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
• • 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
  • G03C1/07—Substances influencing grain growth during silver salt formation

Definitions

• This invention relates to photographic emulsions and more particularly to photographic emulsions, such as those of the gelatino-silverhalide type, of increased speed.
• Hypersensitized emulsions possess generally poor keeping qualities, while the method itself is highly impractical to carry out on a large scale.
• gelatino-silver-halide emulsions can be enhanced by means of an extended digestion or ripening.
• a treatment increases the fog.
• fog retardants in the emulsion during the aforesaid extended digestion.
• such a method does of low fog content and good keeping qualities.
• photographic silver halide emulsions various substances in order to enhance the sensitivity of the emulsions.
• thiocyanates have 5 been employed in photographic processes heretofore, but not in the same manner in which we employ them, nor for the same purpose.
• thiocyanates have been added to finished emulsions in fairly large quantities for the purpose of toning.
• print-out gelatinosilver-halide emulsions have been prepared by first making a solution of gelatin, water, citric acid and silver nitrate by heating the four substances together at 110 F. and then adding to such a solution another solution containing manganese chloride in quantity more than suflicient to precipitate all the silver in the first solution in the form of silver chloride.
• a solution of gold thiocyanate is then added to such a finished, but unwashed emulsion.
• the resulting emulsion is described as a self-toning emulsion.
• thiocyanates in photographic processes, we refer to the self-toning emulsions prepared by adding alkali. thiocyanates, gold chlorides and dyes, such as methyl violet or fuchsin, to finished gelatino-silver-halide emulsions.
• halide emulsions can be prepared according to the following fundamental steps:
• metal and/or ammonium thiocyanates in the emulsion during the preparation thereof, e. g. during precipitation, during the first digestion, or during melting out and the second digestion.
• the thiocyanates which we have found are most advantageously employed are the alkali metal thiocyanates, such as sodium or potassium thiocyanate for example, the alkaline earth metal thiocyanates, such as calcium thiocyanate for example, and ammonium thiocyanate.
• alkali metal thiocyanates such as sodium or potassium thiocyanate for example
• the alkaline earth metal thiocyanates such as calcium thiocyanate for example
• ammonium thiocyanate thiocyanates containing cations, which cations are known to have, in themselves, a deleterious effect on silver halide emulsions should 'be avoided. Otherwise, the beneficial eflects attained by our invention would be partially nullified by the deleterious action of the cation.
• the water-soluble thiocyanates are advantageously added to the emulsions in the form of their solutions in water, although they can be added in the solid form.
• the water insoluble thiocyanates. are advantageously added to the emulsions in the form of a colloidal dispersion in gelatin.
• the amount of thiocyanate which we incorporate in the emulsion can vary widely.
• we have employedan amount of thiocyanate equal to from about2 to about 15% by moles of the silver halide in the emulsion. Larger amounts of thiocyanate can be employed, particularly if the thiocyanate is added before washing. If the thiocyanate is not added until later in the preparation, e. g.
• thiocyanate is not added until the melting-out and second digestion step, we have found it advantageous to employ an amount of thiocyanate equal to not more than about 2% by moles of the silver halide in the emulsion. Likewise, if the emulsion is to be used unwashed, we have found it advantageous to employ not more than about 2% by moles of the" thiocyanates. Very small quantities of thiocyanate, of course, give rise to small benefits, about 0.05% being the lowest concentration at which practical benefits are obtained. If the thiocyanates are added during the first digestion and larger amounts than 2% are employed, the concentration decreases to from about 2 to 1% or less during washing.
• the thiocyanates are added following the first digestion and washing, but before the second digestion of the emulsion is complete, the thiocyanates are, of course, not removed by washing, so that in either case we obtain an emulsion containing the thiocyanates in a concentration equal to not more than from about 2 to 1% or less by moles of the silver halide in the emulsion.
