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

• Photographic fog is of two types: local and general. Local fog is formed by exposure of the film or plate at undesired points as by a light leak in the camera. General fog'is formed in a number of ways. It may be caused by the conditions under which the film or plate is stored, such as conditions of high temperature or humidity r unusually longtime of storage.
• the nature of the emulsion may also produce general jog as well as the conditions of development of the emulsion as by development for protracted periods of time or at temperatures above normal. We are primarily concerned with fog and sensitivity changes produced in films or plates on development after storage under adverse conditions of high temperature and humidity or both.
• a further object is to provide antifogging agents which stabilize the initial sensitivity of the emulsion.
• a still further object is to provide anti-fogging agents which improve the keeping of the emulsion. in tropical regions.
• a solution of palladium nitrate, Pd(NO3)2 when added in suitable concentration before coating to unsensitized or optically sensitized photographic emulsions does not afiect appreciably the sensitometric values for sensitivity and fog when measurements are made soon after coating.
• this compound does stabilize photographic speed and maintain fog at a low level.
• the preparation of silver halide emulsions involves three separate operations, (1) the emulsification and digestion-or ripening of the silver halide, (2) the freeing" of the emulsion from excess soluble salts usually by washing, (3) the second digestion or after-ripening to obtain in creased sensitivity (Mees, The Theory of the Photographic Process, 1942).
• the most useful concentration range of fog. inhibitor is from .260 to 3.90 gm. of fog inhibitor per kilogram of silver nitrate used in making the emulsion and converted to silver halide. This amount will vary,
• the anti-foggant and stabilizing action was determined by incubation of the emulsions under simulated tropical conditions and also by incubation in dry heat at F. for various lengths of time after six days to one month. The results of these aging tests are tabulated here and are compared with the initial speed, gamma and fog'.
• the compound of our invention is unique in that it represents one 'o'f the few'simple 'salts 'of metals of the platinum group which are effective in reducing fog.
• the Smith and :Trivelli U. S. applica-' tion Serial No. 792,843 filed concurrently herewith, now Patent .No. 2,472,626, Iissued June 7, 1949, another simple 'salt of the platinum group, ruthenium tri-chloride, 15 described and claimed.
• the fog inhibitor in use, is dissolved in water at a convenient concentration .and added to 58 melted gelatino-tsilver halide photographic emul' sion in quantities ranging up to about 3.90 gins; per kilogram of silver nitrate converted to :silver halide.
• the "emulsion is coatedon a suitable support, glass, filmr'or other, and dried in a'normal fashion.
• the fog-inhibiting agents which we have dein ordinary non-sensitized emulsions they may also be used in onth'ochromatlc, panchromatic, and X-ray emulsions. It used with sensitizing dyes, they may be "added to the emulsion before or after the dyes are added.
• Various silver salts may be used as the sensitive salt, such as silver bromide, silver iodide, .silver chloride and mixtures of these.
• the dispersing agents may be gelatin or other colloid such as .collodion, albumen, cellulose derivatives, or synthetic resins.
• a silver halide emulsion containing .palladium nitrate 1.
• a silver -halide emulsion layer containin from 0.26 to 3.9 grams of palladium nitrate per kilogram of silver nitrate used in making said emulsion and convertedto silver halide.

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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)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25158249

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (2)

• 1947
  • 1947-12-19 US US792844A patent/US2472627A/en not_active Expired - Lifetime
• 1948
  • 1948-12-17 FR FR977410D patent/FR977410A/fr not_active Expired
  • 1948-12-20 GB GB32864/48A patent/GB650655A/en not_active Expired

Patent Citations (2)

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