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
  • G03C1/015—Apparatus or processes for the preparation of 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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
• • 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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
  • G03C2001/03529—Coefficient of variation
• • 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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
  • G03C2001/03535—Core-shell grains
• • 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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
  • G03C2001/03564—Mixed grains or mixture of 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
  • G03C2200/00—Details
  • G03C2200/06—Additive

Definitions

• This invention relates to a light-sensitive silver halide photographic emulsion, more particularly to a method for sensitizing a silver halide emulsion including silver halide grains mainly comprising silver iodobromide, and a silver halide photographic emulsion sensitized by the aforementioned method.
• silver halides for photography there has been utilized a variety of silver halides such as silver chloride, silver bromide, silver chlorobromide, silver iodobromide and silver chloroiodobromide, but as silver halides for high-sensitive photography, the silver iodobromide has been used to obtain high-sensitive emulsions.
• the monodispersed emulsion can be theoretically presumed to be advantageous.
• a simple system or a mixture system of the monodispersed emulsions is employed, and especially examples of negative-type high sensitive emulsions are scarcely present.
• the silver halide emulsion manufactured under such conditions comprises the so-called regular crystal grains having faces (100) and faces (111) in various ratios, and these grains have any configuration of cube, octahedron and tetradecahedron.
• a hydroxyazaindene compound has been well known as a stabilizer for a photographic emulsion in the art, because of having a property to inhibit a chemical ripening by a sulphur-containing compound. Therefore, the azaindene compound has been used with the aim of terminating a sulphur sensitization reaction and/or preventing the occurrence of the fog in the course of a manufacturing process, a storage step or a development processing. Also, it has been known that this compound has an effect to increase a photographic sensitivity. For example, U.K. Patent No.
• 1,315,755 describes that the inherent sensitivity of the silver halide is higher than by the conventional method, when in the gold-sulphur sensitization method of the silver halide emulsion, the azaindene is added prior to the sulphur sensitization, and at the same time or subsequently a monovalent gold complex salt compound including sulphur is further added, followed by ripening.
• the above sensitization method is merely applied to the silver halide emulsion, a sufficient effect cannot be obtained.
• Japanese Patent Provisional Publication No. 63914/1975 and German Patent Application (OLS) No. 2,419,798 describe that when a monodispersed silver halide cubic grain emulsion, in which a molar percentage of contained silver bromide is 80 % or more, is sulphur sensitized and the hydroxytetrazaindene compound is then added thereto, a sensitivity increases.
• these publications also describe that crystalline grains other than cubes, e.g. octahedral grains and platy grains substantially surrounded with the faces (lll) rather decrease in the sensitivity, or even if it increases, its degree is only a little.
• a first object of this invention is to provide a method by which a monodispersed emulsion including silver halide grains of octahedral or tetradecahedral crystals having faces (111) is noticeably sensitized, scarcely producing a photographic fog
• a second object of this invention is to provide a silver halide photographic emulsion having a high sensitivity obtained by such a chemical sensitization method.
• the object of this invention is accomplished by a method for preparing a silver halide emulsion which comprises subjecting the silver halide emulsion including core-shell type silver halide grains to a gold-sulphur sensitization or gold-selenium sensitization by use of a gold sensitizer and sulphur sensitizer or selenium sensitizer, characterized in that the silver halide grains are octahedral or tetradecahedral crystals each having faces (111); a silver halide constituting the grains is substantially composed of silver iodobromide; the coefficient of variation regarding a grain size distribution of the silver halide grains is 0.18 or less; and the gold-sulphur sensitization or gold-selenium sensitization is carried out in the presence of a nitrogen-containing heterocyclic compound capable of forming a complex with silver or a silver ion.
• This invention is based on the discovery that when the silver halide grains contained in the silver halide emulsion are the monodispersed core-shell type silver iodobromide grains comprising the octahedral or tetradecadedral crystals each having the faces (111), and when the ratio between the selenium sensitizer and gold sensitizer or the ratio between the sulphur sensitizer and gold sensitizer is controlled in a certain range in the presence of the nitrogen-containing heterocyclic compound which forms the complex with silver of an amount enough to cover the grains, the noticeably high sensitization is accomplished.
