Abstract: A positive working photosensitive composition comprising a polymeric compound insoluble in water but soluble in an aqueous alkaline solution and an aromatic sulfonic acid salt of an onium compound. The positive working photosensitive composition having high sensitivity and being capable of forming high-contrast images.

Abstract: A photocurable mixture is disclosed that contains a diazonium salt polycondensation product or an organic azido compound as the photosensitive compound and a high-molecular weight polymer as the binder, the polymer being a graft copolymer with a polyurethane as the graft backbone, onto which chains containing vinyl alcohol units are grafted. The mixture is suitable for use in the production of printing plates and photoresists, which can be developed with aqueous solutions. It yields printing plates having a good ink acceptance and long shelf life that produce large print runs.

Abstract: A photosensitive composition comprising a water-soluble polymer, a dichromate and at least one aromatic diazonium salt selected from aromatic diazonium sulfates, sulfonates and chromates has high sensitivity, and a pattern having high resolution can be formed therefrom with a shortened exposure time.

Abstract: Acid sensitized photoresists with enhanced photospeed are provided. The photoresist compositions include a polymer binder and/or a polymerizable compound and an acid sensitive group which enables patterning of the resist composition, and acid generating photoinitiator, and an hydroxy aromatic compound which enhances the speed of the resist composition under imaging radiation.

Abstract: Polymers comprising perfluoroalkyl groups, reproduction layers containing these polymers and use thereof for waterless offset printing. The novel perfluoroalkyl group-containing polymers comprise polymers or polycondensates and have, in each case as substituents on different carbon atoms of benzene rings, phenolic OH groups and perfluoroalkyl groups which are optionally attached through intermediate members. In particular, at least 10% of the polymer units carry perfluoroalkyl groups. These polymers are either formed by condensation of substituted phenols (e.g., 4-hydroxybenzoic acid-perfluoroalkyl ester) with an aldehyde, a ketone, or a reactive bismethylene compound or by reacting polymers containing phenolic OH groups (e.g., hydroxypolystyrene) or polycondensates containing reactive OH groups (e.g., phenol-formaldehyde resins) with a perfluoroalkyl group-containing compound (e.g., 2,2-dihydroperfluorodecanoic acid chloride).

Abstract: A light-sensitive composition comprises (A) a polymer comprising structural units represented by the following general formula (I): ##STR1## (wherein R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 represents a hydrogen atom, an alkyl group or an aryl group; and Z represents a bivalent connecting group having at least 3 non-metallic atoms in the main chain); (B) a monomer or an oligomer having at least two polymerizable ethylenically unsaturatred double bonds; and (C) a photopolymerization initiator. The light-sensitive composition has high sensitivity and is excellent in stability of sensitivities such as storage stability, temperature dependency and latent image sensitization.

Abstract: A light-sensitive mixture is described which contains a diazonium salt polycondensation product, a free-radical polymerizable compound having at least one terminal ethylenically unsaturated group and a boiling point at atmospheric pressure above 100.degree. C., a polymerization initiator which forms free radicals under the action of actinic radiation, and, as a first binder, a water-insoluble reaction product which is soluble in organic solvents and in aqueous alkaline solutions, which is a reaction product of an intramolecular anhydride of an organic polycarboxylic acid with a hydroxyl-containing synthetic polymer, and which has no further functional groups capable of reacting with acid anhydrides, and, as a further binder, an acid organic polymer having an acid number above 70, preferably a (meth)acrylic acid copolymer. The mixture is useful for producing planographic printing plates which give long print runs, and is notable for a long shelf life at elevated temperature.

Abstract: Disclosed is a method of providing a substrate with a layer comprising a polyvinyl base hydrogel and a biochemically active material by photolithograhy, comprising coating the substrate by centrifugal force with an aqueous solution of a photosensitive hydrogel forming polymer, a crosslinking agent and a biochemically active material, drying said coating, exposing the coated substrate through a photomask to ultraviolet radiation and developing said exposed coating, which is characterized by applying to the substrate an aqueous solution comprising as the cross-linking agent a polyazonium compound and glutardialdehyde. Because of this specific combination of cross-linking agents superior properties with respect to the binding of the biochemically active material are obtained.

