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Publication numberUS3649287 A
Publication typeGrant
Publication dateMar 14, 1972
Filing dateDec 31, 1969
Priority dateJan 25, 1965
Also published asDE1522352A1
Publication numberUS 3649287 A, US 3649287A, US-A-3649287, US3649287 A, US3649287A
InventorsCarpentier Jan Albert, Pauw Alfons Jozef De
Original AssigneeAgfa Gevaert Nv
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of incorporating photographic ingredients into a photographic colloid
US 3649287 A
Abstract
A method of incorporating a slightly water-soluble photographic ingredient containing a water-solubilizing group into an aqueous medium containing dissolved gelatin.
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Description  (OCR text may contain errors)

United States Patent De Pauw et al.

[54] METHOD OF INCORPORATING PHOTOGRAPHIC INGREDIENTS INTO A PHOTOGRAPHIC COLLOID Alfons Jozef De Pauw, Edegem; Jan Albert Carpentler, Walem, both of Belgium Assignee: Gevaert-AGFA N.V., Mortsel, Belgium Filed: Dec. 31, 1969 Appl. No.: 889,722

Related U.S. Application Data Continuation-impart of Ser. No. 511,969, Dec. 6, 1965, abandoned.

[72] Inventors:

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 1/ 1959 Godowski et a1. ..96/97 8/1962 Ben-Ezra et a]. ..96/100 1 l/1966 Williams, Jr ..96/97 Primary Examiner-Norman G. Torchin Assistant Examiner-Alfonso T. SuroPico Attorney-Brufsky, Staas, Breiner & Halsey [57] ABSTRACT A method of incorporating a slightly water-soluble photographic ingredient contain ing a water soltlilizing group [4 1 Mar. 14, 1972 into an aqueous medium containing dissolved gelatin.

The method comprises the steps of 1. dissolving the photographic ingredient in a photographically inert organic liquid consisting essentially of V tetrahydrothiophene-l,l-dioxide, N-methyl-2- pyrrolidinone, ethylene glycol, glycerol, acetonitrile or formamide. 2. forming a dispersion of the photographic ingredient by mixing the solution obtained with an aqueous solution K of a hydrophilic photographically inert colloid miscible v with gelatin more particularly a colloid of the following classes A to C Le.

A. water-soluble, natural colloid substances selected from the group of agar-agar, alginates, amylose and amylopectine,

B. water-soluble modified natural colloid substances selected from the group of:

. non-ionic starches anionic starches water-soluble alginic acid derivatives non-ionic cellulose gums anionic cellulose gums C. Synthetic water-soluble resins selected from the 92. Qn n Qf n r m s ami-a rline i y alcohol, N-binylpyrrolidinone, vinyl methyl ether, acrylic acid and salts thereof, methacrylic acid groups and salts thereof, maleic acid salts thereof or acrylamide units, maleic anhydride, water-soluble polymers containing alkylene oxide units, water-soluble prepolycondensates and polycondensate that are miscible with gelatin and selected from the group consisting of water-soluble urea-formaldehyde, water-soluble melamine formaldehyde, water-soluble guanamineformaldehyde, water-soluble alkyd and water-soluble .B9 Y FF es and 3. homogeneously fistribitin g tlie obtained dispersion into a gelatin solution or photographic gelatino silver ha ideemul lm v 2 leiin flep ew e METHOD OF INCORPORATING PI-IOTOGRAPIIIC INGREDIENTS INTO A PHOTOGRAPHIC COLLOID The present application is a continuation-in-part applica tion of our copending application Ser. No. 511,969 filed Dec. 6, 1965, now abandoned BACKGROUND OF THE INVENTION The invention relates to the field of the preparation of photographic silver halide emulsion materials and more particularly to a method of incorporating photographic ingredients in a light-sensitive gelatin silver halide emulsion.

