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

Definitions

• alkali cyanides have been proposed, as ingredients for self-toning photographic emulsions.
• Alkali cyanides cannot be employed in practicing my invention, since they have a deleterious, rather than a beneficial eifect, on the sensitivity of the emulsions, probably owing to the solvent action of the alkali cyanides on the silver halides.
• I incorporate silver cyanide in unwashed or washed, finished silver halide emulsions, together with a sensitizing dye.
• My invention is particularly directed to washed
• the silver cyanide is advantageously incorporated in the emulsion in the form of a colloidal dispersiomi. e. dispersed in gelatin, gum arabic or other hydrophyllic colloid which is compatible with the emulsion and has substantially no del-
• the silver cyanide can be incorporated in the solid form, advantageously finely divided.
• the silver cyanide can be added to the'emulsion prior to, simultaneously with or after the addition of the sensitizing .dye.
• the amount of silver cyanide added should not be more than about three percent by moles of the silver halide in the emulsion. I have found that larger amounts, e. g.
• sensitizing dyes I employ; any of the known types and advantageously those which are not of a markedly acidic nature, i. e. those devoid of sulfonic acid (S0311), sulfinic acid (S0211), sulof dyes which aredevoid of the aforesaid aeidic groups and their metal or ammonium salt forms.
• a number of sensitizing 'cyanine dyes are, of
• the sensitizing dyes can be employed in various.
• the sensitivity conferred upon an emulsion by a sensitizing dye does not increase proportionately to the concentration of the dye in the'emulsion, but rather passes through a maximum as the concentration is increased.
• the dyes can be employed in the optimum concentration. or in concentrations greater or less than the optimum.
• the optimum concentration of a sensitizing dye can be determined in a manner well known in'the art by measuring the sensitivity of a series of emulsions containing different concentrations of the sensitizing dye. Ordinarily, the optimum or near optimum concentration is of the order of to mg. of the dye per liter of the emulsion.
• the sensitizing dyes are advantageously added u to the emulsion in the form of their solutions in suitable solvents.
• Methyl alcohol suffices as a solvent for most sensitizing dyes.
• Acetone is frequently a satisfactory solvent for those dyes having a very' limited solubility in methyl alcohol. Both the sensitizing dyes and the silver cyanide should be thoroughly dispersed throughout the emulsion.
• My invention is particularly directed to the ordinarily employed gelatino-silver-halide emulsions and more particularly to the gelatino-silver-halide emulsions in which the majority of the silver halide is silver bromide, such as the silver bromide and silver bromiodide emulsions customarily employed in the art.
• tin was prepared as follows: two solutions, A and B were prepared in the following manner:
• Solution A -Prepared by dissolving 200 g. of silver nitrate in 1000 cc. of water.
• Solution B -Prepared by dissolving 65 g. of sodium cyanide in 1000 cc. of water.
• Solution A was poured into solution B at about 25 C. After the precipitate settled, it was washed four or five times. with water by decantation. To the washed precipitate were added 60 cc. of 28% ammonium hydroxide. Tothe resulting paste were added 60 g. of gelatin dissolved in 3000 cc. of water at 50.. C. The resulting mixture was stirred vigorously'ior an of this time, 200 g. of dry gelatin were dissolved in the mixture at 50 C. The resulting dispersion was cooled until it set. ,I It was then shredded and washed with water for one-half hour.
• Silver cyanide can be incorporated in the finished emulsions, as illustrated in the foregoing example, together with other substances, e. g. silver thiocyanate, ammonium thiocyanates, alkali metal thiocyanates or alkaline earth metal Silver thiocyanate is advantageously added to emulsions in the form of a colloidal dispersion in a hydrophyllic colloid, while the water-soluble thiocyanates can be added in the form of their aqueous solutions. See my copending application Ser. No. 254,252 filed of even date herewith.
• Photographic elements comprising my new emulsions can bemade up in the usual manner by coating the fiowable emulsions on to a support of asuitable material, such as glass, photographic paper, cellulose derivatives or resins for example, to desired thickness, and then drying the emulsion,
• Gelatino-silver bro 3-ethyl-5-[(2-ethyl-l(2)-ben- 10 0.5 +80 +80 +80 0 miodide. zoxazylidene) ethylidene'] rhodanine. 4 Gelatino-silver bro- 2-[4-(l-pi eridyl)-A -buta- 20 0.5 +100 +80 +80 0 miodide. dienyl -fl-naphthothiazole ethiodide.
• A represents hydrogen or a Cal-lam group wherein n represents a positive integer not greater than five, Q 'and Q represent'oxygen or sulfur, R and R represent a" CnH2n+1' gI0up "wherein n represents a positive integer not greater than fiveX represents an acid radical, preferably halide, and wherein the nucleus Z may under V above.
