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
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances
  • G03C1/047—Proteins, e.g. gelatine derivatives; Hydrolysis or extraction products of proteins

Definitions

• This invention relates to the preparation of photographic emulsions having silver halide as the sensitive element in which the silver halide is prepared in dispersed form in a gelatin derivative.
• the gelatin derivative-silver halide dis persion is coagulated and washed.
• This, invention also includes the products obtained thereby washed silver-halide grains u ng gelatin or gela tin derivative as the vehicle erefor.
• the most common'method of preparing silverhalide dispersions is by reacting a water-soluble and the emulsions obtained by re-dispersing the f salt, such as silver nitrate and a water-solub1e halide, such as potassium bromide in an aqueous solution of gelatin. There is formed thereby a' dispersion of the silver halide in an aqueous solu-- tion of gelatin, which solution also contains salts resulting as a by-product of the. reaction.
• the A emulsion maker hasin the past been limited in the scope of his operations by the physical properties peculiar to that material.
• Our invention is based upon the discovery that gelatin derivatives are useful as peptizers for dispersions of silver halide and that those derivatives are acidcoagulable and will envelop the silver grains when so precipitated.
• the method of our invention avoids the limitations which have previously characterized the preparation of silver-halide dispersions and is valuable, for exvhanding thepossible(conditions for the manufacture of photo raphic silver halide emulsions of difierent speeds, contrast, andother photographic characteristics.
• our invention offers a simple meansof preparing emulsions of high silver concentration,' this being especially valu able in the manufacture of photographic films bearing large quantities of silver per unitarea.
• Gelatin derivatives are prepared byreacting.
• gelatin with a reagent such as asulfonyl chloride, a carboxylic acid chloride, a, carboxylic acid anhydride, an aromatic isocyanate, or a 1,4 diketone at a pH of8-1l or more imparted by the addition of asuitable base, such 'as sodiumhydroxide or ammonium hydroxide, preferably at a temperature of 2060 C.
• a suitable base such 'as sodiumhydroxide or ammonium hydroxide
• resulting product may be employeddirectly i'nour invention without separating it from the solution employed as dispersing agents for silver halide have the property of enveloping the silver-halide grains upon acidulation of the mass and that the resulting insoluble material consisting of silverhalide grains enveloped by the gelatin derivatives may. be washed free of salts or any other watersoluble materials which may be present therein.
• To effect coagulation it is desirable to acidify the mass to a pH of approximately 4.5 or less. When inert salts are present at relatively high concentration, the per range for this acid coagulation phenomenon may extend as low as 3.
• the silver halide may be prepared in an aqueous solution of gelatin as the peptizer, and the gelatin thus present may .changes'of .water. .--method,1,the coagulum may be redispersedin be converted into the derivative prior toacidifying and washing.
• the gelatin derivative is employed as the protective colloid that material is employed in substantially the same quantity as that of the gelatin usually used in'preparing silver halide emulsions.
• the silver halide maybe prepared by any of the normal methods for emulsification of the silver halides 'for examplegby introducing a stream of an aqueous-solution-of silver nitrate and a stream of an aqueous. solution:
• an alkali metal halide such as potassium-bromide
• an alkali metal halide such as potassium-bromide
• acid is. added ..in.-.a..sufficient. amount to lower the pH: to, less ..than. 4.5, the; range. of pH depending ,uponthe amountof salt present as explainedabove.
• the coagulum may. now be. separated. from, the liquid by any one .ofseveral. techniques. In the. simplest form this rsupernatant motherv liquor may be removed'from .the receptacle .in which. the .mass .is. contained by A means .of..a siphon and the, coagulum may be rinsed with water to remove excess insoluble salts. .Thecoagulum after this. washing operation :consists ..of, silver halide, the gelatin derivative, .any. other water-insoluble. materials whichv are ,present,-and .a small amount of residual soluble salt dissolved. in water trapped in. the. coagulum.
• thiscoagulum may be useddirectly without'further washing. for instance, in the, preparation of emulsions; for the ;.-coating ofpaperor. other permeable supports.
• preparationof .emulsionslfor ,lthe coating. of ifilmorglass: plates, however,1it may be. desirable .,.to reduce further the content .of solubletsalts -.which may be present. .This may be ,done. by any one. of:severa1. methods. I. For.
