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 sta-bilizationof ph'otographic emulsions which aresensiti'zed with gold compounds.
• photographic silver halide emulsions can be sensitized by digesting the emulsions in the presence of gold compounds.
• the gains in speed thus obtained are clearly of value, but it has been found that coatings of such emulsions on the usual supports tend to lose speed on keeping or storage.
• anobject of our invention to provide photographic emulsions sensitized with gold compounds, which emulsions haveimprov'ed resistance to loss of speed, i. e. sensitivity, on keeping or storage.
• a further object is to provide a p'ro'ce'ss for preparing suchimproved-emulsions.
• the usual procedure for preparing photographic silver halide developing-out emulsions, especially photographic gelatino-silver-halide developing-out emulsions comprises the following steps:
• Precipitation wherein the silver halide is precipitated by the interaction of a watersoluble silver salt and a water-soluble halide, in the presence of a carrier, e. g. gelatin.
• Digestion wherein the above precipitate is heated for a period of time at a raised temperature, e. g. 50 to 60 C.-, with or without the addition of further carrier, e. g. gelatin.
• Washing wherein the digested, solidified or set (e. g. by chilling) "emulsion is washed to remove soluble salts.
• the emulsion increases in sensitivity.
• various substances have been added at various'stages in the preparation of the emulsions. Usually the additions are made during one of the digestion periods.
• sulfur compounds i.'e. so-called sulfur sensitizers have been added, e. g. allyl isothiocyanate, thiourea, thiocarbanilide, etc.
• ammonium and/or metal thiocyanates for this purpose.
• gold compounds have been proposed for the same purpose. It is with these photographic silver halide emulsions which during their preparation have been sensitized by digestion in the presence of gold compounds with or without the additional presence of a sulfur sensitizer, that our invention is concerned.
• a photographic silver halide emulsion which during its preparation has been sensitized by digestion in the presence ofa-gold compound
• at least one water-insoluble gold compound which has a solubility in water not greater than the equivalent of 1.0 mg. of gold per ml. of water at 25 C.
• Gold compounds having a solubility in water as low as the equivalent of 0.03 mg. per i 100 ml. of water at 25 'C. can be employed, as can compounds of still lower solubility.
• Typical of the water-insoluble gold compounds are:
• the water-insoluble gold compounds can be added to the emulsions in the form of solutions in suitable solvents, e. g. acetone, methyl alcohol, acetic acid, pyridine, or as dispersions in colloids, such as gelatin, polyvinyl alcohol, partially hydrolyzed cellulose acetate, casein, etc., or without any solvent or colloid.
• suitable solvents e. g. acetone, methyl alcohol, acetic acid, pyridine
• dispersions in colloids such as gelatin, polyvinyl alcohol, partially hydrolyzed cellulose acetate, casein, etc., or without any solvent or colloid.
• the water-insoluble gold compounds should, of course, be thoroughly dispersed throughout the emulsions, e. g. by stirring.
• a concentration of the water-insoluble gold compound equivalent to from 2.5 to mg. of metallic gold per 1000 g. of silver nitrate used in preparing the emulsion is advantageous to employ.
• concentrations can be employed, e. g. a concentration equivalent to 1000 mg. of metallic gold per 1000 g. of silver nitrate used in preparing the emulsion.
• the water-insoluble gold compounds are advantageously added to the emulsions after final digestion, but prior to coating the emulsions on a support. at a pH of from 5 to 9, and most advantageously at a pH of from 6 to '7.
• EXAMPLE 1 A batch of gelatino-silver-bromoiodide emulsion was prepared as described by Trivelli and smith, Phot. J. 79, 330 (1939), using a precipitation time of 20 minutes (emulsion No. 11, page 330), except that just before the final digestion of the emulsion, potassium chloroaurate (KAuCh) in a concentration equivalent to 6.5 mg. of metallic gold per 1000 g. of silver nitrate employed in preparing the emulsion, thiosinamine in a, concentration of 50 mg. per 1000 g. of silver nitrate employed in preparing the emulsion, and sodium thiocyanate in a concentration of 1 g. per 1000 g.
