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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/388—Processes for the incorporation in the emulsion of substances liberating photographically active agents or colour-coupling substances; Solvents therefor
  • G03C7/3882—Processes for the incorporation in the emulsion of substances liberating photographically active agents or colour-coupling substances; Solvents therefor characterised by the use of a specific polymer or latex

Definitions

• This invention relates to photographic silver halide emulsions containing novel polymeric compositions in combination with color couplers, i. e., a color-forming compound capable of reacting with a primary aromatic amino developing agent on photographic development.
• the polymeric composition employed in the instant invention can wholly or partially constitute the vehicle employed in the photographic silver halide emulsion, or these polymeric compositions can be employed together with a coupler or color-forming compound to wholly or partially replace the coupler solvent used in the process of application Serial No. 476,561.
• the polymeric compositions employed in our invention can be used both in the photographic silver halide emulsion and in the coupler compositions or dispersion, which is intermixed with the photographic silver halide emulsion.
• novel polymeric compositions employed in the instant invention can be prepared according to the methods outlined in our copending applications Serial Nos. 398,236; 426,551 and 426,552 mentioned above. These polymeric compositions contain from about 5 to 95 percent by weight of protein material and from about 95 to 5 percent by weight of the polymerized monoethylenically-unsaturated compound mentioned above.
• the saturated protein component which is employed in preparing the polymeric materials of this invention can be an unsubstituted protein such as gelatin, hydrolyzed gelatin, glue, casein, soybean protein, or the like, or it can be an acylated protein such as succinyl protein,
• phthalyl protein or acetyl proteinprepared by reacting an organic acid anhydride or chloride with a protein such as glue, gelatin, .casein, or the like.
• acylated protein derivatives are known to the art, and the preparation of a phthalic anhydride derivative of gelatin suitable for use in practicing the invention is described in Yutzy and Frame, U. S. Patent No. 2,525,753.
• Other protein derivatives can be prepared in similar fashion by reacting any of the well known proteins with any of the saturated organic acid anhydrides.
• a method of preparing derivatives of other proteins than gelatin is described in the Lowe and Gates U. S. Patent 2,691,582, issued October 12, 1954.
• the polymerizable monomer or monomers which is graft polymerized with the proteinmaterial can be any of the well known olefinic polymerizable monomers including vinylic monomers and diolefinic monomers.
• the vinylic monomer (or monomers) can include styrene, substituted styrenes, acrylic acid esters, methacrylic acid esters, vinyl ethers, vinyl ketones, vinylidene chloride, vinyl chloride, vinyl esters, acrylonitrile, substituted acrylonitriles, vinyl pyridines, acrylamides, allylamines, and similar well known vinylic monomers.
• polmerizable diolefins such as 1,3- butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene and similar diolefinic monomers are entirely suitable for use in practicing the instant invention.
• Typical monomers which can be employed in practicing the invention include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethy1hexyl acrylate, n-octyl acrylate, n-decyl acrylate, fi-cyanoethyl acrylate, ,B-chloroethyl acrylate, n-butyl acrylate, 2-methoxye'thyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, and similar alkyl acrylates wherein the alkyl group contains from 1 to 10 carbon atoms; methacrylates containing from 1 to 10 carbon atoms, and preferably from 4 to 10 carbon atoms in the alkyl group, such as n-buty
• the polymeric solutions or hydrosols of this invention are prepared by polymerization in an aqueous system with or without a micell-forming surface-active agent.
• the .use of a surface-active agent facilitates the dispersion of the monomer in the water.
• the surface-active agents which can be employed in practicing the invention include'de the cationic surfactants, anionic surfactants, and amphoteric surfactants. ESuch surface-active materials which form micells are well known in the art, and it is -..-not intended that the invention shall be limited to the par- .iticular surfactants which are particularly described herein. Any of the other micell-forming surface-active agents canbe employed in practicing the invention with advantageous results.
