US2956883A - Preparation of photographic silver halide emulsions - Google Patents

Preparation of photographic silver halide emulsions Download PDF

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Publication number
US2956883A
US2956883A US663885A US66388557A US2956883A US 2956883 A US2956883 A US 2956883A US 663885 A US663885 A US 663885A US 66388557 A US66388557 A US 66388557A US 2956883 A US2956883 A US 2956883A
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United States
Prior art keywords
silver halide
parts
cellulose
sulphate
emulsion
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US663885A
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English (en)
Inventor
Pauw Alfons Jozef De
Gerbaux Rene Camille
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Gevaert Photo Producten NV
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Gevaert Photo Producten NV
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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
    • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances

Definitions

  • the present invention relates to the preparation of photographic silver halide emulsions and of photographic material, such as paper, plates and films, incorporating a layer of such an emulsion.
  • gelatin As a protective colloid for the silver halides, on account of its great peptizing power, good water-permeability and exceptional thermo-reversible gel-formation property.
  • the silver halide is formed inyan aqueous gelatin solution and an additional amount of gelatin may be added after formation of the dispersion, in order to solidify, noodle and Wash the emulsion.
  • gelatin has many disadvantages which place restrictions upon its use.
  • gelatin is susceptible to attack by animal and vegetable organisms. Insects attack it, especially in the tropics, and it is also susceptible to' the action of moulds and bacteria, particularly under conditions of high humidity and when the climate is favourable for such organisms.
  • a supply from agiven source often varies in properties from time to time.
  • emulsion coats of gelatin become very soft' in Warm water, hence processing solutions must 2,956,883 Patented Oct. 18, 19.69
  • a further object of the present invention is to prepare silver halideemulsions with high light-sensitivity even when using polyvinyl alcohol as binding agent.
  • Still another object of the present invention is the ripening of silver halide emulsions in synthetic water-permeable colloid solutions.
  • cellulose sulphates as further defined hereinafter are excellent protective colloids in which silver halide suspensions with excellent photographic properties can easily be prepared.
  • cellulose sulphate as used hereinbefore is meant to cover cellulose esters containing only sulphate groups and also mixed cellulose ether sulphates especially such as for instance hydroXy-ethyl cellulose sulphate, methyl cellulose sulphate, beta-sulpho-ethyl cellulose, and carboxy-methyl cellulose sulphate.
  • the pure cellulose sulphates considered for the present invention are water-soluble salts such as sodium-, potassiumand ammonium-cellulose sulphates. They may be obtained according to US. Nos. 2,559,914 and 2,539,451 by reacting sulphuric acid upon cellulose in the presence of an aliphatic alcohol. The reaction may be carried out at temperatures between 0 and 25 C. By neutralizing with an alkali, the corresponding desired salt is obtained.
  • the degree of esterification may be regulated by varying the concentration of the reagents and the time of reaction, and the viscosity of the endproducts in water depends on the degree of polymerization of the cellulosic starting materials, on the degrada Another difliculty is be'kept cold; also, when exposed to a dry air, such coats advantagesof such synthetic binders include: failure to I allow a growth of the silver halide crystals, liability to cause flocculation of the emulsion and insuflicient water- 'permeability.
  • Another object of the present invention is to produce in a simple way silver'halide free from water-soluble salts. 4
  • cellulose ether sulphates can be used all water-soluble derivatives such as for instance methyl cellulose sulphate, ethyl cellulose sulphate, ethoxy-ethyl cellulose sulphate, hydroxy-ethyl cellulose sulphate, ethyl-hydroxyethyl cellulose sulphate etc. with varying substitution degrees of ether functions and sulphate groups.
  • the sulphate groups can esterify the hydroxyl groups of the cellulose chain and/or the primary hydroxyl groups of the ether function.
  • cellulose sulphate can be obtained in the same w-ayas cellulose sulphate by the action of sulphuric acid upon the cellulose ether in the presence of an aliphatic alcohol.
  • the reaction circumstances: relative amounts of the reagents, temperature, duration etc. must be chosen in function of the nature of the starting products and of the desired structure and properties of the end productl
  • An example of a cellulose sulpho-ether is beta-sulphoethyl cellulose which under the form of an alkali metal salt and with a substitution degree of 0.2 is water-soluble.
  • This product can be prepared according to the methods known in the art, i.e. the action of sodium-beta-bromm ethyl sulphonate upon alkali cellulose.
  • the cellulose sulphates according to the present invention allow as protective colloids the growth of silver halide crystals and give non-flocculated suspensions with high light-sensitivity.
  • aqueous solutions of at least one silver salt for instance silver nitrate, and of at least one halide salt such as sodium chloride or potassium bromide, are mixed in the presence of the cellulose sulphates. This may be done by simultaneously pouring, whilst stirring, the salt solutions in an aqueous solution of the cellulose sulphates. In this way a suit:
  • the cellulose sulphates are completely miscible with polyvinyl alcohol.
  • the latter possesses particularly good layer-forming properties.
  • the sensitive coarse-grained suspensions of silver halide in the cellulose sulphates may be converted by the addition of polyvinyl alcohol into useful photographic emulsions, the coated layers of which possess high physical properties.
  • the emulsions When gelatin is used as binding agent, the emulsions can be gelled, noodled and washed in the usual way. If, when using polyvinyl alcohol, the emulsion is to be washed, gelling agents such as alpha-naphthol or gallic acid can be added, whereby on cooling a gel is obtained which may be washed after noodling.
