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
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/08—Sensitivity-increasing substances
  • G03C1/10—Organic substances
  • G03C1/12—Methine and polymethine dyes
• • 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
  • G03C1/0051—Tabular grain emulsions
• • 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
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances
  • G03C1/047—Proteins, e.g. gelatine derivatives; Hydrolysis or extraction products of proteins
• • 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
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/08—Sensitivity-increasing substances
  • G03C1/28—Sensitivity-increasing substances together with supersensitising substances
  • G03C1/29—Sensitivity-increasing substances together with supersensitising substances the supersensitising mixture being solely composed of dyes ; Combination of dyes, even if the supersensitising effect is not explicitly disclosed

Definitions

• the present invention relates to a silver halide photographic light-sensitive material having a high quality image improved in sharpness and graininess. More particularly, the present invention relates to a silver halide photographic light-sensitive material for medical application, which is free from image deteriorations such as pressure desensitization and roller marks caused by mechanical pressure and has a high diagnostic property.
• Japanese Pat. O.P.I. Pub. No. 92942/1988 proposes use of tabular silver halide grains in which silver iodide rich cores are provided and Japanese Pat. O.P.I. Pub. No. 163451/1988 proposes use of a silver halide emulsion comprised of tabular grains having twin planes.
• a first object of the invention is to provide a silver halide photographic light-sensitive material having a high sensitivity and a high image quality improved in sharpness and graininess.
• a second object of the invention is to provide a silver halide photographic light-sensitive material free from undesirable desinsitization and fog caused by roller pressure or other external pressure in handling.
• a silver halide photographic light-sensitive material having, at least on one side of a support, at least one silver halide emulsion layer, wherein said silver halide emulsion layer is comprised of tarbular silver halide twin crystal grains having an aspect ratio of not less than 3 prepared in a protective colloid containing a hydrogen-peroxide-treated gelatin, and said grains are spectrally sensitized before chemical sensitization with the addition of sensitizing dyes.
• said invention will hereinafter be described in detail.
• characteristics of gelatin used are very important as shown by its physical controlling capabilities, which have not only a large effect on chemical sensitization but also influence on formation and growth of silver halide crystal grains. And such gelatin's characteristics are known to undergo a large change according to extraction conditions or other manufacturing conditions.
• One of the important characteristics is permeability, and it is preferable for a photographic gelatin to have a permeability of not less than 92%, especially not less than 94%.
• ther are known a method to filter gelatin to remove impurities or a method to bleach gelatin with hydrogen peroxide.
• Bleaching of gelatin with hydrogen peroxide to oxidize impurities and certain amino acids contained therein is a general method to prepare an inert gelatin.
• the addition amount of hydrogen peroxide to enhance the permeability is 0.1 to 50 g, preferably 0.1 to 30 g, and especially 0.1 to 10 g per kilogram of gelatin.
• the pH at which gelatin is treated with hydrogen peroxide is preferably higher than 5.6, especially 6.0 to 12.
• the temperature of this treatment is preferably 35 to 70°C, especially 40 to 65°C.
• This hydrogen peroxide treatment may be carried out at any stage between extration and gelation in the manufacturing process of gelatin.
• a silver halide emulsion used in the invention is preferably prepared by depositing silver halide on monodispersed seed crystal grains.
• the particularly preferred manner is to provide a growing process to grow monodispersed spherical twin seed crystal grains described in Japanese Pat. O.P.I. Pub. No. 6643/1986.
• the nucleus grain formation process in the invention is defined as the process before the seed grain formation process, which may cover not only a period from start of adding a water-soluble silver salt to a protective colloid solution to a time at which formation of new crystal nuclei substantially ceases, but a period to grow grains after that.
• the growth condition of the above growing process may be any of the acid process, neutral process and ammoniacal process, and there may be used conventional methods described, for example, in Japanese Pat. O.P.I. Pub. Nos. 6643/1986, 14630/1986, 112142/1986, 157024/1987, 18556/1987, 92942/1988, 151618/1988, 1613451/1988, 220238/1988 and 311244/1988.