• Typical surfactants which can be employed in practicing the invention are the salts of the higher fatty acids, such as sodium stearate, potassium stearate, sodium' palmitate, potassium palmitate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, and the like; salts of higher fatty alcohol sulfates such as the sodium or potassium lauryl sulfates, sodium or potassium di-(Z-ethylhexyl) sulfosuccinates, sodium or potassium cetyl sulfates, sodium or potassium 'stearyl sulfates, and the like; salts of aromatic sulfonic acids, such as the sodium or potassium salts of an alkyl :naphthalene sulfonic scid; high molecular weight quater- ..nary ammonium salts containing the radical C H or .C17H35; and similar well known micell-forming surfaceactive agents.
• the polymerization is facilitated by the use
• Such polymerization catalysts are well known in the art, andany ofthe Well known catalytic materials or combinations such as are commonly em- .ployed in'promoting emulsion polymerizations can be used.
• the per-catalysts are entirely lsuitable, including the organic peroxides, such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, tert.
• persulfatcs such as sodium, potassium or ammonium persulfates, or 'persul-
• furic acid itself perborates, such as sodium or potassium perborates
• perborates such as sodium or potassium perborates
• water-soluble salts of per-carbonic .acid water-soluble salts of perphosphoric acid
• watersoluble salts of sulfoperacids and similar well known per-catalysts.
• the redox-type catalysts can be .used in practicing'the invention, and in some cases, this .may be desirable in order to carry out the reaction at .course, depend upon the other variable factors, such as the .kind and concentration of catalyst, the temperature of polymerization, the nature of the polymerizing reactants, .and similar variable factors. 'When the polymerization is effected at an elevated temperature, it may be necessary :to efiect the polymerization in a reaction system provided with a reflux condenser or in a closed pressure system.
• compositions of our invention which -rcontain 60 percent. or less of hydrophilic material material are generally obtained in the form of polymeric hydrosols, while thosecompositions containing more than 60 percent hydrophilic-material are generally obtained in the form of solutions, the particle size of which is considerably smaller than those particles found in the polymeric hydrosols.
• each of these types of compositions can be advantageously employed.
• Those polymeric compositions containing in excess of 60 percent hydrophilic material are readily soluble in warm water and can be redispersed from a dried film of the polymer. Thus, it is possible to dry these particular polymeric solutions and store them for prolonged periods of time in dried form.
• the dried polymers can thereafter be readily dispersed in warm water and used in emulsion formulas of the instant invention in the same manner as the original aqueous solution or dispersion. Because of'its inherent water solubility or dispersibility, the polymeric composition need not be mixed with gelatin prior to drying.
• the protein component is preferably an unsubstituted or acylated gelatin, hydrolyzed gelatin, glue, casein, or soy protein.
• the casein is particularly useful when it has first'been modified by treating in solution with hydrogen peroxide at an alkaline-pH and at an elevated temperature to cause some oxidation.
• the protein can be completely unmodified, however, and such unmodified proteins give entirely satisfactory results.
• acyl protein derivatives can be employed providing such de rivatives do not contain any ethylenic or carbon-to-carbon unsaturation, which would cause the derivative to enter into a copolymer reaction with the monomer or monomers, rather than the-graftpolymerization.
• the polymeric compositions of our invention can be mixed directly with aqueous solutions of gelatin, or similar naturally occurring hydrophilic colloidal protein materials, which have been rendered soluble or dispersible in water.
• the hydrosols or solutions employed in our invention are compatible with protein in all proportions and they can be used alone or with varying amounts of another protein, such as from 5 to percent by weight of gelatin or other protein materials.
• the coatings which are obtained from the polymeric compositions of our invention when used alone, or in admixture with gelatin or 'the like, have good Optical clarity. That is, by using a graft polymer, polymeric compositions are obtained which have a refractive index quite similar to that of the unmodified protein material.
