Abstract: A photopolymerizable elastomeric mixture for producing ozone-resistant flexographic printing forms is disclosed which contains an elastomeric binder, an olefinically unsaturated compound polymerizable by free radicals, a photoinitiator, and a polyglycol ether of the general formula I ##STR1## in which R.sub.1 and R.sub.2 are alkyl, especially (C.sub.1 -C.sub.3)-alkyl,R.sub.3 is hydrogen or alkyl, especially (C.sub.1 -C.sub.3)-alkyl,A, B, C and D can be identical or different and are oxa-n- or -iso-alkylene, especially oxa-n- or -iso-(C.sub.1 -C.sub.5)-alkylene andl+m+n+o is 3 to 40.A recording material containing the photopolymerizable mixture as well as a process for producing a flexographic printing form are likewise described. The flexographic printing form obtained shows improved ozone resistance as compared with forms of the state of the art.

Abstract: The invention describes a developing solvent for layers which are crosslinkable by photopolymerization and contain a binder based on an elastomeric polymer, a photopolymerizable monomer compatible therewith and a photoinitiator. The developing solvent comprises an aromatic compound of the general formula I ##STR1## wherein R.sup.1 to R.sup.4 are the same or different and denote hydrogen, (C.sub.1 -C.sub.5)n-alkyl or iso-alkyl and R.sup.1 and R.sup.2, provided that R.sup.1 and R.sup.2 are directly adjacent, may also form a cycloaliphatic or aromatic ring having 5 or 6 carbon atoms as ring members which are preferably non-substituted,provided that the sum of carbon atoms of the substituents and ring members is from 9 to 13. Compared with solvents of the prior art, the developing solvent of the present invention is non-toxic, can quickly be removed from the layer, has a high capacity for layer components and is capable of developing plates based on nitrile rubber.

Abstract: A lithographic printing plate for use on a printing press, with minimal or no additional processing after exposure to actinic radiation, comprises a printing plate substrate, a polymeric resist layer capable of imagewise photodegradation or photohardening, and a plurality of microencapsulated developers capable of blanket-wise promoting the washing out of either exposed or unexposed areas of the polymeric resist. The microencapsulated developers may be integrated into the polymeric resist layer, or may form a separate layer deposited atop the polymeric resist layer, or may be coated onto a separate sheet support capable of being brought into face-to-face contact with conventional printing plates.

Abstract: This invention relates to a process for making a flexographic printing plate from a photosensitive printing element having an infrared reduction ablatable layer capable of being selectively removed by a laser beam and wherein the process includes placing a material capture sheet in proximity to a photopolymer layer.

Abstract: In a method of producing master and working pattern plates for etching to form a shadow mask, various etching patterns are needed, for example, a pattern of predetermined holes for passing electron beams, a pattern of register marks necessary for accurate alignment of a pair of obverse and reverse working pattern plates, and a frame pattern for cutting off a portion which is to be a shadow mask from a metal plate by etching process. These individual pattern data required for etching are first prepared and then subjected to logical operation to prepare data representative of a synthetic pattern which is to be finally drawn on a photosensitive plate. Then, all the necessary patterns, including the frame pattern, register mark pattern, hole pattern, etc.

Abstract: A photosensitive element comprising (a) a support, (b) a thermally hardened layer containing the reaction product of (i) either an organic polymer having reactive segments and nonreactive segments or a blend of organic polymers wherein at least one polymer has reactive segments and at least one polymer has nonreactive segments (ii) a crosslinking agent and (iii) a catalyst and (c) a photohardenable layer is described.

Abstract: The invention relates to the use of effective amounts of UV absorbers in a thermoplastic, elastomeric, composition layer of a photosensitive printing element, wherein said layer comprises a thermoplastic, elastomeric, asymmetric, star-shaped block copolymer, to produce enhanced exposure latitude, as well as a method of producing a printing plate with the printing element. The UV absorbers most likely act as internal scavengers of scattered UV light and thereby enhance the exposure latitude of the printing element. The invention also relates to the photosensitive composition of the element.

Abstract: The invention involves a photosensitive composition and a printing element made from the photosensitive composition as well as a method of making the printing element. The photosensitive composition is made from a blend of a crosslinking photoinitiator with an asymmetric, multi-branched, block copolymer containing (a) a polymer block A having at least predominantly a polymerized alkenyl arene block, (b) a polymer block B having at least predominantly a polymerized conjugated diene block, (c) a polymer block C having at least predominantly a polymerized conjugated diene block, and (d) the residue of a multifunctional coupling agent. Block A and block B form the structure A-B and the multifunctional coupling agent is between at least one block C and the block B of at least one A-B. The photosensitive composition may optionally include an ethylenically unsaturated crosslinking agent.

