US2527268A - Production of photographic emulsions - Google Patents

Production of photographic emulsions Download PDF

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US2527268A
US2527268A US84486A US8448649A US2527268A US 2527268 A US2527268 A US 2527268A US 84486 A US84486 A US 84486A US 8448649 A US8448649 A US 8448649A US 2527268 A US2527268 A US 2527268A
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complex
emulsion
gelatin
soluble
emulsions
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Hart John Alfred Henry
Pankhurst Kenneth Georg Alfred
Smith Robert Charles Morris
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Ilford Imaging UK Ltd
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Ilford Ltd
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    • 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
    • G03C1/015—Apparatus or processes for the preparation of emulsions

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  • the precipitated complex may-- contain a -smallproportion of water and-this be "includedinthe organicsolventdispersion.
  • a photographicemulsion so formed a proportion of -anothercolloid-which is soluble in the solvent medium already present i in the emulsion, or; which is solubl'e in' a solvent medium which --is miscible with' the solvent medium already present'in the emulsiong to f orr'n a stable combination.
  • Thegelatin/sulph'onate complexes containing silver halide may be 'p'repar'ed-by the addition of the sulphonic acid or sulphonatesolution to the gelatin silver halide'emuls-ion and allowing the gelatin complex to-sedimei'lit”outr
  • the complexes may be redispersed ⁇ in the organic solvent medium without 'wash'ing;'butit-is preferred'to-vvash the complex to'remov'e un antecl i'ons'; -Instead of the sulphonic acidits'el- --it is preferred to use the corresponding soluble saltsowingto-the rela tive insolubility of the 'free aciidsf 51
  • the precipitated gelatin/sulphonate; complex shouldbe soluble in water-miscible solvents since the precipitated complex invariably contains water, and itisdifficult to remove this water without adversely afiecting the quality ot'the emulsion.
  • it-* isfgenerally desirable to treat the emulsion at a pH below the isoelectric pointof' the gelatin and in the presence of as little-electrolyteas'possible:
  • organic solvents J for dispersing the complexes are those containing hydroxy groups, e. g ⁇ methyl and ethyl alcohols, ethylene glycol mono methyl ether; ethyl lactate and diaceto ne alcohol.
  • Organic solvents not containing hydroxy groups are generally only useful together withfsojme water, ci some hy'droxy so1ve e, g. acetone, meth l ethyl letone; di-
  • the complexesrfnay be; sv réelle; in; the organic solvent 11 medium and dispersion is usually facilitated by gentlei warmmg. l r a
  • the following table showsaexamples of the preferred conditionsfor -precipitatinga gelatin/sul'phonate complex using-various sodium sulphornatcs.
  • complex (a) in solution in aqueous alcohol is not precipitated by the addition of excess alcohol and this complex is also very soluble in carbon tetrachloride, acetone and ethyl acetate.
  • Complex (1)) in solution in aqueous alcohol is precipitated by the addition of excess alcohol and this complex is also soluble in ethyl acetate and very soluble in acetone; the same remarks apply tocomplex Complex (e) in solution in aqueous alcohol is .precipitated by excess alcohol, and complex (1) in solution in aqueous alcohol is precipitated 'by the addition of excess water.
  • the gelatin concentration was 0.5% and the temperature was 35 C. in each case.
  • an important feature of this invention is the formation of photographic emulsions which comprise a gelatin/sulphonate complex, containing silver halide, dispersed in an organic solvent medium, together with a proportion of another colloid soluble in such organic solventmedium or in an organic solvent medium miscible therewith.
  • Such other colloids may be, forv example, cellulose esters, e. g. cellulose nitrate, cellulose acetate, far-hydrolysedv cellulose esters (e. g.
  • cellulose acetate having an acetyl content of to;%), polyvinyl acetates, polyvinyl acetals, methyl methacrylate polymers and the partial hydrolysis products thereof, alkyd resins, and mixed interpolymers suchas the interpolymers of maleic acid or anhydride with styrene or methyl methacrylate.
