Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B23/00—Methine or polymethine dyes, e.g. cyanine dyes
  • C09B23/10—The polymethine chain containing an even number of >CH- groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B23/00—Methine or polymethine dyes, e.g. cyanine dyes
  • C09B23/10—The polymethine chain containing an even number of >CH- groups
  • C09B23/105—The polymethine chain containing an even number of >CH- groups two >CH- groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B23/00—Methine or polymethine dyes, e.g. cyanine dyes
  • C09B23/10—The polymethine chain containing an even number of >CH- groups
  • C09B23/107—The polymethine chain containing an even number of >CH- groups four >CH- groups
• • 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
  • G03C1/485—Direct positive emulsions
  • G03C1/48515—Direct positive emulsions prefogged
  • G03C1/48523—Direct positive emulsions prefogged characterised by the desensitiser
  • G03C1/4853—Direct positive emulsions prefogged characterised by the desensitiser polymethine dyes

Definitions

• ABSTRACT A photographic silver halide emulsion for direct positive use characterized by containing as a novel sensitizing agent at least one cyanine dye in which the 3- position carbon atom of the pyrazolo [5,l-b] quinazolone nucleus and the 1-, 2-, 3- or 4-position of the cyanine heterocyclic nucleus thereof are linked with a methine chain (with the proviso that the linking is at the 4-position only when the cyanine heterocyclic nucleus is a quinoline or pyridine nucleus, and the linking is at the 1- or 3-positions only when the cyanine heterocyclic nucleus is an isoquinoline).
• the photographic emulsion containing the above specific dye exhibits high light-sensitivity with less color retention defects.
• the invention relates to a photographic silver halide emulsion, in more particular, to a direct positive silver halide emulsion which is sensitized with a dye containing a novel pyrazolo [5,l-b] quinazolone nucleus.
• This phenomenon is called solarization.
• a similar reversal phenomenon (where the density lowers with an increase in the exposure dosage) also takes place, in the same way as seen in the case of exposure to light with a silver halide photosensitive material which has been optically or chemically fogged during the preparation of the silver halide emulsion.
• silver halide emulsion for direct positive use employed throughout the specification of this application means a silver halide emulsion so prepared as to directly form a positive image upon development after exposure to light (a positive light image).
• the object ofthis invention is to provide a silver halide emulsion for forming direct positives which exhibits high sensitivity, and keeps a desired maximum picture image density with minimum color retention.
• cyanine heterocyclic nuclei of the cyanine dyes employed in this invention include oxazoline nuclei, oxazole nuclei, benzoxazole nuclei, naphthoxazole nuclei, thiazoline nuclei, thiazole nuclei, benzothiazole nuclei, naphthothiazole nuclei, selenazole nuclei, 2-pyridine nuclei, 4-pyridine nuclei, 2-quinoline nuclei, 4-quinoline nuclei, l-isoquinoline nuclei, 3-isoquinoline nuclei, imidazole nuclei, benzimidazole nuclei, indolenine nuclei, imidazo(4,5- b)quinoxaline nuclei, pyrrolidine nuclei, etc.
• heterocyclic rings or benzene rings in con densed heterocyclic rings may be substituted one or more substituents such as alkyl, aryl, hydroxyl, alkoxyl, carboalkoxyl or alkoxycarbonyl groups (for example,
• cyanine nuclei include, as thiazoles, for instance, thiazole, 4-methyl thiazole, 4-phenyl thiazole, S-(p-hydroxyphenyl)-thiazole, S-methyl thiazole, 5- phenyl thiazole, 4-(o-hydroxyphenyl)thiazole, dimethyl thiazole, 4,5-diphenyl thiazole, etc; as benzothiazoles, for instance, benzothiazole, 4- hydroxybenzthiazole, 7-fluorobenzothiazole, 4- chlorobenzothiazole, 5-chlorobenzothiazole, 6-
• chlorobenzothiazole 7-chlorobenzthiazole, 4-methyl benzothiazole, S-methyl benzothiazole, 6-methyl benzothiazole, 5,6-dimethyl benzothiazole, 5- bromobenzothiazole, 6-bromobenzothiazolc, 5- phenylbenzothiazole, 6-phenyl benzothiazole, 4-phenyl benzothiazole, 4methoxybenzothiazole.