It has been known in the art (see e.g., the US. Pat. No. 3,050,394) to incorporate long chain nondifiusing color couplers containing a salt-forming group e.g., a carboxy or sulfo group in an aqueous gelatin silver halide emulsion by dissolving said color couplers in a water, or a water-alcohol solution of an alkali metal hydroxide such as aqueous sodium hydroxide or alcoholic potassium hydroxide and adding the obtained solution as one of the last additives just prior to coating. Said technique asks for a special pH adjustment of the silver halide emulsion after addition of the alkaline solution.

The color couplers containing a water-solubilizing group such as a sulfonic acid (salt) group or carboxylic acid (salt) group cause an increase of the viscosity of colloid solutions containing gelatin. The increase in viscosity on holding is especially noticeable with gelatin solutions having a relatively low-water content and high-initial viscosity.

SUMMARY OF THE INVENTION The present invention is directed to a process for incorporating photographic ingredients that are only slightly watersoluble and contain a water-solubilizing group, e.g., of the type of a sulphonic acid or carboxylic acid group in free acid or salt form in a gelatin silver halide emulsion.

Said process comprises the steps of 1. dissolving the photographic ingredient in a photographically inert organic liquid consisting essentially of tetrahydrothiophene-l l -dioxide, N-methyl-Z-pyrrolidinone, ethylene glycol, glycerol, acetonitrile or formamide,

2. forming a dispersion of the photographic ingredient by mixing the solution obtained with an aqueous solution of a hydrophilic photographically inert colloid miscible with gelatin more particularly a colloid of the following classes A to C i.e.

A. water-soluble, natural colloid substances selected from the group of agar-agar, alginates, arnylose and amylopectine,

B. water-soluble modified natural colloid substances selected from the group of a. nonionic starches b. anionic starches c. water-soluble alginic acid derivatives d. nonionic cellulose gums e. anionic cellulose gums C. Synthetic water-soluble resins selected from the group consisting of vinyl polymers containing vinyl alcohol, N-vinylpyrrolidinone, vinyl methyl ether, maleic anhydride, acrylic acid and salts thereof, methacrylic acid groups and salts thereof, maleic acid and salts thereof or acrylamide units, water-soluble polymers containing alkylene oxide units, water-soluble prepolycondensates and polycondensates that are miscible with gelatin and selected from the group consisting of water-soluble urea-formaldehyde, water-soluble melamine formaldehyde, water-soluble guanamine-formaldehyde, water-soluble alkyd and water-soluble polyester resins, and

3. homogeneously distributing the obtained dispersion into a gelatin solution or photographic gelatino silver halide emulsion.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention it is possible to prepare very fine particle dispersions of slightly water-soluble photographic ingredients containing a water-solubilizing group of the type of a sulphonic acid or carboxylic acid group in free acid or salt form in an aqueous medium comprising a hydrophilic colloid that is photographically inert and is compatible (miscible) with gelatin.

According to the process of the present invention it is more particularly possible to incorporate color couplers that are poorly water-soluble and contain a water-solubilizing group, salt forming or salt group from a concentrated stock solution without necessitating the use of alkali'and a pl-l-adjustment of the silver halide emulsion. The use ofa photographically inert protective colloid that does not interact like gelatin does with the photographic ingredient makes it possible to prepare stock solutions not suffering from viscosity changes during long storage time.

By slightly or poorly water-soluble photographic ingredient is meant a photographic ingredient such as a dye, e.g., a dye suited for use in a filter or antihalation layer, a color coupler, a mask-forming compound or a developing agent, that practically does not dissolve in water at room temperature although containing a water-solubilizing group, more particularly an ingredient that dissolves for at most 2 g. per ml. of water at a temperature of 20 C.

The photographic ingredients suitable for incorporation into a photographic silver halide emulsion according to the method of the present invention may contain long chain residues to render them fast to difl usion in photographic colloid layers.

As water-soluble nonionic starches are particularly mentioned:

starch acetates, e.g., corn starch acetates containing 1 to 4 percent of acetyl groups.

starch hydroxyethyl ethers.

hydroxyl alkyl starch derivatives, e.g., hydroxyethyl and hydroxypropyl starch derivatives.

Anionic starches are produced by the introduction of carboxyl, sulphonic acid, sulphuric acid or phosphoric acid groups into starch. This permits the preparation of water-soluble alkali metal or ammonium salts.