• the effect of this invention can be obtained by removing the disadvantage that when the known gold-sulphur sensitization or gold-selenium sensitization is used for the octahedral or tetradecahedral silver iodobromide grains, the silver sulphide nuclei are easily produced on the faces (111) and many light-sensitive nuclei are formed on one silver iodobromide grain, which fact prevents the increase in the quantum efficiency.
• the effect of this invention can be procured by constituting the silver iodobromide grains in the form of the core-shell type in the monodispersed emulsion, and intentionally controlling a light-sensitive nucleus-forming reaction on the faces (111) in the presence of the nitrogen-containing heterocyclic compound capable of producing the complex with silver or a silver ion.
• the effect of this invention cannot be obtained, because the cubic silver halide grains allow light-sensitive nuclei to be more easily and selectively formed on the vertexes of each cube than on the faces (100) thereof, without any special attention thereto.
• the method of this invention is applied to the monodispersed octahedral or tetradecahedral silver iodobromide emulsion which is not of the core-shell type, the effet of the sensitization is not so great. Further, when the core-shell type monodispersed octahedral or tetradecahedral silver iodobromide emulsion is gold-sulphur sensitized or gold-selenium sensitized in the absence of any nitrogen-containing heterocyclic compound, the effect of the sensitization is also small.
• the quantum efficiency will increase and the gold-sulphur sensitization or gold-selenium sensitization will also increase, but due to the added iodine, lattice defects increase and thus silver ions between lattices also increase. Further, the iodine atoms which are present on the surfaces of the crystals serve to restrain the gold-sulphur sensitization or gold-selenium sensitization reaction.
• the conventional monodispersed octahedral or tetradecahedral silver iodobromide emulsion does not- increase so much in the sensitivity even by means of the gold-sulphur sensitization or gold-selenium sensitization, but this fact, according to the estimation of the inventors of this invention, would be attributable to the above-mentioned functions and the formation of many light-sensitive nuclei on the faces (111) due to the aforesaid crystal habit dependency of the chemical sensitization reaction in the cases of the octahedral and tetradecahedral silver halide grains.
• the influence of the iodine atoms, on the surfaces, on the chemical sensitization reaction can be weakened by giving the core-shell configulation to reduce the content of the silver iodide on the faces, but such a configulation is not effective against the increase in the lattice defects and the augmentation in the silver ions between the lattices and cannot control the crystal habit dependency in the chemical sensitization reaction.
• the nitrogen-containing heterocyclic compound serves to reduce the amount of the silver ions between the lattices to a level necessary for the chemical sensitization reaction by forming a complex with the silver ion on the surfaces and to control the chemical sensitization reaction so that effective light-sensitive nuclei may be produced in a small amount, but the compound cannot prevent the function of restraining the chemical sensitization reaction by the iodine atoms on the surfaces.
• the core-shell type octahedral or tetradecahedral silver iodobromide emulsion is gold-sulphur sensitized or gold-selenium sensitized in the presence of the nitrogen-containing heterocyclic compound, good results can be expected, and the degree of the obtained sensitization is more remarkable than anticipated, which would be atributed to a synergistic effect other than predicted by the inventors.
• the feature of this invention is that the reaction of forming the nuclei for the chemical sensitization is controlled by taking the above-mentioned technical constitution and the combination effect of the gold-sulphur or gold-selenium sensitization is obtained more remarkably than in the conventional one.
• the nitrogen-containing heterocyclic compound is added at the end of the sulphur sensitization in order to control silver ions on and near the surfaces of the silver halide grains and to thereby improve the efficiency of a latent image formation. Therefore, this invention is different from the disclosed ones in technique.
• U.K. Patent No. 1,315,755 discloses a method in which after the azaindene compound has been added as mentioned above, a monovalent gold complex salt compound including sulphur is added in order to carry out a gold-sulphur sensitization, but it does no refer to the crystal habit of the silver halide grains, the core-shell structure and the like anywhere. Therefore, this invention cannot be anticipated by the instant literature.
• the morphology of the silver halide grains is an octahedron which is substantially formed with faces (111), or a tetradecahedron formed with the faces (111) and faces (100). Diameters of these grains are not to be limited.
• the ratio between the faces (111) and faces (100) is not limited to a specific range, but the percentage of the faces (111) is at least 5 % of the whole surface area of the grains.
• the percentage of the silver halide grains of this invention is preferably 50 % or more, more preferably 70 % or more.
• the emulsion in which the silver halide grains substantially comprise the silver halide grains of this invention is most preferred.