Abstract: A lithographic printing plate that has an imaging layer that comprises an admixture of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber; that is sensitive to both ultraviolet and infrared radiation; and that is capable of functioning in either a positive-working or negative-working manner is imagewise exposed with a laser diode that emits a high-intensity infrared laser beam which provides enhanced image sharpness.

Abstract: A method for preparing a lithographic printing plate comprises imagewise exporting a PS plate comprising an aluminum substrate having an anodized layer and a light-sensitive layer applied on one side of the substrate and then developing the PS plate with a developer comprising an aqueous solution of an alkali metal silicate, while compensating changes in the developer due to the development of the PS plate by supplementing, to the developer, a replenisher comprising an aqueous solution of an alkali metal silicate, wherein the PS plate is provided with a coating layer containing an organic polymeric compound on the back face and the replenisher is an aqueous solution of an alkali metal silicate having a ratio: [SiO.sub.2 ]/[M.sub.2 O] (wherein [SiO.sub.2 ] means molar concentration (mol/l) of SiO.sub.2 and [M.sub.2 O] is molar concentration (mol/l) of oxide M.sub.2 O of an alkali metal (M)) ranging from 0.3 to 1.0 and an SiO.sub.2 content ranging from 0.5 to 4.0% by weight.

Abstract: A silicon film is formed on the surface of a substrate for a photomask, and a silicon nitride film is formed thereon. Then the silicon film and the silicon nitride film are patterned into desired shapes by photolithography method, the edge portion of the patterned silicon film is oxidized to provide a translucent region consisting of a silicon oxide film only on the edge portion, and the silicon nitride film is removed.

Abstract: Photosensitive composition comprising, inter alia, thermoplastic-elastomer block copolymer binders and addition-polymerizable monomer having terminal ethylenically unsaturated end groups wherein at least one monomer has one acrylate or methacrylate group, said monomer forms a homopolymer having a solubility parameter in the range between 7.6 and 9.6 and a glass transition temperature below 0.degree. C. and, further wherein, at least one monomer has more than one acrylate or methacrylate groups, said monomer forms a homopolymer having a solubility parameter in the range between 9.6 and 12.

Abstract: A photosensitive recording element comprises(A) a dimensionally stable substrate,(B) a photopolymerizable relief-forming recording layer and, if required, an adhesion-promoting layer arranged between (A) and (B), a release layer (C) applied to that side of the recording layer (B) which faces away from the substrate (A), and, if required, a cover sheet (D) applied thereon, the photopolymerizable relief-forming recording layer (B) containingb.sub.1) at least one polymeric binder,b.sub.2) at least one photopolymerizable olefinically unsaturated monomer which is compatible with b.sub.1),b.sub.3) at least one photopolymerization initiator andb.sub.4) at least one aryl alkyl ketone,and is suitable for the production of relief printing plates.

Abstract: Aqueous alkaline developing compositions useful in the development of negative-working lithographic printing plates are comprised of an organic solvent, an anionic surface active agent, an alkali metal tetraborate, an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid, an alkali metal citrate, a poly(alkylene glycol), an alkali metal salt of an hydroxylated aromatic carboxylic or sulfonic acid and sufficient alkaline buffering system to provide an alkaline pH. The developing composition is resistant to oxidation, highly effective in dissolution-type processing, able to effectively desensitize the background areas of the printing plate, and capable of preventing excessive deposits in a processing machine and rapidly redissolving deposits that do form.

Abstract: Flexible printing plates are produced from printing plates consisting essentially of a dimensionally stable substrate (1) and a recording layer (2) by a process in which the printing plate is produced alternatively either by photochemical or by mechanical structuring, and in the case of photochemical structuring the photosensitive recording layer (2) is exposed imagewise and the unexposed parts of the recording layer (2) are washed out with a developer and in the case of mechanical structuring the originally photosensitive, uniformly exposed recording layer (2) is cut imagewise and the nonprinting parts of the recording layer (2) are peeled off from the substrate (1).The printing plates produced by this process are suitable for the production of products printed by the flexographic method and for lacquering products printed by the offset method.

Abstract: Polymeric ledges on a metal stencil screen are made using a polymeric layer which is partially removed by a developer solution.