The class of nonionic cellulose gums includes, e.g., hydroxy alkyl cellulose derivatives and polyoxyalkylene cellulose derivatives.

Anionic cellulose gums are produced by the introduction of carboxyl, sulphonic acid, sulphuric acid or phosphoric acid groups into cellulose. This permits the preparation of the corresponding water-soluble alkali metal or ammonium salts.

As anionic cellulose gums are more particularly mentioned carboxymethylcellulose, methyl cellulose-m-sulfobenzoate, ethyl cellulose-sulfosuccinate and acetyl cellulose sulfosuccinate.

As preferred synthetic water-soluble resins are mentioned copoly (styrene/maleic anhydride) (50/50), water-soluble homoand copolymers of ethylene oxide and/or propylene oxide, e.g., the water-soluble alkylene oxide units containing polymers described in the US. Pat. specification No. 2,848,330 and the United Kingdom Pat. specifications Nos. 920,637945,857-945,340 and 940,051 and further watersoluble-melamine-formaldehyde resins.

It has to be noted that in the method of incorporating photographic ingredients into hydrophilic colloids according to the present invention the use of mixtures of the above-mentioned solvents in combination with mixtures of the above-cited water-soluble colloids is also included.

The amount of the water-soluble colloid(s) which are added to a gelatin silver halide emulsion together with the photo graphic ingredient can be comprised between 5 percent and 33 percent by weight in respect of the total weight of binder of the silver halide grains and is preferably between 15 percent and 25 percent.

The solvent or solvents can be removed by washing the gelled and noodled light-sensitive composition, or by evaporation from the gelled light-sensitive emulsion under vacuum.

Remaining amounts of the polar solvents used in the present invention do not cause desensitization or fogging of the lightsensitive silver halide emulsion.

DESCRIPTION OF PREFERRED EMBODIMENT In preparing photographic color emulsions, the following preferred embodiment is applied.

A slightly water-soluble color coupler containing (a) sulphonic acid or (a) carboxylic acid group(s) in free acid or salt form is dissolved, normally by heating preferably between 50 and 80 C. in one of the said polar solvents or a mixture of such a polar solvent and a solvent having a dielectric constant at 20 C. lower than that of ethylene glycol, the less polar solvent however being present only in minor amounts (e.g., 5 to percent by weight) and the solution obtained is thoroughly mixed with a solution of at least one of the said water-soluble high-molecular weight compounds which are dissolved in water or a mixture of water and one of the said polar solvents. Care is taken that the amount of water does not surpass the quantity at which a stable dispersion can no longer be obtained. Thus, a stable transparent composition can be formed, which can be stored for weeks. The said composition is preferably incorporated by stirring into the melted gel of the light-sensitive gelatin silver halide emulsion whereupon the composition obtained is gelled and the polar solvent(s) is (are) removed at least partially by washing the gelled composition with water.

The photographic coatings, when prepared according to the color coupler incorporating technique as described above, produce on color development very sharp, highly transparent colored images.

OTHER EMBODIMENTS AND MODIFICATIONS.

The use of a little wetting agent facilitates the dispersion of the photographic ingredient in the hydrophilic colloid medium. Examples of suitable moistening agents are saponin, arylalkyl sulphonates and polyoxyalkylene compounds, more particularly:

wherein: n is a positive integer from 5 to 50.

As solvents having a dielectric constant (5) lower than that of ethylene glycol (=38.6 at C.) and suitable for use in mixtures substantially consisting of the above strong polar solvents may be mentioned, e.g., ethanol, isopropanol, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether monoacetate, ethylene glycol mono-n-butyl ether, diacetone alcohol, methyl ethyl ketone, tetrahydrofurane, dioxane and ethylene glycol dimethyl ether.