• 4-quinolines such as quinoline, 3-methyl quinoline, 4-methyl quinoline, -5-methoxyquinoline, 6-methoxyquinoline, 7- methoxyquinoline, 8-methoxyquinoline, 6-methyl quinoline, 7-chloroquinoline, 8-chloroquinoline, 8-trifluoromethylquinoline, 6-nitroquinoline, etc.;
• 1- isoquinoline such as isoquinoline, 3-methyl isoquinoline, S-methyl isoquinoline, 7-methyl isoquinoline, 8- methyl isoquinoline, 6 -chloroisoquinoline, 6- methoxyisoquinoline, 8-methoxyisoquinoline, etc.
• 3- isoquinolines such as 3-is0quinoline S-methyl isoquinoline, l-mcthyl isoquinoline, o-chloroisoquinoline, 6-
• dolcnines such as indolenine, 3,3-dimethyl indolenine, 5-hydroxy-3,3-dimethyl indolenine, 3,3-dimethyl-6- chloroindolenine, 3,3,5-trimethyl indolenine, 3,3,7- trimethyl indolenine, 3,3-dimethyl-5-nitroindolenine, et.;
• Z-pyridines such as pyridine, 4-methyl pyridine, 6- methyl pyridine, 4,6-dimethyl pyridine, 4-butyl pyridine, 4-decyl pyridine, 4-octadecyl pyridine, 4,6 dibutyl pyridine, 4-benzyl pyridine, 4-phenyl pyridine,
• chloropyridine 4-bromopyridine, 6-bromopyridine, 4-hydroxy-pyridine, 4-methoxypyridine, 4- ethoxypyridine, 6-methoxypyridine, -ethoxypyridine, 4,6-dimethoxypyridine, etc.; 4-pyridines such as 4- pyridine, Z-methyl pyridine, 2-butyl pyridine, 2-decyl pyridine, 2-octadecyl pyridine, 2,6-dimethyl pyridine, 2,6dibutyl pyridine, 2-ben2yl pyridine, 2phenyl pyridiene, 2-(p-hydroxyphenyllpyridine, 2,6-diphenyl pyridine, 2-chloropyridin e, 2-bromopyridine, 2,6- dichloropyridine, Z-hydroxypyridine, 2- mcthoxypyridine, 2-ethoxypyridine, 2,6-
• Preferred cyanine dyes used in this invention are represented by any one of the following formulae (l), (ll) or (lll).
• R and R each stands for an alkyl or substituted alkyl group, for example, having from 1 to 8 carbon atoms such as, for example, methyl, ethyl, propyl, isopropyl, n-butyl, n-pentyl, n-hexyl and like unsubstituted alkyl groups; B-hydroxyethyl, y-hydroxypropyl and the hydroxalkyl groups; B-acetoxyethyl, y-acetoxypropyl and like acetoxyalky groups; B-methoxyethyl, 'y-methoxypropyl and like alkoxyalkyl groups; B-carboxyethyl y-carboxypropyl, S-carboxybutyl, w-carboxypentyl and like carboxyalkyl groups; B-methoxycarbonylethyl, y-ethoxycarbonylpropyl and like alkoxycarbon
• R stands for any one of the substituent groups which known for pyrazole [5,1-b]quinazoline compounds, such as a hydrogen atoms, an alkyl group (e.g., those having from 1 to 8 carbon atoms, such as methyl, ethyl, propyl, benzyl, etc.), alkoxyl group (e.g., those having from I to 8 carbon atoms, such as methoxyl, ethoxyl, etc.) carboxyl group or alkoxyearbonyl group (e.g., those in which the alkyl group has from 1 to 8 carbon atoms, such as methoxycarbonyl group, ethoxycarbonyl group, etc.), hydroxyl or aryl group (e.g., those monoaryl groups such as phenyl group, methoxyphenyl group, etc.)