• K chloroaurate K chloroaurate
• ace-mes 02 35 AuCh was addedto the same emulsion, in a concentration equivalent to 50mg. of gold, after final digestion but before coating the initial speed ('73') of theemulsion was reduced to only 47; after the same accelerated keeping treatment, as shown at 2.
• the initial speed of 71 was not reduced at all after the same keeping treatment, as shown at'3. Actually in this last instance, there was a gain rather than a loss in speed after the accelerated keeping treatment.
• EXAMPLE 11 A batch of gelatino-silver-bromoiodide emulsion was prepared as described. by Trivelli and Smith; Phot. J. 79, 330 (1939), using a precipitation time of about 20 minutes (emulsion No. 11,. pagev 330)., except. that just before the fin'al digestion. of the emulsion potassiumchloroaurate; and. sodium thiocyanate were-added to the: emulsion. in: they concentrations show-n- Example- 1. A- portionidf theemulsion was coated on cellulose acetate film and dried. Thefilm; was cutinto two portions and the one portion exposed-and developed in the routine manner shownt in Example '1' while the other portion: was
• EXAMPLE 2 S C-SAu 1% Ca Cl A solution containing 1 g. of auric chloride in cc. of 95% ethyl alcohol was added to 50 cc. of 95% ethyl alcohol containing 1.81 g. of 3-methy1- 2(3)-thiobenzothiazolone (prepared by heating 2 methylmercaptobenzothiazole metho-p-toluenesulfonate in boiling pyridine). The above formulated product separated as a white solid at once. The reaction mixture was stood at about C. for several hours and then chilled.
• the white solid was filtered from the chilled mixture and washed on the filter with 95% ethyl alcohol.
• the yield of colorless crystals was 98% crude, and 73% after one recrystallization from acetic acid.
• EXAMPLE 3 A solution containing 0.34 g. of auric chloride in 10 cc. of 95% ethyl alcohol was added to a solution containing 1.11 g. of 3-ethyl-5-[(3-ethyl- 2(3) -benzoxazolylidene) ethylidenel rhodanine in cc. of pyridine and 25 cc. of 95% ethyl alcohol. A reddish solid separated at once. The reaction mixture was stood at about 20 C. for several hours and then the solid was collected on a filter and Washed with 95% ethyl alcohol. The yield of product was 63% crude and 12% after two recrystallizations from nitromethane. The reddish crystals had melting point 231-232 C. with decomposition.
• our invention can be practiced on photographic silver halide emulsions which have been sensitized by digesting the emulsions in the presence of either water-soluble or water-insoluble goldcom ounds.
• S6I $i i a emulsionsfat least one water-soluble gold torn pound, .eQg. any of the water-soluble gold comset forth above, is added to the emulsion :prior to .or during the final digestion.
• the concentration of the gold compound is equivalent to from 2.5 to 1000 mg of gold per 1l00 g. of silver nitrate used in preparing the emulsion.
• a concentration of water-soluble gold compound equivalelllt P m 2 to 9 0f g l P 98??? of silver nitrate used in preparing the emulsion is employed.
• Advantag eously vthe level of pH during the e tion t e emulsion, in we P esen of e -wate -so a l eld mp un is "m inta n at or below 9, although this is not essential.
• Typical of such sulfur sensitizers are:
• Beneficial efiects are also obtained by digesting the emulsions which zaresensitized by dig estion in the presence of a waterr-solublegold compound, in theadditional presence.ofatleastone metal or ammonium thiocyanate, e. -g..alk ali metal thiocyanates ('e. 'g. sodium or potassium thiocyanate), alkaline earth metal thiocyanates (e. g. calcium, strontium .thiocyanate, etc), cad- .mium thiocyanate, ammonium thiocyanate, etc.
• 'thiocyanatescontaining cations. which cations are known to have, in themselves, .a'.
• iron thiocyanate which contains the iron cation should be avoided.
• One or more sulfur sensitizers or one or more thiocyanates selected from the group consisting of metal or ammonium thiocyanates can be employed.
• One or more sulfur sensitizers can be employed in conjunction with one or more thiocyanates containing a cation selected from the group consisting of metal and ammonium cations.
