JPH0461339B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a silver halide photographic light-sensitive material for X-rays, and more specifically, it has high diagnostic ability, high sharpness, and is easy to diagnose. This invention relates to a silver halide photographic material for small X-rays. [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, they will be simply referred to as X-ray silver halide photographic materials. When taking X-ray photographs of various parts of the body using X-ray sensitive materials, high diagnostic performance is required to detect lesions early and prevent misdiagnosis. It's not satisfying. That is, in the characteristic curve of FIG. 1, conventional direct X-ray sensitive materials are broadly classified into high gamma type, denoted by a, low gamma type, denoted by b, and moderate type, denoted by c. Although the sharpness is high, the amount of information in the low-exposure portion is poor, and the low gamma type b, on the other hand, has a rich amount of information in the low-exposure portion, but is difficult to diagnose due to the low sharpness.
The moderate type c has only a medium sharpness and a medium amount of information in low density areas. For each of these types of direct X-ray sensitive materials, in the characteristic curve when processed with developer-1, the gamma γ ₁ produced by the point with optical density 0.50 and the point with optical density 1.50 is the same as the point with optical density 0.05. Typical examples of gamma γ ₂ created by a point of 0.30 are shown in Table 1.

[Purpose of the invention]

Accordingly, a first object of the present invention is to provide an X-ray sensitive material that has high sharpness, wide exposure latitude in low density areas, and high diagnostic ability. A second object of the present invention is to provide an X-ray sensitive material with improved pressure desensitization. [Structure of the Invention] The object of the present invention is to improve the optical density 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) processed under the following processing conditions. The gamma γ ₁ created by the 0.50 point and the same 1.50 point is 2.7 to 3.3, and the same 0.30 as the optical density point of 0.05.
This is achieved by a silver halide photographic material for X-rays, which is characterized in that a characteristic curve with a gamma γ ₂ of 0.36 to 0.65 is obtained. [Processing conditions] Using the developer-1 below, follow the steps below.
Processed using a roller conveyance type automatic processor. Processing temperature Processing time Developing 35°C 30 seconds Fixing 34°C 20 seconds Washing 33°C 18 seconds Drying 45°C 22 seconds Developer-1 Potassium sulfite 55.0g Hydroquinone 25.0g 1-phenyl-3-pyrazolidone 1.2g Boric acid 10.0g Hydroxylation Potassium 21.0g Triethylene glycol 17.5g 5-methylbenztriazole 0.04g 5-nitrobenzimidazole 0.11g 1-phenyl-5-mercaptotetrazole
0.015g Glutaraldehyde bisulfite 15.0g Glacial acetic acid 16.0g Potassium bromide 4.0g Add water to make 1. Further, the characteristic curve referred to in the present invention is obtained by the following optical sensitometry [A]. (Photosensitometry [A]) Exposure is carried out by sandwiching an X-ray sensitive material having a photosensitive emulsion layer on both sides (or one side) of a transparent support between two optical wedges whose density gradients are mirror-symmetrically aligned. temperature
5400°K light source from both sides simultaneously and equally, 1/10
Expose for seconds. The processing is carried out using a roller conveyance type automatic developing machine according to the above-mentioned steps. 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 the optical density D and the 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 + 0.50 and the density point of base density + fog density + 1.50, and the above γ ₂ is the density of base density + fog density + 0.05. It means the slope of the straight line connecting the point and the point of base density + fog density + 0.30 density. Further, expressed numerically, if the angles at _which these straight lines intersect with the exposure axis (horizontal axis) are θ ₁ and θ 2 , γ ₁ and γ ₂ mean tan θ ₁ and tan θ ₂ , respectively. The method of obtaining the characteristic curve of the present invention is arbitrary, such as using 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 particle size. Any technique such as controlling the distribution or optimizing the silver halide crystal habit may be used, but for example, an emulsion (Em ₁ ) mainly embodying γ ₁ and an emulsion mainly embodying γ ₂ may be used. By specifying each emulsion (Em ₂ ) and applying them in combination, a light-sensitive material having such a characteristic curve can be obtained. It is preferable to use a polydisperse emulsion with a high sensitivity as Em ₂ , and to use a monodisperse emulsion with a sensitivity lower by about 15% to 60% than the above-mentioned polydisperse emulsion as Em ₁ . The polydisperse emulsion referred to in the present invention can be prepared by a conventional method, for example, The Photographic Journal, 79, 330-338.