EXAMPLES The following examples illustrate the present invention without limiting it thereto. EXAMPLE I 1 gm. of color coupler having the following structural formula:

SOaNB is dissolved at 60 C in 10 ml. of tetrahydrothiophene-l :ldioxide. The solution obtained is added, while stirring, to a solution of l gm. of ethyl cellulose-a-(B-sulpho )monosuccinate (DS ethoxy 2.2, DS B-sulpho monosuccinic acid ester 0.8, viscosity at 20 C. of a 2 percent solution in water 4 cp.) and 1 ml. of saponine, in 10 ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 50 gm. of a red-sensitized silver bromoiodide emulsion containing 0.33 mole of silver bromide, 0.0075 mole of silver iodide and gm. of gelatin per kg. of emulsion.

Then the emulsion is coated onto a cellulose triacetate support and the coating is dried at 40 C.

EXAMPLE 2 1 gm. of color coupler having the following structural formula is dissolved at 50 C in 10 ml. of N-methyl-2-pyrrolidinone. The solution obtained is added, while stirring, to a solution of 1 gm. of hydroxy ethyl cellulose (DS 0.85, MS:l.33 and viscosity of a 2 percent aqueous solution at 20 C.: l 1.2 cp.), and 1 ml. of saponine in IQ ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 50 gm. of a green-sensitized silver bromoiodide emulsion containing 0.33 mole of silver bromide, 0.0075 mole of silver iodide and gm. of gelatin per kg. The emulsion obtained is allowed to cool and the obtained gel noodled and washed for 90 minutes with cold water. The noodles are then remelted at 50 C whereupon the emulsion is coated in the usual manner.

EXAMPLE 3 1 gm. of color coupler having the following structural formula is dissolved at 60 C in 10 ccs. of formamide. The solution obtained is added, while stirring, to a solution of l g. of methyl cellulose-m-sulphobenzoate (DS methoxy L78, B8 msulphobenzoic acid ester 0.62, viscosity of a 2 percent aqueous solution at 20 C. 3.5 cp.) and 1 ml. of saponine in 10 ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 60 gm. of a positive silver bromoiodide emulsion containing 80 gm. of gelatin, 0.33 mole of silver bromide and 0.0075 mole of silver iodide. The emulsion is coated onto a cellulose triacetate support and then dried at 40C. EXAMPLE 4 1 gm. of color coupler having the following structural formula:

is dissolved at 80 C. in ml. of ethylene glycol. The solution obtained is added while stirring to a solution of 1 gm. of carboxy methyl amylose (DS 1.2, viscosity of a 2 percent aqueous solution at C. 20 cp.) and l ml. of saponine in 10 ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 60 gm. of a positive silver bromoiodide emulsion containing 80 gm. of gelatin, 0.33 mole of silver bromide and 0.0075 mole of silver iodide. The emulsion is coated onto a cellulose triacetate support whereupon the coating is dried at 40 C.

EXAMPLE 5 1 gm. of color coupler having the following structural formula:

SO Na is dissolved at 80 C. in 10 ml. of glycerol. The solution obtained is added while stirring to a solution in 10 ml. of water of 1 gm. of copoly (styrene/maleic anhydride)( 50/50) (intrinsic viscosity [1;] measured at C. in acetone 0.22) and 1 ml. of saponine.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 60 gm. of a positive silver bromoiodide emulsion containing 80 gm. of gelatin, 0.33 mole of silver bromide and 0.0075 mole of silver iodide. The emulsion is coated onto a cellulose triacetate support whereupon the coating is dried at 40 C.

EXAMPLE 6 1 gm. of color coupler having the following structural formula:

is dissolved at 80 C. in l0 ml. of formamide. The solution obtained is added while stirring to a solution of 1 gm. of copoly(styrene/maleic anhydride)(SO/SO) (intrinsic viscosity [1 measured at 25 C. in acetone 0.22), and 1 ml. of saponine in 10 ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 60 gm. of a positive silver bromoiodide emulsion containing 80 gm. of gelatin, 0.33 mole of silver bromide and soan 0:0 N l I ll mcc-Nncois dissolved at 60 C. in 10 ml. of dimethyl sulphoxide. The solution obtained is added, while stirring to a solution of 1 gm. of hydroxy ethyl cellulose (DS 0.85, MS 1.33, viscosity at 20 C. of a 2 percent aqueous solution l 1.2 cp.), and 1 ml. of saponine in 10 ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 60 gm. of silver bromo-iodide emulsion containing 0.33 mole of silver bromide, 0.0075 mole of silver iodide and gm. of gelatin per kg. of emulsion.