  • Example II To a photographic emulsion in methyl alcohol obtained in Example I wasadded, in turn:
  • Ethylene glycol mono-methyl ether 'cc 400 Low viscosity cellulose nitrate (10% solution ...in methyl alcohol) cc 300 Acetone cc 400 the need for any special substratum or anchoring l,
  • Example I the precipitated complex was re-dispersed in methyl alcohol to form an emulsion for coating
  • other watervmiscible solvents may be used, for example ethyl emulsion from which alcohol and ethylene glycol monomethyl ether.
  • the silver halide emulsions of this invention may contain any of the usual additions to silver halide emulsions, e. g. optical sensitising dyes, sulphur sensitisers as for instance allyl isothiocyanate, goldsalts as described in U. S. P. 2,399,- 083, stabilisers, anti-fogging agents, toning agents and other agents for modifying the speed, contrast, graininess, fog level and image colour of the products.
  • optical sensitising dyes e.g. optical sensitising dyes, sulphur sensitisers as for instance allyl isothiocyanate, goldsalts as described in U. S. P. 2,399,- 083, stabilisers, anti-fogging agents, toning agents and other agents for modifying the speed, contrast, graininess, fog level and image colour of the products.
  • sulphur sensitisers as for instance allyl isothiocyanate
  • goldsalts as
  • the invention provides photographic emulsions having a gelatin basis dispersed in organic solvent and the emulsions are therefore of value in a number of special applications. As already indicated they are of particular value for spray coating. Normal gelatin silver halide emulsions present considerable difficulties in spray coating since it is usually necessary to maintain the emulsion warm in the spray-gun to prevent it setting therein. Moreover, the ordinary emulsions will not adhere firmly if sprayed on to lacquered metal sheet. Emulsions may be prepared according to this invention, however, which have little tendency to set in the spray-gun. Moreover, the organic solvent usually has a slight solvent action on lacquered surfaces and thus facilitates adhesion between such surfaces and the emulsion sprayed thereon.
  • the spray-coating of lacquered metal sheets with photographic emulsion is of particular value in the production of photo-templates.
  • the users generally prefer that the emulsion should be supplied in dry granular condition so that it maybe re-dispersed when required to form an emulsion suitable for spraying.
  • the present emulsions are especially suitable in this connection.
  • Emulsions prepared in organic solvent media according to this invention can easily be derived by the Well-known expedlents of film drying, spray drying, and air drying of the emul- I sion in the form of a shredded set jelly, since the organic solvent readily evaporates.
  • a further method is to precipitate the emulsion by adding it to water and, after breaking up the precipitate, to air-dry the product.
  • the emulsions of this invention canbe used in any process where spray-coating is required.
  • the production of photo-templates has already been mentioned, and another useful application is in the preparation of dials, nameplates and the like on metal or other surfaces.
  • a further application is in the preparation of silk-screen printing surfaces. In this application the emulsion is sprayed on to stretched silk, dried, exposed, developed in a tanning developer and washed in hot water to produce a wash-out reliefimage.
  • the emulsions of this invention are also of value in colour photography.
  • they may contain dyes or dye-intermediates, e. g. colourformers which react with the oxidation products of aromatic primary amino developing agents to form quinone-imine or azo-methine dyes, the colour-former being uniformly dispersed in the emulsion.
  • the colour-former especially where particulate or of very high molecular weight, may be included in the original emulsion and precipitated with thecomplex, or it may be added to the final emulsion.
  • the emulsions of this invention are permeable to ordinary alkaline developers, but the degree of permeability depends on the precise constitution of the emulsion.
  • an additional colloid e. g. cellulose nitrate or a hydrophobic acid colloid
  • emulsions of varying degree of developer-permeability may be made, and accordingly it is possible to build up a multilayer photographic material for colour photography in which the several layers have different degrees of permeability to ordinary developers and, by adjusting the constitution of the developers, e. g. by adding organic solvents, to develop each of the layers separately.
  • aromatic primary amino developing agents containing different colour-formers images in different colours may be formed in the various layers, and by a suitable selection of colour-formers a final true-colour image may be obtained.