• R stands for a hydrogen atom, an alkyl group (e.g., those having from 1 to 8 carbon atoms such as methyl, ethyl, propyl etc.), a cycloalkyl group (e.g., those hav ing from 3 to 8 carbon atoms such as cyclohexyl) or aryl group (such as a phenyl group).
• alkyl group e.g., those having from 1 to 8 carbon atoms such as methyl, ethyl, propyl etc.
• a cycloalkyl group e.g., those hav ing from 3 to 8 carbon atoms such as cyclohexyl
• aryl group such as a phenyl group
• Z stands for anatomic group necessary to form a cyanine heterocyclic nucleus, and particularly represents those mentioned hereinabove.
• R stands for a substituent which is known for pyrazole [5,l-blquinazolone compounds, for example, a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, etc.), a lower alkyl group (e.g., those having 1 to 8 carbon atoms, such as methyl, ethyl, etc.), an alkoxy group (e.g., those having 1 to 8 carbon atoms such as methoxyl, cthoxyl, etc.), an aryl group (e.g., mono aryl groups such as a phenyl group, etc.), a carboxyl or alkoxycarbonyl group (e.g., those in which the alkyl group has from I to 8 carbon atoms such as methoxycarbonyl group; etc.), an acylamino group (e.g., those having from 2 to 8 carbon atoms such as acetylamino group, etc.), an amino group,
• n represents to l
• p stands for l,2,3, or 4.
• X* indicates an acid anion such as a chlorine ion
• the dye represented by general formula (I) can be obtained by reacting the compound of the general formula (lV) (B): (I)) with a heterocyclic quaternary ammonium salt represented by the following general formula (V) (wherein R R and p each has the same meaning as previously defined in the case of the general formula (wherein Y denotes SR, Or" or NC5H5 OCH:
• R' and R" each denotes a methyl, ethyl or phenyl group
• R Z,L,,L n m and X each has the same meaning as previously given with respect to general formula (1)
• under elevated temperature e.g., about to C in ethanol in the presence of an organic base, e.g., 2.5 to 3 moles per mole of the compound of the general formula IV for about 30 to 60 minutes under normal pressures such as triethylamine.
• the dye represented by general formula (I) can be prepared by reacting the compound of general formula (VI) which is obtained from the compound of general formula (III) by a Vilsmeiers reaction, with the heterocyclic quaternary ammonium compound of general formula (VII) (wherein R R Z, L L n and in each are the same as were previously defined for general formula (I)) in generally equimolar amounts in acetic anhydride at about 10 to 12 times by weight to the compound of the general formula VI at elevated temperature of about to C and under normal pressures for about 10 minutes followed by treatment with an alkali.
• the compound of general formula (I) can be also obtained in a smilar way by carrying out the above reaction in nitrobenzene at a temperature of about 150 to C and with the nitrobenzene being present in an amount of about 5 to 10 times by weight to the compound of the general formula IV in the presence of from about 3 to 4 mole of an organic base such as triethylamine per mole of the compound of the general formula (IV) fol lowed by treatment with alkali, instead of using acetic anhydride.
• an organic base such as triethylamine per mole of the compound of the general formula (IV) fol lowed by treatment with alkali, instead of using acetic anhydride.
• the dye represented by the general formula (II) can be obtained by alkylating the dye of general formula (I) with a conventional quaternizing agent as is generally used in the synthesis of cyanine dyes, for example, dimethyl sulfate, methyl-p-toluene sulfonate, propane sultone, butane sultone, an alkyl halide, etc,, at a 121.2 to 1:15 molar ratio and at a temperature of about 120 to 140C for about 20 minutes.
• a conventional quaternizing agent as is generally used in the synthesis of cyanine dyes, for example, dimethyl sulfate, methyl-p-toluene sulfonate, propane sultone, butane sultone, an alkyl halide, etc, at a 121.2 to 1:15 molar ratio and at a temperature of about 120 to 140C for about 20 minutes.
