US2835575A - Photographic reproduction process - Google Patents

Photographic reproduction process Download PDF

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Publication number
US2835575A
US2835575A US499328A US49932855A US2835575A US 2835575 A US2835575 A US 2835575A US 499328 A US499328 A US 499328A US 49932855 A US49932855 A US 49932855A US 2835575 A US2835575 A US 2835575A
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United States
Prior art keywords
emulsion
gelatin
emulsion layer
silver halide
tanning
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Expired - Lifetime
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US499328A
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English (en)
Inventor
Herbert B Cowden
Albert W Wise
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Eastman Kodak Co
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Eastman Kodak Co
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Publication date
Priority to BE546664D priority Critical patent/BE546664A/xx
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Priority to US499328A priority patent/US2835575A/en
Priority to DEE12162A priority patent/DE1005371B/de
Priority to FR1156831D priority patent/FR1156831A/fr
Priority to GB10438/56A priority patent/GB813254A/en
Application granted granted Critical
Publication of US2835575A publication Critical patent/US2835575A/en
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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
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/29—Development processes or agents therefor
    • G03C5/315—Tanning development

Definitions

  • This invention relates to photography and more particularly, to a photographic copy method especially adapted to ofiice copy work.
  • the emulsion layer while moist, is then pressed into contact with an absorbent receiving sheet to cause only the unhardened portion of the emulsion layer to adhere to the receiving sheet with the result that when the sheet is removed from the emulsion layer, a thin stratum of the unhardened portions of the emulsion is found to be adhered to the sheet.
  • the mentioned processes are particularly adapted to the reproduction of positive originals such as printed subject matter which contain small dark images on a comparatively large light-colored background.
  • negative subject matter such as paper or film negative which have a light-colored image on a comparatively large dark background
  • the mentioned processes are less useful since in the final transfer step, it is necessary to transfer large areas of the unexposed portions of the emulsion layer to the receiving sheet with the result that the copies, when first made, tend to curl and may be somewhat sticky.
  • the large areas which are transferred are fragile and easily damaged during the mechanical steps of the process with the concomitant loss of definition in the copy.
  • such large areas may transfer as rather thick strata, leaving on the printing element insufiicient nnhardened portions of emulsion for the preparation of additional copies.
  • One object of our invention is to provide the direct positive element useful in the processes of our invention.
  • Other objects reside in providing the procedures for use of the direct positive emulsions in the mentioned colloid image transfer processes.
  • the processes of our invention include exposing an unhardened direct positive emulsion of the nature indicated hereinafter to a line or halftone subject, followed by developing either the exposed or unexposed portions with an alkaline solution in the presence of a gelatin tanning silver halide developing agent which may or may ice not be present in the original emulsion layer, under conditions of gelatin tanning silver halide development, so as to obtain a hardened gelatin and silver image in the emulsion layer. Thereafter, the emulsion is developed with another alkaline solution in the presence of a silver halide developing agent and a compound inhibiting gelatin tanning so as to develop an unhardened gelatin and silver image in the remaining region of the emulsion layer.
  • either one of the alkaline solutions contains a silver halide solvent such as sodium thiosulfate when the other alkaline solution contains a hydrazine compound except that the first alkaline solu tion should not contain an amount of sulfite sufi'icient to inhibit gelatin tanning silver halide development.
  • the first alkaline solution may contain the hydrazine compound but is substantially free of sulfite or other compound inhibiting gelatin tanning and the other alkaline solution contains a silver halide solvent and a gelatin tanning inhibitor.
  • the first alkaline solution contains the silver halide solvent except no substantial amount of sulfite
  • the second alkaline solution contains the hydrazine compound and gelatin tanning inhibitor.
  • the emulsion layer is squeegeed or pressed against a receiving sheet to transfer a thin stratum of the unhardened gelatin and silver image to the receiving sheet.
  • the particular alkaline solutions in which the hydrazine compound and the silver halide solvent are incorporated determine whether a negative or positive reproduction is obtained.
  • Example Ill a negativepositive process is illustrated since the hydrazine compound is present in the first alkaline developer solution and the silver halide solvent is present in the second non-tanning alkaline developer solution, the first alkaline solution causing tanning development in the unexposed portions of the direct positive emulsion layer and the other alkaline solution causing non-tanning development in the exposed portions of the emulsion layer.
  • the direct positive types of emulsion used in our in vention are those known as internal latent image emulsionsthat is, emulsions which form latent images mostly inside the silver halide grains.
