are
An emulsion (-4-1) with an average grain size of 0.90μ, an emulsion (-4-2) with an average grain size of 0.70μ, and an emulsion (-4-3) with an average grain size of 0.35μ were mixed at a ratio of 9:73:18 and 13:67:20, respectively. It was obtained by mixing at the same ratio. Also, emulsion-6 has an average grain size of 0.95μ
emulsion (-6-1), 0.80μ emulsion (-6-
2), a 0.50μ emulsion (-6-3) was mixed at a mixing ratio of 22:48:30. The composition of each sample is summarized in Table 2 below.

[Table] Emulsion-4-1~ obtained as above
-4-3, -6-1 to -6-3 (that is, each emulsion constituting emulsions -4 to -6) were added with the following compound sensitizing dye, and then ammonium thiocyanate and chloroauric acid were added. and hypo were added to perform gold-sulfur sensitization. The other emulsions were subjected to the same gold-sulfur sensitization without adding any sensitizing dye. Therefore, samples -4 to -6 are ortho-sensitized orthotypes, while the others are regular types. The compound added as a sensitizing dye is one of the compounds represented by the above formula [], and the compound is one of the compounds represented by the formula []. The formula of each compound is listed below. After adding usual stabilizers, hardeners, and coating aids, a copolymer consisting of three monomers: 50 wt% glycidyl methacrylate, 10 wt% methyl acrylate, and 40 wt% butyl methacrylate,
This emulsion was coated uniformly on both sides of a polyethylene terephthalate film base coated with an aqueous copolymer dispersion obtained by diluting the copolymer dispersion to a concentration of 10 wt% as a subbing liquid, dried, and then used as a sensitometric sample. I got it. Next, for samples -1 to -3, we used Fluorescent Screen NS (for regular type) manufactured by Konishiroku Photo Industry, and for samples -4 to -6, we used fluorescent screen NS manufactured by Konishi Roku Photo Industry. Using a light screen KS (for orthotype), X-rays were irradiated through an aluminum wedge at a tube voltage of 90 KV and a tube current of 50 mA. After that, using the automatic processor QX-1200 manufactured by Roku Konishi Photo Industry,
A sensitometric curve was obtained by processing for 90 seconds with -90 developing solution. The results are shown in Table-3. The exposure latitude was expressed as the difference in exposure amount (logarithm representation) between the respective optical densities. In this case, the processing conditions were as described above, and the developer used was the developer-1 described above. This is a condition when using the above-mentioned automatic processor or developing processing solution. However, the processing time is about ±2 seconds, and the processing temperature is ±2 seconds.
The temperature may be within a range of about 1° C., and the amount of hydroquinone as a developing agent may be within a range of about ±1 g. Example 2 An attempt was made to evaluate the sharpness of the same sample as in Example 1. The sharpness evaluation is 10 of the MTF curve,
Expressed as values of 1.5 and 2.0 line/mm. Measuring MTF is
An MTF measurement chart containing a lead square wave of 0.8 to 10 line/mm is placed in close contact with the back side of the front side of the fluorescent screen, and the concentration of the part of the sample surface that is not shielded by the lead square wave (that is, the background concentration) on both sides
It was irradiated so that it was 1.0. Thereafter, the same development treatment as in Example 1 was performed.
The square wave pattern of the obtained sample was measured using a Sakura Microdensitometer Model M-5 (Konishiroku Photo Industry).
Scanning measurement was carried out in the direction perpendicular to the rectangular liquid. The aperture size at this time is 230 μm in the parallel direction of the square wave and 25 μm in the perpendicular direction.
m and the magnification is 100 times. The results are shown in Table-3. Example 3 The same sample as in Example 1 was kept at constant temperature and humidity of 23°C relative temperature 35% for about 2 hours, and under these conditions, it was bent about 280 degrees with a radius of curvature of 2 cm, and the pressure desensitization was measured. Ivy. Three minutes after the sample was folded, it was developed in the same manner as in Example 1 by irradiating it with X-rays for 0.06 seconds using an aluminum wedge at a tube voltage of 80 KV and a tube current of 100 mA. The degree of pressure desensitization of the obtained sample was visually evaluated. In addition, using this sample, graininess,
Deterioration of image quality caused by rapid processing at high pH and constant temperature was also visually evaluated. Here, the visual evaluation of desensitization performance due to pressure, graininess, and image quality caused by rapid processing was expressed on a five-point scale from best to worst, with 1 being the best, and the higher the number, the worse it was. . These results are also shown in Table-3.