• the emulsions which we obtain by our new process possess substantially uniformly increased sensitivity throughout the entire region of sensitivity. If we add spectrally (optically) sensitizing dyes to our new emulsions, the regions of extra sensitivity are likewise possessed of substantially uniformly increased sensitivity. It is to be noted that we cannot attain our new emulsions of substantially uniformly increased speedby merely incorporating thiocyanates in finished gelatino-silver-halide emulsions, although emulsions prepared by incorporating such thiocyanates in finished emulsions together with sensitizing dyes are useful.
• the sensitizing dyes are supersensltized in a novel and useful manner by incorporating such thiocyanates in the finished sensitized emulsions in a concentration equal to not more than about three percent by moles of the silver halide in the emulsion. See also the copending application of John A. Leermakers, Serial No. 254,252, filed of even date herewith.
• the washed emulsion was heated to from 50 to 60 C. and further gelatin was added with stirring. After addition of the gelatin, the emulsion was held at a temperature of about 60 C. for about 40 minutes and finally was allowed to cool to about 40 C. when it was readyfor coating.
• sensitizing dyes of all types can be added to the emulsion prior to coating, if desired.
• EXAMPLE lA --Ordinary gelatino silver brom odiole emulsion p epared in the presence of sodium thiocyanate Three solutions, A, B and C, were prepared exactly as in Example 1, except that 4 g. of sodium thiocyanate were added to solution B. An emulsion was prepared from the three solutions precisely as in Example 1 EXAMPLE 1n.-Ordinary gelatino silver brominoliole emulsion prepared in the presence of ammonium thiocyanate Three solutions, A, B and C, were prepared exactly asin Example 1, except that 4 g. of ammonium thiocyanate were added to solution B. An emulsion was prepared from the three solutions precisely as in Example 1. v
• An emulsion was prepared from the above tw solutions as follows: P ecipitation-Solution A' was heated to about 60 C. and solution B, advantageously heated to from 50 to 60 C., was slowly added to solution A with stirring, maintaining the temperature of the mixture at 60 C. Silver chloride precipitated.
• EXAMPLE 2A Ordinary gelotino-siloer-chloride emulsion prepared in the presence of sodium thiocyanate Table II Emulsion of Example 2 Emulsion oi Example 2a H a D speed 0. 05s 27 G ii Still further examples of the preparation of our new emulsions could be given, but the foregoing are believed to demonstrate the manner of practicing our invention.
• Water-soluble thiocyanates are advantageously employed. When waterinsoluble thiocyanates are employed, they are advantageously incorporated in the emulsions during the melting out and second digestion step. A plurality of thiocyanates can be employed.
• Photographic elements comprising our new emulsions can be made up in the usual manner by coating the flowable emulsions on to a support of a suitable material, such as glass, photographic paper, cellulose derivative or resin for example, to the desired thickness,and then drying the coated emulsion.
• a suitable material such as glass, photographic paper, cellulose derivative or resin for example
• sensitizing dyes of all types can be employed to spectrally sensitize our new emulsions, e. g. erythrosin, Congo red, any of the sensitizing cyanine dyes, any of the sensitizing merocyanine dyes (see United States Patent 2,078,233, dated April 27, 1937, for example), any of the sensitizing hemicyanine dyes (see the copending application of Frank L. White and Graiton H. Keyes, Serial No. 138,634, filed April 23, 1937, for example) and any of the sensitizing hemioxonol dyes (see the copending application of Grafton H. Keyes, Serial No. 146,425, filed June 4, 1937, and the copending application of Leslie G. S. Brooker, Serial No. 101,105, filed September 16, 1936, for example).
• a photographic silver halide emulsion which has been subjected to a digestion step during the preparation of the emulsion, "containing a thiocyanate selected from the group consisting of metal and ammonium thiocyanates, said digestion having been conducted in the presence of said thiocyanate.
• a photographic .gelatino-silver-halide emulsion which has been subjected to a digestion step during the preparation of the emulsion contain ing a thiocyanate selected from the group consisting of metal and ammonium thiocyanates,
• a photographic gelatino-silver-halide emulsion which has been subjected to a digestion step 7 during the preparation of the emulsion containing, in a concentration equal to not more than about two percent by moles of the silver halide inthe emulsion, a thiocyanate selected from the group consisting of metal and ammonium thiocyanates, said digestion having been conducted in the presence of said thiocyanate.
