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
  • C09B23/02—Methine or polymethine dyes, e.g. cyanine dyes the polymethine chain containing an odd number of >CH- or >C[alkyl]- groups
  • C09B23/06—Methine or polymethine dyes, e.g. cyanine dyes the polymethine chain containing an odd number of >CH- or >C[alkyl]- groups three >CH- groups, e.g. carbocyanines
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/08—Sensitivity-increasing substances
  • G03C1/28—Sensitivity-increasing substances together with supersensitising substances
  • G03C1/29—Sensitivity-increasing substances together with supersensitising substances the supersensitising mixture being solely composed of dyes ; Combination of dyes, even if the supersensitising effect is not explicitly disclosed

Definitions

• This invention relates to the spectral sensitization of silver halide photographic emulsions and, more particularly, to silver halide photographic emulsions which have been super-sensitized by a combination of sensitizers of two dilferent types.
• it is concerned with silver halide photographic emulsions having high red sensitivities and spectral sensitization maxima within the region between 625m,u and 665 mp.
• sensitization of photo-sensitive materials in a desired spectral range of wave length may usually be attained by the use of a single sensitizing dye, in many cases there are used combinations of two or more sensitizers.
• the degree of spectral sensitization brought about by the use of a combination of two or more sensitizers is between those values achieved by the separate use of each sensititzer or even lower than that intermediate value.
• This phenomenon is usually referred to as super sensitization.
• the sensitized range of wave length occasionally lies in the middle of those values obtained by the use of the individual sensitizers alone.
• a combination of two or more sensitizers of different types is often used for either sensitization in a desired spectral wave length region as a means for obtaining a 3,705,809 Patented Dec 12, 1972 higher spectral sensititvity than that obtained by the individual use of the sensitizers or controlling the spectrally sensitized wave length region of the emulsion to a certain wave length region.
• This spectral wave length region is one which is ordinarily adopted in monochromoic photo-sensitive materials and in red-sensitive layers in color photosensitive materials.
• Z and Z which may be the same or different, each represents sulfur or selenium atoms;
• W and W which may be the same or different, each represents hydrogen or halogen atoms, or methyl, methoxy, an aryl group such as phenyl, or a hydroxyl group;
• R represents a methyl or ethyl group, wherein at least one of W and W is other than a hydrogen atom when R-, is a methyl group;
• R and R which may be the same or different, each represents a lower alkyl group such as methyl or ethyl, a substituted alkyl group such as 'y-sulfopropyl, 'y-sulfobutyl, 6-sulfobutyl, ,B-hydroxyethyl, fi-carboxyethyl or 'ycarboxypropyl, or an allyl group such as vinyl methyl;
• X represents an anion such as described in X of the Formula I
• the present inventors have found that a high red sensitivity is obtained by the use, in combination, of sensitizing dyes (I) and (II) to eifect an interactive remarkable super sensitization.
• the sensitizing dyes according to the present invention may be used in combination with other sensitizers having different spectral sensitization ranges, e.g., a sensitizer for enhancing green sensitivity such as pseudo-cyanin.
• sensitizing dyes used in the present invention are prepresented by the following formulae, but the present invention should not be limited to these merely illustrative compounds:
• sensitizing dyes (I) and (II) may be synthesized by known processes. For instance, synthesis may be attained without difficulty by referring to U.S. Pat. Nos. 2,503,776 and 2,647,051.
• sensitizing dye IC as listed above, is illustrated hereinafter as a representative example of a typical synthesis.
• a mixture of 1.5 g. of -phenyl-3-ethyl-2-thiopropionylmethylene-benzothiazoline and 1.5 g. of methyl paratoluenesulfonate is heated at 110 C. for 2 hours and, after cooling, the reaction mixture is washed with ethyl ether.