• The: number of. rinses which. are neces- -sary to reduce the saltcontent of thecoagulum to the desiredpoi-nt may be determined by experi- -ment,-.but usually..is.within. the range of. 1 to 4
• the coagulum which has been washed by any onexofithe'.three' general methods outlined above may then be.redispersed to form photographic emulsions suitable for the subsequent finishing .10
• gelatin derivative instead of normalgelatinmay beemployed as the vehicle in the formation of the photographic emulsion.
• The'mixtureof coagulum, watenzggelatinand any other desired reagents is stirred at approximately 4:0 C. for a time" suiTicient to: effect aicomplete redispersal of .the coagulum, usually requiring ten to twenty-minutes.
• the emulsionobtained has properties comparable to those of the best types of washed" emulsions and'responds readily to chemical sensitizationmr .iafter ripening .and optical sensitization ofthe types employed upon photographic emulsions. generally.
• The. emulsions. prepared iniaccordance with our invention may be coated onto a support, using the techniques which arestandard in the emulsion coating art.
• the silver-halide gelatin derivative coagulum. mayv be washed toremove insoluble salts by. either offlthe two .methcids. outlined above.
• soluble halide such as potassium bromide
• diketones posses the characteristic of water solubility at pH values above approximately 4.5 and below approximately 4.0, providing, of course,
• salts are absent.
• these derivatives are relatively water-insoluble.
• the pH range of insolubility in water is broadened by the presence of neutral
• the derivative obtained by reacting benzene sulfonyl chloride with gelatin is insoluble in aqueous solutions over a pH range extending from 3 to 4.5 if a concentration of potassium nitrate of at least 0.1 normal is present.
• in electrolyte is usually present in the form of potassiurn nitrate resulting from the double decomposition reaction between silver nitrate and a In some soluble halide also be present. Under such conditions the adjustment of pH in the first coagulation is not particularly critical.
• any acid may be employed which will give the desiredpI-I in the mass and which will not deleteriously affect the photographic material.
• Dilute aqueous sulfuric acid has been found to be particularly useful for this purpose.
• acetic acid or phosphoric acid are useful for this purpose if for some reason sulfuric acid is not available.
• gelatin derivatives In the preparation of gelatin derivatives the gelatin in aqueous solution is treated with a solution of the reagent in a suitable solvent, prefer- Some reagents which are useful in this connection are acetone, dioxane, isopropyl alcohol, and the like. of thecornpounds which aresuitable for use in preparing gelatin derivatives useful in the process of our invention are as follows:
• the, coagulum prepared by the use of gelatin derivatives is especially suitable for preparation of driedemulsions since it may be obtained in a state nearly free of excess water and, therefore, the drying operation is simplified and rendered less expensive.
• the coagulum may be obtained in the suitable physical form for the purpose, and the dried emulsion may readily be redispersed in water containing appropriate alkali.
• the washed coagulum prepared from the dicarboxylic acid anhydride derivatives, such as phthalic anhydride is especially useful.
• the coagulation operation may be carried out either after the preparation of silver halide to remove watersoluble salts or after a heat treatment with appropriate chemical'sensitizers so that coagulated silver-halidetgrains' 'areiobtainedbefore or after having been brought to optimum photographic speed.
• These grains maybedriedat eitherv stage .in the cycle without harming their properties when finally made up in the emulsion,
• gelatin derivatives which. may be employed in accordance with ourinvention may be either derivatives of a high viscosity gelatin or, if desired, they maybe derivatives of gelatin which has been hydrolyzed. or reduced in viscosity.
• Our invention is..not. critical as to the gelatin which is employedin preparing the derivatives to be used in our invention or process including gelatin derivatives generally in .the preparation of washed emulsions by coagulation washing methods.
