Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F3/00—Colour separation; Correction of tonal value
  • G03F3/10—Checking the colour or tonal value of separation negatives or positives
• • 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
  • G03C5/40—Chemically transforming developed images
• • 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
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/06—Silver salts

Definitions

• This invention relates to ecologically acceptable etch-bleach solutions suitable for use in the so-called "etch-bleach" process.
• gelatin relief images can be formed from a gelatin layer containing a developed silver image by treating said layer with hydrogen peroxide and metal ions of multiple valency in their higher oxidation state.
• the silver is oxidized to a silver salt and the hydrophilic colloid associated with the silver image is degraded so that it can be washed away.
• This process is commonly called the "etch-bleach" process and is described e.g. in United States Patent Specifications 3,567,446 of John M.Gleadle issued March 2, 1971 and 3,625,687 of Michael Patrick Dunkle issued December 7, 1971, in the United Kingdom Patent Specification 1,222,415 filed July 3, 1968 by Kodak Ltd. and in J.Proc.. Tech.Ass.Graphic Arts, 1967, p. 1-11.
• the etch-bleach process has been used for the formation of coloured relief images useful in the graphic arts field and for the preparation of lithographic printing plates.
• etch-bleach solutions suited for use in said process are acid solutions comprising hydrogen peroxide; copper(II), tin(IV) or iron(III) ions and anions forming insoluble silver salts, e.g., chloride ions.
• An etch-bleach solution containing the above ingredients is prepared by mixing immediately before use an aqueous hydrogen peroxide solution with an acidic aqueous solution containing at least one of said metal ions in the higher oxidation state and at least one of said anions.
• the reason for keeping said ingredients apart before use is the poor stability of the mixed solution, which rapidly loses its activity by hydrogen peroxide decomposition.
• Tin(IV) ions do not cause a serious pollution problem but have a rather poor activity so that only iron(III) ions are left for practical use.
• iron(III) ions have a greater effect on hydrogen peroxide decomposition than even copper(II) ions.
• the acids which can be used include, for example, citric acid, acetic acid, salicylic acid, tartaric acid, phosphoric acid, formic acid, nitric acid and hydrochloric acid. From these acids citric acid and acetic acid are ecologically acceptable but although giving acceptable stability to copper(II) ion containing hydrogen peroxide baths their stabilizing activity as sole stabilizing agent fails in the presence of iron(III) ions.
• citric acid and alkylene oxide polymers shows a superadditive stabilizing effect with respect to acidic aqueous hydrogen peroxide solutions that contain iron(III) ions and anions capable of forming insoluble silver salts e.g. chloride ions.
• the present invention provides an aqueous acidic etch-bleach solution comprising hydrogen peroxide, iron(III) ions and inorganic anions, which form an insoluble silver salt as defined hereinafter, characterized in that it contains in dissolved state as combination of H 2 0 2 -stabilising agents : citric acid and a polymer containing alkylene oxide units.
• polymers containing ethylene oxide units and/or propylene oxide units are particularly useful for the purpose of the present invention. These polymers have preferably a structure and molecular weight that allow their incorporation in dissolved state at 20°C for at least 0.1 % by weight into an acidic aqueous liquid having a pH in the range of.1 to 5.
• Alkylene oxide polymers that are preferably applied in the present etching solution are polyoxyethyleneglycols having a molecular weight in the range of 200 to 3000 wherein one or both of the terminal hydroxyl groups may have been converted into ether groups e.g.forming polyethylene glycol monomethyl ethers.
• alkylene oxide polymers are actually condensation products of polyoxyalkylene glycols with aliphatic acids, e.g. carboxylic acids, their corresponding anhydrides, or partially esterified oxyacids of phosphorus.
• aliphatic acids e.g. carboxylic acids, their corresponding anhydrides, or partially esterified oxyacids of phosphorus.
• polyoxyalkylene compounds suitable for use according to the invention are listed in the following Table I.
• etch-bleach solutions according to the present invention have a pH preferably in the range of 1 to 5 and comprise hydrogen peroxide preferably in a concentration of 0.01 to 5 % by weight.
• the concentration of the alkylene oxide copolymer in the etch-bleach solution of the present invention is preferably from 0.5 to 2.5 % by weight.
• the amount of iron(III) salt that has been incorporated into. said solution is preferably such that between 0.01 to 0.1 gram ions of iron(III) are present per litre. Any convenient iron(III) salt can be used to supply said ions; iron(III) nitrate and iron(III) chloride are particularly useful.
• the anion which forms an insoluble silver salt and which is present in the etch-bleach solution of this invention is one capable of forming a silver salt having a solubility product not greater than 1 x 10 -8 determined in water at 20°C.
• Anions which are useful for that purpose are halide ions such as chloride and bromide.
• the ion ratio between said anions and iron(III) cations is subject to variation and depends upon such things as the,nature of the anions.