• the so-called monodispersed emulsion is employed in which the silver halide grains contained in the silver halide emulsion are 0.18 or less in the coefficient of variation of a grain size distribution.
• the method according to this invention is based on the concept that the gold-selenium sensitization reaction or gold-sulphur sensitization reaction is controlled by covering the silver halide surfaces with the nitrogen-containing heterocyclic compound capable of forming a complex with silver or a silver ion, but it seems that when a polydispersed emulsion is used, the scatter of a grain surface area is large among the grains, and it is thus difficult to efficiently cover the grain surfaces.
• the uniformity of the size of the silver halide grains included in the silver halide emulsion can be represented with a value obtained by dividing a standard deviation S of a grain size distribution by an average grain size (diameter) r, i.e. the coefficient (hereinafter referred to as the disperse degree) of variation of the grain diameter distribution, as shown by the following formula (1) :
• the average grain diameter referred to here means an average value of diameters obtained by converting projected images of the silver halide grains into circular images having the same areas, and it can be defined as r by the following formula, when each grain diameter is r i and the number of the grains is n..
• the grain diameter mentioned above can be measured in various manners usually used in the art for the aforesaid purpose.
• the typical manners above are described in Loveland, "Analytical Method of Grain Diameter", A.S.T.M. Symposium on Light Microscopy, pages 94 to 122 (1955), and Mies and James, “Theory Of Photographic Process", 3rd Edition, Volume 2, McMillan Co., Ltd. (1966).
• the emulsion of 0.18 or less in the disperse degree will be referred to as a monodispersed emulsion.
• the silver halide emulsion according to this invention can be prepared by the use of methods described in, for example, P. Glafkides, “Chimie et Phyeique Photographique”, Paul Montel Co., Ltd. (1967); G.F. Duffin, “Photographic Emulsion Chemistry", The Focal Press (1966); and V. L. Zelikman, “Making and Coating Photographic Emulsion", The Focal Press (1964). That is to say, the silver halide emulsion may be prepared by any of an acidic method, a neutral method and an ammonia method, and as a manner of allowing a soluble silver salt to react with a soluble halogen salt, an injection mixing process, a simultaneous mixing process or a combination thereof may be employed.
• the simultaneous mixing process there may be used a method of constantly maintaining a pAg in a liquid phase in which the silver halide is produced, i.e. the so-called controlled double-jet method.
• the core-shell type silver halide grains each of this invention have a grain structure comprising two or more layers different in the content of silver iodide, and it is preferred that a portion of the two or more layers and near the surface thereof is smaller in the silver iodide content, as compared with a more inside portion thereof than the above portion.
• the surface-near portion referred to above means an outer portion of the grain which ranges from 0.001 to 0.1 pm in thickness from the surface.
• a difference betwen the respective silver iodide contents in the surface-near portion and the more inside portion of the layers is preferably 5 mol % or more.
• the emulsion including such silver halide grains can provide a high sensitization efficiency and is suitable especially for obtaining a surface latent image type emulsion.
• the transition from the layer having the higher silver iodide content to the layer having the lower content thereof may be bounded in a sharp state or in an indefinite and dim state.
• the distribution of the silver iodide in the aforementioned silver halide grains can be detected by a variety of physical measurements, for example, by measuring luminescence at low temperature, as described in Annual Congres Lecture Summary Bulletin in 1981 published by Nippon Shashin Gakkai.
• the surface-near portion of each grain includes 0 to 4 mol % of silver iodide and the more inside portion includes 2 to 15 mol % of silver iodide.
• a silver halide composition other than the aforementioned silver iodide is mainly silver bromide, but silver chloride may be employed so long as it does not impair the effect of this invention, and its limit is less than approximately 1 mol %.
• the silver halide emulsion according to this invention may include a mixture of the octahedral and tetradecahedral grains.
• the core-shell type silver halide grains included in the silver halide emulsion of this invention can each be prepared by covering, with a shell, a core comprising a monodispersed silver halide grain.
• the monodispersed silver halide grains for the cores having a desired size can be manufactured by the double-jet method, while maintaining a pAg at a constant level.
• the monodispersed silver halide emulsion can be prepared by a method disclosed in Japanese Patent Provisional Publication No. 48521/1979.