A silver halide emulsion in which at least 10% of the grains deviate from the average grain diameter by at least 40% by number or weight when the average grain diameter is measured by the method reported by Trivelli, Smith in (1939). . Methods for preparing such polydisperse emulsions are known, for example, as described in "The Theory of the
Neutral method, acidic method, ammonia method, forward mixing, back mixing, double jet method, controlled double jet method described in literature such as "Photographic Process" 4th edition, published by Macmillan (1977), pp. 38-104. It can be manufactured by applying methods such as , convergence method, core/shell method, etc.
Silver halide composition includes silver bromide, silver chlorobromide,
Although either silver iodide or silver chloroiodobromide can be used, the most preferred emulsion is a silver iodobromide emulsion containing about 10 mol % or less of silver iodide. There is no particular restriction on the grain size of the silver halide grains, but an average grain size of 0.5 to 4 microns is preferred. In addition, these silver halide grains or silver halide emulsions contain
Iridium salts and/or rhodium salts may be included to improve flash exposure characteristics, and thallium salts may be included to further improve pressure resistance. Examples of polydisperse emulsions include polydisperse emulsions mainly composed of tabular silver halide grains having a quotient (aspect ratio) of grain size divided by grain thickness of 5 or more. Such tabular silver halide grains can be prepared by methods known in the art. For example, as described in Hidemaru Sakai's doctoral dissertation "Study on the manufacturing method of photodevelopable silver halide photosensitive materials," small tabular grains prepared at high pBr are mixed with ungrown grains precipitated under similar conditions. A method of growing by adding fine particles is known. Furthermore, as described in JP-A-58-113928, the reaction vessel initially contains substantially no iodide ions;
After preparation with pBr0.6 to 1.6, a method of growing by adding silver salt, bromide, and iodide, and furthermore,
As described in No. 127921, seed crystals containing 40% or more by weight of tabular grains are formed in an atmosphere with a pBr of 1.3 or less, and seed crystals are grown while simultaneously adding silver and halogen solutions while keeping the pBr value at the same level. Methods for growing crystals are known. In preparing the monodisperse emulsion used in the present invention, it is desirable to increase the rate of addition of water-soluble silver salt and water-soluble halide as silver halide grains grow. By increasing the addition rate, the particle size distribution becomes more monodisperse and the mixing time is shortened. Therefore, it is advantageous for industrial production and is also preferable in that the chance of formation of structural defects inside silver halide grains is reduced. As a way to speed up this addition rate,
No. 48-36890, No. 52-16364, JP-A-55-142329
As described in each publication of the above-mentioned publication, the rate of addition of the aqueous silver salt solution and the aqueous halide solution may be increased continuously or stepwise. The upper limit of the above addition rate may be the flow rate just before new core particles are generated, and the value depends on temperature, pH, pAg, degree of stirring, composition of silver halide grains, solubility, grain size, distance between grains, or protection. It varies depending on the type and concentration of colloid. Furthermore, the monodisperse emulsion used in the present invention is as described above.
At least 95% of the particles, by number or weight, are within ±40%, more preferably within ±30% of the mean particle size when the mean particle size is measured by the method reported by Trivelli, Smith. It is preferable to use a silver oxide emulsion. Methods for producing such monodispersed emulsions are known, for example,
J.Photo.Sci., 12, 242-251 (1963), Special Publication Showa 48-
No. 36890, No. 52-16364, and JP-A-55-142329, as well as JP-A-57-179835.
It is also possible to adopt the technology described in No. The silver halide composition may be the same as that of the polydisperse emulsion. The silver halide used in the present invention may be a core-shell type monodisperse emulsion, and these core-shell emulsions are known from, for example, JP-A-54-48521. These silver halide emulsions, both polydisperse and monodisperse, generally contain sulfur sensitizers, such as sodium thiosulfate, thiourea, etc.; noble metal sensitizers, such as gold sensitizers, specifically gold sensitizers. , chlorauric acid salt,
Palladium sensitizers such as gold trichloride, specifically palladium chloride, palladate chloride, platinum compounds, iridium compounds, etc.; Selenium sensitizers, such as selenite, selenourea, etc.; Reduction sensitizers, e.g. Chemical sensitization can be carried out using chemical sensitizers such as stannous chloride, polyamines such as diethylenetriamine, thiourea dioxide, sulfites, silver nitrate, etc. alone or in combination. Additionally, sensitizing dyes and various other additives can be added depending on the purpose. In this case, for example, Research Disclosure No.