  • emulsions of this invention may be put in the production of printing paper to be used for printing from wet negatives.
  • the emulsions of this invention have a good resistance to water, though they are readily developed by ordinary alkaline developing solutions.
  • Paper coated with emulsion according to this invention may be used for printing from wet negatives, though it is usually desirable to employ an emulsion containing a proportion of other colloids, e. g. cellulose nitrate and a methyl methacrylate-methacrylic acid co-polymer.
  • Such emulsions not only have "a good resistance to water but also a good resistance to hypo, which may be carried bv the wet negative.
  • the emulsion should be supercoated with a layerof a plain gelatin/anion soap complex in organic solvent, as described in our copending application Serial No. 623,446, or a plain gelatin/sulphonate complex in organic solvent as described in co-pending application Serial No. 84,485, filed March 30, 1949, which is a continuation-in-part of application No. 623,446.
  • a photographic emulsion containing a complex of gelatin and a sulphonic acid containing a highly hydrophobic radiole in the anion, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
  • a photographic emulsion containing a complex of gelatin and a sulphonic acid containing a highly hydrophobic radicle in the anion, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium containing methyl alcohol and acetone, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
  • a photographic emulsion containing a complex of gelatin and a naphthalene mono sulphonic acid, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
  • a photographic emulsion containing a complex of gelatin and a naphthalene mono sulphonic acid, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium containing methyl alcohol and acetone, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
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Description

Patented Get. 24,
red; Pankhutst, es" Morris Smith 1, more; England; 'afssignorS to 11mm Limited?" anrjitish co ally Application Marchfilk n'iejreap Britai'n' October so, 1944 i g gplaims', (01;:95zr7 This mventionrelates to theproduction'ot N silver"halide-photographic emulsionsw- Ithas been discovered. that when there added to an emulsion of silver-' halide inigelatinfait alow pH value, -a-su'lphonic acidcontaining a highly hydrophobic radicle-inthe-ani'on, elf-coma plex is formed between the gelatin andsulph'onic acid and this separates out carrying-thesilven halide with it. It -has further been discovered that complexes thusformed are readil'y 'dis'pe-rsible in organic.solvents,- e; g: methyl alcoholf The term -sulphonic acid is to beunderstood to include sulphonates. Accordingto thisinvention, therefore, photographic emulsions in-whichi the solvent medium is predominantly organic are formed by dispersingin an or'ganic solvent =m=edium a complex formed by-precipitating gelatin from its aqueous dispersioncontaining silver halide in suspensiongby means of a sulplionic acid containing a highly" hydrophobic radicle m the anion, thesaid aqueous --dispersion being" at: a pH valuev below the isoelectricpoi'nt cf th'e gelatin; The precipitated complex may-- contain a -smallproportion of water and-this be "includedinthe organicsolventdispersion. According to a further feature of the inven-l tion, there is included ina photographicemulsion so formed a proportion of -anothercolloid-which is soluble in the solvent medium already present i in the emulsion, or; which is solubl'e in' a solvent medium which --is miscible with' the solvent medium already present'in the emulsiong to f orr'n a stable combination. 1
Thegelatin/sulph'onate complexes containing silver halide may be 'p'repar'ed-by the addition of the sulphonic acid or sulphonatesolution to the gelatin silver halide'emuls-ion and allowing the gelatin complex to-sedimei'lit"outr The complexes may be redispersed {in the organic solvent medium without 'wash'ing;'butit-is preferred'to-vvash the complex to'remov'e un antecl i'ons'; -Instead of the sulphonic acidits'el- --it is preferred to use the corresponding soluble saltsowingto-the rela tive insolubility of the 'free aciidsf 51 The quantity ofsulphonic acidor sulphonate employed relative to fthegelatin 'm'ayvaryf'but there is no advantage to be gaind'by using a quantity greater than the stoich' iometric 'equi-va lent, i. e. about 10 rn gm. moles per gram of dry gelatin. f
For emulsion-making it is generallydesirable that the precipitated gelatin/sulphonate; complex shouldbe soluble in water-miscible solvents since the precipitated complex invariably contains water, and itisdifficult to remove this water without adversely afiecting the quality ot'the emulsion. To this end it-* isfgenerally" desirable to treat the emulsion at a pH below the isoelectric pointof' the gelatin and in the presence of as little-electrolyteas'possible:
gsgs riall any sulphoniea'cid 0f1WhiCh-the alkali or am monium salt is soluble in water and of whichv the anion is highly hydrophobic may lie-employed. These maybe simpleacids, forexample naphthalene2-sulphonic acid; naphthalene 1.5- disulphonic it acid, naphthalene 1-:3t5'-tri-sulphonic= acid; Z-naphthol-I -sulphonic acid; 2"+naphthole-;
6 sulphonic acid} l-naphthol-a-sulphonic acid,,
tains a sulphoaryl-pyrazolone radicle; Naph thalene Orange GS .(ImperiaL Chemical Indus-v tries Ltd-. and Tartrazine.
