Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/08—Sensitivity-increasing substances
  • G03C1/10—Organic substances
  • G03C1/12—Methine and polymethine dyes
  • G03C1/14—Methine and polymethine dyes with an odd number of CH groups

Definitions

• ABSTRACT A radiation-sensitive silver halide photographic emulsion containing silver halide crystals whose mean grain size is not greater than 0.2 micron or at least 90% in number of which are not greater than 0.25 micron in grain size and at least one sensitizing base represented by the following general formula (1);
• the present invention relates to a radiationsensitized silver halide photographic emulsion and, more particularly, to a silver halide photographic emulsion containing fine-grained silver halide crystals sensitized with certain cyanine bases.
• Electron beam-recording enables one to record with high density, but in order to obtain an image of high quality, it is firstly necessary to minimize the grain size of the silver halide in the light-sensitive material as much as possible. However, a reduction in the grain size of the silver halide generally results in a reduction in the sensitivity to electrons. Therefore, a novel sensitizing method becomes necessary. Secondly, it is of importance to reduce the surface charge of the lightsensitive material irradiated with electrons to form a distinct image. For this purpose, it is necessary to raise the velocity of electron beam recording to reduce the amount of irradiation with electrons. From this viewpoint, a light-sensitive material having high sensitivity to electron beam is also required.
• Another object of the invention is to provide a highly radiation-sensitive photographic emulsion providing improved image quality.
• Another object of the invention is to provide a photographic emulsion having an extended light-sensitive wave-length region.
• Another object of the invention is to provide a silver halide photographic emulsion which solves the abovedescribed problems.
• the inventors havefound that when a silver halide photographic emulsion containing silver halide crystals whose mean grain size is not greater than 0.2 micron, or at least in number of which are not greater than 0.25 micron in grain size, is spectrally sensitized with a certain cyanine base, not only is the light-sensitive wave-length region extended, but also the sensitivity in the absorption wave-length region intrinsic to silver halide is remarkably enhanced, and that the sensitivity of a silver halide photographic emulsion to electrons can be markedly raised by incorporating one or more of such bases in the emulsion.
• the effect discovered in the present invention is absolutely different from the Capri blue effect in that even when a silver halide photographic emulsion containing silver halide crystals of a specific grain size is subjected to sulfur sensitization, reduction sensitization or gold sensitization, the light sensitivity of the emulsion in the absorption wave-length range intrinsic to silver halide can be simultaneously enhanced when the emulsion is spectrally sensitized with a cyanine base represented by the later described formula.
• benzimidazolocarbocyanines such as a halogen atom, (e.g., fluorine atom, chlorine atom, bromine atom, etc.), a trifluoromethyl group, an alkylsulfonyl group, wherein the alkyl moiety preferably has up to 4 carbon atoms (e.g., methylsulfonyl group), an aminosulfonyl group (e.g., sulfo- 1O nyl, methylaminosulfonyl, morpholinosulfonyl, pyrrolidinosulfonyl group, etc.), a cyano group, a carboxyl group, an alkoxycarbonyl group, wherein the alkyl moiety preferably has up to 3 carbon atoms (e.g., methoxycarbonyl, ethoxycarbonyl group, etc.), an acyl group (e.g., an aliphatic atom, e.
• the alkyl moiety preferably has up to 3 carbon atoms (e.g., beta-cyanoethyl, gamma-cyanopropyl, deltacyanobutyl, etc.), carbamoylalkyl, wherein the alkyl moiety preferably has up to 4 carbon atoms (e.g., betacarbamoylethyl, gamma-carbamoylpropyl, deltacarbamoylbutyl, beta-N-ethylcarbamoylethyl, gamma-N-ethylcarbamoylpropyl, delta-N-methylcarbamoylbutyl, etc.), sulfamoylalkyl wherein the alkyl moiety preferably has up to 4 carbon atoms (e.g., gamma-sulfamoylpropyl, delta-sulfamoylbutyl,
• Y represents an oxygen atom, a sulfur atom, a selenium atom or an N---R group and Y represents a sulfur atom, a selenium atom or an NR group, where R and R each represents an alkyl group (i.e.,
• n 1 or 2.
• R and R contains as a substituent a sulfo group or a carboxyl group, for example, a gamma- 1 .11 CH Crl Cl1 SO