Abstract: The present invention provides a conversion liquid for converting silver areas of a silver based printing plate into ink repellant areas while rendering background areas of said silver based printing plate ink accepting, said conversion liquid comprising a hydrophobizing compound capable of adsorbing to said hydrophilic background areas and a hydrophilizing compound capable of adsorbing to said silver areas and/or a bleaching compound capable of oxidizing the silver in said silver based printing plate.

Abstract: A photocurable gel suitable for articles such as printing plates, photoresists and the like is disclosed. The photocurable eel comprises (a) a polymer composition having isotactic polymethyl methacrylate moiety; and syndiotactic polymethyl methacrylate moiety; (b) a photopolymerizable ethylenically unsaturated compound; and (c) a photopolymerization initiator. The gel is solid at ambient temperature and is capable of undergoing reversible gel/sol transition by heating or cooling. Methods of preparing articles, as well as methods of fixing articles, which use the gel are also disclosed. Such methods include sealing or affixing component parts on an electronic circuit board.

Abstract: A developer is disclosed for lithographic printing elements. The developer is single phase and contains an aliphatic cyclic carbonate, water, and optional ingredients.

Abstract: Aqueous alkaline developing compositions useful in the development of negative-working lithographic printing plates are comprised of an organic solvent, an anionic surface active agent, an alkali metal tetraborate, an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid, a long chain aliphatic amine and sufficient alkaline buffering system to provide an alkaline pH. The developing composition is resistant to oxidation, highly effective in dissolution-type processing, able to effectively desensitize the background areas of the printing plate, and effective in enhancing the oleophilicity of the image areas of the printing plate.

Abstract: A radiation-sensitive composition especially adapted to prepare a lithographic printing plate that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner is comprised of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber. The solubility of the composition in aqueous alkaline developing solution is both reduced in exposed areas and increased in unexposed areas by the steps of imagewise exposure to activating radiation and heating.

Abstract: A radiation-sensitive composition especially adapted to prepare a lithographic printing plate that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner is comprised of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber. The solubility of the composition in aqueous alkaline developing solution is both reduced in exposed areas and increased in unexposed areas by the steps of imagewise exposure to activating radiation and heating.

Abstract: Prevention of printing stains occurring on positions corresponding to the end parts of the printing plate in the case of printing on a rolled paper by a rotary press machine, as in newspaper printing can be accomplished by a process for the production of a lithographic printing plate, which comprises subjecting a lithographic printing plate transported in a predetermined direction by a transporting means to a beveling treatment of end parts thereof and then subjecting the beveled parts to a treatment for rendering hydrophilic.

Abstract: The invention relates to a process for producing flexographic printing reliefs by:(a) forming at least one photopolymerizable layer on a support, said layer being crosslinkable by photopolymerization;(b) imagewise exposing the layers to actinic radiation; and(c) removing the noncrosslinked portions of the layers with developer solvents;wherein the improvement comprises using developer solvents which have at least one component selected from the group consisting of: (a) diethylene glycol dialkyl ethers wherein the alkyl group has 1-5 carbon atoms; (b) acetic acid esters of alcohols selected from the group consisting of saturated alcohols having 6-10 carbon atoms and alkoxy substituted saturated alcohols having 6-10 carbon atoms; (c) carboxylic acid esters of acids having 6-10 carbon atoms and alcohols having 1-6 carbon atoms; and (d) esters of alkoxy substituted carboxylic acids wherein the acid has from 2-4 carbon atoms, the alkoxy substituent has from 1-4 carbon atoms, and alcohols having 1-4 carbon atoms.

Abstract: A radiation-sensitive composition especially adapted to prepare a lithographic printing plate that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner is comprised of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber. The solubility of the composition in aqueous alkaline developing solution is both reduced in exposed areas and increased in unexposed areas by the steps of imagewise exposure to activating radiation and heating.

Abstract: A phenolic resist without photoadditives achieves enhanced sensitivity when exposed to patterned short wavelength radiation to form a highly crosslinked barrier layer in the exposed regions of the resist surface. The complementary surface regions are silylated in a silicon-containing reagent, and the exposed regions are readily removed by a oxygen RIE plasma. The laser exposure is a reciprocal process allowing precise control. Pattern definition is enhanced by limiting the exposure and the silylation to the surface of the resist.

Abstract: A negative-working lithographic printing plate having a radiation-sensitive layer comprising a diazo resin, an acid-substituted ternary acetal polymer and an unsaturated polyester is developed with an aqueous developing composition comprising an organic solvent, an anionic surface active agent, sodium oxalate, sodium nitrate or an alkali metal tetraborate an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid and sufficient alkaline buffering system to provide an alkaline pH. The method effectively avoids problems of blinding and background sensitivity which are of critical concern in the printing art.