In general-it is'preferred to form: thecomplex from amaqueous gelatino-silverhalide. emulsion whiehhas alreadybeen washed and digested;
Generally speaking the: most suitable organic solvents J for dispersing the complexes are those containing hydroxy groups, e. g} methyl and ethyl alcohols, ethylene glycol mono methyl ether; ethyl lactate and diaceto ne alcohol. Organic solvents not containing hydroxy groupsare generally only useful together withfsojme water, ci some hy'droxy so1ve e, g. acetone, meth l ethyl letone; di-
\ methylenefchloride, chloroform' and p i eb s" s admixture U methyl alcohol. Srnallquantities Qt ers th l ac te Wy acme etherfs e. g. .diethyl ether, .andfhydrocarbonse g, benzene and toluene, may-also be included in the lven m dium- The c oice (i b t l pend; on the particular nature of the complex; Solubility in, toluene and; chloroform appears to ncr a e th sre tea h u nt we s phonate lative gelatin. The complexesrfnay be; svvollen; in; the organic solvent 11 medium and dispersion is usually facilitated by gentlei warmmg. l r a The following table showsaexamples of the preferred conditionsfor -precipitatinga gelatin/sul'phonate complex using-various sodium sulphornatcs.
tSolubility; clliaracl 4 ifi i flfi PE? I g gg cipitated complex Sulphomc.Acl l d umsal l j 0 8, n: A
, queous Toluene 141001101;
. V Grams (iz) naphthalene-2-sulphonic acid 2.3 s ,vs (b) naphthalene 1.5 disulphonic acid 1.61 v s, vs (0) naphthalene 1.3.5 trisulphonic '21 id. 1.44:. 1 55 (d ZnaphthobG-sulphomc ac d s (e) l-naphthol b s (f) Tartrazine nq -l.102:0- i vs s=solub1e; vs==very soluble; ss slightly ,solublcyiaingoluble;
Referring to this table, complex (a) in solution in aqueous alcohol is not precipitated by the addition of excess alcohol and this complex is also very soluble in carbon tetrachloride, acetone and ethyl acetate. Complex (1)) in solution in aqueous alcohol is precipitated by the addition of excess alcohol and this complex is also soluble in ethyl acetate and very soluble in acetone; the same remarks apply tocomplex Complex (e) in solution in aqueous alcohol is .precipitated by excess alcohol, and complex (1) in solution in aqueous alcohol is precipitated 'by the addition of excess water.
In the preparation of the complexes referred to in this table the gelatin concentration was 0.5% and the temperature was 35 C. in each case.
As already indicated, an important feature of this invention is the formation of photographic emulsions which comprise a gelatin/sulphonate complex, containing silver halide, dispersed in an organic solvent medium, together with a proportion of another colloid soluble in such organic solventmedium or in an organic solvent medium miscible therewith. Such other colloids may be, forv example, cellulose esters, e. g. cellulose nitrate, cellulose acetate, far-hydrolysedv cellulose esters (e. g. cellulose acetate having an acetyl content of to;%), polyvinyl acetates, polyvinyl acetals, methyl methacrylate polymers and the partial hydrolysis products thereof, alkyd resins, and mixed interpolymers suchas the interpolymers of maleic acid or anhydride with styrene or methyl methacrylate.