Abstract: Disclosed is a photocurable mixture which is suited for the production of printing plates, in particular planographic printing plates, and photoresists. The mixture comprises a graft polymer comprised of a polyurethane as the graft backbone and grafted-on chains containing vinyl alcohol units and units with lateral, polymerizable or crosslinkable double bonds, and a photosensitive compound, such as a photoinitiator or a negative-working diazo compound.The printing plates prepared from the mixture are distinguished by high photospeed, good developability with aqueous solutions and long print runs.

Abstract: A developer composition comprises an aqueous alkaline solution which contains at least one alkali-soluble mercapto compound and/or thioether compound. The developer composition is excellent in developing properties and provides lithographic printing plates which do not cause background contamination of non-image areas during printing, when it is used in developing PS plates. It can be stored for a long time. The developer composition further makes it possible to develop both negative and positive working PS plates if its pH value is not less than 12.

Abstract: It surprisingly has been found that a protective coating composition for diazo-containing materials can be prepared from a cellulose ester and microcrystalline silica. The coating compositions of the invention provide protection for diazo-containing materials from physical and chemical damage. In particular, the protective coating compositions of the invention protect the diazo-containing materials from abrasion.The invention further relates to a method for providing a protective coating on a diazo phototool comprising coating at least the surface of the diazo phototool containing diazo material with a composition comprising a cellulose ester and microcrystalline silica.

Abstract: The method for forming an image which comprisesI). providing a mesh fabric substrate, andII). coating said substrate with a light sensitive screen printing composition which comprises in admixtureA). at least one substantially water soluble binder resin component comprising an admixture of polyvinyl alcohol and polyvinyl acetate in an amount of from about 33% to about 90% polyvinyl alcohol and from about 10% to about 67% polyvinyl acetate based on the weight of the resin component, in sufficient amount to bind the composition components in a substantially uniform film when the composition is coated on a substrate and dried; andB). a photosensitive component in sufficient amount to substantially, uniformly photosensitize the composition,C).

Abstract: Excellent resolution and sensitivity in the patterning of resists utilized in device and mask manufacture is obtained with a specific composition. In particular this composition involves polymers having recurring pendant acid labile .alpha.-alkoxyalkyl carboxylic acid ester and/or hydroxyaromatic ether moieties in the presence of a substance that is an acid generator upon exposure to actinic radiation.

Abstract: Disclosed is a novel diazo resin which has at least one repeating unit represented by the following general formula (I): ##STR1## wherein R.sup.2 represents a hydrogen atom, an alkyl group or an alkoxy group, a hydroxyl group, a carboxy ester group or a carboxyl group: R.sup.1 represents a carboxyl group or a group having at least one carboxyl group; R.sup.3 and R.sup.4 each represents a hydrogen atom or an alkyl group or an alkoxy group; X.sup.31 represents an anion; and Y represents --NH--, --O-- or --S--. The diazo resin is useful for a presensitized plate for use in making a lithographic printing plate when it is incorporated into a light-sensitive layer or an underlayer on a substrate. According to the present invention, a presensitized plate using the diazo resin has excellent properties such as high sensitivity, good adhesion between the substrate and the light-sensitive layer and can thus provide a lithographic printing plate having a high printing durability and free of background contamination.

Abstract: A radiation-sensitive mixture, essentially consisting ofa) a binder or binder mixture which is insoluble in water but soluble in aqueous alkaline solutions,b) a compound which forms a strong acid on exposure to radiation andc) an organic compound which contains an acid-cleavable carbamate unit,is suitable for the production of relief structures.

Abstract: Polymers comprising perfluoroalkyl groups, reproduction layers containing these polymers and use thereof for waterless offset printing. The novel perfluoroalkyl group-containing polymers comprise polymers or polycondensates and have, in each case as substituents on different carbon atoms of benzene rings, phenolic OH groups and perfluoroalkyl groups which are optionally attached through intermediate members. In particular, at least 10% of the polymer units carry perfluoroalkyl groups. These polymers are either formed by condensation of substituted phenols (e.g., 4-hydroxybenzoic acid-perfluoroalkyl ester) with an aldehyde, a ketone, or a reactive bismethylene compound or by reacting polymers containing phenolic OH groups (e.g., hydroxypolystyrene) or polycondensates containing reactive OH groups (e.g., phenol-formaldehyde resins) with a perfluoroalkyl group-containing compound (e.g., 2,2-dihydroperfluorodecanoic acid chloride).