Abstract: Grained, anodized and hydrophilized lithographic printing plates which have a negative or positive working radiation-sensitive coating, are exposed and are developed in an aqueous alkaline solution, are subjected, after hydrophilization, to a treatment with a salt solution containing divalent or polyvalent cations in a concentration of not less than 0.02 mol/l, thereby minimizing degradation of the plate and contamination of the printing forms and the development apparatus.

Abstract: The present invention relates to a developer composition for radiation-sensitive positive-working and negative-working and reversible reprographic layers which apart from a radiation-sensitive compound or radiation-sensitive combination of compounds contain, as an essential constituent, a binder which is insoluble in water but soluble in aqueous-alkaline solutions, said developer composition being characterized in that it contains, as essential constituents,(a) O- carboxymethyl- or O,O'-biscarboxymethylethylene glycol or an appropriately substituted polyethylene glycol comprising 2 to about 500 ethylene glycol units,(b) at least one compound showing an alkaline reaction in water, selected from the group including alkali metal hydroxides, alkali metal silicates, alkali metal phosphates, alkali metal borates, ammonium hydroxides, ammonium silicates, ammonium phosphates and ammonium borates, and(c) water.

Abstract: Disclosed is a process for developing a presensitized plate which is used in making a lithographic printing plate requiring no dampening water and which comprises, on a substrate, a photopolymerizable adhesive layer and a silicone rubber layer in the order, said process comprising water as a main component and at least one ethylene glycol derivative represented by the following general formula (I):C.sub.m H.sub.2m+1 --(OCH.sub.2 CH.sub.2).sub.n --OH (I)(wherein m is an integer of 5 to 8 and n is 1 or 2). According to the present invention, the developer is excellent in safety, in developing ability and in half-tone dots reproduction.

Abstract: A photoresin printing plate having a Shore A hardness at 20.degree. C. of 25 to 60, an impact resilience at 20.degree. C. of 35% or more as measured by a falling ball method and a surface tack at 20.degree. C. of 40 g/cm or less has been found not only to be capable of providing prints having an image of high precision but also to be capable of releasing the paper dust or the like, which has adhered to the printing plate, in a short period of time during the printing operation, so that it did not become necessary to interrupt the printing operation in order to clean the printing plate, which leads to an efficient production of the prints.

Abstract: Aqueous alkaline developing compositions useful in the development of negative-working lithographic printing plates are comprised of an organic solvent, an anionic surface active agent, sodium oxalate, sodium nitrate or an alkali metal tetraborate, an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid and sufficient alkaline buffering system to provide an alkaline pH. The developing composition is resistant to oxidation, highly effective in dissolution-type processing, and able to effectively desensitize the background areas of the printing plate.

Abstract: A photosensitive resin printing plate which can provide printed matter with good ink coverage and little dot gain, and a plate making apparatus used therefor.

Abstract: A lithographic printing plate for use on a printing press, with minimal or no additional processing after photoexposure, comprises a printing plate substrate; a photosensitive hydrophilic layer having a polymeric hydrophilic binder and a photopolymerizable, photocrosslinkable or photorearrangeable compound capable of promoting insolubilization or hardening in areas of photoexposure; and a photosensitive hydrophobic layer having a polymeric hydrophobic binder and a photopolymerizable, photocrosslinkable or photorearrangeable compound capable of promoting insolubilization or hardening in areas of photoexposure.

Abstract: A printing plate making apparatus for color printing is provided with a depicting section for recording an image on the surface of a printing plate, a processing section for processing the printing plate, with a processing solution, while conveying the printing plate, and a punching section for punching notches for positioning and winding the printing plate around a plate cylinder of a rotary press, the depicting and punching sections are provided with a first reference pin for abutting against a side edge of the printing plate being moved in a first direction to position the printing plate in the first direction, and a second reference pin for abutting against a side edge of the printing plate being moved in a second direction to position the printing plate in the second direction. The positional relation between the first and second reference pins in the depicting section and the positional relation between the first and second reference pins in the punching section are set identically.