• the emulsion is manufactured by adding an aqueous potassium iodide-gelatin solution and an aqueous ammoniacal silver nitrate solution to an aqueous gelatin solution including silver halide seed crystals, with an addition rate varied as a function of time. In this case, by suitably selecting the time function of the addition rate, pH, pAg, temperature and the like, it is possible to obtain the high-grade monodispersed silver halide grains.
• a cadmium salt zinc salt, lead salt, thallium salt, iridium salt, any one of their complex salts, rhodium salt or its complex salt.
• nitrogen-containing heterocyclic rings include a pyrazole ring, pyrimidine ring, 1,2,4-triazole ring, 1,2,3-triazole ring, 1,3,4-thiadiazole ring, 1,2,3-thiadiazole ring, 1,2,4-thiadiazole ring, 1,2,5-thiadiazole ring, 1,2,3,4-tetrazole ring, pyridazine ring, 1,2,3-triazine ring, 1,2,4-triazine ring, 1,3,5-triazine ring, benzotriazole ring, benzimidazole ring, benzothiazole ring, quinoline ring, benzoxazole ring, benzoselenazole ring, naphthothiazole ring, naphthoimidazole ring, rhodanine ring, thiohydantoin ring, oxazole
• Preferred nitrogen-containing heterocyclic compounds have the azaindene rings among the above rings, and azaindene compounds having hydroxy groups as substituent groups, e.g. hydroxytriazaindene, tetrahydroxyazaindene and hydroxypentazaindene compounds are more preferable.
• the heteroyclic rings may have substituent groups other than the hydroxy group.
• substituent groups include an alkyl group, alkylthio group, amino group, hydroxyamino group, alkylamino group, dialkylamino group, arylamino group, carboxy group, alkoxycarbonyl group, halogen atom, acylamino group, cyano group and mercapto group.
• nitrogen-containing compounds used in this invention are as follows, but they are not to be limited to the examples below:
• An amount of the nitrogen-containing heterocyclic compound to be added varies extensively in compliance with the size of the silver halide grains, composition, ripening condition and the like, but the compound is required to be added in such an amount as to enable the formation of from a single molecular layer to 10 molecular layers on the surface of each silver halide grain. This amount can be adjusted by the control of an adsorption equilibrium condition in accordance with a variation of a pH and/or temperature at the time of ripening.
• the nitrogen-containing heterocyclic compound can be used together with a sensitizing dye at the time of the gold-sulphur sensitization or gold-selenium sensitization of this invention.
• the nitrogen-containing heterocyclic compound and the sensitizing dye are added in such a total amount as to enable the formation of from the single molecular layer to 10 molecular layers on the surface of each silver halide grain, but it is preferred that the amount of the sensitizing dye does not exceed 70 % of an amount to permit forming the single molecular layer on the surface of the silver halide grain.
• the amount of the nitrogen-containing heterocyclic compound necessary for the formation of the single molecular layer can be determined by a drawn adsorption isotherm, but, for example, when the silver iodobromide emulsion grains comprisir octahedral grains of 0.65 um in diameter are covered with 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene, its necessary amount is approximately 210 mg/Ag mol. Therefore, an area occupied by this compound is approximately 30 A 2 per molecule. For other grains different in diameter, the amount of the compound may be found by an area proportion calculation, taking the value of the above example as a standard.
• the nitrogen-containing heterocyclic compounds used in this invention are preferably colorless.
• the addition of the nitrogen-containing heterocyclic compound into the emulsion can be carried out in the form of a solution where it is dissolved in a suitable solvent (e.g., water or an aqueous alkaline solution) which has no harmful influence on the photographic emulsion.
• a suitable solvent e.g., water or an aqueous alkaline solution
• the compound above may exist in the emulsion at the time of the gold-sulphur sensitization or gold-selenium sensitization, and it is preferred that the compound is added thereto at the time of or before the addition of a sulphur sensitizer or selenium sensitizer.
• the addition of the gold sensitizer may be carried out in the course of or at the end of the ripening for the sulphur or selenium sensitization.
• the complex referred to here means a combination of two or more compounds or ions.
• sulphur sensitizers can be used. Their examples include thiosulfate, allythio- carbamidothiourea, allylisothiocyanate, cystine, p-toluenethiosulfonate and rhodanine.