• Example 1.-100 g.,of silver 'nitrate weredissolved in 900 cc. of distilled waterat 25 C. 80g. of potassium bromide, 1 g. of potassium. iodide and 25 g. of gelatin weredissolved in another 900 cc. of distilled water. Thetemperature was adjusted to 50 C. and the silvernitrate solution was added to the bromide-gelatin solution over a period of approximately ten minutes with vigorous stirring. The temperature was maintained at 50 C. The mass was then stirred for ten minutes at 50 Qand then cooled t 40 C. The pH was adjusted to. 9.5 by the addition of dilute ammonium hydroxide and 3 cc. of benzene 'su-lfonyl chloride in 40 cc. of dry acetone were added. The "mass-was stirred at 40 C. for five minutes; Sulfuric acid was then added to. ad-
• the mother. liquor was decanted oh, and the silver halide disper- "sion' waswa'shedtwice with distilled water at -'20' C. There was then added to the mass 150 g. of gelatin in solution in 1500 cc. of distilled water, and the mass was stirred at 40C. Ammonia was added to bring the emulsion pH to 615, and stirring was continued until all of the solid matter was completely dispersed in the "liquid. The resulting emulsion was then processed'and coated as is'usual for photographic emulsions;
• EwampZe The use 0] them-carbony benzene suijonyl derivative of gelatin for making silverhalidedispersions:
• potassum bromide was added.
• the emulsion was finished by heating at C. for 20-40 minutes and was then coated onto glass plates where theemulsion layer was-dried and tested sensitometrically by'exposure in .a sensitometer and development. in. a photographic developer.
• the emulsion showed normal .sensi-tometriccharacteristics.
• the emulsion was prepared as in Example-3 using this furoyl .halide derivativeof gelatin as the peptizing agent. .After the silver-halide grains had been thoroughly washed, the emulsion was cooled to 35, the .pI-I.w,as.lowered..to..3 with dilute sulfuric. acid, the coagulumwas washed, rinsed with three changes .of .cold water and then made up withthe desired quantities of gelatin and water.
• The-.coagulated silverhalide grains and gelatin derivative. were readily dispersed-at a pH of 6-7; The emulsion was made up with an. aqueous solution of gelatin. The pH was adjustedand potassium bromide was added as described herein.
• the emulsion was finished by- .heating at..65. C. for...a.- short time a and was coated on film support which was dried and tested photographically. The emulsion showed normal sensitometric characteristics.
• Example 5 The use of the phthalz'c anhydride derivative of gelatin in making silver-halide dispersz'ons:
• the gelatin derivative was prepared by the method described in Example 3 except that g. of phthalic anhydrideiin 35 cc. of dry acetone was used instead of the benzoyl chloride.
• the silver-halide dispersion was prepared by adding to a solution of80 g. of potassium bromide 1 g. of potassium iodide and g. of the gelatin derivative in 900 cc. of distilled water at 50 C., a solution of 100 g. of silver nitrate in 900 cc. of distilled water at 50 C. all over a period of ten minutes.
• the temperature of the resulting mass was then maintained at 50 C. for another ten minutes.
• the silver-halide dispersion was then cooled to C. and dilute surfuric acid was added thereto to bring the pH to 3.
• the clear supernatant liquid formed upon standing was decanted.
• Dilute ammonium hydroxide was then added to adjust the pH to 3.8-4.2 at which point the gelatin derivative and silver halide settled to the bottom of the container.
• the silverhalide dispersion was made up with gelatin and water and with proper finishing gives an emulsion having normal sensitometric characteristics.
• the washed coagulum consisting of silver-halide grains and the gelatin derivative may be dried.
• the dried coagulum it may be employed by soaking in water for a time whereupon it may be readily dispersed at a pH of approximately 6 or 7.
• the maleic anhydride derivative of gelatin was prepared in the same manner as described in Example 3 except that 4 g. of maleic anhydride was employed in reacting upon the gelatin instead of the benzoyl chloride.
• the emulsion was prepared by mixing a solution of 80 g. of potassium bromide, l g. of potassium iodide and 25 got gelatin in 900 cc. of distilled water at 50 C. and adding over a period of ten minutes a solution of 100 g. of silver nitrate in 300' cc. of distilled water at the same temperature.
• the temperature of the dispersion was maintained at 50 C. for an additional ten minutes, was then cooled to 35 C. and dilute sulfuric acid was added to impart a pH of 3.0.
• the coagulum settled to the bottom of the container, the supernatant liquid was decanted, and a volume of water equal to the original volume was added.
• the temperature was adjusted to 35 C. and while stirring the pH was adjusted to 6-8 with dilute ammonium hydroxide.
• the coagulum was thus redispersed in water.
• Dilute sulfuric acid was added to impart a pH of 3.8-4.2 whereupon the coagulum again settled.
• the liquid was decanted, and the silver-halide dispersion was mixed with an aqueous gelatin.
