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
  • G03C1/28—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

• spectral sensitizing is one of the techniques for producing silver halide photographic-emulsions.
• the spectral sensitivity obtained is largely influenced by the chemical structure of the sensitizing dyes used, the halogen composition of the silver halide contained in the emulsion, the crystalline system thereof, the extent of the chemical sensitization, the method of the chemical sensitization, the pAg of the emulsion, the pH thereof, the kind of binder contained in the emulsion, the kind and properties of of antifoggants properties of the wetting agents emand properties of hardening agent present, the kinds and played, and the kinds present.
• sensitizing dyes are known to impart higher sensitivity when they are used together with other dyes or colorless aromatic compounds having specific chemical structures, as compared with using these dyes individually. This is known as supersensitization. Combinations of compounds which provide supersensitization are required to be very rigidly selected. Thus, it is important to the spectral-sensitizing technique to find combinations of compounds which will coact to provide supersensitization.
• Spectral sensitization for the green-sensitive region corresponding to a spectral region of high visual sensitivity is most important for the color reproduction of a color photographic light-sensitive material and the quality of the color image formed thereon.
• spectral sensitization of the green-sensitive region there is described, e.g., in US.
• 4936/68 is accompanied by the disadvantage that, although it may provide a high spectral sensitivity in the green region, contamination with dye remaining after the development procedure (hereinafter called "color stain) is large. Further, the latter method is accompanied by another disadvantage, in that the sensitivity in the region from 500 to 530 m,u., which is a portion of the shorter wave length, green region, is relatively low. 7
• an object of the present invention is to provide a green-sensitive photographic silver halide emulsion which is not reduced in sensitivity when used in the presence ofa color coupler, which provides a uniformly high spectral sensitivity over the region from 480 to 580 mp., and which further imparts no color stain after the development procedure.
• Another object of the present invention is to provide a color photographic light-sensitive material having, on a support, at least one layer of the aforesaid photographic silver halide emulsion.
• benzimidazolocarbocyanine dyes represented by the formula the above-mentioned objects Ill Emmi a wherein 2;, represents nonmetallic atoms necessary to complete the quinoline nucleus; Y represents a sulfur atom or a selenium atomyR and R each represents an alkyl group or a substituted alkyl group, at least one of said groups R, and R being a sulfo-substituted alkyl group or a carboxy-substituted alkyl group; A represents a hydrogen atom, an alkyl group having one to four carbon atoms, or a' halogen atom; X represents an anion; and q is l or 2.
• sulfa-substituted alkyl group represented by R, or R, in formula I there may be exemplified B-sulfoethylfiy-suly-hydroxy-l-sulfopropyl, 2-(3-sulfoprop0xy)ethyl, 2-[(3-sulfopropoxy)ethoxy]ethyl and the like.
• carboxy-substituted alkyl group represented by R or R there may be exemplified B-carboxyethyl, B-carboxypropyl, 2-(2-carboxyethoxy)ethyl and the like.
• alkyl groups represented by R and R there may be exemplified methyl, ethyl, n-propyl and the like.
• substituted-alkyl group there may be exemplified, besides the aforesaid sulfo-substituted alkyl group and the carboxy-substituted alkyl group, B-hydroxyethyl, B-acetoxyethyl and the like.
• alkyl group and the substituted alkyl group represented by R, and R in formula 1 there may be exemplified methyl, ethyl, n-propyl, B-acetoxyethyl, and an alkyl group.
• Z and Z of the formula represent the atoms necessary to complete the benzimidazole nucleus, as mentioned before, and the benzimidazole nucleus may be halogen, cyano, trifluoromethyl, alkyl-aminosulfonyl, or acetyl-substituted.
• the alkyl group or substituted alkyl group represented by R or R in formula II are as set forth above in connection with R and R,,. At least one of R and R is a substituted alkyl group having either a sulfo group or a carboxyl group as set forth above in connection with R; and R,,. Z; in formula II represents the nonmetallic atoms necessary to complete a quinoline nucleus, as mentioned above, and the quinoline nucleus may be substituted by a methyl group, an ethyl group, a hydroxyl group, an alkoxyl group or a halogen atom.