Abstract: A method for preparing a lithographic printing plate not requiring dampening with water comprising the steps of imagewise exposing to light a presensitized plate for use in preparing a lithographic printing plate not requiring dampening with water which comprises a substrate provided thereon with a light-sensitive layer and a silicone rubber layer in that order and then spraying a pressurized liquid on the plate surface to remove the silicone rubber layer of the image areas. The method does not require the use of brush rolls or developing pads which directly come in contact with the plate surface and give rise to wear and/or bending. Therefore, the method always ensures excellent quality and uniformity of development. Further, the method may be carried out repeatedly with less maintenance of equipment since it is not necessary to use any developing pad or brush roll which must frequently be exchanged due to wear or bending.

Abstract: In a novel, improved process for the production of photopolymeric flexographic relief printing plates from photosensitive recording elements which containA) a dimensionally stable substrate andB) at least one photopolymerizable recording layer havingb.sub.1) at least one elastomeric polymer as a binder,b.sub.2) at least one photopolymerizable monomer which is compatible with the binder (b.sub.1) andb.sub.3) at least one photopolymerization initiator,by(1) imagewise exposure of the photopolymerizable recording layer (B) to actinic light and(2) washout (development) of the unexposed and therefore nonphotopolymerized parts of the imagewise exposed recording layer (B) with an organic developer with formation of a relief layer,the organic developers used are 3-methoxy-n-butyl acetate and/or n-butyl glycolate.

Abstract: A method for preparinq a lithographic printing plate comprising the steps of imagewise exposing, to light, a negative-working presensitized plate for use in making a lithographic printing plate which comprises a substrate provided thereon with a light-sensitive layer comprising an aromatic diazonium compound having at least one member selected from the group consisting of carboxyl groups, phenolic hydroxyl groups, sulfonic acid residues, sulfinic acid residues and phosphorus atom-containing oxyacid residues and developing the imagewise exposed presensitized plate with a developer which comprises an aqueous solution of an alkali metal or ammonium silicate having a ratio: [SiO.sub.2 ]/[M], wherein [SiO.sub.2 ] and [M] represent the molar concentrations of SiO.sub.2 and the alkali metal or ammonia in the developer respectively, ranging from 0.15 to 0.75 and an SiO.sub.2 content ranging from 1.0 to 4.

Abstract: A method for producing a photocured image structure, comprising providing a selectively photocured elastomer composition layer having a photocured image portion and an uncured portion, and contacting the selectively photocured elastomer composition layer with a developer comprising a specific ester and optionally a specific alcohol in a specific volume ratio, to wash-out the uncured portion and develop the photocured image portion, thereby obtaining the photocured image structure. By this method, not only is the swelling of the image structure minimized but also the danger of relief breakage and orange peel formation is eliminated, so that an excellent photocured image structure can be produced by a simple operation.

Abstract: In a novel process for the production of a flexographic relief printing plate from a photosensitive recording element which containsA) a dimensionally stable substrate andB) at least one photopolymerizable recording layer havingb.sub.1) at least one elastomeric polymer as a binder,b.sub.2) at least one photopolymerizable monomer which is compatible with the binder (b.sub.1) andb.sub.3) at least one photopolymerizable initiator, by(1) imagewise exposure of the photopolymerizable recording layer (B) to actinic light and(2) washout (development) of the unexposed and therefore nonphotopolymerized parts of the imagewise exposed recording layer (B) with an organic developer with formation of a relief layer,wherein the organic developer contains from 1 pphm (1 part per 100,000,000) to 3% by weight, based on its total amount, of at least one antistatic agent.

Abstract: A method for preparing a printing plate is disclosed. The method comprises contacting a heat sensitive medium, comprising a support and provided thereon a heat transfer layer containing a colorant, a heat fusible substance and a photo-curable composition, with a recording material having a hydrophilic recording surface through the heat transfer layer, applying heat in an image pattern to the contacted materials to transfer the image onto the recording material, and exposing the transferred image to actinic radiation to cure the transferred image.

Abstract: A developing solution of an imagewise exposed, presensitized offset printing plate is disclosed. The developing solution has a pH of at least 12.5, and contains a low content of a silicate in an amount of up to 1.0 wt % as SiO.sub.2, a surfactant in an amount of 0.01 to 10 wt %, an aromatic carboxylic acid in an amount of 0.1 to 10 wt %, and an amine compound represented by the following general formula (I) in an amount of 0.1 to 10 wt %:R.sub.1 --N(R.sub.2)--J--OH (I)wherein R.sub.1 and R.sub.2 are each independently a hydrogen atom, a group --C.sub.2 H.sub.4 OH or a group --C.sub.3 H.sub.6 OH; and J is a group --C.sub.2 H.sub.4 -- or --C.sub.3 H.sub.6 --.