• the resulting emulsion was coated on film base and tested for photographic characteristics. Normal sensitometric characteristics were obtained therefrom on finishing.
• Example 7 Use of the phenyl ureido derivative of gelatin in preparing silver-halide dispersions: A silver-halide dispersion was preparedby;
• the gelatin derivative prepared may be employed as the dispersing colloid during the silver halide precipitation.
• the coagulation procedures in both cases are identical.
• Example 9-A gelatin derivative was prepared in the same manner as in Example 3 except that diethyl diacetyl succinate was added before rais-' ing the pH to 10, and the reaction time was six hours, the diethyl diacetyl succinate being employed instead of benzoyl chloride.
• the silverhalide dispersion was prepared as described in that example using the diethyl succinate derivative of gelatin as the dispersing colloid. After the temperature of the dispersion had been maintained at 50 C. for ten minutes, the emulsion was cooled to 35 C. and dilute sulfuric acid was added to impart a pH of. 3.
• -I n amethod of preparing washed silver halide-dispersions, thesteps which comprise mixtogether a-water-soluble silver salt and a water-soluble halide salt in an aqueous solution of 'a gelatin-derivative whose presence renders the-dispersioncoagulable at 'a pH within the range of pH- 3-4:.5, which derivative is selected from the group consisting of the aromatic sulfonyl chloride-derivatives of gelatin, the carboxylic acid chloride derivatives of gelatin, the carboxylic acid anhydride derivatives of gelatin.
• a'method of preparing washed silver halide dispersions the steps which comprise n'i'ixing-together a water-soluble silver salt and a water-soluble'halide salt in an aqueous solution of-"an'aromatic sulfonyl chloride derivative of gelatinwhose presence renders the dispersion coagulable' at a pll within the range of pH 3-4.5, coagulatingthe dispersion of silver halide in gelatin derivative thusformed'by adjusting to said-"pH wherebysilver halide-gelatin derivative grains are formed and subsequently separating the" silver halide-gelatin derivative grains thus formed fromthe liquid portion of the mass.
• a method'of preparingwash'ed silver halide dispersions the steps which comprise mixingiutogether a water-soluble silver salt and a water-soluble halide salt in an aqueous solution or a carboxylic acid anhydride derivative of; gelatin whose presence renders the dispersion coagulable at a pH within the range or pH 3-4151, coagulating-the dispersion of silver halide in gelatin derivative thus formed by adjusting to said pH whereby silver halide-gelatin deriva- 12 tive grains are formed andsubsequently-separating the silver halide-gelatin derivative grains thus formed from the liquid portion of the. mass.
• a method of preparing washed silver halide dispersions the steps which comprise mixing together a water-soluble silver salt and a water-soluble halide salt in an aqueous.-solu-' tion of 1,4 diketone derivative of gelatin whosepresence renders the dispersion coagulable ata pH within the range of pH 3-4.5, coagulating the dispersion of silver halide in gelatin'derivative thus formed by adjusting to said pH whereby silver halide-gelatin derivative grains are formed and subsequently separating the silver halide-gelatin derivative grains thus formed from the liquid portion of the mass.
• a method of preparing washed silver halide dispersions the steps which comprise mixing together a water-soluble silver salt and a water-soluble halide salt in an aqueous solution of the benzoyl chloride derivative of gelatin whose presence renders the dispersion coagulable at a pH within the range of pH 3-4.5, coagulating the dispersion of silver halide in gelatin derivative thus formed by adjusting to said pH whereby silver halide-gelatin derivative grains are formed and subsequently separating the silver halide-gelatin derivative grains thus formed from the liquid portion of the'mass.
• a method of preparing washed silver halide dispersions the steps which comprise mixing together a water-soluble silver salt and a water-soluble halide salt in an aqueous solution of the phthalic anhydride derivative of gelatin whose'presence renders the dispersion coagulable at a pH within the range of pH 3-4.5, coagulating the dispersion of silver halide in gelatin derivative thus formed by adjusting to said pH whereby silver halide-gelatin derivative grains are formed and subsequently separating thesilver halide-gelatin derivative grains thus formed from the liquid portion of the mass.
