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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/388—Processes for the incorporation in the emulsion of substances liberating photographically active agents or colour-coupling substances; Solvents therefor

Definitions

• This invention relates to a method of incorporating photographic chemical compounds, particularly color couplers in hydrophilic colloids, and especially in lightsensitive silver halide gelatin photographic emulsions.
• Couplers also contain a salt-forming group, i.e., a carboxy or sulfo group which in the form of their alkali salts provides the couplers with watersoluble groups of hydrophilic character to permit their incorporation in aqueous gelatin silver halide emulsions.
• a salt-forming group i.e., a carboxy or sulfo group which in the form of their alkali salts provides the couplers with watersoluble groups of hydrophilic character to permit their incorporation in aqueous gelatin silver halide emulsions.
• hydrophilic and hydrophobic groups give these color formers a soap-like character.
• the incorporation into the emulsion of long chain high molecular weight couplers containing salt-forming groups poses a number of difficulties.
• the color formers are dissolved in a water, or water-alcohol solution, of an alkali metal hydroxide such as aqueous sodium hydroxide or alcoholic potassium hydroxide, and then added to the emulsions as a so-called coating final, as one of the last additives just prior to coating.
• a further object of this invention is to provide a method of incorporating in a hydrophilic photographic colloid, color formers which are stable to diffusion and have an acid group as a substituent.
• a further object of the invention involves the uniform distribution of a color former in a liquid photographic gelatin silver halide emulsion while insuring that the viscosity of said silver halide emulsion does not increase materially on holding.
• a still further object of this invention comprises a light-sensitive gelatin silver halide emulsion containing a color former uniformly distributed through the gel matrix without the use of an alkali metal hydroxide solvent.
• the color formers are dissolved in butyrolactone.
• the butyrolactone solution of the color former is then diluted with water which may also contain some other coating finals.
• the aqueous butyrolactone solution is then added directly to a melted gelatin silver halide emulsion with adequate stirring.
• the solution of the coupler in butyrolactone is first dissolved in an aqueous solution of a water-soluble colloid such as gelatin and the resulting mixture combined with a melted gelatin silver halide emulsion.
• butyrolactone employed va ies somewhat with different color formers. In general, amounts ranging from 2.5l0.0, and preferably 5.0 parts by weight of butyrolactone per 1.0 part by weight of color former have been found to be most satisfactory.
• the usual coating aids, stabilizers and wetting agents such as saponin and/or synthetic surfactants which. may be of the anionic, cationic, non-ionic or amphoteric type, are added prior to the addition of the color formers.
• wetting agents are those described in United States Patents 1,970,578, 2,118,059, 2,240,476 and 2,768,894.
• the color formers which have the strongest tendency to increase the viscosity on holding contain in their molecule, a benzimidazole nucleus which is substituted on the nitrogen atom in thel-position by an alkyl chain of at least 10 carbon atoms and substituted in the 5-position by a water solubilizing group, in which the benzimidazole nucleus is connected through its carbon atom in the 2- position to the residue of a color-forming residue which is reactive with the oxidation products of a primary amino developing agent and contains a reactive methylene or o) phenolic hydroxyl group.
• These color formers are characterized by the following general formula:
• R is a radical containing a reactive methylene, ethenol or phenolic hydroxyl group capable of reacting with the oxidation products or an aromatic amino developing agent to form an azomethine, indoaniline or phenazonium dyestuff
• R is an alkyl chain containing at least 10 carbon atoms, e.g., decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl and the like
• R is a water solubilizing group such as sulfo, carboxy and the like.
• color formers which contain a benzirnidazole nucleus as part of the molecule and which are capable of forming dye images upon development with a dialkylamino-aniline developing agent are illustrated by the following structural formulae:
• R is a hydroxy aromatic radical, such as substituted or unsubstituted hydroxynaphthyl, hydroxyphenyl and the like in which the hydroxy group is nucleary attached, and said radical being linked to the benzimidazole radical in an ortho-position to said hydroxy group;
• R is a phenyl radical;
• R is the grouping -NH--COCH A, in which A is an alkyloyl radical, e.g., acetyl, propionyl, butyryl and the like, and aroyl radical, e.g., benzoyl, naphthoyl and the like or a cyano or a carbethoxy group;
• n is 1 or 2 and R and R have the same values as above.
• Color formers substituted by a benzimidazole nucleus and capable of forming magenta phenazonium (azine) dye images upon development with t-riaminobenzene developers are described in United States Patent 2,486,440; color formers used with N,N-dialkylphenylenediamine developers are disclosed in United States Patent 2,701,766. They are characterized by the following general formula:
• R R and R have the same values as above;
• R is hydrogen, a carboxyalkyl, allyl or lower alkyl group; and
• R is an allyl, lower alkyl, aryl or heterocyclic group.
• the emulsion with the butyrolactone solvent was coated onto a base and dried. It gave a coating of even thickness and even maximum density after development.
• R is the residue of the color-forming molecule and contains a group selected from the class consisting of reactive methylene and phenolic hydroxy groups capable of reacting with the oxidation products of the primary amino developing agent;
• R is an aliphatic hydrocarbon radical containing at least 10 carbon atoms;
• R is a water solubilizing group and the carbon in the 2-position of said benzimidazole radical is linked to the residue of the color-forming molecule which contains a reactive group selected from the group consisting of methylene and phenolic hydroxy groups which comprises dissolving said color former in butyrolactone, diluting the color former solution thus obtained with an aqueous solution of a surface active agent and adding the resultant solution to a liquid gelatin silver halide emulsion prior to coating the latter upon a support.
• R is a hydroxy aromatic radical, the hydroxy group being nucleary attached and said radical being linked to the benzimidazole nucleus in an ort-ho position to said hydroxy group;
• R is an alkyl chain of at least 10 carbon atoms;
• R is a water solubilizing group;
• R is a phenylene radical;
• R is the group -NH-COCH A in which A is selected from the group consisting of alkyloyl, aroyl, cyano and carbethoxy groups;
• n is selected from the class consisting of 1 and 2;
• R is selected from the class consisting of hydrogen, carboxyalkyl, allyl and lower alkyl groups;
• R is selected from the class consisting of lower alkyl, allyl, aryl and heterocyclic groups; and
• X is a member selected from the class consisting of halogen and sulfo groups which comprise dissolving said color former in butyrolactone, diluti

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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Citations (6)

• 1963
  • 1963-03-11 US US264040A patent/US3316094A/en not_active Expired - Lifetime
• 1964
  • 1964-02-13 GB GB6069/64A patent/GB1045624A/en not_active Expired
  • 1964-02-20 DE DEG39901A patent/DE1258267B/de active Pending
  • 1964-03-09 BE BE644895D patent/BE644895A/xx unknown

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