Abstract: A light-sensitive composition which comprises, (a) an ethylenically unsaturated addition polymerizable compound, (b) an alkaline water-soluble or swellable, and film-forming polymer, (c) a photopolymerization initiator, (d) a negative working diazo resin, and (e) at least one compound selected from the group consisting of a higher fatty acid and a higher fatty acid amide which are solid at ordinary temperatures.The light-sensitive composition is hardly influenced by oxygen and is suitable for a presensitized plate from which a printing plate is to be prepared.

Abstract: The present invention relates to a negative photoresist consisting essentially ofa) at least one solid film-forming polyphenol,b) at least one compound which contains at least two epoxide groups or at least two vinyl ether groups or at least one epoxide and vinyl ether group in the molecule,c) at least one cationic photoinitiator for component b) andd) if appropriate customary additives.The resist can be developed under aqueous-alkaline conditions.

Abstract: A radiation sensitive mixture suitable for producing relief patterns contains(a) a polymeric binder which is insoluble in water but soluble in aqueous alkaline solutions and(b) an organic compound whose solubility in an aqueous alkaline developer is increased by the action of acid and which contains at least one acid cleavable group and additionally a group which forms a strong acid on irradiation,wherein the polymeric binder (a) contains from 5 to 35 mol % of monomer units having acid labile groups as copolymerized or cocondensed units or acid labile groups introduced by polymer analaogous reaction.

Abstract: The present invention relates to dyestuffs soluble in organic solvents having the structure: ##STR1## wherein R is CF.sub.3 or phenyl, R.sub.1 and R.sub.2 are the same or different substituent groups selected from the group consisting of hydrogen, hydroxy, halogen, C.sub.1 to C.sub.3 alkyl and C.sub.1 to C.sub.4 alkoxy, R.sub.3 is selected from the groups consisting of hydrogen, C.sub.1 to C.sub.3 alkyl, C.sub.1 to C.sub.3 alkoxy, COOH, and COOR.sub.5 wherein R.sub.5 is C.sub.1 to C.sub.4 alkyl, R.sub.6 is selected from the group consisting of hydrogen, sulfonyl, C.sub.1 to C.sub.3 alkyl, C.sub.1 to C.sub.3 alkoxy and halogen, and n is zero or a whole number ranging from 1 to 3. The dyestuffs of the invention are useful as light absorbers or antihalation agents in photosensitive compositions. They may also be used as dyeing agents for paper, fibers or films and as components in printing ink formulations.

Abstract: Terpolymers of styrene, mono-iso-butyl maleate and mono-2-(n-butoxy)ethyl maleate wherein the ratio of styrene units to maleate units is in the range of about 1:1 to about 1.6:1 and the ratio of mono-iso-butyl maleate units to mono-2-(n-butoxy)ethyl maleate is in the range of about 3:2 to about 1:3. The terpolymers are useful as alkali soluble binders for photoresist compositions.

Abstract: The present invention relates to an aluminum support for a lithographic plate, whose surface is electrochemically roughened and has the following conditions:a) an arithmetic mean of the pit diameters of the electrolytically etched support is 4 .mu.m or less,b) a difference between an arithmetic mean (D.sub.L) of the maximum pit diameter of the support in the rolling direction and an arithmetic mean (D.sub.LT) of the maximum pit diameter of the support in the direction perpendicular to the rolling direction is larger than 10% of the maximum pit diameter (a larger one of D.sub.L and D.sub.LT),c) the number of pits detected with a surface roughness tester having a profilometer using a stylus having a tip radius of 1 .mu.m is at last 200/mm, andd) an average centerline roughness is 0.2 .mu.m to 1.0 .mu.m.According to the present invention, a lithographic plate having the aluminum support is excellent in both of a printing durability and a stain proofness.

Abstract: This invention relates to negative photosensitized sheet constructions which, upon exposure to an actinic radiation source through a screened image, can accurately reproduce said image. The construction is useful as a color proofing film which can be employed to predict the image quality from a lithographic printing process.

Abstract: A positively photosensitive polyimide composition is disclosed, which composition comprises polyimide having repeating unit represented by formula (I): ##STR1## wherein Ar.sup.1 represents a tetravalent aromatic hydrocarbon group; Ar.sup.2 represents a divalent aromatic hydrocarbon group having an acyloxy group at the ortho-position and/or the meta-position of the aromatic ring; Ar.sup.3 represents a divalent aromatic hydrocarbon group; and the subunit having an amount ratio of m in the repeating unit is present in an amount of at least 20% by weight based on the polyimide. The composition exhibits high photosensitivity in reproduction of a fine pattern and excellent dimensional stability.