• Q represents oxygen, sulfur or selenium
• R represents a CnH2n+l group wherein n represents a positive integer not greater than five
• X represents an acid radical, preferably halide
• the nucleus Z may carry simple substituents, such as chlorine atoms or alkyl groups, for example.
• Z represents the non-metallic atoms necessary to complete a rhodanine nucleus, a 3- alkyl-2,4(3,5) -oxazoledione nucleus, a 2-thiohydantoin nucleus, a 2-diphenylamino-'-4(5) -thiazolone nucleus or a L-benzothiazyl-Zi-methyl 5-pyrazo lone nucleus.
• R represents 'a CnHZn-l-l group wherein n represents a positive integer not greater than five, Q represents oxygen, sulfur or selenium and Z has the values set forth under VIII above and the nucleus Y may carry simple substituents, such as chlorine atoms or alkyl groups.
• I determine the sensitivity of emulsions in the usual manner, first coating the prepared emulsion on a glassplate to suitable thickness and drying the coated emulsion. The resulting photographic plateris thentested by means of a wedge spectrograph and a sensitometer, whereby spectral sensitivity and speed of the emulsion on the plate is determined.
• a photographic gelatino-silver-halide emulsion selected from the group consisting of gelatino-silver-bromide and gelatino-silver-bromiodide emulsion, containing a sensitizing dye for the emulsion and containing silver cyanide, said silver cyanide having been introduced into the finished emulsion in the form of the simple compound silver cyanide, in a concentration equal to not more than about three percent by moles of the silver halide in the emulsion.
• a photographic gelatino-silver-halide emulsion selected from the group consisting of gelatino-silver-bromide and gelatino-silVer-bromiodide emulsions containing a sensitizing dye for the emulsion and containing silver cyanide, said silver cyanide having been introduced into-the washed, finished emulsion in the form of the- 5.
• a photographic gelatino-silver-halide emulsion containing a sensitizing dye for the emulhemioxonol dyes which are devoid of sulfonic,
• silver cyanide having been introduced into the washed, finished emulsion in the form of the simple compound silver cyanide, in a concentration equal to not more than about three percent by moles of the silver halide in the emulsion.
• a photographic gelatino-silver-halide emulsion selected from the group consisting of gelatino-silver-bromide and gelatino-silver-bromiodide emulsions containing a sensitizing dye for the emulsion, said dye being selected from the group consisting of cyanine, merocyanine, hemicyanine and hemioxonol dyes which are devoid of sulfonic, sulfinic, sulfuric and carboxylic acid groups and the metal and ammonium salt forms of said acid groups, and containing silver cyanide, said silver cyanide having been introduced into the washed, finished emulsion in the form of the simple compound silver cyanide, in a concentration equal to not more than about three percent by moles of the silver halide in the emul- SlOIl.
• a photographic gelatino silver halide emulsion selected from the group consisting of gelatino-silver-bromide and gelatino-silver-bromiodide emulsions containing a sensitizing dye for the emulsion, said dye being selected from the group consisting of cyanine, merocyanine, hemicyanine and hemioxonol dyes which are devoid of sulfonic, sulfinic, sulfuric and carboXylic acid groups and the metal and ammonium salt forms of said acid groups, and containing silver cyanide, said silver cyanide having been introduced into the washed, finished emulsion in the form of the simple compound silver cyanide, in a concentration equal to from about 0.05 to about 3 per cent by moles of the silver'halide in the emulsion.
• a photographic gclatino silver halide emulsion selected from the group consisting of gelatino-silver-bromide and gel-atino-silver-bromiodide emulsions containing a sensitizing dye for the emulsion, said dye being selected from the group consisting of cyanine, merocyanine, hemicyanine, and hemioxonol dyes which are devoid of sulfonic, sulfinic, sulfuric and carbonylic acid groups and the metal and ammonium salt forms of said acid groups, and containing silver.
• silver cyanide said silver cyanide having been introduced into the washed, finished emulsion in the form of the simple compound silver cyanide, in a concentration equal to from about one-half to about two per cent by moles of the silver halide in the emulsion.

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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)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22963540

Family Applications (1)

Country Status (2)

• 0
  • FR FR963682D patent/FR963682A/fr not_active Expired
• 1939
  • 1939-02-02 US US254253A patent/US2222262A/en not_active Expired - Lifetime

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