  • gelling agents such as alpha-naphthol or gallic acid can be added, whereby on cooling a gel is obtained which may be washed after noodling.
  • the soluble salts may be separated from the suspension by dialysis, i.e. by diffusion through a semi-permeable membrane out of the emulsion to a solution with a low salt content.
  • a further method for obtaining method for obtaining emulsions free from water-soluble salts comprises precipitating a suspension of silver halide in the cellulose sulphates according to the present invention in a coagulating medium such as a water-miscible organic solvent, e.g. acetone, methanol, ethanol, methyl acetate and ethyl acetate, or in a concentrated aqueous solution of at least one inorganic salt such as sodium sulphate or sodium chloride.
  • a coagulating medium such as a water-miscible organic solvent, e.g. acetone, methanol, ethanol, methyl acetate and ethyl acetate
  • the precipitate thus obtained in finely divided and may easily be freed from the Water-soluble salts formed as by-products in the preparation of the silver halide by repeated washing with mixtures of water and organic solvents and decanting.
  • the powdery precipitate thus Washed forms, on addition of water, a stable suspension to which the necessary amount of binding agent, e.g. polyvinyl alcohol, may be added.
  • binding agent e.g. polyvinyl alcohol
  • Other synthetic, half synthetic, or natural polymers which are miscible with the cellulose sulphates and possess bood layer-forming properties may also be used, e.g. gelatin.
  • Any desired amount of water and binding agent may be added to the washed powdery precipitate of silver halide emulsions with Widely varying concentration, e.g. an emulsion with a high silver halide content.
  • a starting solution of the cellulose sulphates with a concentration of about 0.3% is suflicient, but greater amounts may be used.
  • the light-sensitivity of the silver halide crystals may be increased by chemical sensitization.
  • Some chemical sensitizers may also be added at the precipitation stage of the silver halide or during or after the ripening period, e.g. when before washing, a naturally active gelatin is added as binding agent for the silver halide.
  • sulphur sensitizers which possibly form silver sulphide nuclei with compounds appearing to form silver nuclei, or with compounds of gold or other heavy metals such as palladium and platinum.
  • the emulsion may be digested with naturally active gelatin, or sulphur compounds such as allyl isothiocyanate, allylthiourea, sodium thiosulphate or potassium selenocyanide may be added.
  • sulphur compounds such as allyl isothiocyanate, allylthiourea, sodium thiosulphate or potassium selenocyanide may be added.
  • the emulsions may also be chemically sensitized with compounds apparently forming silver nuclei, e.g. stannous salts, or imino-amino-methane sulphinic acid compounds 4 such as those described in the co-pending U.S.A. patent application Serial No. 581,315.
  • compounds apparently forming silver nuclei e.g. stannous salts, or imino-amino-methane sulphinic acid compounds 4 such as those described in the co-pending U.S.A. patent application Serial No. 581,315.
  • the emulsions may also be treated in the known manner with compounds of gold or other heavy metals such as ruthenium, rhodium, palladium, iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic Weight greater than 100.
  • compounds of gold or other heavy metals such as ruthenium, rhodium, palladium, iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic Weight greater than 100.
  • the process of emulsion preparation according to the present invention is particularly advantageous in that it provides a practical and economical method of emulsion preparation without using gelatin or other protein for the peptization of the silver halide, so that compounds of gold or heavy metals belonging to group VIII of the periodic table may advantageously be used as speed-increasing agents.
  • the compounds of heavy metals may advantageously be added, after removing the excess of water-soluble salts, to the re-suspended silver halide/ cellulose sulphate precipitate, to the re-melted silver halide/ polyvinyl alcohol noodles or to the emulsion which is obtained after polyvinyl alcohol (or other layer-forming polymer) is added to said re-suspended precipitate or re-melted noodles.
  • gelatin may also be used as layer-forming polymer, but in this case the gelatin is preferably added after the addition of the compounds of heavy metals.
  • ingredients such as optical sensitizing dyes, stabilizers, anti-fogging agents, color couplers, hardening agents, and wetting agents, may be added to the emulsion in any convenient manner.
  • Example I To a solution of 2 parts of sodium cellulose sulphate in 280 parts of distilled water and 50 parts of concentrated ammonia, the following two solutions were slowly and simultaneously added at 40 C. whilst stirringfand in the absence of actinic light: A. 50 parts of silver nitrate dissolved in 85 parts of distilled water, 7 B. 43 parts potassium Bromide and 1 part potassium iodide dissolved in 100 parts of distilled water.
  • the emulsion was ripened for about half an hour at the same. temperature. After ripening, the emulsion was precipitated with acetone, the supernatant liquid decanted and the precipitate repeatedly washed with a mixture of acetone and .water. in' about equal proportions and decanted. After washing, the precipitate was added to 450 parts distilled water and, afterdissolv-ing 500 parts of a 10% polyvinyl alcohol solution in water were mixed therewith. .;A ft er';thorough stirring, the emulsion was chemically ripened, with sodium thiosulphate. The finished emulsion was coated onto cellulose triacetate film. The photographic material thus obtained was relatively high-sensitive and could be normally exposed, developed, fixed and rinsed similarly to the photographic papers and films wherein gelatin is used as protective colloid.
  • Example 2 100 parts of silver nitrate, dissolved in a mixture of 80 parts of concentrated ammonia and 85 parts of distilled water, were slowly added to a solution of 50 parts of potassium bromide, 20 parts of ammonium bromide and 5 parts of potassium iodide in 450 parts of a 1% aqueous solution of sodium cellulose sulphate diluted with 200 parts of distilled water, whilst stirring, and in the absence of actinic light at 25 C.