Abstract: A photosensitive recording material comprising (a) a substrate having a hydrophilic surface, (b) an undercoating layer comprising at least one compound having at least one functional group selected from the group consisting of thiol, thioether and disulfide groups, and (c) a photosensitive layer comprising at least one diazonium compound and a high molecular weight binder compound which is insoluble in water and soluble in aqueous alkaline solution. The resulting developed plate yields no background contamination in printing process.

Abstract: A light-sensitive mixture that contains as essential constituents (a) a diazonium salt polycondensation product, (b) a free-radical polymerizable compound, (c) a polymerization initiator which forms free radicals under the action of actinic radiation and (d) a water-insoluble polymeric binder which is soluble in organic solvents and in aqueous alkaline solutions, where the binder is a reaction product of an intramolecular anhydride of an organic polycarboxylic acid with a hydroxyl-containing synthetic polymer, is preferably used for preparing planographic printing plates which combine high image resolution and an extended print run.

Abstract: A positive radiation-sensitive mixture is disclosed containing a compound which forms an acid under the influence of actinic radiation, and an acid-cleavable compound, wherein the acid-cleavable compound is monomeric and contains an acetal group whose aldehyde or ketone component has a developer solubility of about 0.1 to 100 g/l and a boiling point above about 150.degree. C. The mixture does not exhibit different development properties, even at different "holding times", and therefore exhibits a wide processing latitude and makes possible a high structural resolution.

Abstract: A method of fabricating a periodic nonlinear optic radiation modulation zone within a polymeric waveguide structure. The method includes the steps of (a) providing a layer of a polymeric material having an optically active material that is orientable by an electrical field; (b) applying an electrical field to the layer for orienting at least a portion of the optically active material; and (c) photopolymerizing at least a portion of the polymeric layer for fixing the oriented optically active material into the oriented position. In accordance with one embodiment the step of photopolymerizing includes the steps of (d) generating a diffraction pattern within the polymeric layer, the diffraction pattern being characterized by bright and dark fringes; and (e) photoplymerizing a volume of the polymeric layer within substantially only portions thereof that correspond to the bright fringes.

Abstract: An aqueous base developable negative resist composition comprising a phenolic resin, a radio-chemical acid generator and a small molecule which upon irradication and postbake reacts with the phenolic resin to decrease its rate of dissolution.

Abstract: A process for the formation of a negative resist pattern, comprising preparing a mixture consisting of water-soluble polymeric material having at least one hydroxyl group with a photoacid generator capable of releasing an acid upon radiation exposure, coating a solution of the resist material onto a substrate to form a resist layer, exposing layer to patterned radiation, heating the exposed resist layer in the presence of an acid as a catalyst to remove water, and developing resist layer with water to remove unexposed areas to form a resist pattern on the substrate.

Abstract: The polysilanes and polysiloxanes of the present invention are polymers that contain silicon in the principal chain, and contain in the side chains alkaline soluble groups such as phenol-based hydroxy group and carboxyl group.One silicone resist material of the present invention comprises the polysilane or the polysiloxane in the above.Another silicone resist material of the present invention contains the above polysilane or polysiloxane, and an appropriate photosensitive agent.Still another silicone resist material of the present invention does not contain the above photosensitive agent, and in its stead, it contains a group that possesses photosensitive to ultraviolet rays or the like, via a siloxane bonding in the principal chain. As a substance with such photosensitivity, one may mention, for example, o-nitrogenzylsilyl groups that presents alkaline solubility when it is irradiated by ultraviolet rays.

Abstract: A radiation-sensitive mixture is described comprising a compound which produces a strong acid under the action of actinic radiation, a binder which is insoluble in water, but soluble in organic solvents and aqueous-alkaline solutions, and a compound of either of formulae I and II ##STR1## wherein R denotes a substituted or unsubstituted alkyl group,X denotes a hydrogen or halogen atom or a hydroxyl, alkyl, alkoxy, alkoxycarbonyl, aryloxy or aryl group, andn denotes zero or a number from 1 to 3.The mixture is suitable for the production of printing plates and photoresists and is distinguished by improved high flexibility along with good overdevelopment resistance.

Abstract: A photosensitive composition, comprising a photosensitive diazo compound and a polymeric binder, wherein the diazo compound has a polymerizable unsaturated bond in the molecule.