• sulphur sensitizers which are disclosed in U.S. Patent Nos. 1,574,944, 2,410,689, 2,278,947, 2,728,668, 3,501,313 and 3,656,955, German Patent No. 1,422,869, and Japanese Patent Provisional Publication Nos. 24937/1981 and 45016/1980.
• the amount of the sulphur sensitizer is such that it effectively increases the sensitivity of the emulsion. This amount varies over a fairly extensive range under various conditions such as the amount of the used nitrogen-containing heterocyclic compound, a pH, a temperature and the size of the silver halide grains, but about 10 to about 10 -1 mol per mol of the silver halide is preferable, as a standard.
• this invention allows using selenium sensitizers, which include aliphatic isoselenocyanates such as allyisoselenocyanate, selenoureas, selenoketones, selenoamides, selenocarboxylic acids, selenoesters, selenophosphates, and selenides such as diethylselenide and diethyl diselenide.
• selenium sensitizers include aliphatic isoselenocyanates such as allyisoselenocyanate, selenoureas, selenoketones, selenoamides, selenocarboxylic acids, selenoesters, selenophosphates, and selenides such as diethylselenide and diethyl diselenide.
• the amount of the selenium sensitizer varies over an extensive range, but approximately 10 -7 to 10 -1 mol per mol of the silver halide is preferable, as a standard.
• gold sensitizers used in this invention a variety of gold compounds inclusive of ones having oxidation numbers of +1 and +3 can be employed.
• Typical examples of the gold sensitizers include chloroaurate, potassium chloroaurate, auric trichloride, potassium auric thiocyanate, potassium iodoaurate, tetracyanoauric acid, ammonium aurothiocyanate and pyridyltrichlorogold.
• the amount of the gold sensitizer is preferalby within the range of from about 10 -7 to 10- 1 mol per mol of the silver halide as a standard, though varying with various conditions.
• gold nuclei and silver sulphide-gold nuclei or silver selenide-gold nuclei are produced as light-sensitive nuclei.
• the number of these nuclei and especially the composition of the silver gold sulphide or silver gold selenide nuclei excert a great influence on an electron trap character or development character.
• a proportion of the gold sensitizer with respect to the sulphur sensitizer or selenium sensitizer has a great influence on a sensitization effect.
• the proportion of the gold sensitizer with respect to the sulphur sensitizer or selenium sensitizer must be such that the number of gold atoms with respect to the number of sulphur atoms capable of forming silver sulphide with silver ions out of the sulphur atoms included in the sulphur sensitizer or the number of selenium atoms capable of forming silver selenide with the silver ions out of the selenium atoms included in the selenium sensitizer is within the range of 1/2 to 1/200.
• sodium thiosulfate and sodium chloroaurate are used as the sulphur sensitizer and the gold sensitizer respectively, the latter is added within the range of 1/2 to 1/200 with respect to the former.
• the emulsion which will undergo the gold-sulphur sensitization or gold-selenium sensitization in this invention has preferably a pAg of 7.5 to 10.0 and a pH of 5.0 to 9.0
• sensitization step of this invention there can also be together used a sensitization process based on another noble metal such as platinum, palladium, iridum or rhodium, or a salt thereof.
• another noble metal such as platinum, palladium, iridum or rhodium, or a salt thereof.
• reducing agents are not particularly limited, but their examples include known stannous chloride, thiourea dioxide, hydrazine derivatives and silane compounds.
• the reduction sensitization is carried out while the silver halide grains grow or after the sulphur sensitization and gold sensitization have been completed.
• the sensitizing process of this invention can also perform a noticeable spectrophotometric sensitization by using the sensitizing dye on the occasion of the gold-sulphur sensitization or gold-selenium sensitization of this invention.
• the sensitizing dyes referred to above mean dyes which can expand the light-sensitive region of the silver halide for an electromagnetic wave into the outside of an inherent light-sensitive wave range.
• the concrete sensitizing dyes useful in this invention include cyanine dyes, merocyanine dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes and conjugate merocyanine dyes. These dyes are disclosed in, for example, F. M. Hamer, "The Cyanine Dye and Related Compounds" and C. T. H. James, "The Theory of the Photographic Process, Fourth Edition", pages 194 to 234.