  • the emulsion was ripened for 20 minutes at 30 C. Once the desired grain size was obtained, 1000 parts of a aqueous solution of polyvinyl alcohol were added. Whilst thoroughly stirring, 3.5 parts of alpha-naphthol dissolved in 25 parts of ethanol were added. The emulsion jellified on cooling, and after noodling, was washed for 2 hours in running water. After washing, the emulsion was re-melted and chemically ripened in the presence of sodium thiosulphate. The finished emlusion was coated onto baryta paper. The treatment in the processing baths may be the same as for the usual photographic materials with gelatin emulsions.
  • Example 3 A solution of 25 parts of silver nitrate in parts of concentrated ammonia and 20 parts of distilled water and a solution of 22 parts of potassium bromide in 25 parts of distilled water, were slowly and simultaneously added whilst stirring to a solution of 1 part of sodium cellulose sulphate and 1.25 parts potassium iodide in 115 parts of distilled Water, within 7 minutes at 50 C. The total ripening time was 40 minutes. The silver bromide grains had an average diameter of 0.5;. After ripening, 200 parts of an aqueous polyvinyl alcohol solution 10% and 50 parts of distilled water were added.
  • Example 4 To a solution of 2 parts of sodium cellulose sulphate in 200 parts of water and 20 parts of concentrated ammonia, the two following solutions were simultaneously added at 50 C. whilst stirring within 3 minutes and in the absence of actinic light:
  • the emulsion was ripened for 30 minutes at 50 C. and poured into an excess of an aqueous sodium sulphate solution 10%. After decanting the supernatant liquid, the precipitate was repeatedly washed with a mixture of water and alcohol. Next, 300 parts of distilled water were added and the whole heated at 35-40 C. until completely dissolved. 500 parts of a 10% aqueous polyvinyl alcohol solution were then added. The emulsion'was chemically-ripened in the presence of a gold chloride solution and coated onto a suitable support. This photographic material may be treated in the same wayas ordinary gelatin emulsions.
  • Example 5 50 parts of silver nitrate dissolved in parts of con- .,,centrated ammonia,
  • The-emulsion was ripened for 30 minutes at 50 C. and poured into an excess of an aqueous sodium sulphate solution 10%. After decanting the supernatant liquid, the precipitate was repeatedly washed with a mixture of water and alcohol. Next, 300 parts of distilled water were added and the whole heated at 35-40" C. until completely dissolved. 60 parts of gelatin dissolved in 450 parts of distilled water were then added.
  • the emulsion was chemically ripened in the presence of the natural active substances present in the gelatin and coated onto a suitable support. This photographic material may be treated in the same way as ordinary gelatin emulsions.
  • Example 6 To a solution of 2 parts of hydroxy-ethyl cellulose sulphate (3.76 ethoxy groups and 0.34 sulphate groups per glucose unit) in 260 parts of distilled water the two following solutions A and B, previously brought at 50 C., were simultaneously added whilst stirring within three minutes and in the absence of actinic light, giving a priority of some seconds for the addition of solution A.
  • the suspension thus obtained was ripened at 50 C. for 15 minutes, and immediately thereafter poured out into an excess of acetone.
  • a grainy precipitate was obtained which could easily be washed out with a mixture of equal amounts water and acetone. After washing, the precipitate was brought into 400 parts of Water and dispersed again by thorough stirring.
  • a stable suspension was obtained.
  • To this suspension were added 450 parts of a 10% polyvinyl alcohol solution in water and the mixture was homogenized.
  • the emulsion was chemically ripened at 50 C. by means of the reducing substances present in the polyvinyl alcohol. In this way a sensitve and rather hard emulsion was obtained which was: coated onto paper. this way could be processed in the same way as the ordinary gelatin silver halide papers.
  • Example 7 If in the process according to Example 6, hydroxy* ethyl cellulose sulphate were replaced by methyl cellulosesulphate (1.85 methyl groups and 0.13 sulphate groups per glucose units), equivalent photographic material; could be prepared with the emulsion obtained.
  • a process for the production of silver halide photographic emulsions which comprises precipitating and dis- The photographic paper prepared in.
  • a cellulose compound selected from the group consisting of cellulose sulphate, alkyl-cellulose sulphate and hydroxy-alkylcellulose sulphate, said cellulose compound having at least about 0.13 sulphate groups per glucose unit, ripening the silver halide dispersion in said solution, and adding a water-permeable colloid selected from the group consisting of gelatin and polyvinyl alcohol.
  • a process for the production of silver halide photographic emulsions which comprises precipitating and dispersing silver halide in a dispersing medium consisting of a solution of an aqueous cellulose compound selected from the group consisting of cellulose sulphate, alkylcellulose sulphate, and hydroxy-alkyl-cellulose sulphate, said cellulose compound having at least about 0.13 sulphate groups per glucose unit, ripening the silver halide dispersion in said solution, coagulating and washing the silver halide, and redispersing the said precipitate in an aqueous medium containing a colloid selected from the group consisting of gelatin and polyvinyl alcohol.
  • a process for the production of silver halide photographic emulsions which comprises precipitating silver halide in a dispersing medium consisting of a solution of an aqueous cellulose compound selected from the group consisting of cellulose sulphate, alkyl-cellulose sulphate,
  • a photographic silver halide emulsion comprising silver halide particles dispersed in a mixture of a cellulose compound selected from the group consisting of cellulose sulphate, alkyl-cellulose sulphate, and hydroxy-alk'yl-cel! lulose sulphate, and a water-permeable colloid selected from the group consisting of gelatin and polyvinyl alcohol, said cellulose compound having at least about 0.13 sulphate group per glucose unit.

