Abstract: Disclosed is a photosensitive composition comprising a diazo resin and a polymeric compound containing a structural unit represented by the following formula (I) in the molecule: ##STR1## wherein J represents a divalent linking group and n is 0 or 1. Disclosed is also a photosensitive lithographic printing using the photosensitive composition.

Abstract: A radiation sensitive material suitable for the production of radiation sensitive plates for lithographic printing plate manufacture comprises a polymer having appendent azide-substituted aromatic ester groups and sulphonyl urethane groups. The radiation sensitive compound is produced by a process in which some hydroxyl and/or epoxide groups of a polymer are reacted with an azide substituted carboxylic acid or ester forming derivative thereof, and some hydroxyl groups are reacted with a sulphonyl isocyanate.

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 photopolymerizable mixture is disclosed which contains:a) a graft copolymer having a polyurethane as the graft backbone, onto chains containing vinyl alcohol units and vinyl acetal units are grafted,b) a free-radically polymerizable compound possessing at least one terminal ethylenically unsaturated group and having a boiling point of more than 100.degree. C. at normal pressure, andc) a compound or a combination of compounds which under the action of actinic light is capable of initiating the polymerization of compound b).The mixture is suitable for use in the production of printing plates and photoresists. It is distinguished by high photospeed and can be developed with aqueous solutions. It yields printing plates producing large print runs.

Abstract: A heat-developable copying material comprising a support having thereon a heat-developable light-sensitive layer comprising microcapsules containing a diazo compound and substantially no solvent, a coupling component and a color basic substance.

Abstract: A dry PS plate comprises a substrate having provided thereon in order a primer layer, a light-sensitive layer and a silicone rubber layer wherein the primer layer comprises a film forming polyurethane resin and a diazonium salt polycondensate. The dry PS plate is excellent in the adhesion strength between the substrate and the light-sensitive layer. The adhesion is surely maintained even after imagewise exposure to light and the subsequent development. The dry PS plate shows excellent image reproduction and the resulting dry lithographic plate is excellent in printing durability as well as resistance to scratch.

Abstract: The present invention concerns a phototackifiable composition useful as a coating on a substrate consisting of an optically clear blend of two or more polymers and a photosensitive compound that forms a strong acid on exposure to actinic radiation. The invention also relates to a process for coating such a composition on a support and toning the image-wise exposed composition on the support.

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: Photosensitive compositions, useful in lithographic printing plates which can be developed with aqueous developing solutions, comprise a diazo resin and an acid-substituted ternary acetal polymer which functions as a polymeric binder. The acid-substituted ternary acetal polymers are comprised of recurring units which include three six-membered cyclic acetal groups, one of which is unsubstituted or substituted with an alkyl or hydroxyalkyl group, another of which is substituted with an aromatic or heterocyclic moiety, and a third of which is substituted with an acid group, an acid-substituted alkyl group or an acid-substituted aryl group.

Abstract: An aromatic diazo compound having at least two groups of Formula (I) in the molecule.This aromatic diazo compound can be handled under visible light free from ultraviolet, is high in photosensitivity, and can be produced by a simple synthesis method.The diazo compound has a high solubility in organic solvents, appropriate for use as a photosensitive material for a lithographic printing plate, can be easily developed by an alkaline developing solution mainly based on an alkaline aqueous solution, and has a water solubility appropriate for use in a screen printing plate. ##STR1## wherein Z.sup.1 indicates ##STR2## wherein .phi..sup.1 is arylene or substituted arylene; and -.phi..sup.2 is >C.dbd.O, lower alkyl, lower alkylene, or aryl or substituted aryl.R.sup.1 and R.sup.2 are H, alkyl of C.sub.1 to C.sub.8, or alkyloxy of C.sub.1 to C.sub.8 ; X.sup.- is anion; and R.sup.

Abstract: A polymeric compound having the formula ##STR1## wherein x ranges from about 0.05 to about 0.5y ranges from about 0.80 to about 0.35z ranges from about 0.10 to about 0.25n ranges from about 50 to about 1500R is selected from the group consisting of phenyl and C.sub.1 to C.sub.4 alkyl substituted phenyl;K is selected from the group consisting of ##STR2## --S--, --O--, and --CH.sub.2 --, or is absent; P and P.sub.1 are selected from the group consisting of C.sub.1 to C.sub.4 alkyl, methoxy, ethoxy, butoxy, and H; andP.sub.1 may be the same as P or different.