• the dye represented by general formula (Ill) can be. obtained by reacting the compound represented by general formula (ylll) wherein R R R and p are each the same as defined for general formula (I)) with a heterocyclic quaternary ammonium salt as represented by general formula (VII) in acetic anhydride at an elevated temperature under conditions as described above the dye of the general formulae (l).
• the emulsion for direct positive use of this invention preferably contains an organic desensitizer.
• the organic desensitizer optionally used in this invention is a substance having the capability of trapping free electrons which have been generated in the silver halide grains upon irradiation with radiant energy, and which is absorbed in the silver halide.
• the organic desensitizer can further be defined as a substance having a minimum vacant electron energy sublevel which is lower than the electron energy sublevel ofthe conducting zone of the silver halide grains.
• it is a compound having a maximum electron energy sublevel which is occupied which is lower than the valence electron zone of the silver halide grain.
• the measurement of the electron energy sublevels is complicated, but it is possible to determine it practically.
• any of the above-mentioned organic desensitizers may be satisfactorily used in this invention. However, most desirable result are obtained using a desensitizing compound having a cathodic polarographic half wave potential (Ered) value of at least 1 .0 volt which is represented by the following general formula (X).
• R stands for alkyl (e.g., having 1 to 8 carbon atoms) or allyl Z, X and In each has the same meaning as defined for general formula (1), and a is l or 2.
• R examples include, for instance, a methyl, ethyl, butyl, hydroxyalkyl (e.g., hydroxyethyl), carboxyalkyl (e.g., carboxymethyl, 3-carboxypropyl) or sulfoalkyl group (e.g., 2-sulfoethyl) and the like.
• hydroxyalkyl e.g., hydroxyethyl
• carboxyalkyl e.g., carboxymethyl, 3-carboxypropyl
• sulfoalkyl group e.g., 2-sulfoethyl
• Organic desensitizers used in this invention include, as typical examples, phenosafranine, pinacryptol yellow, S-m-nitrobenzilidene rhodanine, 3-ethyl-5-mnitrobenzylidene rhodanine, 3-ethyl-5-m-(2,4-dinitrobcnzylidene)rhodanine, S-o-nitrobenzylidene 3- phenyl rhodanine, l',3-diethyl-6-nitrothia-2'-cyanine iodide, 4-nitro-6-chlorobenzotriazole, 3,3-diethyl-6,6'-dinitro-9-phenylthiacarbocyanine iodide, 2-(p-dimethylaminophenyliminomethyl)- benzothiazole ethoetliyl sulfate, crystal violet, 3,3- diethyl-6,6'-dinitrothiacarb
• the silver halide emulsion to be used in this invention includes, for example, emulsions of silver chloride, silver bromide, silver chlorobromide, silver iodochloride, silver iodochlorobromide and the like.
• sivler halide will be present at a level of from 1:2 to 2:1 by weight to the binder.
• the grain size of such silver halides can be as are commonly used in the direct positive emulsion art, butespecially good results are obtained when the average particle size is included within the range of from 0.05 p. to 1.0 lL.
• the silver halide particles may be either reg ular or irregular, but most advantageous results are obtained when regular particles are employed.
• Either single dispersion type emulsions or non-single dispersion type emulsions may be used in this invention, but the use of the former is preferred.
• an original emulsion to be used as a silver halide photosensitive material for direct positive use can be classified into one of the following two groups.
• the first group of emulsions includes those having nuclei which can trap free electron in the interior of the silver halide crystal, the surface of which has been chemically fogged.
• the feature of this type emulsion resides in that it directly forms positive images by itself and is sensitized at its intrinsic absorption zone as well as having high sensitization by the spectral sensitization action due to the addition of a sensitizing dye.
• the halogen composition of the silver halide should be such as to ensure easy combination between the interior of the silver halide and the chemical sensitizer or Group VIII metal salt employed for providing free electron trapping nuclei.