• X, and X, in general formulas l and II, respectively, are an anion, such as, a bromine ion, an iodine ion, a thiocyanate ion, an alkylsulfate ion, a perchlorate ion, and a p-toluenesulfonate ion. Also, the case wherein p is l and q is 1 in these formulas represents the formation of an intramolecular salt.
• R, in general formula III is the alkyl group or the substituted alkyl group as set forth in connection with groups R; and R, in general formula 1.
• substituent for the substituted phenyl group shown by group 2 there may be illustrated an alkyl group such as a methyl group, an ethyl group, or a propyl group; and alkoxyl group such as a methoxy group or an ethoxy group; and a halogen atom such as a chlorine atom or bromine atom.
• the feature of the sensitizing dye represented by general formula I is that at least one of R and R is a sulfo-substituted alkyl group or a carboxy substituted alkyl group as mentioned above, which renders the dye reactive for supersensitization by the sensitizing dye represented by general formula ll as well as for supersensitization by the compound represented by general formula III.
• the feature of the sensitizing dye represented by general formula ll is that the benzothiazole or the benzoselenazole nucleus has a hydroxyl group at the 5- position thereof and also at least one of R and R is a sulfosubstituted alkyl group or a carboxyl substituted alkyl group. Most preferably, R is a sulfo-substituted alkyl group.
• Sensitizing dyes wherein the benzothiazole or the benzoselenazole nucleus has a hydroxyl group at the 6-position have the drawback that the dye has high desensitizing properties and such dyes tend to form fog upon development. Also, sensitizing dyes having a hydroxyl group on the quinoline nucleus have the disadvantage that such dyes are weak in supersensitizing properties.
• the sensitizing dye have a hydroxyl group at the 5-position of the benzothiazole or benzoselenazole nucleus.
• pseudocyanine dyes having a phenyl group at the 5-position have very weak supersensitizing action to the sensitizing dye represented by general formula I and form severe fog.
• pseudocyanine dyes having a hydroxyl group at the 5-position provide a strong supersensitizing action.
• the pseudocyanine dye represented by general formula II and used in the present invention has a sulfo-alkyl or a carboxy-alkyl group and also has a hydroxyl group at the 5- position of the benzothiazole or benzoselenazole nucleus, photographic light-sensitive material having a photographic silver halide emulsion layer containing the dye gives less color stain after development. Also, in the case of using the aforesaid pseudocyanine dye, the reduction in spectrally sensitized sensitivity caused by the use of a color coupler is considerably less.
• the use of said pseudocyanine dye is accompanied with the disadvantage that the dye is diffused into adjacent emulsion layers to spectrally sensitize said emulsion layers owing to the poor adsorption power of the dye to silver halide.
• the pseudocyanine dye mentioned above is used together with the sensitizing dye represented by general formula I, the spectrally sensitized sensitivity obtained by supersensitization is markedly increased, the harmful reduction of sensitivity caused by the presence of a color coupler together with the pseudocyanine dye can be completely prevented, and also the formation of color stain is reduced.
• the sensitivity in the spectrally sensitive region of from 500 to 530 mu obtained by the use of the combination of the sensitizing dye represented by general formula I and the sensitizing dye represented by general formula ll is higher than the sensitivity in that region obtained by the method disclosed in Japanese Pat. Publication No. 4936/68 mentioned above but, strictly speaking, is still not as great as desired.
• This difficulty can be overcome by further adding at least one compound represented by general formula III.
• the sensitizing dyes and, if necessary, the compound used in the present invention may be dissolved in a water-miscible organic solvent such as methanol, ethanol, alkalified ethanol, acidified methanol, acetone, or pyridine and they may be added to a photographic emulsion either as a mixture or separately.
• a water-miscible organic solvent such as methanol, ethanol, alkalified ethanol, acidified methanol, acetone, or pyridine and they may be added to a photographic emulsion either as a mixture or separately.