• the inorganic anions that combine with the silver ions to form an insoluble silver salt as defined may be varied in order to obtain optimum results and the concentration of these ions in the etch-bleach solution is preferably maintained above about 0.05 gram ions per litre of solution.
• the anions forming silver salts can be incorporated as water-soluble salts, e.g. alkali metal or alkaline earth metal halide.
• Preferred salts are sodium chloride, calcium chloride and/or potassium bromide.
• the concentration of these salts is preferably such that the gram ion concentration of halide is between 0.1 and 0.4 gram ions per litre.
• acids other than citric acid can be used in minor amounts (at most 5 % by weight) with respect to the total amount of acid e.g. to adjust the pH of the etch-bleach solution in the preferred range of 1 to 5 e.g. nitric acid, phosphoric acid, formic acid and hydrochloric acid, or for complexing iron(III) ions e.g. oxalic acid, phosphoric acid, hydrofluoric acid, salicylic acid and derivatives thereof such as sulfo- salicylic acid.
• Gelatin softeners can be incorporated into the etch-bleach solution, particularly for use with hardened gelatin layers.
• Various softeners can be used including, e.g. salicylic acid, citric acid, guanidine nitrate, guanidine hydrochloride and urea.
• it may be desirable to use more than one gelatin softener such as a combination of citric acid and urea in which citric acid serves a multiple function in providing acidity to the solution, complexing of iron(III) ions as well as facilitating gelatin softening.
• Hydrogen peroxide may be incorporated in the etch-bleach solution from an aqueous solution e.g. containing 30 % by weight of hydrogen peroxide or according to a preferred embodiment as "urea peroxide" being an addition product of urea and hydrogen peroxide corresponding to the following-formula CO(NH 2 ) 2 .H 2 0 2 . It is a white, crystalline substance that is easily soluble in water and contains 34 % by weight of H 2 0 2 (see Hermann Rompp - Chemie Lexikon; Franckh'sche Verlags Stuttgart - Stuttgart, W.Germany; 5th ed. (1962) 2073).
• water-soluble perborates and/or persulphates can be used. These can be in the form of ammonium or alkali metal perborates or sulphates yielding in situ hydrogen peroxide.
• the etch-bleaching process according to the present invention contains the step of treating a photographically formed silver image in or on a hydrophilic polymeric colloid layer with the above defined etch-bleach solution.
• the silver image subjected to etch-bleaching according to the process o.f this invention can be obtained in any desired manner, for example, by physical or chemical development of image-wise photoexposed silver halide- containing layers.
• the silver image may likewise be obtained through the silver halide'complex diffusion transfer (DTR) process by transfer and development of complexed silver halide onto a non-light-sensitive receptor material containing a degradable hydrophilic colloid layer.
• DTR silver halide'complex diffusion transfer
• the DTR-process may be carried out with separate photo-sensitive silver halide materials and receptor materials or with a so-called integral receptor material containing the photosensitive silver halide emulsion layer and image receiving layer in water-permeable relationship on the same support.
• a so-called integral receptor material containing the photosensitive silver halide emulsion layer and image receiving layer in water-permeable relationship on the same support.
• the photosensitive materials may contain as light-, sensitive silver salts, e.g., silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof.
• sensitive silver salts e.g., silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof.
• the colloid layer carrying the silver image contains as hydrophilic degradable colloid preferably a proteinaceous colloid such as gelatin.
• hydrophilic degradable colloid preferably a proteinaceous colloid such as gelatin.
• gelatin In preparing photographic silver halide emulsion layers it is preferred to use gelatin as a sole binding agent for the silver halide, although other hydrophilic photographic binding agents of proteinaceous nature known to those skilled in the art may be used instead or in addition to gelatin.
• hydrophilic image receiving layers for use in the DTR-process likewise preferably gelatin is used to incorporate therein or coat thereon developing nuclei.
• Other hydrophilic colloids such as hydrophilic cellulose derivatives and alginic acid may be used in conjunction with gelatin.
• Development nuclei suited for use in the DTR-process are nickel sulphide nuclei. though other development nuclei can be used as well, e.g. sulphides of heavy metals such as sulphides of antimony, bismuth, cadmium, cobalt, lead, silver, and zinc. Other suitable nuclei are formed by selenides, polyselenides, polysulphides, mercaptans and tin(II) halides. The complex salts of lead and zinc sulphides are active both alone and when mixed with thioacetamide, dithiobiuret and dithio-oxamide. Fogged silver halides can also be used as well as heavy metals themselves in colloidal form, preferably silver, gold, platinum, palladium, and mercury may be used.
• the image-receiving layer may be hardened so as to improve its mechanical strength.