• the addition of the organic desensitizer serves to improve the degree of removal of highlights, especially for the prevention of re-reversal.
• the addition of bromine ions or iodine ions e.g., of about 0.01 to 0.2 mole per mole of silver facilitates an increase in maximum density, in sensitivity and improve in highlight removal.
• the type of original emulsion includes those which have no electron trapping nuclei inside the silver halide grains, the surface of the silver halide grains thereof having been chemically fogged.
• This type of emulsion is a silver halide emulsion consisting of regular crystals, preferably of pure silver bromide, having no twin crystal plane and being as free of crystal defects as is possible.
• This emulsion yields no direct positive image by itself. However, a direct positive image of high sensitivity can be obtained after an organic desensitizer has been adsorbed thereon.
• the compound represented by the general formula (I) effectively sensitizes 19 either one of the above two types of original emulsions.
• the silver halide emulsions used in this invention are fogged by light or by a chemical treatment. Chemically fogged nuclei are formed by the addition reducing organic compounds such as, for example, hydrazine derivatives such as NH NH HCl or formaldehyde, thiourea dioxide, pounds, amine boranes, methyl dichlorosilane, etc.
• fogged nuclei which involve the use of a reducing agent in combinationwith metallic ions nobler than silver (e.g., gold ions, platinum ions, iridium ions, etc.) and further combinations of the reducing agent and the metallic ion with halogen ions.
• metallic ions nobler than silver e.g., gold ions, platinum ions, iridium ions, etc.
• the emulsion used in this invention mainly comprises gelatin as its protective colloid, and the use ofinert gelatin is especially advantageous.
• gelatin can be replaced withdiagally inert gelatin derivatives, water-soluble synthetic polymers (e.g., polyvinyl acrylate, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl alginate, carboxymethyl cellulose, hydroxymethyl cellulose, etc.
• water-soluble synthetic polymers e.g., polyvinyl acrylate, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl alginate, carboxymethyl cellulose, hydroxymethyl cellulose, etc.
• the silver halide emulsion for direct positive use ofthis invention may further contain a variety of other additives commonly used in direct positive emulsions, e.g., a stabilizer for fogged nuclei (e.g., mercapto compounds, thione compounds, tetrazaindene type compounds etc.), highlight permeability improvers (e.g., stilbene type compounds, triazine type compounds ets.), optical brightening agents, ultraviolet absorbants, hardeners (e.g., chrome alum, aziridine compounds, epoxy-type compounds, mucohalogenic acid type compounds (halogen formyl, maleie acid type compounds ets.), coating aid (e.g., sodium polyalkylene sulfonate, saponin, anionic surface active agents having a betaine structure, antiseptic agents, plasticizers (e.g., polyalkyl acrylates, vinylic compounds such as a copolymer of an alkyl acrylate with acrylic acid,
• the amount of the dimethine dye or dyes used in this invention can not be generally defined since it depends upon the content of silver halide in the emulsion and upon the degree of surface area of the silver halide grain. However, the use of the dimethine dye in an amount ranging from 1 X to 2 X 10 mol per mol of silver gives particularly good results.
• These dyes can be added as a solution in a Watermiscible solvent such as methanol, ethanol, ethylene glycol monomethyl ether, methyl ethyl ketone, acetone, pyridine. etc.
• a Watermiscible solvent such as methanol, ethanol, ethylene glycol monomethyl ether, methyl ethyl ketone, acetone, pyridine. etc.
• the dissolution of the dye can be facilitated by the application of ultrasonic vibrations.
• the addition of the dye to the emulsion is conveniently carried out directly before coating, it may be effected during chemical ripening of and/or the formation of precipitates of the silver halide.
• the amount of organic desensitizer or desensitizers cannot generally be defined since it varies depending upon the type of organic desensitizer used, but it is preferably in an amount ranging from 2 X 10 to 10 mol per mol of silver halide.