【table】

[Table] As can be seen from Table 3, samples Nos.-4 to -6 that meet the conditions of the present invention have high sharpness, and have a wide exposure latitude in low-density and high-density areas.
It was also found that there was little pressure desensitization. Also,
These samples were found to have less graininess and less deterioration in image quality due to high pH and high temperature rapid processing. As described above, according to the samples corresponding to the examples of the present invention, good results can be obtained that achieve the above-mentioned objectives. Comparative Example 1 Emulsions -4-1 to -4- in Example 1
3. In the process of preparing six types of emulsions -6-1 to -6-3, the pAg after grain growth was set to 10.0, and the other conditions were the same as in Example 1, and comparative emulsions No. 1 to No. 6 were prepared, respectively. I got it. These emulsions were mixed as shown in Table 4, sensitizing dyes were added in the same manner as in Example 1, and the emulsion was prepared.
7 and -8 were produced. Furthermore, coating samples were prepared and evaluated in the same manner as in Example 1 (Table 5).
reference). Furthermore, emulsion-4-1 prepared in Example 1
Emulsions-9 to 12 were prepared by mixing emulsions and adding dyes as shown in Table 4 using -4-3 and the following comparative dyes D-1 to D-4. Furthermore, coated samples were prepared and evaluated in the same manner as in Example 1 (see Table 5).

【table】

【table】

[Table] As can be understood from Table 5, samples -7 and -8 using emulsions other than the present invention had poor graininess and image quality, and samples using sensitizing dyes other than the present invention For -9 to -12, unfavorable results were obtained such as a decrease in the MTF value and a decrease in graininess and image quality. As can be understood from this, it is clear that excellent effects can be obtained only when a light-sensitive material having the characteristic curve according to the present invention is assembled using the emulsion according to the present invention and the sensitizing dye. [Effects of the Invention] As described above, the X-ray sensitive material of the present invention has high sharpness and a wide exposure latitude at low and high concentrations, and therefore can improve diagnostic performance when used for medical purposes. Furthermore, it has the advantage of good graininess, resistance to pressure desensitization, and low deterioration of image quality.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing characteristic curves of high comma type a, low gamma type b, and moderate type c of direct X-ray sensitive materials. FIG. 2 is a diagram showing the addition flow rate pattern of the example.

Claims (1)

[Claims] 1. In a characteristic curve on a rectangular coordinate system with the same unit length of the coordinate axes of optical density (D) and exposure dose (logE), the gamma (γ ₁ )
is between 0.36 and 0.65, and the optical density is 0.50.
The gamma (γ ₂ ) created by the 1.50 point is 2.7 to 3.3,
and a gamma (γ ₃ ) between optical density 2.00 and optical density 3.00.
is 1.5 to 2.5, the silver halide photographic material is
Contains at least one compound selected from the group of compounds represented by the following general formulas [] [] and [], and also contains a
1. A silver halide photographic material for X-rays, comprising at least one emulsion layer made of an emulsion that has passed through an atmosphere having a pAg of at least 10.5 at least once. General formula [] [In the formula, R ₁ , R ₂ , and R ₃ each represent a substituted or unsubstituted alkyl group, alkenyl group, or aryl group, and at least one of R ₁ and R ₃ is a sulfoalkyl group or a carboxyalkyl group. .
X ₁ ^- is an anion, Z ₁ and Z ₂ are nonmetallic atomic groups necessary to complete a substituted or unsubstituted benzene ring,
n represents 1 or 2. (However, when forming an inner salt, n is 1.) [In the formula, R ₄ and R ₅ each represent a substituted or unsubstituted alkyl group, alkenyl group, or aryl group, and at least one of R ₄ and R ₅ is a sulfoalkyl group or a carboxyalkyl group.
R ₆ represents a hydrogen atom, a lower alkyl group, or an aryl group. X ₂ ^- represents an anion, Z ₁ and Z ₂ represent a group of nonmetallic atoms necessary to complete a substituted or unsubstituted benzene ring, and n represents 1 or 2. (However, when forming an inner salt, n is 1.) [In the formula, R ₇ and R ₉ are each substituted or unsubstituted lower alkyl group, R ₈ and R ₁₀ are lower alkyl group, hydroxyalkyl group, sulfoalkyl group,
The carboxyalkyl group, X ₃ ^- represents an anion, Z ₁ and Z ₂ represent a group of nonmetallic atoms necessary to complete a substituted or unsubstituted benzene ring, and n represents 1 or 2. (However, when forming an inner salt, n is 1
It is. )〕