• the sulfur sensitizers and thiocyanates are advantageously incorporated in the emulsions in the form of their solutions in a suitable solvent, such as water, methyl or ethyl alcohol.
• the sulfur sensitizers can be incorporated in the emulsions at any stage of the preparation of the emulsions, e. g. during precipitation of the silver halides, during the first digestions (ripening) or during the second digestion of the emulsions.
• the amount can vary widely.
• an amount of thiocyanate equal to from about to about 75 g. per kilogram of silver nitrate used in preparing the emulsion is employed. If the thiocyanate or sulfur sensitizer is not added until later in the preparation, e. g.
• the pH of the emulsion is advantageously adjusted to between 5 and 7.
• sensitizing dyes of all types can be employed to spectrally (optically) sensitize our new stabilized emulsions, e. g. erythrosin, Congo red, any of the sensitizing cyanine dyes (monomethine, trimethine, pentamethine, heptamethine, etc), and 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 United States Patent 2,166,736, dated July 18, 1939, for example), any of the sensitizing hemioxonol dyes (see United States Patent 2,216,441, dated October 1, 1940, and United States Patent 2,165,339, dated July 11, 1939, for example), etc.
• Our new stabilized emulsions can be coated in the usual manner on any suitable support, such as glass, cellulose nitrate film, cellulose acetate film, polyvinyl acetal resin film, etc. to desired thickness, and then set in the usual manner.
• Hardening agents, setting agents and supersensitizing combinations of sensitizing dyes or a supersensitizing combination of one or more sensitizing dyes and another substance can be added to the emulsions.
• Emulsions in which the carrier for the silver halide is other than gelatin and which have been 12 sensitized by digesting in the presence of a gold compound can be stabilized in accordance with our invention.
• non-gelatin silver halide emulsions are silver halide emulsions prepared using as the vehicle or carrier polyvinyl alcohol (polyvinyl alcohol is herein intended to include all water-soluble hydrolyzed polyvinyl esters containing an ester group content equivalent to from 0 to 5% by weight of polyvinyl ester) silver halide emulsions prepared using as the vehicle or carrier hydrolyzed polyvinyl acetate containing an acetate group content equivalent to from 59 to 71% by weight of poyvinyl acetate; silver halide emulsions prepared using as the vehicle or carrier polyvinyl acetals containing a large proportion of polyvinyl alcohol hydroxyl groups, e.
• Any polyvinyl compound especially those containing only carbon, hydrogen and oxygen atoms, or those containing carbon, hydrogen, oxygen and amine nitrogen atoms or ammonium nitrogen atoms, which is soluble in a mixture of ethyl alcohol and water (containing from 0 to 50% by volume of ethyl alcohol) to the extent of 10 g. per 100 g. of solvent can be employed as the vehicle or carrier in preparing our non-gelatin silver halide emulsions.
• any other resinous or colloidal material soluble in any ethyl alcohol-water mixture or in water can be employed in preparing our non-gelatin silver halide emulsions, e. g.
• col loidal materials which can be employed as vehicles or carriers in preparing our non-gelatin emulsions are hydrolyzed cellulose carboxylic esters, such as hydrolyzed cellulose acetate or hydrolyzed cellulose acetate propionate, containing from 19 to 33% by Weight of acyl groups, for example.
• Any cellulose compound especially those containing only carbon, hydrogen and oxygen atoms, or those containing only carbon, hydrogen, oxygen and amino nitrogen atoms or ammonium nitrogen atoms, which is soluble in a mixture of ethyl alcohol and water (containing from 0 to 50% by volume of ethyl alcohol) to the extent of 10 g. per g. of solvent can be employed as the vehicle or carrier in preparing our non-gelatin silver halide emulsion.
• the silver halide emulsions can be prepared using gelling agents, such as phenols, e. g. orcinol, gallic acid, 2,4-dihydroxybenzoic acid, 4-chlororesorcinol, e-naphthol, phloroglucinol, 2,7-dihydroxynaphthalene, etc.
• the non-gelatin silver halide emulsions can be prepared using silver halide dispersing agents, e. g.
