HIGH-SPEED PROCESSING OF SILVER HALIDE PHOTOGRAPHIC LIGHT- SENSITIVE MATERIALS

Abstract: A silver halide photographic material which is capable of super-rapid processing with the total time of 20 to 60 minutes while processing high sensitivity, low fog and excellent pressure resistance and lack of graininess is described. The photographic material comprises a support bearing a hydrophilic colloidal layer including at least one light sensitive silver halide emulsion layer thereon, wherein at least some of the silver halide grains present in the said silver halide emulsion layer are tabular grains which have an aspect ratio of the grain size to the grain thickness of at least 5, such that the projective areas of said tabular grains represent not less than 50% of the projective areas of all the silver halide grains in said emulsion layer, the melting time taken for at least one silver halide emulsion layer of a 1 cm x 2 cm position of said silver halide photographic light-sensitive material in a 1.5% by weight aqueous solution of sodium hydroxide at 50°C to commence to dissolve is at least 45 minutes, and on the side bearing the hydrophilic colloidal layer containing said silver halide emulsion layer, gelatin is present in an amount from 2.00 to 3.20 g/m².

Description: This invention relates to a method for processing a silver halide photographic light-sensitive material which comprises processing the material in an automatic processor, in which the whole processing time is from 20 to 60 seconds, said material being capable of being used in high-speed processing, the silver halide photographic light-sensitive material having high sensitivity, low fogginess and being excellent as regards both pressure resistance and graininess, even when used in super-rapid processing. In recent years, the use of silver halide photographic light-sensitive materials has been on the increase. Accordingly, the amount of processing of silver halide photographic light-sensitive materials has also been on the increase. As a result, there is a need to make processing more rapid, namely to increase the amount of material processed within the same period of time. There has also been an increase in the use of X-ray light-sensitive materials such as medical X-ray films. Promotion of regular medical inspections has rapidly increased of the number X-rays that are taken and it is considered important to notify the results of these medical inspections without delay to patients. Thus, there is a greater need to develop X-ray films more rapidly than previously. For example, in angiography, that is, operation radiography, it is necessary to observe X-ray photographs with the minimum of delay. To meet these demands it is necessary to adopt automated procedures such as X-ray photographing and film transport and to process films more rapidly. There are a number of problems which arise when carrying out super-rapid processing; such as (a) Density may be insufficient, for example, sensitivity, contrast and maximum density may be low; (b) Fixing may be insufficient; (c) Films may not be adequately washed; (d) Films may not be adequately dried. The insufficient fixing and washing of films may result in tone variation and low image quality, during film storage. One way to overcome these problems is to reduce the amount of gelatin in a film. However, films containing only small amounts of gelatin may display a high degree of graininess in the photographic image. Another problem arises from the so-called black-abrasion mark that is, when a film is scratched with another film or other substance and the film is then processed, the part of the film that is scratched has a higher density than the rest of the film. In this specification, super-rapid processing means the following: The leading edge of a film is inserted into an automatic processor and the film is eventually delivered to the drying section of the processor after it has passed through typically, the developing tank, the first cross-over section, the fixing tank, the second cross-over section, the washing tank, and the third cross-over section. The overall time taken from insertion into the processor until delivery thereof to the drying section, that is, the quotient obtained by dividing the whole length, in meters, of the processing line by the transport rate, in meters/second, is within the range of from 20 seconds to 60 seconds. The reason why the time taken passing through the cross-over sections is included in the overall time is that, it is deemed that processing is still in progress in those sections, as the solution used in the preceeding process still swells the