• the residue is crystallized by treatment with ethyl ether.
• the crystals are recovered by filtration, thoroughly washed with acetone and recrystallized from a methanol-chloroform mixture to obtain 1.1 g. of a dye having a M.P. of 287 C. and a mat.
• the other sensitizing dyes of the present invention may be synthesized by methods similar to that described above.
• the spectral sensitization process of the present invention is elfective for the spectral sensitization of gelatino silver halide emulsions.
• emulsions containing a synthetic or natural hydrophilic resinous material other than gelatin such as agar agar, Water-soluble cellulose derivatives, colloidion or polyvinyl alcohol, may also be sufficiently sensitized.
• the photographic emulsion suitable used in the present invention includes silver iodobromide, silver chlorobromide and like mixed silver halide emulsions.
• the spectrally sensitized photographic emulsion of the present invention may be prepared by incorporating the sensitizing dyes (I) and (II) in a photographic emulsion in a conventional manner.
• a solution of the dyes to an emulsion in a suitable solvent, such as methanol or ethanol.
• the molar ratio of sensitizing dye (I) to dye (II) may be varied in a wide range of from 9:1 to 1:9, according to the desired effects.
• each of dyes (I) and (II) may be added to each 1 kg. of emulsion.
• the photographic emulsion of the present invention may also be subjected to a hyper-sensitization by known processes.
• a sensitizer e.g., a stabilizer, a toner, a hardener, a surface active agent, an anti-fogging agent, a plasticizer, a developing promoter, a color developer and an optical whitening agent.
• a stabilitizer e.g., a stabilizer, a toner, a hardener, a surface active agent, an anti-fogging agent, a plasticizer, a developing promoter, a color developer and an optical whitening agent.
• the photographic emulsion of the present invention may be applied to a suitable support such as, e.g., sheet glass, a film of a cellulose derivative, a film of a synthetic resin or baryta paper in a conventional manner.
• a suitable support such as, e.g., sheet glass, a film of a cellulose derivative, a film of a synthetic resin or baryta paper in a conventional manner.
• R represents a hydrogen atom or a lower alkyl group
• W represents a hydrogen atom and W represents a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group, an aryl group or a hydroxyl group, or in combination W and W represent atomic groups necessary to complete a benzene ring
• R and R each represent an ethyl, n-propyl, -sulfopropyl, 'y-sulfobutyl, 6- sulfobutyl or vinylmethyl group
• R represents an ethyl or aryl group
• X represents an anion
• a photographic light-sensitive element comprising a support having thereon at least one layer containing the silver halide emulsion as claimed in claim 1.
• the silver halide photographic emulsion as claimed in claim 4 having a high red sensitivity in the spectrally sensitized wavelength region of from 625 m to 665 m wherein from 0.009 to 0.14 mol of each of the dyes of Formula I and II is added to 1 kg. of emulsion.
• the photographic light-sensitive element as claimed in claim 5 having a high red sensitivity in the spectrally sensitized wavelength region of from 625 mp. to 665 mp wherein from 0.009 to 0.14 mol of each of the dyes of Formula I and II is added to 1 kg. of emulsion.
• Z and Z are both sulfur or one of Z and Z is sulfur and the other is selenium, and wherein Z, and Z, are both sulfur or wherein Z and Z; are both selenium.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Organic Chemistry (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=13612251

Family Applications (1)

Country Status (7)

Cited By (3)

Families Citing this family (1)

• 0
  • BE BE756597D patent/BE756597A/xx unknown
• 1969
  • 1969-09-26 JP JP44076684A patent/JPS4827691B1/ja active Pending
• 1970
  • 1970-09-23 FR FR707034471A patent/FR2065711B1/fr not_active Expired
  • 1970-09-23 CA CA094,049A patent/CA983766A/en not_active Expired
  • 1970-09-25 DE DE2047306A patent/DE2047306C3/de not_active Expired
  • 1970-09-25 GB GB4587270A patent/GB1312105A/en not_active Expired
  • 1970-10-20 US US82537A patent/US3705809A/en not_active Expired - Lifetime

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