The techniques described in No. 17643 and No. 18431 can be applied. When chemically sensitizing the silver halide emulsion Em ₂ for the leg portion and the silver halide emulsion Em ₁ for the medium density portion of the present invention, the optimal chemical sensitization may be carried out separately, or both may be chemically sensitized. Although they may be chemically sensitized after being mixed, it is preferable to chemically sensitize each separately. The layer structure of the photosensitive material of the present invention can take various configurations. For example, a mixture of a silver halide emulsion Em ₂ for the legs and a silver halide emulsion Em ₁ for the medium density area in an appropriate ratio is coated on a support, and a gelatin protective layer is provided on the support. A silver halide emulsion Em ₁ for the medium density area is coated on top, a silver halide emulsion Em ₂ for the legs is coated on top, and a gelatin protective layer is provided on top of that. A silver halide emulsion Em ₂ for a medium density area is provided thereon, a silver halide emulsion Em ₁ for a medium density area is provided thereon, and a gelatin protective layer is provided thereon. For example, a dye layer is provided to cut out cross-over light. Silver halide emulsion for legs used in the present invention
The weight (silver halide) ratio of Em ₂ and medium density silver halide emulsion Em ₁ is preferably from 3:97 to
The ratio is 35:65, particularly preferably 5:95 to 25:75. The hydrophilic colloids used in connection with the present invention include not only gelatin but also various gelatin derivatives such as gelatin and aromatic sulfonyl chlorides, acid chlorides, acid anhydrides, isocyanates,
Gelatin derivatives produced by the reaction with 4-diketones, gelatin derivatives produced by the reaction between gelatin and trimellitic anhydride, gelatin derivatives produced by the reaction between gelatin and an organic acid having an active halogen, and gelatin derivatives produced by the reaction between gelatin and aromatic glycidyl ether. gelatin derivatives by the reaction of gelatin with maleimide, maleamic acid, unsaturated aliphatic diamide, etc., sulfoalkylated gelatin, polyoxyalkylene derivatives of gelatin, polymer grafted products of gelatin, synthetic hydrophilic Polymer substances and natural hydrophilic polymer substances other than gelatin, such as casein, agar, alginate polysaccharides, etc., can also be used alone or in combination. The emulsion according to the present invention can contain various commonly used additives depending on the purpose. Examples of these additives include stabilizers and antifoggants such as azaindenes, triazoles, tetrazoles, imidazolium salts, tetrazolium salts, and polyhydroxy compounds; aldehyde-based, aziridine-based, inoxazole-based, vinylsulfone-based, Hardeners such as acryloyl, alposiimide, maleimide, methanesulfonic acid ester, and triazine; Development accelerators such as benzyl alcohol and polyoxyethylene compounds; Chroman, Claman, bisphenol, and phosphorous acid Ester-based image stabilizers; lubricants such as wax, glycerides of higher fatty acids, higher alcohol esters of higher fatty acids, and the like. In addition, anionic, cationic, nonionic, or A variety of both sexes can be used. Effective antistatic agents include diacetyl cellulose, styrene perfluoroalkyl sodium maleate copolymers, and alkali salts of reaction products of styrene-maleic anhydride copolymers and p-aminobenzenesulfonic acid. Examples of matting agents include polymethyl methacrylate, polystyrene, and alkali-soluble polymers. It is also possible to use colloidal silicon oxide. Further, examples of the latex added to improve the physical properties of the film include copolymers of acrylic esters, vinyl esters, etc. and other monomers having ethylene groups. Gelatin plasticizers include glycerin and glycol compounds, and thickeners include styrene-sodium maleate copolymer and alkyl vinyl ether.