gelatin. Japanese, Patent Publication No. 47045-1976, describes the importance of the gelatin quantities used in super-rapid processing. The whole processing time in this process, including the time taken through the cross-over sections, is within the range of 60 to 120 seconds. This processing time does not satisfy recent demands for super-rapid processing. As a result of the increase in the number of medical X-ray inspections in particular, there is a growing need for a reduction in the radiation doses used. Accordingly, there is a demand for the development of photographic products capable of producing precise images with only a small X-ray dose, that is there is a need for highly sensitive photographic products. To achieve increased sensitivity while maintaining grain size, i.e., to sensitize, there are a variety of techniques available, including, for example: when a development accelerator, such as thioether, is added to an emulsion; or when a spectrally sensitized silver halide emulsion is color-supersensitized by using a combination of suitable dyes. However, the above techniques may not always be suitable when using highly sensitive silver halide photographic light-sensitive materials. As a result of using one of the above-mentioned techniques with highly sensitive silver halide emulsions of a silver halide photographic light-sensitive material, in order to achieve as great a chemical-sensitization as possible, fog is apt to form on storage of the emulsions. In the past, in the field of medical X-ray photographs, it was usual to use a regular type X-ray film having a light-sensitive wavelength of 450 nm. More recently, an ortho type light-sensitive material, which is so ortho-sensitized as to be sensitive to the wavelength region of 540 to 550 nm, has been used. Such light-sensitive materials have a widened light-sensitive wavelength region and thus have increased sensitivity, as a result the X-ray dose necessary may be reduced. Dye sensitization is a very useful sensitizing technique, although many problems remain unsolved, such as the sufficient sensitivity of some types of photographic emulsions. It is known that indazole and benztriazole are useful as antifoggants in developers and they have been used for this purpose in both black-and-white and color developers; U.S.-A-2,271,229 discloses an indazole-type antifoggant for use in both black-and-white and color developers; GB-B 1,437,053 describes an indazole that may be used as an antifoggant in X-ray developers; and U.S.-A-4,172,728 describes an indazole that may be used as an antifoggant in a developer for graphic art use. Although indazoles and benztriazoles are very effective anti-foggants when used as such sensitivity is reduced considerably. As a result of mechanical pressure of various kinds being applied to a film before exposure, desensitization may occur, which may be observed during the development stage. For example medical X-ray films are so large in size they are liable to be bent, or creased resulting in pressure desensitization. Recently, medical X-ray photographic systems, which use automatic exposure and developing apparatus, have been developed. In these systems, a mechanical stress is applied to films. In a dry atmosphere, such as in wintertime, pressure-blackening and black abrasion marks are a likely occurence which may seriously affect a medical diagnosis. It is well known that the greater the silver halide grain sizes used and the greater the sensitivity of the film the more likely is a pressure desensitization. In order to reduce pressure desensitization, U.S.-A-2,628,167, 2,759,822, 3,455,235 and 2,296,204; FR-A-2,296,204; Japanese Patent Publication Open to Public Inspection (hereinafter called Japanese Patent O.P.I. Publication) Nos. 107129-1976 and 116025-1975; suggest the use of thallium and certain types of dye. Of the available improved silver halide photographic light-sensitive materials, one is still insufficiently improved, another has a problem with dye stains and the other one cannot always be regarded as a light-sensitive material having a large grain size. There have been various attempts to improve pressure desensitization by altering the physical properties of the binders used in the silver halide photographic light-sensitive material. These attempts are described in, for example. U.S.