The-following examples illustrate the invention, but are not to be regarded as limiting it in a y YZ Example I 1 1000 cc. of an aqueous gelatino silver bromid emulsion' contalning 11% gelatin and 17% silver bromide wasbrought to pH 2.0-2.4 by addition of 10 cc. concentrated hydrochloric acid. To this was added 400 cc. of an 8% solution in water of sodium 2-naphthalene monosulphonate. The gelatin/sulphonate complex (containing suspended silver bromide) separated as a stiff oily complex. The supernatant liquid was decanted and the complex-dissolved in warm methyl alcohol to form a 7% solution. This was a satisfactory photographic emulsion and could be coated in the usual way. Its sensitometric characteristies were substantially the same as those of the original aqueous gelatin it was obtained.
Example II To a photographic emulsion in methyl alcohol obtained in Example I wasadded, in turn:
Ethylene glycol mono-methyl ether 'cc 400 Low viscosity cellulose nitrate (10% solution ...in methyl alcohol) cc 300 Acetone cc 400 the need for any special substratum or anchoring l,
layer since it adhered strongly to the lacquer coating both in the dry condition and during all stages of processing. The emulsion developed normally, and it was found that the coating was not melted by hot water.
Although in the above Example I the precipitated complex was re-dispersed in methyl alcohol to form an emulsion for coating, other watervmiscible solvents may be used, for example ethyl emulsion from which alcohol and ethylene glycol monomethyl ether.
The silver halide emulsions of this invention may contain any of the usual additions to silver halide emulsions, e. g. optical sensitising dyes, sulphur sensitisers as for instance allyl isothiocyanate, goldsalts as described in U. S. P. 2,399,- 083, stabilisers, anti-fogging agents, toning agents and other agents for modifying the speed, contrast, graininess, fog level and image colour of the products.
The invention provides photographic emulsions having a gelatin basis dispersed in organic solvent and the emulsions are therefore of value in a number of special applications. As already indicated they are of particular value for spray coating. Normal gelatin silver halide emulsions present considerable difficulties in spray coating since it is usually necessary to maintain the emulsion warm in the spray-gun to prevent it setting therein. Moreover, the ordinary emulsions will not adhere firmly if sprayed on to lacquered metal sheet. Emulsions may be prepared according to this invention, however, which have little tendency to set in the spray-gun. Moreover, the organic solvent usually has a slight solvent action on lacquered surfaces and thus facilitates adhesion between such surfaces and the emulsion sprayed thereon.
The spray-coating of lacquered metal sheets with photographic emulsion is of particular value in the production of photo-templates. In the commercial application of this process, however, the users generally prefer that the emulsion should be supplied in dry granular condition so that it maybe re-dispersed when required to form an emulsion suitable for spraying. The present emulsions are especially suitable in this connection. Emulsions prepared in organic solvent media according to this invention can easily be derived by the Well-known expedlents of film drying, spray drying, and air drying of the emul- I sion in the form of a shredded set jelly, since the organic solvent readily evaporates. A further method is to precipitate the emulsion by adding it to water and, after breaking up the precipitate, to air-dry the product.
The emulsions of this invention, either as originally prepared or as re-constituted after drying, canbe used in any process where spray-coating is required. The production of photo-templates has already been mentioned, and another useful application is in the preparation of dials, nameplates and the like on metal or other surfaces. A further application is in the preparation of silk-screen printing surfaces. In this application the emulsion is sprayed on to stretched silk, dried, exposed, developed in a tanning developer and washed in hot water to produce a wash-out reliefimage. It is a peculiar characteristic of the emulsions of this invention that, though quite insoluble in water when coated, they tend to become soluble when allowed to stand in contact with alkali, as in normal development, though the emulsions are still not soluble in water except at high temperatures. Fixing in an acid fixing bath, however, restores the insolubility of the complex even in hot water. Thus a suitable technique for using the emulsions in the production of silk-screen relief images is to develop the exposed image in alkaline pyrocatechol, plunge the silk into hot water and then to fix the wash-out relief image. An alternative technique is to prepare the wash-out relief image on a support from which it may be stripped and to transfer the image to a silk support.
