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

• non-labile selenium compounds could not be eifectively employed in combination with noble metals in a sensitizing process for photographic systems. I have found, however, that non-labile selenium compounds can be activated by the process of this invention so that they become labile and, in combination with noble metals, give synergistic sensitization.
• the noble metal sensitizers useful in my invention include the well-known gold sensitizers and other noble metals such as palladium, platinum and any of those disclosed in Smith et al., U.S. Patent No. 2,448,060 issued August 31, 1948. Typical suitable gold sensitizers are described in Waller et al., U.S. Patent No. 2,399,083 issued April 23, 1946, and Damschroder et al., U.S. Patent 2,642,361 issued June 16, 1953.
• the concentration of noble metal sensitizer useful in my invention can be any amount suitable for the intended purpose. I have found, for example, that amounts varying from about 0.1 to about 10.0 milligrams of gold sensitizer per mole of silver halide are quite satisfactory although higher amounts can also be employed.
• the temperature and length of time for the heating steps in my novel sensitizing process can be considerably varied depending upon the particular photographic system, the concentration of the non-labile selenium compound, the concentration of the noble metal compound, etc. Generally, varying each heating step from about 55 C. to about C. for about 20 minutes to about minutes has been found to be satisfactory for silver halide emulsions.
• Vacuum deposited photographicsystems substantially free of conventional vehicles, binders or dispersing agents can also be sensitized in accordance with the invention by incorporating the sensitizers in a coatingor layer contiguous to the vacuum deposited light-sensitive material.
• Suitable vacuum deposited silver halide systems that can be sensitized in accordance with the invention are disclosed in Rasch et a1. application U.S. Serial No. 415,596 filed December 3, 1964; Rees application U.S. Serial No. 421,725 filed December 28, 1964; and Belgian Patent 639,020.
• the silver halide emulsion layer of a photographic element which can be sensitized according to the instant invention can contain any of the hydrophilic waterpermeable binding materials suitable for this purpose. Suitable materials include gelatin, colloidal albumin, polyvinyl compounds, cellulose derivatives, acrylamide polymers, etc. Mixtures of these binding agents can also be used.
• the binding agents for the emulsion layer of the photographic element can also contain dispersed polymerized vinyl compounds. Such compounds are disclosed, for example, in US.
• a medium-grain silver bromoiodide emulsion containing 3.4 mole percent iodide is prepared.
• a first portion of the emulsion is chemically sensitized by the addition of 2 mg. of potassium chloroaurate per silver mole, 50 mg. of sodium thiocyanate per silver mole and 8 mg. of sodium thiosulfate per silver mole.
• the emulsion is then heated for 10 minutes at C.
• This example shows the increase in sensitivity which is obtained by employing the process of the invention (compare the third portion with the fourth portion).
• no increase in sensitivity is obtained by adding conventional sulfur-and-gold-sensitizers in two steps (see first and second portions) or by adding labile selenium-and-gold sensitizers in two steps (see fifth and sixth portions).
• non-labile selenium compound is either potassium selenccyanate or selenous acid.
• noble metal I References Cited NORMAN G. TORCHIN, Primary Examiner.

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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 (10)

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Publications (1)

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Cited By (10)

Citations (2)

• 1967
  • 1967-01-03 US US606586A patent/US3408197A/en not_active Expired - Lifetime
• 1968
  • 1968-01-02 DE DE19681622266 patent/DE1622266A1/de active Pending

Patent Citations (2)

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