  • To the internal latent image emulsions may be added one or more gelatin tanning silver halide developing agents.
  • Most of the internal latent image emulsions to which the gelatin tanning silver halide developing agents may be added are silver bromoiodide emulsions of high iodide content, preferably containing at least l0%-20% of iodide.
  • Burtons emulsion is an emulsion of this type, having a silver iodide content of approximately 40% of the content of silver halide. It is not absolutely essential, however, for the emulsion to contain silver iodide.
  • Dry gelatin grams 250 (B is heated to 70 C., and A, cold, added to B with constant shaking, digested for 20 minutes at 50 C., and allowed to cool slowly. C is added after being allowed to swell for 20 minutes in water, drained and melted. The emulsion is then set and washed.)
  • a gelatin tanning silver halide developing agent can then be added to the emulsion in the manner described in the examples hereinafter.
  • An internal latent image emulsion made as described in the Davey and Knott U. S. Patent 2,592,250 is particularly useful in the processes of our invention.
  • This emulsion is prepared by first forming in the absence of ammonia and in one or more stages silver salt grains consisting at least partly of a silver salt which is more soluble in water than silver bromide, subsequently converting the grains to silver bromide or silver bromoiodide and if the silver iodide content of the emulsion is less than 6% calculated on the total silver halide, preferably treating such grains with an iodine compound to bring the silver iodide up to at least 6%, ripening preferably in the absence of ammonia and then either washing out some of the soluble salts or washing out the whole of the soluble salts, followed by the addition of soluble salts such as soluble chloride or bromide.
  • An example of an emulsion made in this way is as follows:
  • An internal latent image type of silver halide emulsion may be defined as one which, when a test portion is exposed to a light intensity scale for a fixed time between M and 1 second, and developed for 4 minutes at F. in the ordinary, surface developer (Example I), exhibits a maximum density not greater than /3 the maximum density obtained when the same emulsion is equally exposed and developed for 3 minutes at 20 C. in an internal type developer (Example II).
  • the maximum density obtained with the surface developer is not greater than the maximum density obtained when the same emulsion is developed in the internal type developer.
  • an internal latent image emulsion when developed in an internal type cleveloper (Example II) exhibits a maximum density at least 5, and preferably at least 10, times the maximum density obtained when the same emulsion is exposed 2,835,675 I i A 4 in the same way and developed in a surface developer (Example I).
  • An ordinary, surface-type developer that is, one which develops an image only on the surface of the grains of an internal latent image emulsion, is the following:
  • Example I Grams p-Hydroxyphenylglycine 10 Sodium carbonate (crystals) 100 Water to 1 liter.
  • An internal type developer that is, one which develops an image inside the grains of an internal latent image emulsion, is the following:
  • Example II Grams Hydroquinone 15 Monemethyl-p-aminophenol. sulfate 15 Sodium sulfite (anhydrous) 50 Potassium bromide 10 Sodium hydroxide 25 Sodium thiosulfate (crystals) 20 Water to 1 liter.
  • the internal latent image emulsions useful in our invention are separate and distinct from direct positive emulsions, such as described in the Kendall U. S. Patent 2,541,472, which are fogged before image-forming exposure. Such emulsions have not been found to be useful in our processes.
  • Example III An internal latent image emulsion prepared as described by the method of the Davey and Knott patent above and containing one mol of silver halide, 476 grams of gelatin and 4000 cc. of water, was melted at 40 C. and the following additions made: 100 grams of 8% aqueous saponin solution and 600 grams of a developer dispersion prepared by dissolving 44.5 grams of 4-phenyl catcchol (3,4-dihydroxydiphenyl) in 67.5 grams of dibutyl phthalate at C. and pouring slowly into a rapidly stirred solution of 44.5 grams of gelatin and 44.5 cc. of 8% aqueous saponin solution in 475 cc. of water at 50 C.
  • the mixture wasthen coated over 400 square feet of paper which had been made without addition of a gelatin hardening agent.
  • the accompanying drawing illustrates in greatly enlarged crosssectional view the manner of use of the resulting element having an unhardened internal latent image gelatino-silver halide emulsion 10 containing the gelatin tanning silver halide developing agent 4-phenyl catcchol on support 11.
  • the emulsion layer 10 is exposed to a subject 12 which may be either a negative or positive line or halftone subject having the image 13 on the dark background 14 until area 15 of the emulsion layer has been adequately exposed.
  • the exposed emulsion is then treated in the manner described in the Ives U. S. Patents 2,563,785 and 2,588,982 for 20 seconds with an alkaline solution preferably containing an aromatic hydrazine (if the hydrazine has not already been incorporated into the emulsion layer) such as the following:
  • This treatment brings about tanning development of the emulsion layer 10 only in the unexposed areas 16, a hardened gelatin and sliver image being obtained therein, whereas development does not take place in the exposed areas 15 of the emulsion layer as shown in stage 2 of the drawing.
  • the developed emulsion layer is directly treated with an alkaline solution containing a silver halide solvent such as sodium thiosulfate which dissolves the surface of the exposed silver halide grains and uncovers the underlying internal latent image.