The emulsions of this invention are also of value in colour photography. Thus they may contain dyes or dye-intermediates, e. g. colourformers which react with the oxidation products of aromatic primary amino developing agents to form quinone-imine or azo-methine dyes, the colour-former being uniformly dispersed in the emulsion. The colour-former, especially where particulate or of very high molecular weight, may be included in the original emulsion and precipitated with thecomplex, or it may be added to the final emulsion. Many of the high-molecular weight colour-formers, which are preferred from the standpoint of being non-diffusing in the emulsion, are difi'lcult to disperse in ordinary aqueous gelatin silver halide emulsions, but more easily dispersed in the organic solvent emulsions of this invention. 7
The emulsions of this invention are permeable to ordinary alkaline developers, but the degree of permeability depends on the precise constitution of the emulsion. By a suitable selection of an additional colloid, e. g. cellulose nitrate or a hydrophobic acid colloid, emulsions of varying degree of developer-permeability may be made, and accordingly it is possible to build up a multilayer photographic material for colour photography in which the several layers have different degrees of permeability to ordinary developers and, by adjusting the constitution of the developers, e. g. by adding organic solvents, to develop each of the layers separately. In such a process, by using aromatic primary amino developing agents containing different colour-formers, images in different colours may be formed in the various layers, and by a suitable selection of colour-formers a final true-colour image may be obtained.
Another use to which the emulsions of this invention may be put is in the production of printing paper to be used for printing from wet negatives. As already stated the emulsions of this invention have a good resistance to water, though they are readily developed by ordinary alkaline developing solutions. Paper coated with emulsion according to this invention may be used for printing from wet negatives, though it is usually desirable to employ an emulsion containing a proportion of other colloids, e. g. cellulose nitrate and a methyl methacrylate-methacrylic acid co-polymer. Such emulsions not only have "a good resistance to water but also a good resistance to hypo, which may be carried bv the wet negative. Advantageously, in the production of wet-printing paper using the emulsions of this invention the emulsion should be supercoated with a layerof a plain gelatin/anion soap complex in organic solvent, as described in our copending application Serial No. 623,446, or a plain gelatin/sulphonate complex in organic solvent as described in co-pending application Serial No. 84,485, filed March 30, 1949, which is a continuation-in-part of application No. 623,446.
What we claim is:
1.. A photographic emulsion containing a complex of gelatin and a sulphonic acid containing a highly hydrophobic radicle in the anion, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium.
2. A photographic emulsion containing a complex of gelatin and a sulphonic acid containing a highly hydrophobic radiole in the anion, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
3. A photographic emulsion containing a complex of gelatin and a sulphonic acid containing a highly hydrophobic radicle in the anion, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium containing methyl alcohol.
4. A photographic emulsion containing a complex of gelatin and a sulphonic acid containing a highly hydrophobic radicle in the anion, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium containing methyl alcohol and acetone, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
5. A photographic emulsion containing a complex of gelatin and a naphthalene mono sulphonic acid, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium.
6. A photographic emulsion containing a complex of gelatin and a naphthalene mono sulphonic acid, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
7. A photographic emulsion containing a complex of gelatin and a naphthalene mono sulphonic acid, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium containing methyl alcohol.
8. A photographic emulsion containing a complex of gelatin and a naphthalene mono sulphonic acid, said complex being soluble in a solution composed of methyl alcohol and containing dispersed silver halide, dispersed in a predominantly organic solvent medium containing methyl alcohol and acetone, said emulsion further containing a proportion of another colloid which is soluble in the said solvent medium.
JOHN ALFRED HENRY HART.