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Colloid Chemistry (AREA)
  • Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US663885A 1956-06-07 1957-06-06 Preparation of photographic silver halide emulsions Expired - Lifetime US2956883A (en)

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GB17650/56A GB828217A (en) 1956-06-07 1956-06-07 Improvements in or relating to the preparation of photographic silver halide emulsions

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BE (1) BE558143A (enrdf_load_html_response)
DE (1) DE1045228B (enrdf_load_html_response)
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3904417A (en) * 1973-12-11 1975-09-09 Polaroid Corp Color diffusion transfer dye image-forming material binder layers containing a water-soluble cellulose salt

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11266A (en) * 1854-07-11 Improvement in compositions for making photographic pictures
US2127573A (en) * 1936-04-16 1938-08-23 Eastman Kodak Co Photographic emulsions
GB496049A (en) * 1937-04-19 1938-11-21 Ig Farbenindustrie Ag Improved manufacture of light-sensitive photographic preparations
US2322085A (en) * 1941-05-14 1943-06-15 Eastman Kodak Co Photographic emulsion

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11266A (en) * 1854-07-11 Improvement in compositions for making photographic pictures
US2127573A (en) * 1936-04-16 1938-08-23 Eastman Kodak Co Photographic emulsions
GB496049A (en) * 1937-04-19 1938-11-21 Ig Farbenindustrie Ag Improved manufacture of light-sensitive photographic preparations
US2322085A (en) * 1941-05-14 1943-06-15 Eastman Kodak Co Photographic emulsion

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3904417A (en) * 1973-12-11 1975-09-09 Polaroid Corp Color diffusion transfer dye image-forming material binder layers containing a water-soluble cellulose salt

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NL103557C (enrdf_load_html_response)
DE1045228B (de) 1958-11-27
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FR1177195A (fr) 1959-04-21
GB828217A (en) 1960-02-17

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