The emulsion is coated onto a cellulose triacetate support whereupon the coating is dried at 40 C.

EXAMPLE 8 1 gm. of color coupler having the following structural formula is dissolved at 60 C. in i0 ml. of formamide. The solution obtained is added while stirring to a solution of l g. of NIKRU- LAN HW (Registered Trademark for a water-soluble melamine-formaldehyde textile resin of Cassella Farbwerke Mainkur A.G. Frankfurt (Main) W-Germany) in 10 ml. of water.

A homogeneous and very fine dispersion of color coupler is obtained. The said dispersion is mixed at a temperature of 38 C. with 60 gm. of a positive silver bromo-iodide emulsion containing 80 gm. of gelatin, 0.33 mole of silver bromide and 0.0075 mole of silver iodide. The emulsion is coated onto a cellulose triacetate support whereupon the coating is dried at 40 C.

EXAMPLE 9 1 gm. of color coupler as described in example 8 is dissolved at 60 C. in formamide. The thus obtained solution is added while stirring to a solution of 1 gm. of methyl cellulose-msulphobenzoate (DS methoxy 1.78, DS m-sulphobenzoic acid ester 0.62, viscosity of a 2 percent aqueous solution at 20 C. 3.5 cp.) in 5 ml. of formamide. The solution obtained is mixed at a temperature of 38 C. with a mixture of 60 gm. of a positive emulsion as described in example 8, 20 ml. of water and 1 ml. of saponine. The thus prepared light-sensitive composition is coated onto a cellulose triacetate support and dried at 40 C.

EXAMPLE l0 1 gm. of color coupler as described in example 5 is dissolved in 5 ml. of ethylene glycol. The obtained solution is added while stirring to a solution of 1 gm. of copoly(styrene/maleic anhydride) (50/50) (intrinsic viscosity [1;] measured at 25 C.

i acetone 012) i a mi of L of meth ol and 5 l, to the desired thickness in order to form a yellow lilter layer. of water. The thus obtained solution is mixed at a temperature we l im: of 38 C. with a mixture of 60 gm. of a p i i l i as l. A method of incorporating a slightly water-soluble photodescribed in example 8, ml. of water and 1 ml. of saponine. p ingredient containing a watr'solubililiflg g p into a The thus prepared emulsion yields very clear magenta image 5 gelatin solution or photographic gelatino silver halide emul- EXAMPLE 1 1 sion comprising the steps of 0.5 gm. of a dye having the following structu l f l 1. dissolving the photographic ingredient in a photographiis dissolved at 50 C. in 15 ml. of N-methylpyrrolidinone. The cally inert organic water-miscible liquid consisting essensolution obtained is added while stirring to a solution of 1 gm. tially of tetrahydrothiophene-l ,l-dioxide, N-methyl-2- of (poly-hydroxyethyl)-polyhydroxyethyl-methyl)-methyl celpyrrolidinone, ethylene glycol, glycerol, acetonitrile or lulose in 30 ml. of N-methylpyrrolidinone. The solution obformamide. tained can be incorporated homogeneously into a melted 2. forming a dispersion of the photographic ingredient by gelatin gel (i.e., a gelatin sol or gelatin solution) or coated mixing the solution obtained with an aqueous solution of directly on a transparent support to the desired thickness in a hydrophilic photographically inert colloid miscible with order to form an antihalation layer (absorption maximum 435 gelatin, said colloid being selected from the group connm.). sisting of agar-agar, amylose, amylopectine, nonionic EXAMPLE l2 starches, anionic starches, water-soluble alginic acid Example 11 is repeated but in lieu of l gm. of the cellulose derivatives, nonionic cellulose gums, anionic cellulose derivative, 1 gm. of the (B-dimethyl amino ethyleneoxy gums, synthetic water-soluble resins selected from the propyl ester) ('y-hydroxy propyl ester) (fi-dimethyl group consisting of vinyl polymers containing vinyl alaminoethyl ester (B-dimethylaminoethyl ether) of alginic cohol N-vinylp olidinone, vin l methyl ether, maleic acid is anhydnde, acry 1c acid and salts ereof, methacryhc acid EXAMPLE 13 and salts thereof, maleic acid and salts thereof or acryla- 0.5 gm. of the dye of example 11 is dissolved at 50 C. in 15 I mid: water'soluble polymers containing alkylene ml. of acetonitrile. The solution obtained is added, while stiroxide unllsi water'soluble pl'epolyco ndensate s and ring, to a solution of 1 gm. of methylcellulose in 30 ml. of 40 Polycolldensates that are lfncible wlth gelatm and water and 2 ml. of a 80 percent aqueous solution of n-dodecyl selected from the group conslsnng of iater'soluble urea sodium sulphate. A very fine dispersion of the dye is obtained formaldehyde watef'sPluble melammefmmaldehlde, which can be homogeneously mixed with a melted gelatin gel water'soluble guanamme-fol'maldellyde Water-Soluble or coated directly as a filter layer on a transparent support. alkyd and walersoluble Polyester "isms, and EXAMPLE 14 3. homogeneously distributing the obtained dispersion into 0 5 gm EYE d f example 1 1 i dissolved at 15 a gelatin solution or a photographic gelatino silver halide ml. of formamide. The solution obtained is added, while stiremulsion ring, to a solution of 1 gm. of hydroxyethyl cellulose (with The method according claim wherein the P DS=0.85, MS=1.33 and a viscosity of a 2 percent aqueous graphic ingredient is a dye or a Color p comaln'mg a solution at 20 c. of 11.2 cp.) in 30 ml. of formamide. The 50 water-solubililing group being a carboxylic acid or sulphonic solution obtained can be incorporated homogeneously in a acid groupsln free acid or Salt formmelted gelatin gel or coated directly on a transparent support