• the amount of the additive is varied according to the kind of the silver halide emulsion to be employed but is preferably from 1Xl0'6 mole to 1X 104 mole per g. of the silver halide emulsion.
• the order of addition of these additives and the proportions may be varied according to the intended purpose.
• the ratio of the cyanine dye represented by general formula II to the cyanine dye represented by the general formula I may be from one-tenth to 10
• the ratio of the cyanine dye represented by the general formula Ill to the cyanine dye represented by the general formula I may be from one-tenth to 10.
• the photographic silver halide emulsion used in the present invention there may be mentioned silver chloride emulsion, silver chlorobromide emulsion, silver bromide emulsion, silver iodobromide emulsion and the like.
• the photographic emulsion of this invention may further contain, aside from the sensitizing dyes of the present invention and, if necessary, the compound of general formula lll, such additives as a stabilizer, an antifoggant, a hardening agent, a wetting agent, a plasticizer, and the like.
• a magenta coupler may be incorporated in the silver halide emulsion containing the aforesaid additives.
• the photographic silver halide emulsion of this invention may be applied to a suitable support such as a cellulose derivative film, a baryta-coated paper, a glass plate, a polyethylene terephthalate film and the like.
• sensitizing dyes and the compound of formula 111 used in the present invention are shown below, although the invention is not limited only to those shown.
• sensitizing dyes represented by general formula I may be prepared by the methods described in, for instance, the specifications of U.S. Pat. No. 2,912,329 and Belgian Fat. Ni; 697,245.
• EXAMPLE i In abeaker was melted 100 g. of a conventionally prepared gelatino silver iodobrornide emulsion (Agl 6.0 mole percent) and, after adding to the emulsion a methanol solution of the sensitizing dye or methanol solutions of the sensitizing dyes,
• EXAMPLE 2' In a beaker was melted 100 g. of a conventionally prepared gelatino silver iodobromide emulsion (Agl 4.0 mole percent) and, after adding to the emulsion a methanol solution of the light Sensitive material' 5 sensitizin d e or methanol solutions of the sensitizin d es The film was cut into strips and the same strip was exposed g y g y o 1 shown in table 2, the system was st1rred for 15 m1nutes at 35 to yellow llght through Fu 1 Filter 012 (a yellow filter made by FM Photo Film co usin an ti 3] Wed 6 d C.
• a conventionally prepared gelatino silver iodobromide emulsion Al 4.0 mole percent
• the light-sensitive film was cut into strips and the sample the developer having the following composition.
• strip was subjected to a yellow exposure by means of a sensitometer.
• the sample thus exposed was subjected to a color Black and white developer development for 10 minutes at 20 C. in a color developer,
• a photographic silver halide emulsion comprising at least one cyanine dye represented by general formula] wherein Z and Z are each nonmetallic atoms necessary to complete the benzimidazole nucleus; R and R are each selected from the group consisting of an alkyl group, a substituted alkyl group and an allyl group; R and R. are each selected from the group consisting of an alkyl group and a substituted alkyl group, at least one of said groups R and R being eTtlTfi6ih the group coHsTst'iiig" '6?
• a color photographic light-sensitive material comprising a support and at least one layer of a photographic silver halide emulsion as set forth in claim 1.
• a photographic silver halide emulsion as set forth in claim 1 further comprising at least one compound represented by general formula III I h (III) wherein 2., represents nonmetallic atoms necessary to complete a benzimidazole nucleus; Z is selected from the group consisting of a phenyl group and a substituted phenyl group; and R is selected from the group consisting of an alkyl group and a substituted alkyl group.

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• 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)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)

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Citations (6)

• 1969
  • 1969-09-08 FR FR6930478A patent/FR2017640A1/fr not_active Withdrawn
  • 1969-09-09 GB GB44500/69A patent/GB1279493A/en not_active Expired
  • 1969-09-09 US US856487A patent/US3617294A/en not_active Expired - Lifetime

Patent Citations (6)

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