• the average silver iodide content of the silver halide used in the invention is 0.1 to 45 mole%, preferably 0.5 to 25 mole% and especially 1 to 20 mole%.
• Silver halide grains according to the invention are spectrally sensitized in a process before chemical sensitization with the addition of spectral sensitizing dyes.
• a process before chemical sensitization mentioned here may be a physical ripening process to prepare silver halide grains or a desalting process to remove excessive salts, or a period from completion of the desalting to start of addition of chemical sensitizing dyes in chemical sensitization. Of them, the physical ripening process is preferred, and the time when the physical ripening is completed is particularly preferred.
• Spectral sensitizing dyes used in the invention are not particularly limited in kinds and may be any of conventional spectral sensitizing dyes.
• twin crystals are silver halide crystal grains having one or more twin planes in one cystal grain. Classification of twin forms is discussed in detail by E. Klein and E. Moiser in Photographishe Korrespondenz Vol. 99, p. 99 and Vol. 100, p. 57.
• silver halide grains comprised of twin crystals used in the invention means that at least 70% of the total projection area of the silver halide grains is comprised of grains having twin planes. This ratio is desirably not less than 75%, more desirably, at least 80% of the grains are ones having twin planes.
• twin crystals according to the invention [are] may be any of ones having (111) face, ones having (100) face and a mixture thereof, but ones having (111) face are preferred.
• twin crystals according to the invention are preferably tabular crystal grains having two primary parallel planes facing with each other.
• the diameter/thickness ratio, namely aspect ratio, of these tabular silver halide grains is 3 to 20, preferably 3 to 15 and especially 4 to 13 on the average.
• This average value may be obtained by taking an average of cross sections of all the tabular grains, or may be determined as a ratio of the average diameter of the total grains to the average thickness of the total grains.
• the diameter of a tabular silver halide grain is given as a diameter of a circle having a projected area equal to the primary plane area of the grain.
• This diameter is generally 0.1 to 5.0 ⁇ m, preferably 0.2 to 4.0 ⁇ m and especially 0.3 to 3.0 ⁇ m.
• the silver halide emulsion used in the invention is preferably one of which grain size distribution is monodispersed.
• the silver halide composition of an emulsion used in the silver halide photographic light-sensitive material of the invention may be any of silver iodobromide, silver iodochloride and silver iodochlorobromide, but silver iodobromide is preferred for its capability of providing a high sensitivity.
• a silver halide emulsion used in the invention is comprised of tabular crystal grains having an aspect ratio of not less than 3.
• Such tabular crystal grains allow an emulsion to have a high spectral sensitization efficiency and a capability of providing images of improved graininess and sharpness as disclosed, for example, in British Pat. No. 2,112,157, U.S. Pat. Nos. 4,439,520, 4,433,048, 4,414,310, 4,434,226 and Japanese Pat. O.P.I. Pub. Nos. 113927/1983, 127921/1983, 138342/1988, 284272/1988, 305343/1988.
• Preparation of an emulsion comprised of tabular crystal grains can be made by methods disclosed therein.
• the above emulsions may be a surface latent image type which forms a latent image inside of a grain or an internal latent image type which forms a latent image inside of a grain, or a type which forms a latent image on the surface and inside of a grain.
• These emulsions may use, in the stages of physical ripening or grain preparation, a cadmium salt, lead salt, zinc salt, thallium salt, iridium salt or its complex salt, rhodium salt or its complex salt, or iron salt or its complex salt.
• the emulsion may be subjected to a desalting treatment by means of noodle washing or flocculation.
• Preferable desalting methods include, for example, a method to use a sulfo-group-containing aromatic hydrocarbon type aldehyde resin described in Japanese Pat. Exam. Pub. No. 16086/1960 and a method to employ exemplified high-molecular weight flocculants G 3 or G 8 in Japanese Pat. O.P.I. Pub. No. 158644/1988.
• the emulsion according to the invention may use various photographic additives in processes before and after physical ripening or chemical ripening.
• Conventional additives are those described, for example, in Research Diclosure Nos. 17643 (December, 1978), 18716 (November, 1979) and 308119 (December, 1989).
