Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/16—X-ray, infrared, or ultraviolet ray processes
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/46—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein having more than one photosensitive layer

Definitions

• This invention relates to a light-sensitive silver halide photographic material for medical use excellent in sensitivity and sharpness, and also improved in diagnostic properties.
• an object of the present invention is to provide a light-sensitive silver halide photographic material for medical use improved in sharpness without impairing sensitivity and also improved in diagnostic properties.
• Other objects of the present invention will be apparent from the following description.
• the present inventors have studied intensively to improve sharpness, and consequently found that the above object can be accomplished by the method described below, to accomplish the present invention.
• the object of the present invention can be accomplished by:
• a sensitivity of a light-sensitive silver halide photographic material refers to a value determined according to the following method.
• a sample exposed only from an A surface side is divided into two pieces. From one piece, a B surface is removed for measuring sA, and from the other piece, an A surface is removed for measuring sB'. Next, also from a sample exposed only from a B surface side, an A surface and a B surface are removed in the same manner for measuring sB and sA', respectively.
• characteristic curves are measured, and from the characteristic curves obtained, reciprocals of exposure dosages required for obtaining a density of base density + fog density + 1.0 are determined to obtain sA, sB, sA' and sB'.
• an exposure method varies depending on each light-sensitive material.
• the A surface and the B surface of the light-sensitive silver halide photographic material according to the present invention have a sensitivity of sA/sA' > 4.0, preferably 4.5 or more, more preferably 5.0 to 15.0.
• the sensitivity of the material is preferably sA/sB of 1.5 to 20, more preferably 2.5 to 10.
• At least one of the light-sensitive silver halide photographic emulsion layer and the hydrophilic colloidal layer at the B surface side contains at least one water-soluble dye.
• a silver halide grain at the B surface side As another method, as a silver halide grain at the B surface side, one kind of grains with a small grain size is used, or when a plural kinds of grains are mixedly used, these grains are combinedly used so as to become an average grain size of the mixture small.
• small means that the grain size of the B surface side is 70 to 80 % or less of that of the A surface side.
• water-soluble dye those generally known in the art can be employed.
• silver halide grains with a small grain size is used at the B surface side, and at least one of the above silver halide emulsion layer and the hydrophilic colloidal layer contains the dye as described above.
• a covering power mentioned in the present invention is a photographic density obtained by a predetermined amount of silver, and defined as described below.
• a covering power (C.P) is represented by the following formula:
• a ratio of the covering power of the A surface to that of the B surface of the light-sensitive silver halide photographic material according to the present invention is 1 : 1.5 or more (the covering power of the B surface is larger than that of the A surface), preferably 1 : 1.5 to 5.0, more preferably 1 : 1.5 to 2.0, the effect of the present invention can be exhibited favorably.
• the dye which can be used in the present invention include, for example, arylidene dyes disclosed in U.K. Patents No. 584,609 and No. 1,210,252, U.S. Patents No. 2,538,008, No. 2,538,009, No. 2,688,541 and No. 4,420,555, styryl dyes disclosed in Japanese Patent Publications No. 3082/1953, No. 16594/1969 and No. 28898/1984, merocyanine dyes disclosed in U.S. Patents No. 3,486,897, No. 2,706,193, No. 3,260,601 and No. 4,035,190, cyanine dyes disclosed in U.S. Patents No. 2,843,486, No. 3,294,539 and No.
• any layer may be selected, but the dye may be contained in at least one layer of a light-sensitive emulsion layer and other hydrophilic colloidal layers at the side where said emulsion layer is coated (e.g. non-light-sensitive layers such as an intermediate layer, a protective layer, a subbing layer and a mordant layer) or may be contained by dispersing therein.
• the dye may be contained in a silver halide emulsion layer or a layer nearer to a support than the silver halide emulsion layer or in both of these layers.
• the amount of the above dye to be added is preferably 0.2 mg/m2 to 150 mg/m2, more preferably 0.8 mg/m2 to 50 mg/m2.
• the dye can be introduced into a hydrophilic colloidal layer according to a conventional method.
• the dye is prepared to be an aqueous solution having an appropriate concentration, and when an emulsion layer is colored, the aqueous solution of the dye may be added in a silver halide emulsion or an aqueous hydrophilic colloidal solution before coating, and then coated.
• the dye according to the present invention may be carried within a layer by using a mordant.
• mordant which can make a dye nondiffusible by bonding at least one dye as described above to a mordant
• compounds disclosed in, for example, U.S. Patents No. 2,548,564, No. 2,675,316, No. 2,795,519, No. 2,839,401, No. 2,882,156, No. 3,048,487, No. 3,184,309, No. 3,444,138, No. 3,445,231, No. 3,706,563, No. 3,709,690 and No. 3,788,855 can be preferably used.