Abstract: Polymers comprising perfluoralkyl groups, reproduction layers containing these polymers and use thereof for waterless offset printing. The novel perfluoralkyl group-containing polymers comprise polymers or polycondensates and have, in each case as substituents on different carbon atoms of benzene rings, phenolic OH groups and perfluoroalkyl groups which are optionally attached through intermediate members. In particular, at least 10% of the polymer units carry perfluoroalkyl groups. These polymers are either formed by condensation of substituted phenols (e.g., 4-hydroxybenzoic acid-perfluoroalkyl ester) with an aldehyde, a ketone, or a reactive bismethylene compound or by reacting polymers containing phenolic OH groups (e.g., hydroxypolystyrene) or polycondensates containing reactive OH groups (e.g., phenol-formaldehyde resins) with a perfluoroalkyl group-containing compound (e.g., 2,2-dihydroperfluorodecanoic acid chloride).

Abstract: This invention relates to carbazole diazonium salts which are used in pre-polymer or polymer compositions as sources of photoinitiated strong acids in such developments as imaging films where strong acids are needed to effect polymerization of the film or to remove protective groups.

Abstract: Polymeric compounds comprise groups of the formula ##STR1## attached to carbon atoms of a polymer containing hydroxyl and optionally epoxide groups wherein X is ##STR2## The compounds are produced by reacting a starting polymer, which contains hydroxy groups and optionally epoxide groups with a reagent containing a cyclic anhydride group and a further functional group capable of reacting with the hydroxyl (and/or epoxide) groups preferentially to the anhydride group. The compounds are useful as bakeable support resins for radiation sensitive compounds in the production of printing plates.

Abstract: A photosensitive resin composition having high heat resistance, sensitivity, and resolution performance, including a novolak resin prepared by condensing 2,5-xylenol with m-cresol and/or p-cresol using a carbonyl compound, a novolak resin prepared by condensing 3,5-xylenol with m-cresol and/or p-cresol, and a photosensitive reagent. In addition, four other types of photosensitive resin compositions are disclosed.

Abstract: An image forming material comprising a support, a coloring material-containing organic polymer layer and a photosensitive resin layer in order in the form of a laminate, wherein the organic polymer of the organic polymer layer comprises a copolymer of an aralkyl (meth)acrylate and (meth)acrylic acid.

Abstract: A process for forming a pattern comprising forming an alkali-soluble polymer layer on a substrate, forming a radiation-sensitive composition layer containing a diazonium salt on the alkali-soluble polymer layer to form a resist layer having a two-layer structure, exposing the resist layer to a radiation to cause the change in solubility in an aqueous alkaline solution at the boundary between the two layers and forming a predetermined pattern in the resist layer by a usual resist process. The resist layer may comprise a plurality of layers comprising the two-layer structure as a repeating unit structure.

Abstract: Excellent resolution and sensitivity in the patterning of resists utilized in device and mask manufacture is obtained with a specific composition. In particular this composition involves polymers having recurring pendant acid labile .alpha.-alkoxyalkyl carboxylic acid ester and/or hydroxyaromatic ether moieties in the presence of an acid generator comprising a novel diazonium salt.

Abstract: Disclosed is a radiation sensitive composition which comprises a radiation sensitive compound decreased in absorption of radiation upon irradiation with radiation and an organic polymer which, upon being formed into a film, changes in its solubility and decreases in solubility in a desired solvent due to the presence of decomposition product of said radiation sensitive compound which is produced by irradiation with the radiation. A process of formation of pattern using said composition is also disclosed. Fine resist pattern of 0.5 .mu.m line-and-space patterns or less can be formed with sufficiently high contrast.

Abstract: A photosensitive composition is described, comprising a diazonium compound and a polyurethane resin having a carboxyl group in its main chain. The composition can be developed with an aqueous alkali developer to provide a lithographic printing plate having a long press life.

Abstract: Plasma-resistant polymeric materials are prepared by reacting a polymeric material containing reactive hydrogen functional groups with a multifunctional organometallic material containing at least two functional groups which are reactive with the reactive hydrogen functional groups of the polymeric material, such as hexamethylcyclotrisilazane.

Abstract: A light-sensitive composition comprises a diazo resin, a polymeric binder, and at least one compound having at least one structural unit selected from the group consisting of ureido bond, thioureido bond, urethane bond and thiourethane bond. The light-sensitive composition can suitably be used for preparing a presensitized plate for use in making lithographic printing plates and is excellent in developability with an aqueous alkaline developer.