• the emulsion of this invention can be applied any desired votally compatible support material to thereby produce a variety of photographic elements.
• the emulsion can be applied to one or both sides of the support which can be transparent or opaque.
• Typical supports used include cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film and the other polyester films in addition to glass, paper, metal, wood, etc. Plastic resin laminated paper can also be employed.
• the emulsion of this invention is suitably treated after exposure by known procedures for direct positive emulsions by treating it in a developing bath, fixing bath, stabilizing bath and the like baths, or at least one bath which combines such treatments.
• the primary characteristic feature of this invention resides in sensitizing silver halide emulsions for direct positive use by employing a cyanine dye having a pyrazolo[5,l-b]quinazolone nucleus.
• a cyanine dye having a pyrazolo[5,l-b]quinazolone nucleus The use of alkylated derivatives gives particularly high sensitivity.
• the third characteristic feature of this invention resides in that the cyanine dye containing pyrazolo[5,lblquinazolone nucleus exhibits a superior effect of not lowering the maximum density of the silver halide cramp emulsion.
• the fourth characteristic feature of this invention resides in that substantially no reduction in maximum density during storage of the silver halide emulsion for direct positive use takes place.
• novel dimethine dye or dyes used in this invention not only have a number of outstanding characteristic features as mentioned above, but also enable an increase in the reversal sensitivity and high light permeability to be obtained by used in combination with the organic desensitizer.
• the silver halide emulsions for direct positive use of this invention are not further only useful for exposure with visibles light but also useful for irradiation with electron rays, X-rays, 'y-rays, etc.
• the dye used in this invention can also be used for other photographic puroses, such as, for example, as a 'filter dye, irradiation inhibiting dye, antihalation dye,
• the second and the third solutions were added at 60C to the first solution over a period of 50 minutes and the mixture subjected to physical ripening by standing at 60C for an additional 5 minutes. After the resultant solution was combined with cc of a 0.2 N solution of potassium iodide, the pAg was adjusted to 6.0 by adding a silver nitrate solution.
• Hydrazine generally 1.5 cc of 0.1% solution per Kg of emulsion
• gold chloride generally 1 cc of 0.1% solution per Kg of emulsion
• the forth solution was added to form an original emulsion which contained silver halide grains having an average particle size of approximately 0.2 ,u. with a normal tetragonal system with a (100 face.
• Each sample film was wedge-exposed to light from a tungsten lamp (2,854K) (1.000 lux, 10 sec.) and developed at 20C for 2 minutes with a developer liquid having the following recipe, fixed with an acidic hard film fixed and dried.
• the results of measurement on sensitivity, maximum optical density (Dmax) and minimum optical density (Dmin) of each sampale are given in Table l.
• the sensitivity is shown by the relative value of the reciprocal of the exposure dosage required for obtaining a density of (Dmax Dmin)/2.
• composition was diluted with water at a ratio of 1:1.
• a first solution prepared by dissolving 10 g inactive gelatin. 5 cc of a 1N aqueous solution of sodium chloride and 500 cc of water by heating at 60C, there were added under stirring at 60C a second solution (prepared by adding 500 cc of water to 100 g of silver nitrate followed by heating at 60C) and a third solution (prepared by adding 300 cc of water to 35 g of sodium chloride followed by heating at 60C for dissolution) over a period of 20 minutes.
• the resultant solution was ripened for 5 minutes by standing at 60C and thereafter a fourth solution (prepared by adding 200 cc of water to 14 g of potassium bromide followed by heating at 60C for dissolution) was added over 5 minutes while stirring. After ripening for 10 minutes by standing at 60C, the mixture was cooled, rinsed with water and heated again to effect dissolution. Then hydrazine and gold chloride (as described in Example 1) were added after the pH had been adjusted at 10, and the mixture was ripened at 60C for another 10 minutes followed by the adjustment of the pH thereof to 6.5 by the addition of citric acid. To this mixture. a fifth solution (prepared by dissolving g of inert gelatin in 300 cc water) at 60C was admixed to obtain original emulsion.