• nonionic surfactants known in the art may be used.
• the hydrophilic colloidal layer mentioned in the present invention refers to a hydrophilic layer provided in layers of a light-sensitive silver halide photographic material, and refers to various layers which contain a binder component such as gelatin and are necessary for a light-sensitive material for photography such as a silver halide emulsion layer, a protective layer, an intermediate layer, an antihalation layer, a filter layer, a development controlling layer, an UV absorbing layer and a prime-coating layer.
• a high sensitivity silver halide emulsion layer is coated as an A surface, and a protective layer containing gelatin as a binder component is provided thereon.
• a low sensitivity silver halide emulsion layer having a sensitivity different from that of the A surface is coated as a B surface.
• the water-soluble dye according to the present invention may be added and contained, and further, a hydrophilic colloidal layer (e.g. a gelatin layer containing a dye or a mordant layer on which a dye is carried) may be provided above or under said emulsion layer.
• the emulsion to be used in the light-sensitive silver halide photographic material of the present invention may be any silver halide such as silver iodobromide, silver iodochloride and silver iodochlorobromide, but silver iodobromide is preferred since a light-sensitive material having a particularly high sensitivity can be obtained.
• the silver halide grains in the photographic emulsion may have any shape such as cube, octahedron and tetradecahedron which grow in an isotropic manner, or polyhedral crystal such as sphere and twin having defects in phases or a mixture or complex thereof.
• the silver halide grains may have a grain size of from 0.1 ⁇ m (fine particles) or less to 20 ⁇ m (big particles).
• the emulsion to be used in the light-sensitive silver halide photographic material of the present invention can be prepared according to the known method.
• the emulsion can be prepared according to "1. Emulsion Preparing Method (Emulsion Preparation and types)" disclosed at pp. 22 to 23 of Research Disclosure (RD) No. 17643 (December, 1978) and the method disclosed at p. 648 of RD No. 18716 (November, 1979).
• a monodispersed emulsion in which silver iodide exists locally internally of its grain can be mentioned.
• the monodispersed emulsion herein mentioned refers to silver halide grains wherein, for example, when an average grain diameter is measured according to the conventional method, at least 95 % of the grains in terms of the grain number or weight have a grain diameter preferably within ⁇ 40 %, more preferably within ⁇ 30 % of the average grain size.
• a grain size distribution of the silver halide may be a narrow distribution as in the case of a monodispersed emulsion or a wide distribution as in the case of a polydispersed emulsion.
• Crystalline structure of the silver halide may comprise different silver halide compositions at an inner portion and an outer portion.
• the emulsion is a core/shell type monodispersed emulsion having a clearly two-layered structure comprising a core portion with a high iodine content and a shell layer with a low iodine content.
• An amount of silver iodide in the portion with a high iodine content of the present invention is 20 to 40 mole %, particularly preferably 20 to 30 mole %.
• a method for preparing such a monodispersed emulsion is known in the art, and disclosed in, for example, Journal of Photographic Science, vol. 12, pp. 242 to 251 (1963), Japanese Unexamined Patent Publications No. 36890/1973, No. 16364/1977, No. 142329/1980 and No. 49938/1983, U.K. Patent No. 1,413,748, and U.S. Patents No. 3,574,628 and No. 3,655,394.
• the monodispersed emulsion as described above particularly preferred is an emulsion in which a seed crystal is used as a growth nucleus and grains are grown by supplying a silver ion and a halide ion.
• a method for obtaining a core/shell emulsion is disclosed in detail in, for example, U.K. Patent No. 1,027,146, U.S. Patents No. 3,505,068 and No. 4,444,877, and Japanese Unexamined Patent Publication No. 14331/1985.
• the silver halide emulsion to be used in the present invention may be a tabular grain having an aspect ratio of 5 or more.
• Such a tabular grain have advantages that improvement in spectral sensitizing efficiency and improvement in graininess and sharpness of images can be accomplished, and it can be prepared according to the methods disclosed in, for example, U.K. Patent No. 2,112,157, and U.S. Patents No. 4,439,520, No. 4,433,048, No. 4,414,310 and No. 4,434,226.
• the above emulsion may be any emulsion of a surface latent image type in which an latent image is formed on a grain surface, an internal latent image type in which a latent image is formed internally of a grain or a type in which a latent image is formed both on a grain surface and internally of a grain.
• cadmium salt, lead salt, zinc salt, thallium salt, iridium salt or complex salt thereof, rhodium salt or complex salt thereof and iron salt or complex salt thereof may be used.