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: This invention relates to a method for forming a colored image on a degradable sheet material. As a result, a negative- or positive-working color proofing sheet can be produced on a variety of printing paper stocks. Upon exposure to an actinic radiation source through a screened image and development, it can accurately reproduce the image on the degradable sheet. The construction is useful as a color proof which can be employed to accurately predict the image quality from a lithographic printing process on a variety of printing surfaces.

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: The compounds in a preferred form are represented by general formula (I): ##STR1## wherein A and A' are each a group which can be hydrolyzed by hydrogen or alkali; X, Y and Z are each hydrogen, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a thioalkyl group or an electron-withdrawing group; PUG is a group released by a reaction with a light-exposed silver halide and/or the oxidized product of the developing agent, Time is a timing group; Time.sub.t PUG is a group released as .crclbar.TimePUG first when the oxidation-reduction moiety causes a cross reaction during the development and becomes an oxidized product, and is bonded to the benzene nucleus via a sulfur atom, a nitrogen atom or a selenium atom; and t is 0 or 1.

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: An aluminum alloy substrate for presensitized plates for use in making lithographic printing plates comprises an aluminum alloy plate composed of not less than 0.05% by weight and less than 0.5% by weight of Si; 0.2 to 0.7% by weight of Fe; 0.3 to 1.5% by weight of Mn; less than 0.5% by weight of Cu; and the balance of aluminum and unavoidable impurities, the surface of the aluminum alloy plate being subjected to electrolytic graining treatment. The aluminum alloy substrates for PS plates are favorable for appropriate electrolytic graining treatment and show good printing properties and sufficient strength suitable for high-speed printing operation.

Abstract: This invention relates to a method for forming a colored image on a degradable sheet material. As a result, a negative- or positive-working color proofing sheet can be produced on a variety of printing paper stocks. Upon exposure to an actinic radiation source through a screened image and development, it can accurately reproduce the image on the degradable sheet. The construction is useful as a color proof which can be employed to accurately predict the image quality from a lithographic printing process on a variety of printing surfaces.

Abstract: A light-sensitive composition for the preparation of printing plates is described, which contains a water-insoluble binder which is soluble in aqueous-alkaline solutions; a light-sensitive component which is an o- or p-quinone diazide, a diazonium salt polycondensation product or a mixture ofa) a compound which eliminates an acid on exposure to light andb) a compound having at least one C--O--C group which can be split by acid; and a thermo-crosslinking compound which is a cyclical acid amide of the general formula: ##STR1## wherein R denotes a hydrogen atom or an alkyl group. The printing plates can be baked at lower temperatures than plates without a crosslinking agent, but nevertheless have a long shelf life.

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 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: A presensitized plate for use in making a lithographic printing plate which comprises an aluminum substrate provided thereon with a light-sensitive layer comprising a polymer having at least two photodimerizable unsaturated double bonds in the molecule, wherein the light-sensitive layer further comprises a compound having at least one photodimerizable unsaturated double bond and at least one phosphinyl group in each molecule as well as a molecular weight of not more than 2,000. The presensitized plate shows excellent sensitivity and makes it possible to provide a lithographic printing plate showing high printing durability.

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 light-sensitive composition for the preparation of printing plates is described, which contains a water-insoluble binder which is soluble in aqueous-alkaline solutions; a light-sensitive component which is an o- or p- quinone diazide, a diazonium salt polycondensation product or a mixture of(a) a compound which eliminates an acid on exposure to light and(b) a compound having at least one C--O--C group which can be split by acid; and a thermo-crosslinking compound which is a cyclical acid amide of the general formula: ##STR1## wherein R denotes a hydrogen atom or an alkyl group. The printing plates can be baked at lower temperatures than plates without a crosslinking agent, but nevertheless have a long shelf life.

Abstract: The invention provides a photographic article having a protected image which comprisesa) a colored image disposed on a substrate; andb) a thin, transparent, colorless, thermoplastic adhesive composition directly on the surface of the image, wherein said adhesive is substantially non-tacky at room temperature, and comprises one or more thermoplastic polymers of copolymers capable of forming a flexible film, said adhesive being capable of being transferred directly to the image when the adhesive is first disposed on the release surface of a temporary support and said image and adhesive are laminated together under pressure at temperatures of between about 60.degree. C. and about 90.degree. C. and said temporary support is peeled away; andc) a non-self supporting antiblocking layer directly on said adhesive said antiblocking layer being transparent, colorless and comprises one or more organic polymers or copolymers, which coating does not cohesively block at about 50.degree. C. or less.

Abstract: A light-sensitive transfer material is disclosed, comprising a substantially transparent support having provided on one side thereof, in order from the support, a stripping layer, and a lamination of a colorant layer containing a dye or a pigment and a photoresist layer or a photoresist layer containing a dye or a pigment, and having provided on the other side thereof a physical development nuclei-containing layer adapted for diffusion transfer processing using a silver halide emulsion.