  • a silver halide solvent such as sodium thiosulfate which dissolves the surface of the exposed silver halide grains and uncovers the underlying internal latent image.
  • the alkaline solution also contains a compound such as sodium sulfite which inhibits tanning of the gelatin in the presence of the fogged silver halide and the gelatin tanning silver halide developing agent, such as the following solution:
  • urea or another gelatin softening agent may be added to the above solution to facilitate the subsequent transfer operation.
  • urea or another gelatin softening agent may be added to the above solution to facilitate the subsequent transfer operation.
  • the emulsion layer is squeegeed to free it of excess moisture and while it is still moist the emulsion layer is pressed into contact with a fairly dry absorbent surface or receiving sheet such as paper, to cause only the unhardened emulsion areas to adhere to the paper. Thereafter the receiving paper is peeled off of the emulsion layer to obtain a thin stratum 13 of the unhardened gelatin and silver image 17 on the paper 19, as shown in stage 4 of the drawing. Image 18 is therefore a negative with respect to the original subject 12.
  • the gelatin tanning silver halide developing agent be incorporated into the emulsion layer
  • the more soluble tanning developing agents such as hydroquinone and pyrogallol can be incorporated into the first-mentioned alkaline developer solution, in which case it may be necessary also to incorporate a quantity of the same developing agent or even a non-tanning silver halide developing agent, such as p-methyl-aminophenol sulfate, in the second developer solution to insure that a print containing adequate density is obtained in the subsequent transfer step.
  • the process materially As follows: After exposure of the emulsion containing the tanning developing agent as shown in stage 1 of the drawing, followed directly by treatment with the alkaline hydrazine solution, the resuling emulsion layer containing unhardened emulsion only in the exposed region, while moist, may be pressed into contact with a fairly dry receiving sheet in the presence of a compound such as a sulfur compound which reacts with the silver halide to form a dark image.
  • a compound such as a sulfur compound which reacts with the silver halide to form a dark image.
  • thiourea is a suitable compound which can be present on the surface of the receiving sheet.
  • thiourea may be used other compounds which react with the gelatinosilver halide image transferred to the receiving sheet to form an image of appreciable optical density, or cause the silver halide to become developable, e. g., sodium sulfide, sodium stannite, stannous chloride, mercaptans or zinc sulfide.
  • gelatin tanning silver halide developing agents which can be used in the invention in the manner described include, for example, hydroquinone, catechol, and pyrogallol, although these gelatin tanning silver halide developing agents are less preferred because of their water-solubility and wandering characteristics in gelatin emulsion layers as mentioned.
  • the most preferred gelatin tanning silver halide developing agents are those which are substantially insoluble in water, for example,
  • the hydrazine compounds which can be used in the alkaline solutions employed in the process of the invention as described above, have the general formula in which at least two Rs are hydrogen atoms and when less than four Rs are hydrogen atoms, the remaining Rs are aryl, aralkyl, acyl, or carboxylic acid amide groups.
  • the hydrazine compound does not contain more than one aralkyl, acyl, or carboxylic acid amide group, although it may contain either one or two aryl groups.
  • the hydrazine compound may be present either in the developing solution itself or in the emulsion. In the latter case, of course, the development of the exposed emulsion layer (stage 1 of the drawing) can be carried out with a simple alkaline solution containing little or no sulfite which would inhibit tanning development.
  • S. Patents 2,663,732 and 2,618,565 are preferred for use in the alkaline processing solutions of the invention or in the emulsion layers.
  • These hydrazines have the general formula in which D represents a divalent mononuclear arylene group of the benzene series, 11 represents a positive integer of from 1 to 5 and R represents an alkyl group of from 1 to 4 carbon atoms.
  • Representative hydrazines having this general formula are as follows:
  • the compounds used in the alkaline processing solutions of the invention to inhibit the tanning of the emulsion layer in the desired region include those compounds well known in the art to inhibit gelatin tanning silver halide development, for example, alkali metal sulfites, borax and alkali metal formaldehyde bisulfites.
  • the emulsion layer be not harder than would be the case with gelatin containing 0.25 oz. of formaldehyde (40% diluted 1 to 3 with water) or 0.7 gram of dry formaldehyde per pound, when freshly coated or 0.1 oz. of the solution per pound for a sample aged three to six months.
  • formaldehyde 50% diluted 1 to 3 with water
  • 0.1 oz. of the solution per pound for a sample aged three to six months.
  • a suitable quantity of a compound having a softening effect upon gelatin such as urea, sodium nitrate, glycerol, formamide or ethylene chlorohydrin.
  • the emulsion was exposed by contact printing.
  • the exposure can be made by well known projection or reflex exposure methods.
  • This exposure may be made with a halftone screen having about 120 or 133 lines per inch in contact with the emulsion layer before or after the image exposure.
  • the emulsion is processed as described in the above specific example with the result that the final copy obtained on the receiving sheet is composed of a series of dots and the dark and light images of the original are reproduced with adequate legibility.