• the average particle size of the silver halide grains thus obtained was approximately 0.15 it.
• 32 cc of a 5 X 10 mol per liter solution in methanol of pinaryptol yellow was added, and then a methanol solution ofa dye as shown in Table 2 added thereto.
• the resultant mixtures were further combined with a suitable amount of mucochlorie acid (20 to 30 ml of 2% solution per Kg of emulsion) and saponine (20 ml of 1% solution per Kgof emulsion), and the emulsions so formed applied onto individual cellulose triacetate films at a dried thickness of about 2 ,u to thereby give sample photosensitive films.
• Each sample film was wedge-exposed to light from a tungsten lamp (2,854K) (1,000 lux. 10 sec.) and developed at C for 3 minutes with a developer liquid having the following recipe and, thereafter fixed with an acidic hard film fixer and dried.
• composition of the developer liquid is composition of the developer liquid
• Composition of the developer liquid Water (about 30C) Anhydrous sodium sulfite Paraformaldehyde Sodium bisulfite Hydroquinone Potassium bromide Water to make The dcnsitometry of the developed sample using a dcnsitometer manufactured by Fuji Photo Film Co., Ltd. yielded the characteristic curve thereof.
• the re- .sults obtained after measuring sensitivity, Dmax and Dmin as in Example 1 are given in Table 2.
• the silver halide emulsion for direct positive use of this invention has high sensitivity and Cmax and also exhibits good highlight permeability.
• a silver halide emulsion for direct positive use comprising fogged silver halide grains and containing at least one cyanine dye in which the 3-position carbon atom in the pyrazole [5. l-b] quinazolone nucleus thereof and the 1-, 2-, 3-, or 4-position of the cyanine heterocyclic nucleus thereof is directly linked or linked by way of a methine chain with 2 or 4 methine groups, with the proviso that the linking at the 4-position being only when the cyanine hetcrocyclic nucleus is a quinoline or u pyridine nucleus. and the linking at the land 3-position being only when the cyanine hcterocyclic nucleus is an isoquinoline nucleus.
• cyanine heterocyclic nucleus is a benzoxalzole nucleus, a benzothiazole nucleus, a benzoselenazole nucleus, an indolenine nucleus, a thiazoline nucleus or an imidazo [4,5-b]quinoxalinenucleus.
• R is an alkyl group or an allyl group
• Z is an atomic group forming a cyanine heterocyclic nucleus.
• X is an acid anion
• m is l or 2 and a is a l or 2.
• R, and R each represents an alkyl group. a hydroxy alkyl group, an acetoxyalkyl group, an alkoxyalkyl group, a carboxyalkyl group, an alkoxycarbonylalkyl group, a sulfoalkyl group, a aralkyl group, a sulfoaralkyl group, a carboxyaralkyl group or a vinyl methyl group;
• R represents a hydrogen atom, an alkyl group, an alkoxyl group, a carboxyl group, an alkoxycarbonyl group, a hydroxyl group or an aryl group; wherein R is a hydrogen atom an alkyl group, a cycloalkyl group or an aryl group; wherein L and L each represents a methine chain; wherein Z represents the atoms necessary to form a cyanine heterocyelic nucleus;
• R represents a halogen atom
• an alkyl X is an acid anion
• a silver halide photographic material for direct group, an alkoxycarbonyl group, an amino group, positive use comprising a support having thereon the a nitro group, a phcnoxy group, an alkylamino silver halide emulsion of claim 1. group, or a sulfonic acid group; wherein n is (l or 1. m is l or 2, and p is l, 2, 3 or 4;

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• 1972
  • 1972-07-14 JP JP47070499A patent/JPS5222243B2/ja not_active Expired
• 1973
  • 1973-07-13 DE DE2335748A patent/DE2335748C2/de not_active Expired
  • 1973-07-13 GB GB3362873A patent/GB1408529A/en not_active Expired
  • 1973-07-13 FR FR7325716A patent/FR2193215B1/fr not_active Expired
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