• the emulsion may be subjected to a noodle washing method, a flocculation sedimentation method or an ultra-filtration method.
• washing method there may be included, as particularly preferred desalting methods, a method of using an aromatic hydrocarbon type aldehyde resin containing sulfo group as disclosed in Japanese Patent Publication No. 16086/1960 and a method of using exemplary compounds G3 and G8 of a coagulating polymeric agent as disclosed in Japanese Unexamined Patent Publication No. 158644/1988.
• a suitable support is a plastic film.
• a prime-coating layer may be provided on a surface of the support or a surface of the support may be subjected to corona discharging or UV ray irradiation. On one surface or both surfaces of the support thus treated, the emulsion according to the present invention can be coated.
• the present invention can be applied to all light-sensitive silver halide photographic materials, but it is particularly suitable for high sensitivity black and white light-sensitive materials.
• a fluorescent screen composed mainly of a fluorescent substance which emits near ultraviolet light or visible light by irradiating transmissive radiation is employed. It is desired to bring the fluorescent screen close contact with both surfaces of the light-sensitive material comprising the emulsion of the present invention coated on both surfaces thereof and then to effect exposure.
• the transmissive radiation herein mentioned refers to an electromagnetic wave with high energy such as X-ray and gamma ray.
• the fluorescent screen includes a fluorescent screen comprising a fluorescent component composed mainly of calcium tungstate or a fluorescent screen composed mainly of a rare earth compound activated by terbium.
• Monodispersed grains of silver iodobromide containing 2.0 mole % of silver iodide with an average grain size of 0.2 ⁇ m were used as nuclei, and silver iodobromide containing 30 mole % of silver iodide was grown at pH 9.3 and pAg 7.5.
• monodispersed emulsion grains (A) with an average grain size of 1.50 ⁇ m, (B) with that of 1.20 ⁇ m, (C) with that of 0.70 ⁇ m and (D) with that of 0.41 ⁇ m, respectively, so that all the monodispersed emulsion grains obtained were silver iodobromide grains with an average silver iodide content of 2.3 mole.
• These emulsions were subjected to desalting to remove excessive salts according to the conventional coagulation method.
• (A), (B) and (C) were chemically ripened by adding 2.4 x 10 ⁇ 3 mole of ammonium thiocyanate per mole of silver, an optimum amount of chloroauric acid and hypo, and then stabilized by adding 2 x 10 ⁇ 2 mole of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene.
• the water-soluble dye was added in the emulsion coating solution for the side of the B surface.
• the respective coating solutions obtained were coated by two slide hopper type coaters simultaneously on both surfaces of a polyethylene terephthalate base with a thickness of 175 ⁇ m subjected to a subbing treatment so as to have a constitution as shown in Table 1, followed by drying for 2 minutes and 50 seconds, to obtain Samples No. 1 to No. 16.
• Silver amounts of both A and B surfaces were made 56 mg/dm2, respectively.
• sensitivities sA, sA', sB, sB' and Sw
• MTF MTF
• the additives used in the protective layer solution are shown below. An amount added is indicated as an amount per liter of the coating solution.
• the samples were developed by using an automatic processor KX-500 (trade name) and a developing solution XD-90 (trade name) at 35 °C for 30 sec, and fixed by a fixing solution XF, followed by washing and drying according to the conventional method.
• reciprocals of exposure dosages required for obtaining a density of base density + fog density + 1.0 were determined to obtain sensitivities.
• sA, sB, sA' and sB' they were measured by the method as mentioned above (as the flurescent screen, NR-160 (trade name, produced by KONICA CORPORATION) was used).
• MTF was a value at a space frequency of 2.0/mm.
• the covering power (C.P) was measured by the method as described above.
• MTF is elevated without lowering sensitivity to greatly contribute to diagnostic properties.
• Example 2 To three kinds of the emulsions obtained, the same emulsion additives as in Example 1, water-soluble dyes shown in Table 2 and lime-treated gelatin were added to prepare emulsion coating solutions shown below. The water-soluble dye was added in the emulsion coating solution for the side of the B surface.
• the samples were developed by using an automatic processor KX-500 and a developing solution XD-90 at 35 °C for 30 sec, and fixed by a fixing solution XF, followed by washing and drying according to a conventional method.
• reciprocals of exposure dosages required for obtaining a density of base density + fog density + 1.0 were determined to obtain sensitivities.
• sA, sB, sA' and sB' they were measured by the method as mentioned above (as the flurescent screen, KO-250 (trade name, produced by KONICA CORPORATION) was used).

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• 1990
  • 1990-12-31 EP EP90314462A patent/EP0437117A1/de not_active Withdrawn

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