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

• This invention relates to fog-inhibiting agents and stabilizers for photographic emulsions and to photographic emulsions containing them.
• 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 or unusually long time of storage. The nature of the emulsion may also produce chemical fog 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 concernel with fog and sensitivity changes in photographic films produced by storage under adverse conditions of temperature and humidity or for prolonged periods of time before exposure and development.
• General fog and, loss of sensitivity of the emulsion are especially likely to occur when the sensitive material is stored under conditions other than ideal, that is, under conditions of high temperature and humidity as in tropical regions.
• a further object is to provid 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.
• the object of our invention is to maintain the sensitivity and fog of silver halide emulsions at or close to initial optimum values under keeping conditions of high temperature and humidity.
• the fog inhibitors which we propose to use are added to the emulsion during the process of 2 manufacture to avoid loss of sensitivity and, to inhibit the growth of incubation or keeping fog with passage of time under non-ideal conditions of storage.
• a solution of ruthenium chloride when added in suitable concentration before coating to unsensitized or optically sensitized photographic emulsions does not appreciably affect 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 increased sensitivity.
• the most useful concentra tion 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, e. g. depending on the silver halide used.
• 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 120 F. for various lengths of time. The results of these aging tests are tabulated here and compare speed, gamma, and fog of the emulsions with and without the antifoggant and stabilizing compound. For the tests from which the following tabulation was made, was used a high-speed bromoiodide emulsion exposed on an Eastman type 118 sensitometer and developed for five minutes at 68 F. in a developer of the following composition:
• One of the chief advantages of our invention is the extent of stabilization action over a Wide range of climatic conditions.
• the fog-inhibiting compounds of the invention are unique in the respect that they represent a group of a very limited number of simple salts of metals of the platinum group which are eflective in inhibiting fog in photographic emulsion.
• Another compound of this limited group Pd(NO3)2 is disclosed in the copending U. S. application Serial No. 792,844, filed December 19, 1947, in the names of Smith and Stauffer, now Patent No. 2,472,627, issued June 7, 1949.
• the compounds when employed for use in emulsions are dissolved in water at a convenient concentration and added to a melted gelatino dye silver halide photographic emulsion in quantities ranging up to about 3.90 grams per kilogram of silver nitrate converted to silver halide.
• the emulsion is coated on a suitable support such as gla s, film, or other, and dried in the conventional manner.
• the fog-inhibiting agents which we have described may be used in various kinds of photographic emulsions. In addition to being useful in ordinary non-sensitized emulsions they may also be used in orthochromatic, panchromatic and X-ray emulsions. If 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,
• the dispersing agents may be gelatin or other colloid such as collodion, albumen, cellulose derivatives or synthetic resins.
• a silver halide emulsion containing ruthenium chloride 3.
• a silver halide emulsion containing ruthenium bromide 4.
• a silver halide emulsion containing ruthenium iodide 5.
• a light-sensitive photographic element comprising a silver halide emulsion layer and a col: loid layer contiguous to said silver halide emulsion layer, at least one of said layers containing a compound having the structure RuXz Where X is a halogen atom.

Landscapes

• 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)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25158245

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (2)

• 1947
  • 1947-12-19 US US792843A patent/US2472626A/en not_active Expired - Lifetime
• 1948
  • 1948-12-17 FR FR977409D patent/FR977409A/fr not_active Expired
  • 1948-12-20 GB GB31865/48A patent/GB650656A/en not_active Expired

Patent Citations (2)

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