• the properties of the polymeric compositions employed in the invention will depend, of course, on the particular ingredients going into the polymerization. Generally speaking, the alkyl acrylates containing from 2 to it) carbon atoms in the alkyl group, the alkyl methac- -rylates containing from 4 to 10 carbon atoms in the alkyl group'and the diolelins (butadiene, isoprene, chloroprene, and the like) give polymeric compositions having moderate flexibility.
• the polymeric compositions of the instant invention can :be combined with the coupler or color-forming com- ;pound directly, rby using the-method described in .the
• Fierke and Chechak application Serial No. 476,561 mentioned above, or these polymeric compositions can be first mixed with the silver halide dispersion, and this dispersion combined with such dispersions as are described in the Fierke and Chechak application.
• the polymeric compositions of our invention can wholly or partially replace the vehicle, such as gelatin, used in preparing the silver halide dispersion itself.
• the coupler dispersion employed in our invention and containing the novel polymeric composition can be made by dissolving the coupler in a low-boiling organic solvent for the coupler, e. g., ethyl acetate, dispersing the solution in gelatin (or the graft polymer composition), then adding gelatin (or graft polymer) and the polymeric composition.
• a low-boiling organic solvent for the coupler e. ethyl acetate
• the coupler dispersion ingelatin can be added to a solution of the protein material and monomers before emulsion polymerization.
• the dispersion containing the polymeric composition can be chilled and dried for storage, or can be added immediately to a gelatino-silver halide emulsion, or other silver halide emulsion using one of the graft polymers of our invention as a vehicle. If dried, the dispersion is re-melted before adding to the silver halide emulsion.
• the coupler dispersion can also contain a high boiling crystalloidal organic solvent for the coupler, e. g., di-n-butylphthalate, which can be added at any stage during the preparation of the dispersion.
• Couplers or color-forming compounds which can be employed in our invention have been described in Jelley and Vittum U. S. Patent 2,322,027.
• Other couplers which can be employed include the following:
• phenoxy-acetanilide tert.amyltert.amyl- High boiling coupler solvents which can be used in conjunction with the polymeric materials of our invention, in addition to the di-n-butylphthalate mentioned above, are organic crystalloidal solvents which are substantially water-insoluble, have low molecular weight and a boiling point above 175 C., in addition to high solvent action for the coupler and dyes formed from it. Also, such solvents should be permeable to photographic developer oxidation products. Additional examples of such products are methyl, ethyl, propyl, etc., phthalates, triphenylphosphates, tricresylphosphates, etc.
• Low boiling solvents for the coupler or color-forming compound include methyl, ethyl, propyl, butyl and like acetates, isopropyl acetate, ethyl propionate, sec. butyl alcohol, carbon tetrachloride, chloroform, methyl isobutylquinone, fi-ethoxyethyl acetate, fl-butoxy-p-ethoxyethyl acetate, tetrahydrofurfural adiphate, and the like.
• a hydrosol was made as described in Example 1, containing .16 ,percent glue, 59 percent n-butyl acrylate and 23 percent styrene instead of the components listed in Example 1.
• a similar emulsion was made without the hydrosol, and this was separately coated on film base (coating B).
• a separate coupler dispersion was made by dissolving 8 grams of coupler No. 9 in a solution of 25 cc. of ethyl acetate and 16 .c c.of di-n-butyl phthalate at the reflux temperature of ethyl acetate. This mixture was then poured into a solution of 65 cc. of 10 percent gelatin C., stirred for about one minute and run through a colloid mill .five times, after which the mill was rinsed with 25 cc. of water. The dispersion was set up on a chill plate ,at F., noodled and air dried at 78 C. and percent .relative humidity.
• C coupler to hydrosol solidsratio
• Examples 5-8 below the beneficial effect .of the graft polymers ofour invention, when incorporated in a silver halide emulsion as the vehicle therefor, is shown.