• Hardening agents for colloid layers include, e.g., formaldehyde, glyoxal, mucochloric acid, and chrome alum. Hardening may also be effected by incorporating a latent hardener in the colloid layer, whereby a hardener is released at the stage of applying the alkaline processing liquid.
• the developing agents For carrying out the silver complex diffusion transfer process it is common practice to incorporate the developing agents into the light-sensitive silver halide emulsion layer and/or the image-receiving layer, or other water-permeable layers adjacent thereto, as it has been described, e.g., in United Kingdom Patent Specifications 1,093,177 filed December 16, 1964, 1,000,115 filed August 4, 1961, 1,012,476 filed December 18, 1961, 1,042,477 filed June 17, 1963, 1,054,253 filed August 6, 1963 all five by Gevaert Photo-Producten N.V.
• the processing liquid accordingly used in the development stage can be limited to a so-called alkaline activating liquid being a mere aqueous alkaline solution comprising no developing agent(s).
• Suitable developing agents for the exposed silver halide are, e.g., hydroquinone and 1-phenyl-3-pyrazolidi- none and p-monomethylaminophenol and combinations thereof.
• the development or activating liquid contains in the process for forming a silver image through the silver complex diffusion transfer process a silver halide solvent, e.g., a silver halide complexing compound such as an alkali metal or ammonium thiosulphate or thiocyanate, or ammonia. Alternatively or in addition such complexing compound may be present in the image-receiving layer.
• the exposure of the light-sensitive material and the diffusion transfer proceed preferably with, or in the apparatus commercially available therefor and of which several types have been described in the already mentioned book of A.Rott and E.Weyde.
• the formation of the silver image may proceed through any type of silver halide emulsion material, e.g. with one of the negative type or with one of the direct-positive type i.e. one in which the silver image on development is formed in the ron-exposed areas.
• any direct-positive silver halide emulsion is suited, which in-a simple development yields a positive silver image and a corresponding image-wise distribution of developing agent oxidation products.
• silver halide emulsions can be used wherein a developable fog has been produced by overall exposure or chemical treatment, the said fog being destroyed image-wise during the image-wise exposure.
• Another group of direct-positive silver halide emulsion materials comprises a so-called unfogged direct-positive silver halide emulsion, which has its sensitivity predominantly in the interior of the silver halide grains. Upon image-wise exposure of such emulsion a latent image forms predominantly in the interior of the silver halide grains.
• unfogged direct-positive silver halide emulsion is carried out under fogging conditions, wherein fog forms predominantly in the unexposed areas and a positive silver image results upon development.
• the unfogged, direct-positive silver halide emulsion material is characterized thereby that in the exposed parts no silver image is produced or only one of very poor density upon development by the use of a typical surface developer of the following composition : whereas a silver image with sufficient density forms if an internal type developer of the following composition is used :
• the selective fogging of the image-wise exposed unfogged direct-positive emulsion materials can be carried out before or during development by a treatment with a fogging agent.
• Suitable fogging agents are reducing agents such as hydrazine or substituted hydrazine compounds. Reference may be made to US Patent Specification 3,227,552 of Keith E.Whitmore issued January 4, 1966.
• Unfogged direct-positive emulsions are e.g. those showing defects in the interior of the silver halide grains (ref. US Patent Specification 2,592,250 of Edward Philip Davey and Edward Bowes Knott issued April 8, 1952) or silver halide emulsions with covered-grain structure (ref. published German Patent Application 2,308,239 filed February 20, 1973 by Agfa-Gevaert AG).
• the relief patterns are to be used for the support of the imaging material is transparent or opaque. So, it is possible to use metal layers or sheets, glass, ceramics, resin supports and paper.
• the support of the receptor layer is preferably a transparent resin film support, e.g. a subbed polyethylene terephthalate support.
• a transparent resin film support e.g. a subbed polyethylene terephthalate support.
• subbed film supports are described, e.g., in the United Kingdom Patent Specification 1,234,755 filed September 28, 1967 by Agfa-Gevaert N.V.
• the degradable colloid layer in which or whereon the photographic silver image is produced is preferably applied to a hydrophobic support, e.g. polyethylene terephthalate having an oleophilic coating as described, e.g., in the United States Patent Specification 3,625,687 of Michael Patrick Dunkle issued December 7, 1971.
• a hydrophobic support e.g. polyethylene terephthalate having an oleophilic coating as described, e.g., in the United States Patent Specification 3,625,687 of Michael Patrick Dunkle issued December 7, 1971.
• the colloid layer whereon or wherein the silver image is produced photographically contains one or more dyes or pigments.
• Cold colour tones are standardized e.g. in the U.S.A. in the GATF-Color Charts and in the German Standards DIN 16508 and 16509.
• Warm colour tones are standardized e.g. in the German Standard DIN 16538.
• Pigments that are very poorly soluble or insoluble in water and organic liquids of the alcohol or polyhydric alcohol type, e.g. glycerol, are preferred for their resistance to diffusion.