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: 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: A multicolor recording material having on one side of a support at least two layers capable of producing colors different from each other in hue through respective color-producing reactions, which further has an interlayer constituted by a water-soluble polyanionic polymer having gelled through the interaction with a polycation between every adjacent two of said color-producing layers to prevent migration of ingredients from one color-producing layer to another.

Abstract: This invention relates to positive working color proofing sheet construction which, upon exposure to an actinic radiation source through a screened image, can accuratley reprouce said image. The construction is useful as a color proofing film which can be employed to accurately predict the image quality from a lithographic printing process. The image is produced by forming a composite of a receiver base, diazo or diazide layer, photopolymerizable layer and cover sheet. Upon imagewise exposure, a positive image appears on the receiver base after dry peel apart development.

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 light-sensitive composition comprises at least one water-insoluble and aqueous alkaline-soluble polyurethane resin having N-sulfonylamido, N-sulfonylureido or N-aminosulfonylamido groups. The light-sensitive composition is excellent in developing properties in an aqueous alkaline developer and coating properties. In addition, the images obtained from the composition are good in wear resistance and exhibit high adhesion to the substrate. Thus, the composition is very suitable for use in making IC circuits, photomasks and PS plates which provide lithographic printing plates exhibiting high printing durability.

Abstract: Presensitized sheets for color proofing comprising a removable carrier sheet bearing a photosensitive medium sensitive to radiation within the wavelength band 325 to 700 nm and comprising photohardenable, photoadherent, photoinsolubilisable or photosolubilisable material, the sheet including a removable antihalation layer which is removed either when stripping the carrier sheet or during subsequent processing. The antihalation dyes may be positioned within a transparent carrier sheet, in a layer on the carrier sheet opposite to the photosensitive medium or in a layer positioned between the carrier sheet and light-sensitive medium.

Abstract: This invention relates to a radiation polymerizable composition for use in a photographic element such as a lithographic printing plate comprising in admixture(a) a polymeric binder;(b) a photoinitiator;(c) a diazonium salt; and(d) a photopolymerizable mixture of(i) a polyfunctional acrylic monomer having from 3 to 6 unsaturated groups; and(ii) a monofunctional acrylic monomer having 1 unsaturated group.

Abstract: The 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 light-sensitive compound having the formula: ##STR1## wherein R.sub.3 is selected from the group consisting of phenyl and C.sub.1 to C.sub.4 alklyl substituted phenyl.--K-- is selected from the group consisting of ##STR2## --S--, --O--, and --CH.sub.2 --, or is absent; R.sub.1 and R.sub.2 are independently selected from the group consisting of C.sub.1 to C.sub.4 alkyl, methoxy, ethoxy, butoxy, and H;X-- is an anion; andR denotes a hydrogen atom or a C.sub.1 to C.sub.4 alkyl group.

Abstract: A process for producing a toner comprising:heating a monomer composition containing at least a polymerizable monomer and a release agent to a temperature not lower than the melting point or the softening point of said release agent todissolve the release agent in the polymerizable monomer and therebypreparing a monomer composition in which the release agent is dissolved;cooling the monomer composition to a temperature lower than the melting point or the softening point of the release agent to precipitate said release agent and therebypreparing a monomer composition containing the precipitated releasing agent particles having a number average size of 0.5 to 5 .mu.m;granulating in an aqueous dispersion medium the monomer composition to prepare a particle;carrying out suspension polymerization of the particle of the monomer composition at a temperature lower than the melting point or the softening point of the release agent.

Abstract: Light-sensitive compositions comprise a light-sensitive diazo resin, a binder and a compound having a pivaloyl group. Lithographic printing plates prepared by using the light-sensitive compositions of the invention are excellent in ink receptivity.

Abstract: Photopolymeric printing plates wherein an electrochemically etched, anodized and silicated aluminum plate has a plurality of coatings applied thereon and wherein at least one of the coatings include a solvent soluble diazo therein.

Abstract: This invention relates to a radiation polymerizable composition for use in a photographic element such as a lithographic printing plate comprising in admixturea) a polymeric binder;b) a photoinitiator;c) a diazonium salt; andd) a photopolymerizable mixture ofi) a polyfunctional acrylic monomer having from 3 to 6 unsaturated groups; andii) a monofunctional acrylic monomer having 1 unsaturated group.