• a method of preparing a gelatino-silver halide emulsion which comprises preparing a silver halide dispersion by mixing together a water-soluble silver salt and a Water-soluble halide in an aqueous solution of a phthalicanhydride derivative of gelatin whose presence renders the dispersion obtained coagulable at a pH within the range of pH 3-4.5, coagulating the dispersion of silver halide in gelatin derivative by adjusting to said pH whereby silver halide-gelatin, derivative grains are formed, separating the thus-formed silver halide-gelatin derivative grains from the liquid portion of the mass and subsequently mixing those grains with gelatin and water as a protective colloid for the silver halide whereby a photosensitive emulsion is formed.
• a method of preparing washed silver halide dispersions the steps which comprise mixing together a water-soluble silver salt and a water-soluble halide salt in an aqueous solution of a gelatin derivative whose presence renders the dispersion coagulable at a pH within the range of pH 3-4.5, which derivative is selected from the group consisting of the aromatic sulfonyl chloride derivatives of gelatin, the carboxylic acid chloride derivatives of gelatin, the carboxylic acid anhydride derivatives of gelatin, the aromatic isocyanate derivatives of gelatin and the 1,4 diketone derivatives of gelatin, coagulating the dispersion of silver halide in gelatin derivative by adjusting to said pH whereby silver halide-gelatin derivative grains are formed, separating those grains from the liquid portion of the mass, redispersing the grains thus obtained in water at an elevated pH followed by adjusting the pH of the solution to that which will coagulate the silver halide dispersion which pH is within the range of 3-4.5, and
• a method of preparing washed silver halide dispersions the steps which comprise mixing together a water-soluble halide salt and a water-soluble silver salt in an aqueous solution of a phthalic anhydride derivative of gelatin, whose presence renders the dispersion thus obtained coagulable at a pH within the range of pH 3-4.5, coagulating the dispersion of silver halide in gelatin derivative by adjusting to said pH whereby silver halide-gelatin derivative grains are formed, separating those grains from the liquid portion of the mass, redispersing those grains in water at an elevated pH followed by adjusting the solution to a pH which will coagulate the silver halide dispersion. which pH is within the range of 3-4.5 and separating the thus-formed silver halide-gelatin derivative grains from the liquid portion of the mass.
• a method of preparing a gelatino-silver halide emulsion which comprises pre aring a silver halide dispersion by mixing together a water-soluble silver salt and a water-soluble halide in an aqueous solution of a gelatin derivative whose presence renders the dispersion coagulable at a pH within the range or pH 3-4.5,
• silver halide dispersions the steps which comprise mixing together a water-soluble silver salt and a water-soluble halide salt in an aqueous solution of a maleic anhydride derivative of gelatin Whose presence renders the dispersion coagulable at a pH within the range of 3-4.5, coagulating the dispersion of silver halide in gelatin derivative thus formed by adjustin to said pH whereby silver halide-gelatin derivative grains are formed, and subsequently separating the thus-formed grains from the liquid portion of the mass.
• a method of preparing a washed gelatinosilver halide photographic emulsion which comprises preparing a silver halide dispersion by mixing together a water-soluble silver salt and a water-soluble halide in an aqueous solution of a gelatin derivative whose presence renders the dispersion coagulable at a pH within the range of pH 3-4.5, which derivative is selected from the group consisting of the aromatic sulfonyl chloride derivatives of gelatin, the carboxylic acid chloride derivatives of gelatin, the carboxylic acid anhydride derivatives of gelatin, the aromatic isocyanate derivatives of gelatin and the 1,4 diketone derivatives of gelatin coagulating the dispersion of silver halide in gelatin derivative thus formed by adjusting to said pI-I whereby silver halidegelatin derivative grains are formed, separating the thus-formed grains from the liquid portion of the mass, redispersing those grains in water at a dispersing pH therefor, followed by adjusting the pH of the solution

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• Chemical & Material Sciences (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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• 0
  • BE BE484325D patent/BE484325A/xx unknown
• 1947
  • 1947-08-13 US US768475A patent/US2614928A/en not_active Expired - Lifetime
  • 1947-08-13 US US768476A patent/US2614929A/en not_active Expired - Lifetime
• 1948
  • 1948-03-09 GB GB7273/48A patent/GB649545A/en not_active Expired
  • 1948-03-09 GB GB7274/48A patent/GB649546A/en not_active Expired
  • 1948-08-11 FR FR980386D patent/FR980386A/fr not_active Expired

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