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
  • G03C1/09—Noble metals or mercury; Salts or compounds thereof; Sulfur, selenium or tellurium, or compounds thereof, e.g. for chemical sensitising

Definitions

• the present invention is concerned primarily with chemical sensitization apparently of the latter type.
• one object of our invention is to provide chemically sensitized emulsions of enhanced light sensitivity. Another object is to provide emulsions having sensitivity enhanced by the combined efiect of sulfur, gold and certain organic sulfide compounds. A further object is to provide the methods of augmenting emulsion sensitivity utilizing the novel combination of sensitizing agents. Another object is to provide photographic elements in which the novel emulsions are useful. Further objects of our invention will become apparent from consideration of the following description.
• the objects of our invention are accomplished by the incorporation into silver halide emulsions of a mixture of' (A) a sulfur-sensitizing agent such as disclosed in Sheppard U. S. Patents 1,574,944 granted March 2, 1926, and 1,623,499 granted April 5, 1927, e. g. thiourea, di-o-tolyl thiourea, allyl isothiocyanate, thiocarbanilide, sodium thiosulfate, thioacetamide and allyl thiourea, (B) a gold salt sensitizing agent such as disclosed in Waller 2 t and Dodd U. S. Patent 2,399,083 e. g.
• A a sulfur-sensitizing agent such as disclosed in Sheppard U. S. Patents 1,574,944 granted March 2, 1926, and 1,623,499 granted April 5, 1927, e. g. thiourea, di-o-tolyl
• gold chloride potassium chloroaurate or an alkali metal aurothiocyanate such as potassium aurothiocyanate
• an alkali metal aurothiocyanate such as potassium aurothiocyanate
• C either bis- (fi-aminoethyl) sulfide (NHzCH2CH2)2S and its watersoluble salts obtained from non-desensitizing acids such as the acetates, carbonates, sulfates and hydrochloride salts, or bis-(y-diethyl aminopropyl) disulfide at any stage in their preparation but preferably before digestion is complete.
• the quantity of sulfur, gold and organic sulfide sensitizing agents used in the emulsions is not especially critical and can be varied from the optimum amounts indicated in the following examples.
• the sensitizing agents are incorporated into the emulsions at any stage in their preparation but, preferably before digestion is complete. That is, the emulson can first be sensitized with a sulfur sensitizing agent and a gold salt sensitizing agent and then one of the organic sulfide sensitizing agents indicated, or the addition of the organic sulfide compound can be made prior to the'addition of p the gold salt sensitizing compound. However, it is preferred to partially digest the emulsion in the presence of the selected sulfur and gold sensitizing agents and to finish the emulsion by digesting it further after addition of the organic sulfide compound since the greatest One rather speed increases are obtained in this manner.
• Example 1 p A In a positive type of silver bromoiodide emulsion were incorporated 20 milligrams of allyl thiourea per mol of silver halide and 2 milligrams of potassium chloro aurate per mol of silver halide and the emulsion was digested for 61 minutes at 62 C. A sample of the emulsion was coated onto film base. i
• An emulsion was prepared as in B except using 600 milligrams of the sulfide per mol of silver'halide.
• Example 2 D To a fine-grained gelatino silver bromoiodide emulsion were added a sulfur sensitizer such as described above and a gold salt sensitizer such as described above. The emulsion was then digested to. optimum sensitivity and a sample coated on film.
• silver halide emulsions can be treated with the novel combination of sulfur, gold and organic sulfide sensitizing agents.
• the novel sensitizers may, in general, be employed in hydrophilic colloid emulsion vehicles; for example, gelatin, polyvinyl alcohol, partially hydrolyzed cellulose ester, such as cellulose acetate and copolymers of polyvinyl alcohol.
• the sensitizers are suitable 017 the well known types of silver chloride, silver bromide and silver iodide emulsions and emulsions containing mixtures of these halides, containing the usual emulsion addenda such as antifoggants, spreading agents, coupler compounds, etc.
• Such emulsions are suitable to use in forming single as well as multilayer film useful in color photography which customarily include on a support two or more emulsion layers sensitized to different regions of the visible spectrum and may or may not contain coupler compounds. According to our invention such color films carry at least one emulsion layer containing the mentioned combination of sensitizing agents.
• a light-sensitive photographic emulsion comprising silver halide sensitized with a sulfur sensitizing agent, a gold salt sensitizing agent and bis-(Y-diethylaminopropyl) disulfide.

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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 (5)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Cited By (2)

Citations (4)

• 0
  • BE BE523959D patent/BE523959A/xx unknown
• 1952
  • 1952-11-08 US US319618A patent/US2739060A/en not_active Expired - Lifetime
• 1953
  • 1953-11-05 FR FR64779D patent/FR64779E/fr not_active Expired
  • 1953-11-06 GB GB30698/53A patent/GB734472A/en not_active Expired
  • 1953-11-08 DE DEE8092A patent/DE960871C/de not_active Expired

Patent Citations (4)

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