KENNETH GEORGE ALFRED PANKHURST.
ROBERT CHARLES MORRIS SMITH.
REFERENCES CITED The following references are of record in the:
file of this patent:
UNITED STATES PATENTS

Claims (1)

1. A PHOTOGRAPHIC EMULSION CONTAINING A COMPLEX OF GELATIN AND A SULPHONIC ACID CONTAINGIN A HIGHLY HYDROPHOBIC RADICLE IN THE ANION, SAID COMPLEX BEING SOLUBLE IN A SOLUTION COMPOSED OF METHYL ALCOHOL AND CONTAINING DISPERSED SILVER HALIDE, DISPERSED IN A PREDOMINANTLY ORGANIC SOLVENT MEDIUM.
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2982652A (en) * 1957-06-18 1961-05-02 Gevaert Photo Prod Nv Preparation of photographic emulsions
US3718593A (en) * 1969-02-05 1973-02-27 Fuji Photo Film Co Ltd Process for the production of an electrophotographic liquid developer containing gelatin
US3755177A (en) * 1969-02-04 1973-08-28 Xerox Corp Process of making liquid electrostatic developers containing gelatin
US4021247A (en) * 1973-11-13 1977-05-03 Fuji Photo Film Co., Ltd. Method of dispersing organic compounds useful in photography
US4119463A (en) * 1975-04-24 1978-10-10 Mitsubishi Paper Mills, Ltd. Photographic binder comprising isobutylene-maleic anhydride copolymer
US4153458A (en) * 1975-04-24 1979-05-08 Mitsubishi Paper Mills, Ltd. Photographic binder mixture of three polymers
US4965184A (en) * 1989-02-23 1990-10-23 E. I. Du Pont De Nemours And Company Silver halide emulsions with improved speed

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US1290794A (en) * 1917-05-24 1919-01-07 Eastman Kodak Co Colored photographic element and process of making the same.
US2142311A (en) * 1934-03-15 1939-01-03 Heidenhain Johannes Process for the preparation of washed out reliefs
US2304940A (en) * 1939-01-23 1942-12-15 Eastman Kodak Co Color photography
GB556360A (en) * 1942-01-28 1943-10-01 Thomas Thorne Baker Improvements in or relating to photographic processes
US2489341A (en) * 1944-07-04 1949-11-29 Ilford Ltd Production of photographic silver halide emulsions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1290794A (en) * 1917-05-24 1919-01-07 Eastman Kodak Co Colored photographic element and process of making the same.
US2142311A (en) * 1934-03-15 1939-01-03 Heidenhain Johannes Process for the preparation of washed out reliefs
US2304940A (en) * 1939-01-23 1942-12-15 Eastman Kodak Co Color photography
GB556360A (en) * 1942-01-28 1943-10-01 Thomas Thorne Baker Improvements in or relating to photographic processes
US2489341A (en) * 1944-07-04 1949-11-29 Ilford Ltd Production of photographic silver halide emulsions

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2982652A (en) * 1957-06-18 1961-05-02 Gevaert Photo Prod Nv Preparation of photographic emulsions
US3755177A (en) * 1969-02-04 1973-08-28 Xerox Corp Process of making liquid electrostatic developers containing gelatin
US3718593A (en) * 1969-02-05 1973-02-27 Fuji Photo Film Co Ltd Process for the production of an electrophotographic liquid developer containing gelatin
US4021247A (en) * 1973-11-13 1977-05-03 Fuji Photo Film Co., Ltd. Method of dispersing organic compounds useful in photography
US4119463A (en) * 1975-04-24 1978-10-10 Mitsubishi Paper Mills, Ltd. Photographic binder comprising isobutylene-maleic anhydride copolymer
US4153458A (en) * 1975-04-24 1979-05-08 Mitsubishi Paper Mills, Ltd. Photographic binder mixture of three polymers
US4965184A (en) * 1989-02-23 1990-10-23 E. I. Du Pont De Nemours And Company Silver halide emulsions with improved speed

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