• the log E speed, density in terms of D max, and gamma for the coatings of Examples 5-8 are given, and compared with a check'coating prepared in exactly the same manner except that gelatin alone was used as the vehicle for the silver halide emulsion.
• the silver halide emulsion employed in each example was a positive silver bromiodide emulsion and contained approximately 0.03 mol. of silver.
• the same color coupler was employed in each of the coatings of Example 5-8 and also in the check coating. This coupler :Was of the same type as coupler No. 9 above. The results are given in Table 1 below.
• EXAMPLE 5 g. of coupler No. 9 were dissolved in 350 cc. of ethyl acetateat the reflux temperature. This solution was poured into a solution containing 1000 cc. of 10% gelatin solution and 125 cc. of Alkanol B (-alkylnaphthalene sodium sulfonate) solution and then milled five times in a colloid mill. The mill was then rinsed out with 50 cc. of water and the dispersion Was set up on a chill plate at 40 F., noodled, and air dried. Dry weight of the dispersion was 237.5 g.
• Alkanol B -alkylnaphthalene sodium sulfonate
• the graft polymer used in Example 5 was prepared as follows:
• EXAMPLE 6 This coating was made and processed exactly as the coating in Example 5 above, except that a graft polymer composed of gelatin and n-butyl acrylate was employed in placecf the graft polymer in Example 5.
• the speed, density and gamma for the coating are given in Table I below.
• the graft polymer used in Example 6 was prepared as follows:
• EXAMPLE 7 The coating in this example was made exactly as that .pa e i the 1 o lewiuaman w- To a stirred solution of 260 g. of photographic gelatin, 4.0 g. of potassium persulfate and 2.0 g. of sodium bisulfite in 6000 cc. of water at 45 C. were added dropwise 140 g. of ethyl acrylate over a period of 30 minutes. The reaction mixture was stirred at 45 C. for 75 minutes and cooled before use.
• EXAMPLE 8 The coating of this example was prepared in exactly the same manner as that of Example 5 above except that a graft polymer composed of gelatin and ethyl acrylate was employed in place of the graft polymer used in Example 5. The speed, density, and gamma for the coating was made in exactly the same manner as that in Example 5 and the results are given in Table I below.
• Example 8 The graft polymer employed in Example 8 was identical to that employed in Example 7, except that the graft polymer contained 40% by weight of ethyl acrylate instead of the 35% by weight, which was used in Example 7.
• EXAMPLE 9 A solution of 8 g. of coupler No. 9 in 25 g. of ethyl acetate was added to a 10% solution containing 46 g. of a graft polymer prepared in exactly the same manner as that used in Example 6 above, and 8 cc. of 5% Alkanol B solution. The resulting mixture was passed through a colloid mill five times, set on a chill plate, noodled and dried. The dried product was obtained as hard, transparent noodles that could be readily redispersed by plumping in water and warming to 40 C.
• EXAMPLE 10 The coating of this example was prepared in exactly the manner shown in Example 9, except that the graft polymer employed in Example 7 was employed instead
• the coatings in Examples 11 and 12 were obtained in exactly the same manner as those in Examples 9 and 10 above, i. e., the graft polymers were employed in the coupler dispersions rather than in the silver halide emulsion, as in the case of Examples 58.
• the log E speed, density in terms of D max., gamma and fog for the various coatings are given in Table III below. These coatings were compared with a check which contained gelatin in place of the graft polymers employed in the coupler dispersions of Examples 11 and 12.
• EXAMPLE 11 8.0 g. of coupler No. 9 were dissolved in ethyl acetate and this solution was poured into a solution containing 46 g. of a graft polymer composed of gelatin, acrylamide, n-outyl acrylate and styrene, and 8 cc. of a 5% Alkanol 8 solution. The resulting mixture was milled five times in a colloid mill, chill set, noodled and air dried.