Abstract: A method of making a lithographic printing plate comprises the steps of imagewise exposing to light a presensitized plate which comprises a hydrophilized substrate provided thereon with an organic layer comprising at least one compound selected from the group consisting of substituted or unsubstituted aliphatic or aromatic compounds represented by the following general formula:R.sup.1 (PO(OH.sub.2).sub.n (I) orR.sup.1 (PO(OH)(R.sup.2)).sub.n (II)wherein n is 1 or 2, if n is 1, R.sup.1 and R.sup.2 each represents a substituted or unsubstituted alkyl, alkoxy, aryloxy, aryl, acyl or acyloxy group and if n is 2, R.sup.1 represents a substituted or unsubstituted alkylene or arylene group and R.sup.

Abstract: A developer for a presensitized plate for use in making a lithographic printing plate requiring no dampening water comprises: (1) 1 to 39% by weight of at least one alcohol derivative selected from the group consisting of those represented by the following general formula (I): ##STR1## (wherein R.sup.1 represents an alkyl or alkenyl group having 4 to 12 carbon atoms; R.sup.2 represents a hydrogen atom or a methyl group; and n is an integer ranging from 1 to 6); (2) 1 to 39% by weight of at least one water-soluble organic solvent having a boiling point of not less than 100.degree. C.; and (3) 60 to 98% by weight of water. If this developer is used, foaming is hardly caused during the development processing a PS plate requiring no dampening water, it has excellent developing ability and half tone dot reproduction and can provide an excellent lithographic printing plate free of defects such as scratch marks.

Abstract: Disclosed are a method and an apparatus for processing with a developing solution repeatedly used, both an imagewise exposed, positive-working presensitized lithographic printing plate and an imagewise exposed negative-working presensitized lithographic printing plate. The plates each comprise an aluminum support and a light-sensitive layer formed thereon. A replenishing solution is added to the developing solution to compensate for the degradation of the developing solution brought about by development and/or by carbon dioxide in the air. The method comprises the steps of; measuring a reflection density of the light-sensitive layer of the printing plates to discriminate the type of the printing plate, selecting a predetermined developing condition according to the discriminated type of the printing plate, and developing the printing plates according to the selected developing condition.

Abstract: Negative-acting flexographic printing plates display enhanced performance when backside irradiated with ionizing radiation instead of longer wavelength ultraviolet radiation. A better defined floor and more readily controlled floor is produced on the final printing plate.

Abstract: An aqueous composition useful for the protection of actinic light-exposed presensitized lithographic printing plates. The composition comprises an effective amount of (a) an ammonium, sodium, potassium or lithium salt of a strong organic acid, and (b) an ammonium, sodium, potassium or lithium salt of an anionic surfactant which contains functionalities of the salt of a strong organic acid and the salt of a weak organic acid, and (c) an ammonium, sodium, potassium or lithium salt of a weak organic acid. The composition is applied to the surface of the plates after they have been developed, but before they have been baked, thereby preventing surface contamination that would otherwise occur from the heat treatment.

Abstract: Disclosed is an eluting solution for eluting a non-image area of an electrophotographic printing plate having a toner image formed and fixed thereon by electrophotography, to expose a hydrophilic substrate or a substrate that can be rendered hydrophilic. This eluting solution is an aqueous solution containing at least an alkali chelating agent.

Abstract: A radiation-sensitive mixture is disclosed which contains as essential constituentsa) at least one thermoplastic, elastomeric block copolymer of the formulae(A-B).sub.m -A, (B-A).sub.m+a -B, (A-B).sub.m+1 or (A-B).sub.o Y,in whichA is a thermoplastic, nonelastomeric polymer block having a glass transition temperature of 25.degree. C. or above andB is an elastomeric polymer block having a glass transition temperature of 10.degree. C. or below,Y is Sn or Si,m is an integer from 1 to 10, ando is 2 if y is Sn, or 4 if y is Si,b) at least one ethylenically polyunsaturated compound, andc) a photopolymerization initiator,wherein at least one of the ethylenically polyunsaturated compounds corresponds to the formula I ##STR1## where R is a straight-chain or branched alkyl radical,X is a straight-chain alkylene or cycloalkylene, it being possible for individual methylene groups to be substituted by --O--, --S--, carbonyl or carbonyloxy groups, and n is 1 to 5.

Abstract: Disclosed is an aqueous acidic developing solution for a photoresist comprising an acid having from about 1 to 8 carbon atoms, in an effective combination with a solubilizing solvent for the photoresist.