-A-3,536,491, 3,775,128, 3,003,878, 2,759,821 and 3,772,032; and Japanese Patent O.P.I. Publication Nos. 3325-1978, 56227-1975, 147324-1975 and 141625-1976. As a result, although, pressure desensitization may be improved, tackiness and dryness of film surfaces and physical properties such as scratch resistance are seriously deteriorated. It is an object of the present invention to provide a method of processing a silver halide photographic light-sensitive material, said material being high in sensitivity, and low in fogginess and is excellent as regards both pressure resistance and graininess, even when used in super-rapid processing. The object of the invention may be achieved using a silver halide photographic light-sensitive material comprising a support bearing a hydrophilic colloidal layer which includes at least one light-sensitive silver halide emulsion layer thereon. wherein, at least some of the silver halide grains present in the said silver halide emulsion layer are tabular grains which have an aspect ratio of grain size to grain thickness of at least 5, and the projective area of the whole tabular grains occupy at least 50% of the whole projective areas of the whole silver halide grains in the emulsion layer; the melting time (hereinafter defined) of the silver halide emulsion layer is within the range of from eight minutes to 45 minutes; on the side bearing the hydrophilic colloidal layer containing the silver halide emulsion layer, the amount of gelatin is within the range of from 2.00 to 3.20 g/m²; and by processing the light-sensitive material with an automatic processor the whole processing time is within the range of from 20 to 60 seconds. It is preferred that at least one layer of the silver halide photographic light-sensitive material should be hardened with at least one hardener which is a vinyl sulfone type hardener and/or a halogen-substituted-S-triazine type hardener. The expression, 'A support bears a hydrophilic colloidal layer containing at least one light-sensitive silver halide emulsion layer thereon' or a similar expression means that at least one light-sensitive silver halide emulsion layer is arranged on at least one side of the support and, if required, non-light-sensitive hydrophilic colloidal layers such as a backing layer, an interlayer, and a protective layer may also be provided on to the support. In order to be able to perform super-rapid processing the gelatin content must be reduced. Pressure desensitization, which is likely to occur on reduction of the gelatin content, may be prevented by making use of tabular silver halide grains; and graininess deterioration which may also result from reduction of the gelatin content, may also be prevented by raising the hardener content i.e., by prolonging the melting time. The vinyl sulfone type hardening agents which are preferred include, for example, aromatic compounds such as those described in DE-C 1,100,942; alkyl compounds containing a hetero atom such as those described in Japanese Patent Publication Nos. 29622-1969 and 25373-1972; sulfonamide ester type compounds such as those described in Japanese Patent Publication No. 8736-1972; 1,3,5-tris [β-(vinyl sulfonyl)-propionyl]-hexahydro-s-triazine such as described in Japanese Patent O.P.I. Publication No. 24435-1974; and alkyl compounds such as those described in Japanese Patent O.P.I. Publication No. 44164-1976. Typical examples (H-1) to (H-22) are given below. Besides the above compounds, vinyl sulfone type compounds capable of being used in the invention also include the reaction product obtained by reacting a compound having at least three vinylsulfone groups, such as Exemplified in Compounds (H-5) to (H-22), with a compound having a group which is capable of reacting with a vinylsulfone group and a water-soluble group, such as diethanol amine, thio glycolic acid, sodium sarcosinate and sodium taurinate. The halogen-substituted-s-triazine type hardeners which are preferred include compounds represented by Formula [I] or [II]; wherein, R₁ and R₂ independently represent a chlorine atom or hydroxy, alkyl, alkoxy, alkylthio, -OM in which M is a univalent metal atom, -NR¹R² in which R¹ and R² independently represent a hydrogen atom or an alkyl or aryl group, or -NHCOR³ in which R³ represents a hydrogen atom or alkyl or aryl; wherein R₃ and R₄ each independently represent a chlorine atom or hydroxy, alkyl, alkoxy or -OM in which M represents a univalent metal atom; Q and Q' each independently represent -O-, -S- or -NH-; L represents alkylene or arylene; and l and m are 0 or 1. Typical examples, (I-1) to (1-22), of compounds represented by formulas [I] or [II] will be given below. Vinylsulfone type or halogen-substituted-s-triazine type hardeners may be added to the silver halide emulsion layer or other component layers by dissolving them in either water or a water-miscible solvent, such as methanol or ethanol, and adding the resulting solution to the coating