• a photographic gelatino-silver-halide developing-out emulsion which has been subjected to a digestion step during the preparation of the emulsion containing a thiocyanate selected from the group consisting of metal and ammonium thiocyanates, said digestion having been conducted in the presence of said thiocyanate.
• a photographic gelatino-silver-halide developing-out emulsion which has been subjected to a digestion step during the preparation of the emulsion containing, in a concentration of from about 0.05 percent to about 2 percent by moles of the silver halide in the emulsion, a thiocyanate selected from the group consisting of metal and ammonium thiocyanates, said digestion having been conducted in the presence of said thiocyanate.
• a photographic gelatino-silver-halide developing-out emulsion which has been subjected to a digestion step during the preparation of the emulsion containing, in a concentration of from about 0.05 to about two percent by moles of the silver halide in the emulsion, an ammonium thiocyanate, said digestion having been conducted in the presence of said thiocyanate.
• a washed, finished photographic gelatinosilver-halide developing-out emulsion which has been subjected to a digestion step during the preparation of the emulsion containing, in a concentration equal to not more than about two percent by moles of the silver halide in the emulsion, a thiocyanate selected from the group consisting of metal and ammonium thiocyanates which do not contain a cation which has a deleterious effect on the emulsion, said digestion having been conducted in the presence of said thiocyanate.
• a washed, finished photographic gelatinosilver-halide emulsion which has been subjected to a digestion step during the preparation of the emulsion containing, in a concentration equal to from about 0.05 percent to about two percent by moles of the silver halide in the emulsion, a thiocyanate selected from the group consisting of metal and ammonium thiocyanates which do not contain a cation which has a deleterious effeet on the emulsion, said digestion having been conducted in the presence of said thiocyanate.
• a washed, finished photographic gelatinosilver-halide developing-out emulsion which has been subjected to a digestion step during the preparation of the emulsion containing, in a concentration equal to from about 0.05 to about two percent by moles of the silver halide in the emulsion, a thiocyanate selected from the group consisting of metal and ammonium thiocyanates which do not contain a cation having a deleterious effect on the emulsion, said digestion having been conducted in the presence of said thiocyanate.
• a photographic gelatino-silver-halide developi'ng-out emulsion which has been subjected to a digestion step during the preparation of the emulsion containing, in a concentration of from about 0.05 percent to about 2 percent by moles of the silver halide in the emulsion, an alkali metal thiocyanate, said digestion having been conducted in the presence of said thiocyanate.
• a photographic gelatino-silver-halide developing-out emulsion which has been subjected to a digestion step during the preparation of the to a digestion step during the preparation of the emulsion containing in a concentration of from about 0.05 to about two percent by moles of the silver halide in the emulsion, a thiocyanate selected from the group consisting of metal and ammonium thiocyanates which do not contain a cation which has a deleterious effect on the emulsion, said digestion having been conducted in the presence of said thiocyanate.

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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)
• Colloid Chemistry (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)

Priority Applications (10)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (8)

Cited By (22)

Families Citing this family (2)

• 0
  • NL NL62395D patent/NL62395C/xx active
  • BE BE437840D patent/BE437840A/xx unknown
• 1939
  • 1939-02-02 US US254267A patent/US2222264A/en not_active Expired - Lifetime
• 1940
  • 1940-01-27 FR FR868562D patent/FR868562A/fr not_active Expired
  • 1940-02-02 GB GB2059/40A patent/GB539355A/en not_active Expired
  • 1940-02-14 DE DEK156762D patent/DE736554C/de not_active Expired
  • 1940-02-15 DE DEK156776D patent/DE736692C/de not_active Expired
• 1946
  • 1946-05-15 CH CH254820D patent/CH254820A/fr unknown
  • 1946-05-15 CH CH251893D patent/CH251893A/fr unknown
• 1947
  • 1947-04-22 ES ES0177718A patent/ES177718A1/es not_active Expired

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