• R 1 and R 2 are groups selected from alkyl groups (e.g., a methyl group, ethyl group, propyl group, pentyl group, chloroethyl group, hydroxyethyl group, methoxyethyl group, acetoxyethyl group, carboxymethyl group, carboxyethyl group, ethoxycarbonylmethyl group, sulfoethyl group, sulfopropyl group, sulfobutyl group, 2-hydroxy-y-sulfopropyl group, propyl sulphate group, allyl group, benzyl group and phenethyl group) and aryl group (e.g., a phenyl group, carboxyphenyl group, sulfonyl group and the like); L 1 , L 2 and L
• Typical examples of the sensitizing dyes represented by the aforesaid general formula (I) used in this invention are as follows, but the compounds which are usable in this invention are not to be limited thereto:
• a particular limitation is not made and any procedure is applicable.
• the silver halide photographic emulsion manufactured by the method of this invention can suitably be applied to many silver halide photographic light-sensitive materials, because it has a noticeably high photographic sensitivity, a less high intensity failure and a less photographic fog.
• the aforementioned silver halide photographic emulsion can be applied effectively to a variety of the light-sensitive materials for use in a black-and-white photography, X-ray photography,color photography, infrared photography, microphotography, silver dye bleach, reversal process and diffusion transfer process.
• Emulsion (1) An octahedral monodispersed emulsion including grains was prepared by a double jet method, in which a pAg and pH were controlled, according to the procedure disclosed in Japanese Patent Provisional Publication No. 48521/1979 (the thus prepared emulsion will hereinafter be referred to as Emulsion (1)).
• Each of the above grains had an average diameter of 0.9 F m and comprised a core of silver iodobromide containing 2 mol % of silver iodide and a shell thereon of silver bromide having an average thickness of 0.016 pm.
• the degree of dispersion of their grain size distribution was 0.15.
• this emulsion was divided into 9 portions, and a pre- predetermined amount of 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene (hereinafter briefly referred to as Compound (I)) was added thereto, as shown in Table 1.
• Compound (I) 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene
• Table 1 a pH of each portion was adjusted to a predetermined level with an aqueous potassium hydroxide solution.
• the sensitometry of these samples was performed as follows: With regard to exposure, a 1/50 second exposure was carried out through an optical wedge by the use of a tungsten lamp (color temperature 5,400°K) and a 10 -6 second exposure was done by the use of a xenon flash. Development was performed at a temperature of 20°C for a period of 10 minutes with the following developing solution:
• Sensitivities each mean a reciprocal number of an exposure necessary to obtain a fog density of +0.1 and are represented with relative sensitivites, taking a value of Samples 1 and 6 as 100.
• Emulsion (1) prepared in Example 1 was divided into 2 portions, and to these emulsions, a panchromatic sensitizingew dye, anhydro-3,3'-di-(3-sulfopropyl)-5,5'-dichloro-9-ethylthiacarbocyanine hydroxide, was added in an amount of 140 mg/mol AgX as a methanolic solution. Then, 5 minutes after the addition, 210 mg/mol AgX of Compound (I) was added to either emulsion and the pH was adjusted to 6.5.
• a panchromatic sensitizingew dye anhydro-3,3'-di-(3-sulfopropyl)-5,5'-dichloro-9-ethylthiacarbocyanine hydroxide
• Compound (II) l-phenyl-5-mercaptotetrazole
• coupler dispersing solution as well as usually used photographic additives such as a spreading agent and a hardening agent.
• triacetate bases were coated with the respective emulsions so that the amount of the silver might be 20 mg/dm 2 , followed by drying in order to prepare Sample 12 and 13.
• the coupler dispersing solution was prepared as follows: In a mixture of 100 ml of tricresyl phosphate and 50 ml of ethyl acetate was completely dissolved 80 g of 1-hydroxy-N-[ ⁇ -(2,4-di-tert-amylphenoxypropyl)]-2-naphtho- amide, and 2 g of sorbitan monolaurate was further added thereto.
• the resultant solution was added to 1 kg of a 10 % by weight aqueous gelatin solution including 2.5 g of dodecylbenzenesulfonate, and a high-speed agitation and ultrasonic agitation followed for emulsification and dispersion, thereby preparing the desired coupler dispersing solution.
• Example 2 The above samples were subjected to the same wedge exposure as in Example 1, and were then color developed at a temperature of 38°C for a period of 3 minutes with a color developing solution having the following composition:
• Results are set forth in Table 2 below. As is clear from Table 2, the sample, which was prepared under conditions that the nitrogen-containing heterocyclic compound and the sensitizing dye were together present at the time of the gold-sulphur sensitization of this invention, had also a remarkably high sensitivity.