solution. The method of addition may be either a batch process or an in-line process. The time of addition is not crucial, however, it is preferred to add the hardeners immediately before coating. The hardeners are typically added in amounts ranging from 0.5 to 100 mg, preferably from 2.0 to 50 mg per g of coated gelatin. The term, melting time, used herein means the time taken for said at least one silver halide emulsion layer of a 1cm x 2cm portion of said silver halide photographic light-sensitive material in a 1.5% by weight aqueous solution of sodium hydroxide at 50°C to commence to dissolve. The melting time may be achieved using a mixture of a hardener used in the invention and a conventional hardener. For example, chromium salts such as chrome alum and chromium acetate, aldehydes such as formaldehyde, glyoxal, and glutaraldehyde N-methylol compounds such as dimethylolurea, and methyloldimethyl hydantoin, dioxane derivatives such as 2,3-dihydroxydioxane, active vinyl compounds such as 1,3,5-triacryloylhexahydro-2-triazine, and 1,3-vinylsulfonyl-2-propanol forth, active halogen compounds such as 2,4-dichloro-6-hydroxy-3-triazine, mucohalogen acids such as mucochloric acid, and mucophenoxychloric acid may be mixed independently or in combination with a hardener used in the present invention. A preferable embodiment of the invention is where, the gelatin content is from 2.00 to 3.20 g/m². Where the gelatin content is within this range, problems with coating may be reduced as compared to where the gelatin content is less than 2.00 g/m², and dryness is much improved as compared to where the gelatin content is more than 3.20 g/m². The gelatin content is more preferably from 2.40 to 2.90 g/m² and more preferably from 2.50 to 2.80 g/m². Sensitivity and, yellow staining can also be improved. Supports which may be used in the invention include, for example; paper sheets laminated with polyethylene, polypropylene and α-olefin polymers such as ethylene-butene copolymer; synthetic paper sheets; film sheets comprising a semisynthetic or synthetic macromolecule such as cellulose acetate, cellulose nitrate, polyethylene, polyvinyl chloride, polyethyleneterephthalate, polycarbonate and polyamide. The silver halide emulsions include for example, tabular silver halide grains comprising silver bromide, silver iodobromide, silver iodochloride, silver chlorobromide and silver chloride. The tabular silver halide grains generally take the tabular form having two parallel faces. The 'thickness' may be expressed in terms of the distance between the two parallel dominant faces constituting a tabular silver halide grain. The 'size' of the dominant face means the diameter of either the circular face of a grain or the face area thereof converted into a circular area, i.e., a projective area of the tabular grain. In the invention, the ratio of the size of a grain to the thickness thereof is generally called an aspect ratio which is defined as follows: The tabular silver halide grains generally have an aspect ratio of at least 5, preferably from 5 to 40 and, more preferably from 8 to 30. Known methods may be used to prepare the tabular silver halide grains having a grain size of at least 5 times the grain thickness. For example, there is the well known method in which minute tabular silver halide grains prepared at a low pBr are added to ungrown minute silver halide grains precipitated under the same conditions, in order to grow the required grains. This is described in Hidemaru Sakai's doctorate thesis 'A Study on the Preparation of Photodevelopment Type Silver Halide Light-Sensitive Materials'. There are other well known methods. For example, a method in which silver halide grains, substantially devoid of iodine ions, are prepared at pBr of from 0.6 to 1.6 in a reaction vessel, and then a water-soluble silver salt, such as a bromide and a iodide, are added to the grains, so that silver halide grains are formed is as described in Japanese Patent O.P.I. Publication No. 113928-1983; a method in which seed crystals, having tabular grains making up at least 40% by weight of the total grains, are formed at pBr of not higher than 1.3, so that the seed crystals are formed while maintaining the pBr value while adding a water-soluble silver salt and a halide solution at the same time; and a method in which seed crystals are formed according to the prescribed correlation between pI and pBr as described in Japanese Patent O.P.I. Publication No. 151840-1987. While preparing the tabular silver halide grains used in the invention, it is preferred to increase the addition rate of the water-soluble silver salt and the water-soluble