  • the internal latent image emulsion such as provided in Example III above, containing a gelatin tanning silver halide developing agent
  • an alkaline developing solution such as a sodium carbonate solution containing a silver halide solvent, such as sodium thiosulfate, under conditions of tanning development, that is, the solution should be substantially free of sulfite, to uncover the internal latent image in the exposed emulsion region and develop a hardened gelatin and silver image only in the exposed area of the emulsion layer.
  • the emulsion is developed with an alkaline solution such as provided in the above specific example and containing the hydrazine compound and sodium sulfite to obtain an unhardened gelatin and silver image in the unexposed portion of the emulsion layer.
  • a direct-positive print is then obtained by merely pressing the emulsion layer against an absorbent receiving surface to transfer a thin stratum of the unhardened image area to the receiving surface.
  • the tanning developing agent may also be present only in the first alkaline developing solution rather than in the emulsion layer and then it may be necessary to add silver halide developing agent of either the tanning or nontanning variety to the second alkaline developing solution to insure adequate density in the final print.
  • a photographic reproduction process which comprises exposing to a two-tone subject an unhardened gelatino-silver halide emulsion layer a test portion of which upon exposure to a light intensity scale for a fixed time between and 1 second and development for 3 minutes at 20 C. in the following internal type developer (II):
  • a photographic reproduction process which comprises exposing to a two-tone subject an unhardened gelatino-silver halide emulsion layer a test portion of which upon exposure to a light intensity scale for a fixed time between ,5 and 1 second and development for 3 minutes at 20 C. in the following internal type developer Grams Hydroquinone l5 Monomethyl-p-aminophenol sulfate l5 Anhydrous sodium sulfite 50 Potassium bromide Sodium hydoxide 25 Sodium thiosulfate 20 Water to 1 liter.
  • said emulsion containing a gelatin tanning silver halide developing agent treating the exposed emulsion layer with an alkaline solution containing a hydrazine compound having the general formula conditions of gelatin tanning silver halide development until a hardened gelatin and silver image is obtained only in the unexposed portion of the emulsion layer, treating the resulting developed emulsion layer with an alkaline solution containing a silver halide solvent and a compound inhibiting gelatin tanning, until an unhardened gelatin and silver image is obtained in the exposed portion of the emulsion layer, pressing an absorbent sheet against said emulsion layer while the emulsion layer is moist to cause the unhardened gelatin and silver image to adhere to said sheet, and separating said sheet and emulsion layer to transfer only a stratum of said unhardened gelatin and silver image to said sheet.
  • a photographic reproduction process which comprises exposing to a two-tone subject an unhardened gelatino-silver halide emulsion layer a test portion of which upon exposure to a light intensity scale for a fixed time between A and 1 second and development for 3 minutes at 20 C. in the following internal type developer (II):
  • said emulsion layer containing a compound of the class consisting of 3,4-dihydroxy diphenyl 2,5-dihydroxy diphenyl 2,3-dihydroxy diphenyl 4-phenoxy catechol 4-(2-cyclopenteny1) catechol 1,2-diethoxallyl-4-phenyl catechol 1,2,3-triethoxallyl pyrogallol developing the exposed emulsion layer with an alkaline solution containing a compound of the class consisting of until a hardened gelatin and silver image is obtained only in the unexposed portion of the emulsion layer, treating the resulting developed emulsion layer with an alkaline solution containing an alkali metal sulfite and an alkali metal thiosulfate until an unhardened gelatin and silver image is obtained in the exposed portion of the emul- 11 sion layer, pressing an absorbent sheet against said emulsion layer while the emulsion layer is moist to cause the unhardened gelatin and silver image to adhere to said sheet, and
  • a photographic reproduction process which comprises exposing to a two-tone subject an unhardened gelatino-silver halide emulsion layer a test portion of which upon exposure to a light intensity scale for a fixed time between and 1 second and development for 3 minutes at 20 C. in the following internal type developer (II) Water to 1 liter.
  • said emulsion layer containing 3,4-dihydroxy diphenyl as a gelatin tanning silver halide developing agent, developing the exposed emulsion layer with an alkaline solution containing p-(p-methylsulfonamidoethyl)phenyl hydrazine,
  • hydrazine compound used has the general formula wherein D represents a divalent mononuclear arylene group of the benzene series, n represents a positive integer of from 1 to 5, and R represents an alkyl group of from 1 to 4 carbon atoms.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
US499328A 1955-04-05 1955-04-05 Photographic reproduction process Expired - Lifetime US2835575A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE546664D BE546664A (d) 1955-04-05
US499328A US2835575A (en) 1955-04-05 1955-04-05 Photographic reproduction process
DEE12162A DE1005371B (de) 1955-04-05 1956-03-29 Photographisches Reproduktionsverfahren
FR1156831D FR1156831A (fr) 1955-04-05 1956-04-05 Procédé de reproduction photographique et produits pour sa mise en oeuvre
GB10438/56A GB813254A (en) 1955-04-05 1956-04-05 Improvements in photographic reproduction processes and sensitive materials therefor