• the graft polymer pared as follows:
• EXAMPLE 12 This coating was prepared in exactly the same manner as that in Example 11, except that only 13.7 g. of graft polymer (same polymer as used in Example 11), in admixture with 16 g. of an ordinary copolymer composed of n-butyl acrylate and styrene was employed in place of the single graft polymer employed in Example 11.
• the speed, density and gamma and fog for the coatings are given in Table III below.
• Example 11 employed in Example 11 was pre- T able III
• the copolymer employed in Example 12 was prepared as follows:
• graft protein polymers containing from about 5 to by weight of protein material have been found to be particularly useful in practicing our invention, although graft polymers containing in excess of 75% by weight of protein material can also be employed to advantage.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a silver halide emulsion containing an organic material selected from the group consisting of a color-forming compound capable of reacting with said developing agent on photographic development and a composition comprising (a) an organic color-forming compound capable of reacting with said developing agent on photographic development and (b) an organic crystalloidal solvent for said organic color-forming compound, said solvent having a boiling point above 175 C.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a silver halide emulsion containing an organic material selected from the group consisting of a color-forming compound capable of reacting with said developing agent on photographic development and a composition comprising (a) an organic color-forming compound capable of reacting with said developing agent on photographic development and (b) an organic crystalloidal solvent for said organic color-forming compound, said solvent having a boiling point above 175 C.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a gelatino-silver halide emulsion containing an organic dispersion of a colorforming compound capable of reacting with said developing agent on photographic development, and a dispersion of a polymeric hydrosol resulting from the emulsion polymerization of a mixture of (l) 5 to 60% by weight of a protein material selected from the group consisting of unsubstituted proteins and saturated acylated proteins, 2) a flexibilizing component selected from the group consisting of alkyl acrylates in which the alkyl group contains from 2 to 10 carbon atoms, alkyl methacrylates in which the alkyl group contains from 4 to 10 carbon atoms, butadiene, isoprene, and chloroprene, and (3) a strengthening component selected from the group consisting of styrene, substituted styrenes, acrylon
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a gelatinosilver halide emulsioncontaining an organic dispersion ot a color-forming compound capable of reacting with said developing agent on photographic development, and a dispersion of a polymeric hydrosol resulting from the emulsion polymerization of a mixture of (l) 5 to 60% by weight of a saturated acylated protein, (2) an alkyl acrylate in which the alkyl group contains from 2 to 10 carbon atoms, and (3) acrylonitrile, said acrylate and said acrylonitrile comprising from 95 to by weight of said mixture, and said silver halide emulsion being substantially free of organic crystalloidal solvent for said color-formingcompound, said solvent having a boiling point above 175 C. and being permeable to the oxidation products of said developing agent formed during photographic development.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a gelatino silver halide emulsion containing an organic dispersion of a color-forming compound capable of reacting with said developing agent on photographic development, and a dispersion of a polymeric hydrosol resulting from emulsion polymerization of (l) 5 to by weight of succinyl glue, (2) n-butyl acrylate, and (3) acrylonitrile, said acrylatejand said acrylonitrile comprising from to 40% by weight of said mixture, and said silver halide emulsion being substantially free of organic crystalloidal solvent for said color-forming compound, said solvent having a boiling point above C. and being permeable to the oxidation products of said developing agent formed during photographic development.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a gelatinosilver halide emulsion containing an organic dispersion of a color-forming compound capable of reacting with said developing agent on photographic development, and a dispersion of a polymeric hydrosol resulting from the emulsion polymerization of a mixture of 1 part of succinyl glue, 1.88 parts of n-butyl acrylate and 0.46 part of acrylonitrile, said silver halide emulsion being substantially tree of organic crystalloidal solvent for said colorforrning compound, said solvent having a boiling point above 175 C. and being permeable to the oxidation products of said developing agent formed during photographic development, V
• photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent, comprising a photographic silver halide emulsion containing an organic material selected from the group consisting of a colorforming compound capable of reacting with said developing agent'on photographic development and a composition comprising (a) an organic color-forming compound capable of reacting with said developing agent on photographic development and (b) an organic crystalloidal solvent for said organic color-forming compound, said solvent having a boiling point above 175 C.