• Emulsion (2) a tetradecahedral monodispersed emulsion including grains of 0.9 pm in average diameter was prepared by a double jet method in which a pAg and pH were controlled.
• Each of the grains above comprised a core of silver iodobromide containing 2 mole % of silver iodide and a shell thereon of silver bromide having an average thickness of 0.016 pm.
• the degree of dispersion of their grain size distribution was 0.14.
• this emulsion was divided into 3 portions. One of them was processed as a control, and Compound (I) was added to each of the remainder in an amount shown in Table 3. Afterward, a pH of each emulsion was adjusted to a predetermined level.
• Emulsion (3) In place of Emulsion (1), an emulsion (hereinafter referred to as Emulsion (3); degree of dispersion 0.15) and another emulsion (hereinafter referred to as Emulsion (4); degree of dispersion 0.14) were used.
• Emulsion (3) above comprised core-shell type silver iodobromide grains (core ... silver iodobromide including 2 mol % of silver iodide; shell ...
• Example 1 silver bromide of 0.02 pm in average thickness
• Emulsion (4) above comprised twinned crystal silver iodobromide grains (including 2 mol % of silver iodide) having irregular shapes which had heretofore been used generally on products.
• the same chemical sensitization as in Example 1 was then carried out to prepare Samples 15 to 17 in which Emulsion (3) was used, and Samples 18 to 20 in which.Emulsion (4) was used. These samples were evaluated in the same manner as in Example 1.
• Results obtained are set forth in Table 4 below: In the case of Reference Example described above, 10 to 50 mg/AgX mol of ammonium thiocyanate was added, because when sodium thiosulfate and chloroauric acid alone were used as sensitizers, the sensitization rate was very bad.
• Emulsion (5) was a silver iodobromide emulsion (the content of silver iodide was 6 mol % and the degree of dispersion was 0.12) comprising a silver halide of octahedral crystals having an average diameter of 0.65 pm, with the silver iodide distributed uniformly in the silver halide;
• Emulsion (6) above was a silver iodobromide emulsion (the content of silver iodide was 8 mol % and the degree of dispersion was 0.12) comprising a silver halide of octahedral crystals having an average diameter of 0.65 pm, with the cores of the crystals coated with the silver bromide shells of 0.016 um in thickness.
• Emulsions (5) and (6) above were then subjected to the type of sensitizations of a sulphur sensitization and gold-sulphur sensitization in the same manner as in Example 1.
• chemical sensitizers there were employed 5.7 mg/mol AgX of sodium thiosulfate (pentahydrate), 0.62 mg/mol AgX of chloroauric acid (tetrahydrate) and 50 mg/mol AgX of ammonium thiocyanate.
• Results obtained are set forth in Table 8 below.
• the relative sensitivities in the table are represented with relative values, taking, as 100, sensitivities obtained by subjecting, to a 1/50 second exposure, the samples which were prepared by adding Compound (I) to the respective emulsions at addition time (3) above and by carrying out the chemical sensitization.
• a monodispersed emulsion was prepared by the double jet method in which a pAg and pH were controlled, which monodispersed emulsion was composed of tetradecahedral grains having an average diameter of 0.9 pm and having a degree of disperse of 0.15, each of the grains comprising a core of silver iodobromide including 10 mol % of silver iodide and a shell thereon of silver bromide having an average thickness of 0.016 pm.
• the thus prepared emulsion was divided into 9 portions, and 3 portions of them were treated as controls; to the remainder were added compounds in amounts shown in Table 9 and their pH and pAg were adjusted to predetermined levels.
• Example 9 The thus prepared emulsions were subjected to gold-sulphur sensitization and dye sensitization as in Example 2. The same photographic additives as in Example 2 were then added thereto, followed by coating and drying in order to prepare Samples 45 to 53. These samples were evaluated as in Example 2, and results obtained are set forth in Table 9 below:
• Example 2 in place of Compound (I), benzotriazole was added. The obtained sensitization effect was good similarly to that of Example 2.
• Example 2 in place of Compound (I), benzothiazole was added. The obtained sensitization effect was good similarly to that of Example 2.
• Example 2 in place of Compound (I), benzimidazole was added. The obtained sensitization effect was good similarly to that of Example 2.

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• 1981
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