• Supports usable in the light-sensitive material of the invention are, for example, those described on page 28 of the above RD-17643 and on page 100, of RD-308119.
• Preferable supports are plastic films; the surface of such supports may be coated with a subbing layer or subjected to corona discharge or X-ray irradiation to enhance adesion to a coating layer.
• a lime-treated ossein gelatin was extracted at 45°C and divided into two equal parts; one part was labeled as ossein gelatin A, and the other part was treated with hydrogen peroxide and labeled as ossein gelatin B.
• solution D1 was added within one minut thereto, followed by a 5-minute Ostwald ripening.
• the potassium concentration was kept at 0.028 mole/l, the ammonia concentration at 0.63 mole/l, and the pH at 11.7.
• Silver halide emulsion E-1 comprised of tabular twin crystals was prepared by use of seed emulsion S-1 and the solutions shown below.
• Solutions B2 and C2 were added by the double-jet method in 38 minutes to solution A2 being stirred vigorously.
• the addition rate of solutions B2 and C2 was linerly increased so as to make the final addition rate 2.4 times the initial addition rate.
• solutions D2 and E2 were added thereto in 6 minutes at a constant rate.
• the pAg was kept at 10.
• the pH was adjusted to 6.0 and then 400 mg per mole silver of spectral sensitizing dye (A) described later was added, followed by stirring for 30 minutes. Subsequently, excessive salts in the liquor were removed by desalting using an aqueous solution of Demol made by Kao Atlas and an aqueous solution of magnesium sulfate. E-1 obtained had a pH of 5.90 and a pAg of 8.5 at 40°C.
• Electron microscopic observations of the emulsion proved that it was comprised of grains having an average grain size of 0.90 ⁇ m, an average thickness of 0.41 ⁇ m and a variation coefficient of grain size distribution of 28%, and that the percentage of tabular grains having an aspect ratio of 2 or more was 80% and the average aspect ratio of grains having an aspect ratio of 2 or more was 2.2.
• Seed emulsion S-2 was prepared in the same manner as with seed emulsion S-1 used in comparative emulsion E-1, except that hydrogen-peroxide-treated ossein gelatin B was used. During the ripening, the potassium bromide concentration was kept at 0.026 mole/l, the ammonia concentration at 0.63 mole/l, and the pH at 11.6. This seed emulsion S-2 was found to be comprised of spherical grains having an average grain size of 0.20 ⁇ m and a variation coefficient of grain size distribution of 18% by electron microscopic observations.
• silver halide emulsion E-2 comprised of tabular twin crystal grains was prepared by use of seed emulsion S-2 in a similar manner as with comparative emulsion E-1.
• the pAg and pH of this emulsion after desalting were 8.5 and 5.90, respectively, at 40°C.
• Electron microscopic observations of the emulsion proved that it was comprised of tabular grains having an average grain size of 1.20 ⁇ m, an average thickness of 0.24 ⁇ m and a variation coefficient of grain size distribution of 19%, and that the percentage of tabular grains having an aspect ratio of 2 or more was 85% and the average aspect ratio of grains having an aspect ratio of 2 or more was 5.0.
• Seed emulsion S-3 was prepared in the same manner as with seed emulsion S-2 used in emulsion E-2, except that the temparature of Ostwald ripening was kept at 15°C on the average. During the ripening, the potassium bromide concentration was kept at 0.026 mole/l, the ammonia concentration at 0.63 mole/l, and the pH at 11.7.
• this seed emulsion proved that it was comprised of spherical grains having an average grain size of 0.18 ⁇ m and a variation coefficient of grain size distribution of 20% Using seed emulsion S-3, silver halide emulsion E-3 comprised of tabular twin crystal grains was prepared in a similar manner as with comparative emulsion E-1. After desalting, this emulsion showed a pH of 5.91 and a pAg of 8.5 at 40°C.
• the emulsion was comprised of tabular grains having an average grain size of 2.13 ⁇ m, an average thickness of 0.22 ⁇ m and a variation coefficient of grain size distribution of 21%; the percentage of tabular grains having an aspect ratio of 2 or more was 90%, and the average aspect ratio of tabular grains having an aspect ratio of 2 or more was 9.7.