halide, as the silver halide grains are being formed. When increasing the addition rate of the water-soluble silver salt and the water-soluble halide, the grain size distribution of the silver halide grains is monodispersed and the mixing period is reduced during addition. This is advantageous for industrial production and is also preferred from the viewpoint that the probability of causing a structural defect in the silver halide grains is reduced. The mode of increasing the addition rate of the water-soluble silver salt and the water-soluble halide, may be continuous or stepwise, as described in Japanese Patent Publication Nos. 36890-1973 and 16364-1977 and Japanese Patent O.P.I. Publication No. 142329-1980. The upper limit of the addition rate may be determined by the flow velocity immediately before the new nuclei of the silverhalide grains are produced. This flow verocity will vary according to, e.g. the temperature, pH, pAg and stirring conditions applied to the preparation of silver halide grains; the production, solubility, grain size and intergrain distance of the silver halide grains; and types the and concentrations of protective colloids used. In preparing the tabular silver halide grains, the pH is preferably from 1.5 to 10 and more preferably from pH 2 to 9. Preferred growth accelerators used for the silver halide grains are ammonia, thiocyanate, thioether, and thiourea. The preferred temperature is from 35 to 90°C. Typical examples of growing accelerators include those described in Japanese Patent O.P.I. Publication Nos. 136736-1985, and 14646-1987. A method of producing tabular silver halide grains using the above-mentioned growing accelerators, is described in Japanese Patent O.P.I. Publication No. 3134-1986. The preferred thickness of the tabular silver halide grains is less than 0.5 µm, more preferably less than 0.3 µm. The size is preferably at least 0.6 µm and more preferably at least 0.8 µm, and the grain size is at least 5 times the thickness, preferably from 5 times to 40 times the thickness and, more preferably, from 8 to 30 times, the thickness. In the layers containing tabular silver halide grains the tabular silver halide grains preferably constitute at least 40% by weight of the total silver halide grains of the layer and more preferably at least 60% by weight thereof. Furthermore, the silver halide composition of the tubular silver halide grains is preferably silver iodobromide and is, more preferably, silver iodobromide having a silver iodide content of from 0 to 10 mole% preferably, from 0.1 to 6 mole%. The tabular silver halide grains, preferably the silver iodobromide grains, may be chemically sensitized preferably using a noble metal or a sulfur sensitizer. In this specification, the term, 'the whole processing time' means the total period of time required for each processing step and each cross-over from one step to the next. The following examples further illustrate the invention. Example-1 In a double-jet precipitation process, in which the conditions were kept at 60°C, pAg=8.0 and pH=2.0, there was prepared a silver iodobromide monodisperse type cubic crystal emulsion having a silver iodide content of 2.5 mole% and an average grain size of 0.27 µm. Part of the emulsion was used in the formation of core grains. In the double-jet precipitation process, a solution containing core grains and gelatin was added at 40°C, pAg=9.0 and pH=9.0 to both an ammoniacal silver nitrate solution and a solution containing potassium iodide and potassium bromide, so that the first coating layer, containing silver iodide at 30 mole%, was formed. Subsequently in the double-jet precipitation process at pAg=9.0 and pH-9.0, both an ammoniacal silver nitrate solution and a potassium bromide solution were added thereto, so that the second coating layer of pure silver bromide was formed. Thus, a cubic crystal monodisperse silver iodobromide emulsion having an average grain size of 0.63 µm was prepared. The resulted emulsion was called [E-1]. The average silver iodide content of this emulsion was 2.0 mole%. Next, in the normal precipitation process, a thick tabular emulsion [E-2] was prepared in the following manner. First, the following two kinds of solutions were prepared. Solution A: Silver nitrate 100 g Add water to make 240 cc Solution B: Ossein gelatin 8 g Potassium bromide 80 g Potassium iodide 1.3 g Add water to make 550 cc After solution B was poured into a reaction vessel for preparing an emulsion, the solution was stirred with a propeller-type stirrer having a revolution number of 300 rev/sec, and the reaction temperature was kept at 48°C. Next, solution A was