• Y represents a sulfur atom or a NR group
• Z Z R R R and n each have the same meanings as defined in general formula (1).
• the sensitizing bases represented by general formula (I) can be synthesized by refluxing a compound repre- C C ⁇ (V) sented by the following general formula (IV) and a 2 1- 2 compound represented by the following general for- 50 mula (V) in alcohol in the presence of triethylamine according to a method described in the textbook by F. R M. Hamer (The Chemistry of Heterocyclic Com- 2 pounds: The Cyanine Dyes And Related Compounds, lnterscience Publishers): 55
• synthesis is under the following reaction conditions: molar ratio of reactants: stoichiometric amount; temperature: on a water bath; time: within 1 hour; pres sure: atmospheric; amount of alcohol: sufficient to dissolve reactants; triethylamine: as shown in the Synthesis example.
• the present invention not only is the lightsensitive wave-length region of a silver halide photographic emulsion extended, but the light sensitivity in the absorption wave-length region intrinsic to silver halides is remarkably enhanced as well.
• gelatino-silver halide photographic emulsion This effect is particularly conspicuous with a gelatino-silver halide photographic emulsion.
• the present invention is effective also in silver halide photographic emulsions containing other synthetic or natural hydrophilic high molecular weight polymer binders which do not harm photographic properties such as gelatin derivatives (e.g., acetylated gelatin, malonated gelatin, phthaloylated gelatin, etc.), a water-soluble cellulose derivative (e.g., hydroxyethyl cellulose, carboxymethyl cellulose, etc.) hydrophilic polymers (e.g., polyvinyl alcohol, polyvinyl pyrrolidone, polystyrene sulfonic acid, polyacrylamide) and the like.
• the ratio by weight of silver halide to hydrophilic binder is preferred to be within a range of from about A to about 4/1.
• the sensitizing effect in the absorption range intrinsic to silver halide in the invention depends greatly upon the grain size of the silver halide crystals used. That is, in silver halide photographic emulsions having the same halogen composition andd the same base, the effect varies depending upon the grain size of the silver halide crstals. In a silver halide photographic emulsion containing silver halide crystals whose mean grain size is greater than 0.2 micron, e.g., 0.6 micron, there is observed little or no sensitizing effect.
• the sensitization ratios are shown in terms of relative ratios based on the sensitivity value of a silver halide photographic emulsion containing no Base (5), which value is taken as l.
• the mean grain size can be determined in a Conventional manner, e.g., measuring the projected area as described in The Photographic Journal, vol. LXXIX, pp.330-338 (1939).
• the radiation-sensitive silver halide used in the invention can be any of silver chloride, silver bromide, silver chlorobromide, silver bromoiodide and silver chlorobromoiodide.
• an excellent effect is exhibited in the case of silver bromide and silver bromoiodide.
• one or several bases represented by the general formula (I) can be added in a conventional manner to a silver halide emulsion.
• the emulsion can be previously chemically sensitized in a conventional manner, such as by gold sensitization (e.g., see U.S. Pat. Nos. 2,540,085; 2,597,856; 2,597,9l5; 2,399,083, etc.) by Group VIII metal ion sensitization, sulfur sensitization (e.g., see U.S. Pat. Nos.
• the base(s) can be added to a silver halide photographic emulsion as a solution prepared by dissolving the bases in a suitable solvent such as methanol, ethanol, methyl cellosolve, etc.
• a suitable solvent such as methanol, ethanol, methyl cellosolve, etc.
• the amount of the base(s) incorporated can be varied over a wide range, for example, of from about 1X10 to about 1X10 mol/mol Ag.
• compositional bounds set out above are not mandatory in the present invention. However, as one begins to use much lower concentrations of the sensitizing dye the sensitizing effect gradually reduced. On the other hand, using greater amounts of sensitizing dye does not appreciably increase or conversely decreases the sensitizing effect and is economically wasteful.
• the silver halide photographic emulsion of the invention can further be supersensitized or hypersensitized.
• the sensitizing effect of the present invention can be obtained, in one embodiment, by adding the sensitizing base to a silver halide photographic emulsion prepared in a usual manner immediately before applying the emulsion to a support.