• Silver halide emulsion E-4 comprised of tabular twin crystal grains was prepared in the same manner as with comparative emulsion E-1, except that the spectral sensitizing dye was not added before the desalting of seed emulsion S-3.
• the emulsion prepared showed a pAg of 8.5 and pH of 5.90 at 40°C. Electron microscopic obsevations of this emulsion proved that it was comprised of tabular grains having an average grain size of 2.13 ⁇ m, an average thickness of 0.22 ⁇ m and a variation coefficient of grain size distribution of 21%, and that the percentage of tabular grains having an aspect ratio of 2 or more was 90% and the average aspect ratio of tabular grains having an aspect ratio of 2 or more was 9.7.
• Silver halide emulsion E-5 comprised of tabular twin crystal grains was prepared in the same manner as with comparative emulsion E-1, except that hydrogen-peroxide-treated ossein gelatin B was used in preparation of seed emulsion S-3. After desalting, the emulsion obtained had a pAg of 8.5 and a pH of 5.91 at 40°C. Electron microscopic obsevations of this emulsion proved that it was comprised of tabular grains having an average grain size of 2.35 ⁇ m, an average thickness of 0.21 ⁇ m and a variation coefficient of grain size distribution of 20%, and that the percentage of tabular grains having an aspect ratio of 2 or more was 90% and the average aspect ratio of tabular grains having an aspect ratio of 2 or more was 11.2.
• spectral sensitizing dyes (A) and (B) were added to each of the emulsions at a weight ratio of 200:1 in a total amount of 800 mg per mole of silver halide, and each emulsion was chemically ripened by adding 2.4 X 10 ⁇ 3 mole per silver halide of ammonium thiocyanate and optimum amounts 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 coating solutions prepared were double-layerdly and simultaneously coated in the order of silver halide emulsion layer and protective layer, with a slide hopper type coater, on both sides of a polyethylene terephthalate film base provided with 175 ⁇ m thick subbing layers.
• the thickness of the emulsion layer was adjusted to give a silver amount of 1.6 g/m2 and a gelatin amount of 1.8 g/m2 for each side; the thickness of the protective layer was adjusted to give a gelatin amount of 1.1 g/m2 for each side.
• the additives incorporated in the emulsion are shown below; addition amounts thereof are per mole of silver halide.
• the additives used in the protective layer are shown below; addition amounts thereof are per liter of the coating solution.
• the sample prepared was sandwiched between fluorescence intensifying screens KO-250 made by Konica Corp. and exposed through an aluminium step wedge at a tube voltage of 90 KV, a tube current of 20 mA and an illumination time of 50 msec. Subsequently, it was developed for 30 seconds at 35°C with a developer XD-90 and fixed with XF in an automatic processor model KX-500 (each of which is made by Konica Corp.), and then washed and dried according to usual manners. For the processed sample, a reciprocal of the exposure amount necessary to obtain a density of base density + fog density + 1.0 was determined.
• the sensitivities shown in Table 1 are sensitivities relative to that of sample No. 1 which is set at 100.
• each sample was bent up to about 280° with a radius of curvature of about 2 cm in the same environmental conditions.
• X-rays were irradiated to the sample for 0.06 sec at a tube voltage of 80 KV and a tube current of 100 mA through an aluminium wedge.
• the irradiated sample was processed in the same manner as in the above sensitometry and then visually checked for pressure desensitization.
• the silver halide photographic light-sensitive materials according to the invention are high in sensitivity, excellent in sharpness and graininess and moreover improved in pressure desensitization.
• a silver halide photographic light-sensitive material with high sensitivity and high sharpness was obtained without lowering graininess of images.
• pressure desensitization was also improved with the present invention.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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Cited By (4)

Citations (1)

• 1991
  • 1991-01-21 JP JP3005148A patent/JP2881504B2/ja not_active Expired - Fee Related
• 1992
  • 1992-01-21 EP EP92100913A patent/EP0556413A1/de not_active Ceased

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