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2870012 *Dec 23, 1955Jan 20, 1959Eastman Kodak CoMicrodispersions of photographic color couplers
US3050394 *Sep 30, 1959Aug 21, 1962Gen Aniline & Film CorpMethod of incorporating color couplers in hydrophlic colloids
US3287133 *Mar 1, 1963Nov 22, 1966Eastman Kodak CoPhotographic dye developer dispersions utilizing water-soluble sulfites
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4214047 *May 4, 1979Jul 22, 1980Eastman Kodak CompanyPhotographic elements having hydrophilic colloid layers containing hydrophobic addenda uniformly loaded in latex polymer particles
US4247627 *Oct 10, 1979Jan 27, 1981Eastman Kodak CompanyPhotographic elements having hydrophilic colloid layers containing hydrophobic ultraviolet absorbers uniformly loaded in latex polymer particles
US4395479 *Aug 17, 1982Jul 26, 1983J. T. Baker Chemical CompanyUsing a 2-pyrrolidinone and tetrahydrothiophene 1,1-dioxide
US4957857 *Dec 23, 1988Sep 18, 1990Eastman Kodak CompanyStabilization of precipitated dispersions of hydrophobic couplers
US5015564 *Jun 1, 1990May 14, 1991Eastman Kodak CompanyStabilizatin of precipitated dispersions of hydrophobic couplers, surfactants and polymers
US5087554 *Jun 27, 1990Feb 11, 1992Eastman Kodak CompanyStabilization of precipitated dispersions of hydrophobic couplers
US5256527 *Sep 9, 1991Oct 26, 1993Eastman Kodak CompanyAnionic surfactant, nonionic water soluble polymer
US5607828 *Jun 14, 1996Mar 4, 1997Eastman Kodak CompanyHigh chloride {100} tabular grain emulsions improved by peptizer modification
Classifications
U.S. Classification430/377, 430/390, 430/569
International ClassificationG03C1/005, G03C7/388, G03C1/825
Cooperative ClassificationG03C7/388, G03C1/005, G03C1/825
European ClassificationG03C7/388, G03C1/005, G03C1/825