divided into two, in the proportion of one part to two parts. The one part in 100 ml was added to the reaction solution, and left for one minute. After stirring for 5 minutes, the remaining solution A of 200 ml, was then added over 2 minutes. The resulted solution was stirred continuously for another 15 minutes. Thus, emulsion [E-2] was obtained. The ratio of grain size to thickness was four. The silver iodide content was 1.3 mole% and the average grainsize was 0.08 µm. Next, tabular emulsion [E-3] was prepared in the following manner. To a solution containing 12 g of gelatin, 0.3 g of potassium bromide and 720 ml of water, at 70°C, was added, over 30 seconds, a solution containing 240 ml of water and 36 g of silver nitrate. Then, Ostward ripening was applied to the resulting solution for 15 minutes, so that emulsion [A] containing tabular silver bromide grains was obtained. To a part of emulsion [A], an aqueous potassium bromide solution was added and the pBr was adjusted to 0.7. To the resulting solution was added 0.2 g of potassium iodide and then gradually the remaining parts of emulsion [A] was added as a supply-source emulsion, so that a tabular silver halide iodobromide grain emulsion [E-3] was obtained. The tabular silver halide grains obtained were 1.60 µm average grain size and 13.5 in the ratio of average grain size to thickness. In this emulsion, grains having a ratio of average grain size to thickness of at least five were distributed over at least 80% of the whole projective area of the total silver halide grains. For emulsions [E-1] to [E-3], excessive water-soluble salts were removed in a flocculation precipitation process. To each of these emulsions, 8x10⁻⁷ mole of chloroaurate, 7x10⁻⁶ mole of sodium thiosulfate and 7x10⁻⁴ mole of ammonium thiocyanate were added per mole of silver halide used, and optimum gold-sulfur sensitization was applied. To the emulsions were added the following spectral sensitizers (43), (74) and potassium iodide in 1x10⁻³ mole per mole of AgX and to these were then applied an optimum spectral sensitization. The emulsions were then stabilized with 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene using 2x10⁻² mole per mole of AgX, and the gelatin concentrations of the emulsions were then adjusted as shown in Table 1. To both the emulsions and the protective layer solutions the following additives were added together with the hardeners shown in Table 1 to give a melting time as shown in Table 1. Additives for the emulsion layers were as follows: 400 mg of t-butylcatechol. 1.0 g of polyvinyl pyrolidone having a molecular weight of 10,000, 2.5 g of styrene-anhydrous maleic acid copolymer, 10 g of trimethylol propane, 5 g of diethylene glycol, 50 mg of nitrophenyl-triphenylphosphonium chloride, 4 g of ammonium 1,3-dihydroxybenzene-4-sulfonate, 15 mg of sodium 2-mercaptobenzimidazole-5-sulfonate, Seventy milligrams of One gram of Ten milligrams of 1,1-dimethylol-1-bromo-1-nitromethane. Each of Samples No. 1 to No.20 was prepared in the following manner. To both sides of a sublayered polyester film support was added a protective layer having a gelatin content as shown in Table 1, to which had been added a hardener and a variety of additives. The melting time of each sample is shown in Table 1. In addition a silver halide emulsion layer was coated on both sides of a sublayered polyester film support using a slide-hopper process. During coating, the two layers, i.e., the silver halide emulsion layer and a protective layer, were simultaneously interlayered to the support from the support side at a coating speed of 60 m/min. The silver halide emulsion layer had a viscosity of 11 cp, surface tension of 35 dyn/cm and a coating layer thickness of 20 µm, and the protective layer had a viscosity of 11 cp, surface tension of 25 dyn/cm and a coating layer thickness of 20 µm. The silver content of each sample was 45 mg/dm², As additives for the protective layer, the following compounds were added per g of gelatin: Ten milligrams of Two milligrams of Seven milligrams of Fifteen milligrams of Seven milligrams of matting agent comprising polymethyl metaacrylate having an average grain size of 5 µm, Seventy milligrams of colloidal silica having an average grain size of 0.013 µm, and so forth. In each of the samples, the hardener content was adjusted so that the melting time measured in the following manner was as shown in Table 1. In this example, the melting time was defined as the period of time from when a sample which was cut into 1 cm x 2 cm in size is dipped in a 15% sodium hydroxide solution being kept at 50°C until when the emulsion layer of the sample