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US499328A US2835575A (en) 1955-04-05 1955-04-05 Photographic reproduction process

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US2835575A true US2835575A (en) 1958-05-20

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DE (1) DE1005371B (d)
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GB (1) GB813254A (d)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3061434A (en) * 1957-08-26 1962-10-30 Polaroid Corp Novel substituted silver halide developing agents
US3062648A (en) * 1960-02-09 1962-11-06 Eastman Kodak Co Photographically sensitive lithographic printing plate
US3080230A (en) * 1956-02-18 1963-03-05 Agfa Ag Photographic stratum transfer process and element therefor
US3219445A (en) * 1962-04-09 1965-11-23 Technical Operations Inc Photographic processes
US3293035A (en) * 1962-04-26 1966-12-20 Gevaert Photo Prod Nv Tanning development
US3295969A (en) * 1961-04-12 1967-01-03 Eastman Kodak Co Photographic spirit duplicating process
US3471295A (en) * 1964-06-20 1969-10-07 Beate Elisabeth Loffler Production of colored direct-positive images
US3793027A (en) * 1971-03-26 1974-02-19 Fuji Photo Film Co Ltd Developing composition for use with photographic materials for the graphic arts

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596756A (en) * 1947-11-04 1952-05-13 Eastman Kodak Co Photomechanical copy method
US2716059A (en) * 1952-01-21 1955-08-23 Eastman Kodak Co Photographic transfer process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596756A (en) * 1947-11-04 1952-05-13 Eastman Kodak Co Photomechanical copy method
US2716059A (en) * 1952-01-21 1955-08-23 Eastman Kodak Co Photographic transfer process

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3080230A (en) * 1956-02-18 1963-03-05 Agfa Ag Photographic stratum transfer process and element therefor
US3061434A (en) * 1957-08-26 1962-10-30 Polaroid Corp Novel substituted silver halide developing agents
US3062648A (en) * 1960-02-09 1962-11-06 Eastman Kodak Co Photographically sensitive lithographic printing plate
US3295969A (en) * 1961-04-12 1967-01-03 Eastman Kodak Co Photographic spirit duplicating process
US3219445A (en) * 1962-04-09 1965-11-23 Technical Operations Inc Photographic processes
US3293035A (en) * 1962-04-26 1966-12-20 Gevaert Photo Prod Nv Tanning development
US3471295A (en) * 1964-06-20 1969-10-07 Beate Elisabeth Loffler Production of colored direct-positive images
US3793027A (en) * 1971-03-26 1974-02-19 Fuji Photo Film Co Ltd Developing composition for use with photographic materials for the graphic arts

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FR1156831A (fr) 1958-05-21
DE1005371B (de) 1957-03-28
GB813254A (en) 1959-05-13
BE546664A (d)

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