Abstract: Disclosed is a drafting material comprising a transparent base material with a hydrophilic coating which readily accepts ink, ensures rapid drying of the ink and can be marked in a wipe-resistant manner. The hydrophilic coating of the drafting material includes sulfonate group-containing copolyesters which are preferably present in an amount of 30 to 70 percent by weight. The drafting material can be marked with felt-tip pens containing aqueous inks.

Abstract: An aluminum alloy support for lithographic printing plate comprising 0.05 to 0.5 wt. % of Fe, 0.1 to 0.9 wt. % of Mg, 0.01 to 0.3 wt % of V and/or Ni, not more than 0.2 wt. % of Si, not more than 0.05 wt. % of Cu and the remainder of Al and inevitable impurities is disclosed. In addition, 0.01-0.3 wt. % of Zr and/or 0.05-2 wt. % of Mn may be contained.

Abstract: A light-sensitive composition for use in making a light-sensitive layer of, for instance, a presensitized plate from which a lithographic printing plate is to be prepared, which comprises a fluorine-containing surfactant and is characterized in that the fluorine-containing surfactant is a copolymer of (i) an acrylate or methacrylate having a fluoroaliphatic group, Rf, which has 3 to 20 carbon atoms and at least 40% by weight of fluorine atoms and at least three terminal carbon atoms of which are fully fluorinated; and (ii) a poly(oxyalkylene) (meth)acrylate and that Rf group-containing (meth)acrylate monomer unit is present in the copolymer in an amount of from 25 to 70% by weight based on the total weight of the copolymer. The composition provides a light-sensitive layer of a uniform thickness and it provides a lithographic printing plate having acceptable and excellent properties.

Abstract: A metal base lithographic printing plate cleaned and treated by RF plasma to render the non-exposed area hydrophilic, then coated with either a negative working or positive working photosensitive coating. The method is characterized by its elimination of the conventional alkaline etch with attendant hazard, pollution and toxicity problems.

Abstract: A light-sensitive printing plate for waterless offset printing is comprised of a layer carrier, a light-sensitive layer containing a diazonium salt polycondensation product, and of an ink-repellent crosslinked silicone elastomer layer superimposed on the light-sensitive layer, wherein the diazonium salt polycondensation product comprises recurrent A-N.sub.2 X and B units which are mutually linked by bridge members, preferably methylene groups, derived from carbonyl compounds capable of condensation, A being the radical of an aromatic diazonium compound capable of condensation with formaldehyde and B being the radical of a compound, in particular an aromatic amine, a phenol, a phenol ether, an aromatic thioether, an aromatic hydrocarbon, an aromatic heterocyclic compound or an organic acid amide, that is free of diazonium groups and that is capable of condensation with formaldehyde.

Abstract: The invention relates to a method of preparing a varnish blanket. Instead of a proof being used for pre-location of required varnish-free zones on a blanket for blanked-out in-line varnishing in rotary presses, the zones required not to be varnished are transferred by means of a reference copy, and after physico-chemical pretreatment adapted to the surface properties of the blanket, to a blanket stuck to a support plate. In addition to polyvinyl alcohol copying layers or coatings sensitized by bichromate, wipe-on copying layers sensitized by diazo salts are suitable, a positive or negative original being copied by direct contact in known manner onto a blanket thus pretreated. The zones required not to be varnished can therefore be preformed by cutting out the top layer of the blanket.

Abstract: This invention relates to negative photosensitized sheet contructions 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 photosensitive composition of this invention comprises:(a) a photosensitive diazo resin represented by the following general formula (I): ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 each represents a hydrogen atom, an alkyl or alkoxy group, R represents a hydrogen atom, an alkyl or phenyl group, X represents PF.sub.6 or BF.sub.4 and n represents a number of 1 to 200, in which a resin with the number n in the above formula being 5 or more is contained by more than 20 mol %,(b) an oleophilic high molecular weight compound with hydroxyl group and(c) a high molecular weight organic acid without hydroxyl group, and in which the content of the ingredient (c) is from 1.5 to 30% by weight based on the solid matter in said composition.The photosensitive composition of this invention can provide a photosensitive layer having high sensitivity and being excellent in storage stability and developability as well as excellent in the film strength.

Abstract: A coated lithographic printing plate comprises a grained, anodized aluminum substrate and coating thereon comprising a diazo resin in admixture with particulate energy absorbing material that will absorb incident radiation and re-radiate it as radiation that will change the diazo resin coating which is imageable with a Crosfield Datrax 760 YAG laser plate maker producing incident radiation of 1/06 microns. The topography of the substrate and the particulate material in the coating trap and convert a substantial portion of the incident laser radiation which passes through the coating without substantially affecting same into radiation that will change the coating.