starts to melt. Furthermore, sensitivity and fogginess were measured in the following manner. Namely, a sample was sandwiched between two sheets of a fluorescent intensifying screen for orthochromatic use, Model KO-250 (manufactured by Konishiroku Photo Ind. Co., Ltd.), and was exposed to X-rays, through an Al-wedge, at a tube voltage of 100 KVP, a tube amperage of 100 mA and for an exposure time of 0.07 second. The samples were processed using the following steps in a roller transport type automatic processor; the whole processing time took 45 seconds. Processing temperature Processing time Inserting - 1.2 sec Developing + Cross-over 35°C 14.6 sec Fixing + Cross-over 33°C 8.2 sec Washing + Cross-over 25°C 7.2 sec Squeezing 40°C 5.7 sec Drying 45°C 8.1 sec TOTAL - 45.0 sec The structure of the automatic processor used in this example was as follows. In the processor used in this example, rubber rollers were used. Rollers made of silicone having a stiffness of 48 degrees were used in the cross-over sections, and the rollers made of EPDM, a kind of ethylene propylene rubber, having a stiffness of 46 degrees in processing solutions were used in the processing solutions. The surface coarseness of the rollers was Dmax = 4 µm, and the number of the rollers used was 6 rollers in the developing section, and 84 rollers in total. The number of opposite rollers was 51 and the ratio of the number of opposite rollers to the total number of the rollers was 51/84 = 0.61. The amount of developer replenisher was 20 cc per sheet of 10" x 12" in size, the amount of fixer replenisher was 45 cc per sheet of 10" x 12" in size and the amount of washing water was 1.5 liters per minute. The airflow in the drying section was 11 cm² per minute and a heater having a capacity of 3 KW at 200V was used. The following developer-1 and fixer-1 was used. From the obtained characteristic curves, each of the exposure amounts was obtained in the condition of the base density plus fog density +1.0, respectively, and the relative sensitivity of each sample was obtained from the sensitivity of Sample No.1 which was regarded as the reference value of 100. Compositions of the developer and fixer Developer-1 Potassium sulfite 55.0 g Hydroquinone 25.0 g 1-phenyl-3-pyrazolidone 1.2 g Boric acid 10.0 g Sodium hydroxide 21.0 g Triethylene glycol 17.5 g 5-methylnemztriazole 0.07 g 5-nitroindazole 0.14 g 1-phenyl-5-mercapto-tetrazole 0.015 g Glutaraldehyde bisulfite 15.0 g Glacial acetic acid 16.0 g Potassium bromide 4.0 g Add triethylenetetramine hexaacetic acid to make one liter 2.5 g Fixer-1 Ammonium thiosulfate 130.9 g Sodium sulfite, anhydrous 7.3 g Boric acid 7.0 g Acetic acid of 90 wt% 5.5 g Sodium acetate, trihydrate 25.8 g Aluminium sulfate, octadecahydrate 14.6 g Sulfuric acid of 50 wt% 6.77 g Add water to make 1 liter Next, the graininess of each sample was evaluated. Each of the samples was processed under the above-mentioned conditions using a roller-transport type automatic processor, the coarseness of the developed silver grains was visually evaluated when the density of the samples reached 1.0. The results of the evaluation are ranked using 5 grades, grade 1 is inferior to grade 5 which is superior. Samples with grades from 3 to 5, are acceptable, however, grade 1 and 2 samples are not of any practical use. The pressure desensitization of each sample was measured in the following manner. The humidity of the samples was adjusted over 5 hours at 23°C and 30%RH and they were then bent at an angle of 280 degrees, approximately, with a radius of curvature of 2 cm. Three minutes after they were bent, they were exposed to X-rays similar to those used in the sensitivity measurements and were then treated using the same 45 second automatic processing procedure. There was obtained a density difference ΔD between the desensitized portion having a blackened density of 1.0 caused by bending and the portion having a density of 1.0 where it was not bent. The density difference ΔD is the difference between the density formed in the portion of a sample which is bended and exposed to the amount of X-rays necessary to give a density of 1.0 in an unbended portion of a sample, and a density of 1.0. According to the ΔD values, the evaluations were ranked from grade 1 to grade - 5, that is from poor to excellent. The relationship between the ΔD values to the evaluations is as follows. ΔD Evaluation 0 to 0.03 5 0.04 to 0.06 4 0.07 to 0.10 3 0.11 to 0.16 2 0.17 to 0.22 1 With respect to the fogginess of samples, results were obtained both of fogginess caused 7 days after the samples were coated and the fogginess caused after the samples were