• similar effects can be obtained by adding the sensitizing base during physical ripening or chemical ripening, etc. There is no restriction as to the stage of the addition of the base.
• additives such as other chemical sensitizing agents, a stabilizer, an anti-fogging agent, a toning agent, a hardener, a surface active agent, a thickener, a plasticizer, a lubricant, a development accelerator, a color coupler, a brightening agent or the like can be added in a conventional manner and in conventional amounts.
• EXAMPLE 1 To g of a chemically repened gelatino silver bromoiodide Br: 99 mol I:1 mol emulsion (gelatino: silver halide 1:1 by weight) containing silver halide crystals of 0.07 micron or 0.6 micron (for comparison) in mean grain size (prepared in a known manner) were added, respectively, methanol solutions of bases in the amounts shown in Table 2. Chemical sensitization was performed with triethyl thiourea and potassium chloroaurate. mg. triethyl thiourea per mole of silver, 1 mg. potasium chloroaurate per mol of silver. 7 milliliters of the thus produced silver halide photographic emulsions were applied to cabinet-sized glass plates and dried to prepare samples.
• the photographic sensitivity is relatively Also, in the case of silver halide crystals of grains at shown by determining the irradiation amount required least 90% in number of which are not greater than 0.25 for the foog-free photographic density to go up to 0.5 micron in grain size, a markedly high sensitization ratio while taking the (sensitivity value of a sensitizing basewas similarly obtained. free emulsion as 100.
• Sensiti- Sensiti zation Mean zation Mean ratio grain ratio Sensi- Amount of grain (in the size (in the tizing mol of base added size jm i (for intrinsic base (mol of base (present absorp compaabsorp-.
• the photographic emulsions of the invention of fine grain size provide high image quality and have a high sensitivity to electrons beams without a substantial increase in fog. Therefore, it can be said that substantial technical progress has been attained by the present invention.
• Z and Z each represent the atoms necessary to form a benzene ring
• Y represents an oxygen atom, a sulfur atom, a selenium atom or a NR group
• Y represents a sulfur atom, a selenium atom or a N--R group
• R and R which may be the same or different each represents an alkyl group
• R represents a hydrogen atom or an alkyl group
• n represents 1 or 2
• Y represents a sulfur atom or N-R and Z Z R R R and n each have the following meaning: Z and Z each represent the atoms necessary to form a benzene ring; R and R which may be the same or different, each represents an alkyl groups, R represents a hydrogen atom or an alkyl group, and n represents l or 2.
• sensitizing base is selected from the class consisting of the following bases:
• An electron beam-sensitive photographic emulsion 8 The emulsion as claimed in claim 3 wherein the as claimed in claim 3 wherein the sensitizing base is seamount of base(s) is about 1X10 to about 1X10 lected from the class consisting of the following bases: mol/mol of silver in the emulsion.
• amount of base(s) is about 1X10 to about lXlO 11.
• emulsion comprises gelatin as a hydrophilic binder.
• Z, and Z each represent the atoms necessary to form a benzene ring wherein the Z benzene ring is unsubstituted or if substituted is substituted with halogen, trifluoromethyl, alkyl sulfonyl, where the alkyl moiety has up to 4 carbon atoms, aminosulfonyl, where the alkyl moiety has up to 4 carbon atoms, cyano carboxyl, alkoxycarbonyl, where the alkoxy moiety has up to 3 carbon atoms, acyl, or one or more thereof, and the Z benzene ring is unsubstituted or if substituted is substituted with an alkyl group of up to 4 carbon atoms, a halogen atom, an alkoxy group where the alkyl moiety has up to 3 carbon atoms, or one or more thereof, Y represents an oxygen atom, a sulfur atom, a selenium atom or a l IR group, R
• R represents an alkyl group of up to 4 carbon atoms.
• R represents an alkyl group with up to 4 carbon atoms.

Landscapes

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

Applications Claiming Priority (1)

Publications (1)

Family

ID=12476444

Family Applications (1)

Country Status (2)

Cited By (3)

Families Citing this family (1)

Citations (5)

• 1972
  • 1972-04-12 JP JP3667672A patent/JPS5434330B2/ja not_active Expired
• 1973
  • 1973-04-12 US US350579A patent/US3890155A/en not_active Expired - Lifetime

Patent Citations (5)

Also Published As

Similar Documents