• Non-gelatin proteins can also be employed as vehiclesorcarriers in preparing the silver halide emulsions which are stabilized in accordance-with our invention.
• Proteins such as casein, soybeanbilization of photographic.
• silver halide emulsions 1 which have been sensitized by digestion in the presence 'ofsat least one gold compound (watersoluble or Water-insoluble) and in which the silver halide is principally silver bromide, but canbe employed with anysilver halide emulsion which has been so sensitized, particularly with the customary silver chloride, silver chloro- :brom-ide, silver chlorobromoiodide, silver chloroiodide, silver bromide and silver bromoiodide developing-out emulsions which have been so sensitized.
• photographic silver halide emulsion in which the silver halide is principally silver bromide we mean a photographic silver halide -emulsion i-n which from 60 to 100% of the weight of the silver halide is silver bromide.
• a process for-stabilizing against loss of speed a photographic gelatino-silver-halide developingout emulsion in which the silver halide is principally silver bromide, which has'been sensitized by digesting the emulsion in the presence of a gold compound comprising adding to the-goldcompound-sensitized emulsion at a pH of from S te-9, after the final digestion of the emulsion, but prior to coating the emulsion on "a ,support, a water-insoluble gold compound which has a solubility in water not greater than the 7 per 1000 g. of silvernitrate used. in preparing the emulsion.
• a process for stabilizing a ainstloss .of speed a photographic gelatinoesilver-bromoiodide developing-out emulsion in which the silver halide is principally silver bromide, which has been sensitized by digesting the emulsion in the presence of a gold compound comprising adding to the.gold-compound-sensitized emulsion at a pH of 5 to 9, after the final digestion of the emulsion,.b.ut prior to coating the emulsionone support, awater-insoluble gold compound whichhas a solubility inwater not greater than the. equivalent of 1.0 mg. of gold per 100 ml. of water at 25C. and not less thanthe equivalent of 0.03 mg. of,goldp er 100 ml. of water at 25 C; the concentration .of the water-insoluble gold compound being equivalent to from 225 to 20 mg.;-per 1GOQ-g. of silver nitrate used in preparing theemulsion.
• the concentration of the waterinsoluble gold compound being equivalent to from 2.5 to 20 mg. per 1000 g. of silver nitrate used in preparing the emulsion.
• a process for stabilizing against loss of speed a photographic gelatino-silver-bromoiodide developing-out emulsion in which the silver halide is principally silver bromide, which has been sensitized by digesting the emulsion in the presence of a gold compound and a sulfur sensitizer comprising adding to the gold-compound-sensitized emulsion at a pH of to 9, after the final digestion of the emulsion, but prior to coating the emulsion on a support, a water-insoluble gold compound which has a solubility in water not greater than the equivalent of 1.0 mg. of gold per 100 ml. of water at 25 C. and not less than the equivalent 010.03 mg. of gold per 100 ml. of water at 25 C., the concentration of the waterinsoluble gold compound being equivalent to from 2.5 to 20 mg. per 1000 g. of silver nitrate used in preparing the emulsion.
• the concentration of the water-insoluble gold compound being equivalent to from 2.5 to 20 mg. per 1000 g. of silver nitrate used in preparing the emulsion.
• the concentration of the water-insoluble gold compound being equivalent to from 2.5 to 20 mg. per 1000 g. of silver nitrate used in preparing the emulsion.
• the potassium-chloroaurate-sensitized emulsion at a pH of from 5 to 9, after the final digestion of the emulsion, but prior to coating the emulsion on a support, aurous sulfide in a concentration of from 2.5 to 20 mg. per 1000 g. of silver nitrate used in preparing the emulsion.

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• Physics & Mathematics (AREA)
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• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
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• Colloid Chemistry (AREA)
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  • BE BE498286D patent/BE498286A/xx unknown
• 1949
  • 1949-09-24 US US117718A patent/US2597915A/en not_active Expired - Lifetime
• 1950
  • 1950-09-23 FR FR1053786D patent/FR1053786A/fr not_active Expired
  • 1950-09-25 GB GB23497/50A patent/GB682355A/en not_active Expired
  • 1950-10-03 DE DEE2757A patent/DE848910C/de not_active Expired

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