• a unitary polymeric material resulting from the polymerization of a mixture comprising (A) from 5-95 percent by weight of a protein material selected from the group consisting oi unsubstituted proteins and acylated proteins tree of olefinic unsaturation, and (B) from 95-5 percentv by weight of a mixture of at least two different types of 13 polymerizable monomers, said types of monomers being (1) a flexibilizing component selected from the group consisting of alkyl acrylates in which the alkyl group contains fiom 2 to carbon atoms, alkyl methacrylates in which the alkyl group contains from 4 to 10 carbon atoms, butadiene, isoprene and chloroprene and (2) a strengthening component selected from the group consisting of styrene, substituted styrenes, acrylonitrile, substituted acrylonitriles, vinyl acetate, vinylidene chlor
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a photographic silver halide emulsion containing an organic colorforming compound capable of reacting with said developing agent on photographic development, and a polymeric material resulting from the polymerization of a mixture of (1) 60 to 75% by weight of a protein material selected from the group consisting of unsubstituted proteins and saturated acylated proteins and (2) from 40 to 25% by weight of a single polymerizable material represented by the following general formula:
• R is a member selected from the group consisting of hydrogen and methyl and R represents an alkyl group of from 1 to 10 carbon atoms, said silver halide emulsion being substantially free of organic crystalloidal solvent for said color-forming compound, said solvent having a boiling point above 175 C. and being permeable to the oxidation products of said developing agent formed during photographic development.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a photo graphic silver halide emulsion containing an organic colorforming compound capable of reacting with said developing agent on photographic development, and a polymeric material resulting from the polymerization of a mixture of (1) from 60 to 75% by weight of gelatin and (2) from 40 to 25 by weight of an alkyl acrylate in which 'the alkyl group contains from 2 to 10 carbon atoms, said silver halide emulsion being substantially free of organic crystalloidal solvent for said color-forming compound, said solvent having a boiling point above 175 C. and being permeable to the oxidation products of said developing agent formed during photographic development.
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a photographic silver halide emulsion containing an organic colorforming compound capable of reacting with said developing agent on photographic development, and a polymeric material resulting from the polymerization of a mixture of (l) to by weight of a protein material selected from the group consisting of unsubstituted proteins and saturated acylated proteins, (2) a flexibilizing component selected from the group consisting of alkyl acrylates in which the alkyl group contains from 2 to 10 carbon atoms, alkyl methacrylates in which the alkyl group contains from 4 to 10 carbon atoms, butadiene, iso- 'prene and chloroprene, and 3) a strengthening component selected from the group consisting of styrene, substituted styrenes, acrylonitrile, substituted acrylonitriles, vinyl acetate, vinylidene
• a photographic silver halide emulsion capable of producing a dye image having improved contrast and dye density upon exposure and development with a primary aromatic amine developing agent comprising a photographic silver halide emulsion containing an organic colorforming compound capable of reacting with said developing agent on photographic development, and a polymeric material resulting from the polymerization of a mixture of (1) from 60 to 75 by Weight of unsubstituted protein, n-bu'tyl acrylate, p and (4) styrene, said mixture comprising from 40 to 25% by weight of said acrylamide, said n-butyl acrylate and said styrene, and said silver halide emulsion being substantially free of organic crystalloidal solvent for said color-forming compound, said solvent having a boiling point above 175 C. and being permeable to the oxidation products of said developing agent formed during photographic development.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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  • BE BE543746D patent/BE543746A/xx unknown
• 1955
  • 1955-08-11 US US527872A patent/US2852382A/en not_active Expired - Lifetime
  • 1955-12-19 FR FR1151480D patent/FR1151480A/fr not_active Expired
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