Examples include maleic acid copolymers. Examples of the support used in the photosensitive material of the present invention include glass, cellulose acetate,
Examples include cellulose nitrate, polyvinyl acetal, polypropylene, polyester films such as polyethylene terephthalate, polystyrene, and the like, and these supports are appropriately selected depending on the intended use or form of each. These supports are subjected to undercoat processing if necessary. Various methods of coating the constituent layers of the light-sensitive material according to the present invention include dip coating, air knife coating, curtain coating, or extrusion coating using a hopper of the type described in U.S. Pat. No. 2,681,294. Application methods are used. If desired, two or multiple layers can be applied simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent No. 837,095. [Operations and Effects of the Invention] According to the present invention, since high sharpness and wide exposure latitude in low density areas are simultaneously solved, it is possible to provide an X-ray sensitive material with high diagnostic ability, and it is particularly suitable for conventional type chest imaging. It is possible to eliminate the drawbacks of In addition, the pressure desensitization has been improved, making diagnosis easier.
We can provide line-sensitive materials. [Example] Next, the present invention will be specifically explained with reference to Examples. Note that the present invention is not limited to these examples. Example 1 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 10.0
The pH was gradually lowered from 9.0 to 8.0. This emulsion is designated as A. This emulsion A has an average grain size of
It was a 1.25 μm regular octahedral monodisperse emulsion. Further, a silver iodobromide emulsion having the same halide composition as Emulsion A was prepared by a forward mixing method to obtain Emulsion B. This emulsion B
was a twinned polydisperse emulsion with an average grain size of 1.25 μm. Also gelatin 12g, potassium bromide 0.3g, water 720cc
Add 36g of silver nitrate in 240cc of water to a solution at 70℃ containing
25.4g of potassium bromide in a solution containing 240cc of water
A solution containing . An aqueous solution of silver nitrate and an aqueous potassium bromide solution containing 2.0 mol % of potassium iodide were further added to this emulsion by a double jet method. During this time, pBr
At 0.8, the pH was kept at 2.0. The obtained tabular grains had an average grain size of 1.65 μm, and the grain size was 12.0 times the thickness. This emulsion was designated as C. Furthermore, by the same method as Emulsion A, the average grain size
A 1.65 μm regular octahedral monodisperse emulsion was obtained. This emulsion was designated as D. In addition, using the same manufacturing method as Emulsion B, the average grain size was 1.65 μm.
A twinned polydisperse emulsion E was obtained. After desalting, these emulsions were subjected to gold and sulfur sensitization, and then 4-hydroxy-6-methyl-
1,3,3a,7-tetrazaindene was added to stabilize the mixture, and an emulsion was mixed as shown in Table 2. After further addition of common photographic additives such as spreading agents and hardening agents, the amount of silver on each side is 30 mg/100 cm ² on a blue-dyed and subbed polyethylene terephthalate film base. The samples were coated on both sides and dried to prepare samples (Nos. 1 to 17) of X-ray sensitive materials for direct use. Sensitometry of each of these samples was carried out by the above-mentioned sensitometry A using the developer-1 of the present invention. The developing machine used was a roller conveyance type automatic developing machine NewQX-1200 (manufactured by Konishiroku Photo Industry Co., Ltd.). Note that the sharpness evaluation is based on the MTF curve of 1.0, 1.5,
Expressed as a value of 2.0 lines/mm. MTF measurement is 0.8
The MTF measurement chart containing a lead square wave of ~10 lines/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 is 1.0 on both sides. The back side of the emulsion was peeled off, and the square wave pattern on the other side was measured using a Sakura Microdensitometer Model M-5 (manufactured by Konishiroku Photo Industry Co., Ltd.). , Scanning measurements were performed in the direction perpendicular to the square wave. In addition, the averture size at this time is 230 μm in the parallel direction of the rectangular wave and 25 μm in the perpendicular direction.
The magnification is 100x. The evaluation of exposure latitude was expressed as the difference in exposure amount (in logarithmic representation) between the optical density of base density + fog density + 0.05 and 0.30. Further, pressure desensitization was measured as follows.
That is, each sample was kept at a constant temperature and humidity of 25°C and 50% relative humidity for about 12 hours, and under that condition, the radius of curvature was about 280 mm with a radius of 2 cm.