• Pigment dyes that are applied from an aqueous dispersion are used preferably, though the use of substantive dyes that are chemically linked to the hydrophilic colloid or admixed polymer is not excluded.
• the selectively degradable layer contains pigments in such concentration that the optical density in the wavelength range of maximum absorption is at least 0.35.
• colours can be employed e.g. cyan, light cyan, magenta, warm magenta, black, yellow, green, brown, orange, red, white, blue as well as metallic colours such as pale gold, rich gold, copper, and silver.
• colours e.g. cyan, light cyan, magenta, warm magenta, black, yellow, green, brown, orange, red, white, blue
• metallic colours such as pale gold, rich gold, copper, and silver.
• Non-migratory pigments suitable for use in gelatin- containing layers are known by the name "PIGMOSOL” and “COLANYL” dyes.
• PIGMOSOL and COLANYL are Trade Marks of Badische Anilin- & Soda-Fabrik AG, Ludwigshafen/Rh., W.Germany for organic pigment dyes that are mixed with a dispersing agent for aqueous medium.
• These pigment dyes excel in resistance to light, heat, acids, bases, oxidizing agents, and solvents. They are insoluble in hydrophilic colloids such as gelatin.
• the black-pigment for the black-toned proofing image is preferably carbon black.
• a dye may be applied by soaking the developed hydrophilic colloid relief pattern in a dye solution.
• the dye may be fixed in the relief pattern with a mordanting agent to offer a stable colour print.
• a desired colour can be applied in selected relief areas by means of a brush or porous pen (felt marker) provided with an aqueous ink.
• Easy pattern recognition by dyeing selected areas with a pen is obtained by producing first a white relief pattern starting with a colloid layer containing white pigment particles e.g. titanium dioxide.
• Dyeing in different colours with the pen of selected relief parts may find application in image composition work e.g. title-setting or other graphic art work.
• the dye transfer process for producing multicolour prints three positive reliefs corresponding respectively with the primary colour patterns of a multicolour original are soaked in dye solutions of the appropriate minus colour and squeegeed into contact with a paper coated with mordanted gelatin. Said paper is called the dye transfer matrix.
• the successive transfer, in register, of the three dye images gives a colour print.
• Matrices can, of course, be used to produce motion-picture films according to the Technicolor dye transfer process (ref. : The Science of Photography by H.Baines - Fountain Press - London (1958) p.260)
• a coloured image-receiving layer suited for use in the DTR-processing was coated from the following coating composition at a coverage of 30 g per sq.m :
• a silver image containing in the silver covered parts 0.5 g of silver per sq.m was formed onto the image-receiving layer through the DTR-process using a light-sensitive material comprising a direct-positive fogged silver halide emulsion layer that was exposed image-wise in a process camera to a halftone pattern.
• the obtained silver image was used to test the etching power of the following etch-bleach solutions A to H after storage for several days at 20°C as indicated in Table II.
• the etching power is expressed by the quality numbers 1, 2 and 3 in which 1 stands for sufficient activity, 2 for poor activity and 3 for insufficient activity.
• the etching time and etching temperature were the same in each test viz. 30 s and 22°C respectively.
• the etch-bleach solution A had the following composition :
• the etch-bleach solutions B to D contained 20, 50 and 100 g respectively of citric acid instead of 10 g.
• the etch-bleach solution E contained 50 g of citric acid instead of 10 g and in addition thereto 10 g of polyoxyethyleneglycol having an average molecular weight of 2000.
• the etch-bleach solution F contained 10 g of citric acid and 10 g of said polyoxyethylene glycol.
• the etch-bleach solution G contained instead of citric acid nitric acid in an amount sufficient to reach a pH 1.2 and no polyoxyethylene glycol.
• the etch-bleach solution H was identical to solution G but contained in addition thereto 10 g of said polyoxyethylene glycol.
• Etch-bleach solutions containing the following ingredients were tested with respect to stability in the absence or presence of polyoxyethylene glycol (average molecular weight 2000) as stabilizing agent.
• the hydrogen peroxide was added as CO( NH 2 ) 2 . H 2 0 2 .
• Table III lists the hydrogen peroxide content per litre of solutions 1 to 6 as a function of storage time expressed in days.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Epoxy Compounds (AREA)

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• 1977
  • 1977-08-25 FR FR7726019A patent/FR2373080A1/fr not_active Withdrawn
• 1978
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  • 1978-05-31 CA CA000304550A patent/CA1117350A/fr not_active Expired
  • 1978-06-01 EP EP78200021A patent/EP0000081B1/fr not_active Expired
  • 1978-06-01 DE DE7878200021T patent/DE2861664D1/de not_active Expired
  • 1978-06-01 US US05/911,484 patent/US4203765A/en not_active Expired - Lifetime

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