heat-treated at 55°C and 30%RH for 3 days. Dryness was evaluated in the following manner. Namely, samples were treated using the 45 second automatic processing and, the treated samples which passed through the drying section, were evaluated regarding touch feeling and the degrees of stickiness to other samples. The grades of the evaluations were ranked by 5 grades from grade 1 which is inferior to grade 5 which is superior. Samples with grades 3 to 5, were acceptable however, grade 1 and 2, samples were not of any practical use. The sensitivity of each sample processed in conventional 90 second automatic processing was obtained by decreasing the line-speed of the 45 second automatic processor by one half. The results thereof are shown in Table 1. As is obvious from Table 1, it is found the samples relating to the invention generally have excellent properties of sensitivity, fogginess. pressure desensitization, graininess, and dryness, and are suitable for use in super-rapid processing. In comparison to conventional 90 second processing, it is also found that the samples of the invention have higher sensitivity and, in addition, that the processing time can be shortened by one half and processability can be doubled, as compared to the conventional system applied to, for example, Samples No. 1 and No.2. As described above, according to the invention, a silver halide photographic light-sensitive material can be prepared which displays high sensitivity even if super-rapidly processed; a low fogginess, even immediately after it is coated and heat-treated; a high pressure resistance; and a low graininess.

Claims: A method for processing a silver halide photographic light-sensitive material which comprises processing the material in an automatic processor of which the whole processing time is from 20 to 60 seconds, wherein said material comprises a support bearing a hydrophilic colloidal layer including at least one light-sensitive silver halide emulsion layer thereon, wherein at least some of the silver halide grains present in the said silver halide emulsion layer are tabular grains which have an aspect ratio of the grain size to the grain thickness of at least 5, such that the projective areas of said tabular grains represent not less than 50% of the projective areas of all the silver halide grains in said emulsion layer, the time taken for said at least one silver halide emulsion layer of a 1 cm x 2 cm portion of said silver halide photographic light-sensitive material in a 1.5% by weight aqueous solution of sodium hydroxide at 50°C to commence to dissolve is within the range of from 8 to 45 minutes and on the side bearing the hydrophilic colloidal layer containing said silver halide emulsion layer, gelatin is present in an amount from 2.00 to 3.20 g/m². A method according to claim 1, wherein at least one layer of the silver halide photographic light-sensitive material has been hardened with at least one vinylsulfone or halogen substituted-s-triazine type hardener. A method according to claim 1 or 2, wherein said aspect ratio of the tabular grains in the silver halide photographic light-sensitive material is from 5 to 40. A method according to claim 3, wherein said aspect ratio is from 8 to 30. A method according to any one of the preceding claims wherein the thickness of said tabular grains in the silver halide photographic light-sensitive material does not exceed 0.50µm. A method according to claim 5, wherein the thickness of said tabular grain does not exceed 0.3µm. A method according to any one of the preceding claims, wherein the size of said tabular grains in the silver halide photographic light-sensitive material is at least 0.6µm. A method according to claim 7, wherein the size of said tabular grains is at least 0.8µm. A method according to any one of the preceding claims, wherein gelatin is present in the silver halide photographic light-sensitive material in an amount from 2.40 to 2.90 g/m². A method according to claim 9, wherein the gelatin is present in an amount from 2.50 to 2.80 g/m². A method according to any one of the preceding claims, wherein the said tabular grains in the silver halide photographic light-sensitive material are of silver iodobromide. A method according to claim 11, wherein said tabular grains are of silver iodobromide and 0 to 10 mol% of silver iodide. A method according to claim 12, wherein said tabular grains are of silver iodobromide and 0.1 to 6 mol% of silver iodide.

Inventors: ARAI, MASUMI, NAGASAKI, SATORU, SUZUKI, AKIO, TSUKI, NOBUAKI, YOSHIDA, EIJI
Applicants: KONICA CORPORATION
Application year: 1988
Main classification: G03C1
IPC codes: G03C5, G03C1