I folded it. Three minutes after bending, the film was exposed using an optical wedge for 10 ^-2 seconds using a tungsten lamp as a light source, and processed in the same manner as above using developer-1. Evaluation of pressure desensitization was performed as follows. That is,
Obtain results for several points with blackening density between 0.5 and 1.5, and let the density difference between the desensitized area caused by bending and the area without bending be ΔD,
ΔD was divided by each concentration D to obtain the average value. This value was used as a measure of desensitization due to bending. In other words, the smaller this value is, the smaller the desensitization caused by the pressure caused by bending. The above results are shown in Table-2.

[Table] As is clear from Table 2, samples Nos. 3 to 8 that meet the conditions of the present invention have high sharpness, wide exposure latitude in low density areas, and little pressure desensitization. Example 2 Same as Emulsion A of Example-1, except that pAg was 9.0.
Emulsion F was prepared with the only change being that the emulsion was kept at . This emulsion F was a cubic monodisperse emulsion with an average grain size of 1.25 μm. Emulsion F and emulsions B to E were chemically sensitized in the same manner as in Example 1, and various additives were added thereto. Multilayer coating was performed as shown to prepare samples of X-ray sensitive materials for direct use (Nos. 18 to 31). Sensitometric and image quality of each of these samples,
Evaluation of pressure desensitization was carried out as in Example 1, and the results are shown in Table 3.

[Table] As is clear from Table 3, samples Nos. 20 to 25 that meet the conditions of the present invention have high sharpness, wide exposure latitude in low density areas, and little pressure desensitization. Example 3 A silver iodobromide octahedral monodisperse emulsion A having an average grain size of 1.25 μm was obtained by the method of Example 1. Similarly, a twinned polydisperse emulsion B having an average grain size of 1.25 μm was obtained.
Furthermore, the average grain size was determined by the same method as for emulsion A.
A regular octahedral monodisperse emulsion D of 1.65 μm was obtained. By raising the mixing temperature in the forward mixing method of emulsion B, a twinned polydisperse emulsion G having an average grain size of 2.0 μm was obtained. Furthermore, a silver iodobromide regular octahedral monodisperse emulsion H having a highly monodisperse average grain size of 0.95 μm was obtained by the controlled double jet method. Further, by changing the mixing time in the forward mixing method, a twinned polydisperse emulsion I having an average grain size of 1.20 μm, which was more polydisperse than emulsion B, was obtained. Using these emulsions, samples of direct X-ray sensitive materials (Nos. 32 to 40) were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 4. The mixing ratio of the emulsions is shown in Table 4.

【table】 [Brief explanation of the drawing]

FIG. 1 is a diagram showing characteristic curves of high gamma type a, low gamma type b, and moderate type c of direct X-ray sensitive materials.

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) processed under the following processing conditions, the optical density is 0.50.
A characteristic curve is obtained in which the gamma γ ₁ produced by the point with the same 1.50 as the point of is 2.7 to 3.3, and the gamma γ ₂ produced by the point with the optical density of 0.05 and the same 0.30 is 0.36 to 0.65. A silver halide photographic material for X-rays. [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°C 30 seconds Fixing 34°C 20 seconds Washing 33°C 18 seconds Drying 45°C 22 seconds Developer-1 Potassium sulfite 55.0g Hydroquinone 25.0g 1-phenyl-3-pyrazolidone 1.2g Boric acid 10.0g Hydroxylation Potassium 21.0g Triethylene glycol 17.5g 5-methylbenztriazole 0.04g 5-nitrobenzimidazole 0.11g 1-phenyl-5-mercaptotetrazole
0.015g Glutaraldehyde bisulfite 15.0g Glacial acetic acid 16.0g Potassium bromide 4.0g Add water to make 1. 2 The silver halide emulsion layer of the above photographic light-sensitive material is
A patent claim comprising a silver halide emulsion () for the leg of a characteristic curve and a silver halide emulsion () for the intermediate density part, characterized in that a polydisperse silver halide emulsion is used as the emulsion () A silver halide photographic material for X-rays according to item 1. 3. Claim 2, characterized in that the silver halide grains of the emulsion (2) are silver halide emulsions mainly consisting of tabular silver halide grains whose grain size is 5 times or more the grain thickness. X listed
Silver halide photographic material for lines. 4. The silver halide photographic material for X-rays according to claim 2 or 3, wherein a monodisperse silver halide emulsion is used as the emulsion (2).