Abstract: Presensitized imaging element comprising a support and a light-sensitive hyrophilic layer thereon, said light-sensitive hydrophilic layer containing in homogeneously distributed state throughout the entire layer a hydrophilic (co)polymer or (co)polymer mixture, a tetraalkyl orthosilicate crosslinking agent in an amount of at least 0.2 parts by weight per part by weight of hydrophilic (co)polymer or (co)polymer mixture and a low-molecular weight diazonium salt and preferably also (a) substance(s) that increase(s) the mechanical strength and the porosity of the layer, by means of which a lithographic printing plate can be produced by imagewise exposing said imaging element to an ultraviolet radiation source, subsequently bringing it in the presence of an aqueous liquid in contact with a receptor element comprising a receiving layer containing a polyionic mordant for the diazonium salt and separating it from the receiving layer to leave the residual non-exposed diazonium salt on the receiving layer.

Abstract: This invention relates to a screen printing stencil composition which comprises (a) a stabilized aqueous dispersion of a water insoluble addition copolymer having units of formulas: A and B where A is preferably a polyvinyl acetate group and B is preferably a polyvinyl n-methylol acrylamide group and B comprises about 3% by weight of the copolymer; (b) a water soluble colloid; and (c) a photosensitizer: The composition is useful in the formation of a screen printing stencil, the composition having both a long stable profile and forming a durable stencil; the composition on exposure through a photographic positive can be developed with water and cross-linked with acid.

Abstract: A heat-sensitive recording material comprising a base and, on top of the said base, a heat-sensitive layer containing a cyclic diazo component and a coupling component, the cyclic diazo component being a benzotriazine compound of the formula ##STR1## wherein Q is --CH.sub.2 --, --CO-- or --SO.sub.2 --, R is hydrogen, hydroxyl, or aryl or alkenyl, each unsubstituted or substituted by halogen, hydroxyl, cyano, lower alkoxy, lower alkylthio, acyloxy, lower alkoxycarbonyl or lower alkylsulfonyl, or is acyl, acyloxy or acylamino, cycloalkyl, or is aryl or aralkyl such as phenyl, phenylalkyl or naphthyl each unsubstituted or substituted on the ring by cyano, halogen, nitro, trifluoromethyl, lower alkyl, lower alkylthio, lower alkoxy, lower alkylcarbonyl or lower alkoxycarbonyl, or is a heterocyclic radical, and the benzene ring A is unsubstituted or substituted by halogen, cyano, nitro, lower alkyl, lower alkoxy, lower alkylthio, lower alkylcarbonyl or lower alkoxycarbonyl.

Abstract: A photosensitive recording material with a layer base and a photosensitive layer, which essentially contains a diazonium salt polycondensation product, a polymeric binder which is insoluble in water and soluble in organic solvents and soluble or at least swellable in aqueous alkaline solutions, a polymerization initiator which forms free radicals when exposed to actinic radiation and a polymerizable ethylenically unsaturated compound containing at least one unsaturated group and having a boiling point at normal pressure of over 100.degree. C., wherein the recording material contains, between the photosensitive layer and the layer base, a photosensitive intermediate layer which essentially contains a diazonium salt polycondensation product and a polymeric binder which is insoluble in water and soluble in organic solvents and soluble or at least swellable in aqueous alkaline solutions.

Abstract: A photoresist film containing a phosphate of a formalin condensate of diazodiphenylamine, 2.5-bis(4'-azide-2'-sulphobenzilidene) cyclopentanone Na, polyvinylalcohol, and polyvinylpyrrolidone is formed on the inner surface of a faceplate. The photoresist film is hardened by light exposure using a point or linear light source, which is essentially a circular light source, via a shadow mask having a large number of apertures. A light absorbing film is formed on this photoresist film. Then the hardened photoresist film and the light absorbing film on top of it are removed using a peeling agent.

Abstract: A polyvinyl acetal is described which contains 4 to 40 mol-% vinyl alcohol units, 1 to 20 mol-% vinyl acetate units, 0 to 85 mol-% vinyl acetal units derived from an aldehyde free of OH groups and 1 to 85 mol-% vinyl acetal units derived from an aldehyde containing OH groups. The polymer is suitable as binder for photosensitive mixtures, in particular for the preparation of printing plates and photoresists. The layers obtained therewith can be developed with neutral or weakly alkaline, purely aqueous solutions and produce printing plates with a high print run performance and good ink receptivity.