Abstract: A wear-resistant, ink-repellent coating, for printing-press components, and in particular, web-fed printing presses. In order to provide a seal for this low-wear coating which results in a permanent ink-repellent surface quality and which additionally has a high resistance to standard cleaning agents used in printing technology, the printing-press component which is to be protected is first provided with oxide ceramic or hard metal layer. This layer may be applied by thermal spraying. In addition, the component is treated with a polyorganosiloxane sealant, particularly polyhydridomethylsiloxane, including the necessary heat-curing at moderate temperatures of from 100° C. to 170° C. so as to prevent ink deposition. The sealing may also take place after the wear-resistant layer has undergone a grinding and polishing treatment.

Abstract: There is provided a lithographic plate material which can be desensitized by distilled water or a fountain solution used for other lithographic plates, without desensitizing using an etching solution, and with less scumming in non-image portions of the print. The lithographic plate material has an image-receptive layer formed on a support and containing polyvinyl alcohol cross-linked by tetra alkoxy silane hydroxylate, titanium oxide microparticles, and silica having an average particle size of 1 nm to 100 nm. The image-receptive layer has a surface with an arithmetic mean roughness of not less than 0.40 &mgr;m and less than 1.20 &mgr;m, a contact angle of less than 50 degrees with distilled water at room temperature, and ink-receptiveness for hot-melt and lipophilic ink.

Abstract: Provided is a lithographic printing plate comprising a support substrate having disposed thereon a hydrophilic layer interposed between the substrate and an ink-accepting ablative-absorbing surface layer. The ink-accepting surface layer comprising a one or more polymers and a sensitizer characterized by absorption of laser radiation. The printing plate may also comprise a primer layer underlying the ink-accepting surface layer with an adhesion-promoting agent present in the primer layer. Also provided are methods of preparing such lithographic printing plates, and methods of preparing imaged lithographic printing plates from such lithographic printing plates by imagewise exposure to a laser and a subsequent cleaning step with water or with a cleaning solution.

Abstract: The recording medium comprises a recording layer. The recording layer has a first material and a second material independently dispersed. The first material has a property that a backward contact angle to a liquid lowers when the material is heated or cooled in a state of being in contact with the liquid, and that the value of the backward contact angle recovers when heated in the air. The second material has a polyorgano-siloxane structure.

Abstract: Provided are methods of imaging a wet positive working lithographic printing member comprising the steps of providing a positive working printing member comprising a substrate, a hydrophilic layer, an infrared-absorbing layer, and, optionally, an ink-accepting surface layer; exposing the printing member to infrared layer imaging in an imagewise pattern removing by ablation not greater than 10% by weight, and most preferably none of the infrared-absorbing layer and optional ink-accepting surface layer; and removing with water the laser-exposed areas of the infrared-absorbing layer and optional ink-accepting surface layer to reveal the underlying hydrophilic layer. These methods are advantageous in reducing airborne debris and vapors during laser imaging, in increasing the speed of laser imaging, and in providing excellent cleanability and image quality. The printing member may further comprise a primer layer underlying the infrared-absorbing layer with an adhesion-promoting agent present in the primer layer.

Abstract: A lithographic printing plate precursor is disclosed, comprising a metal support having formed thereon an anodic oxide film, and an image-forming layer containing a light-to-heat converting agent, or a light-sensitive layer capable of image-forming with infrared laser exposure provided in this order from the support.

Abstract: Lithographic plate constructions include imaging layers having dispersed therein a radiation-scattering material and a radiation-absorbing material, both of which cooperate to increase the overall absorption of radiation in that layer. The radiation-scattering material may be in particulate form, the particles reflecting the imaging radiation from their surfaces. The use of particulate scattering material within the imaging layer creates a highly porous matrix that favors deep penetration of the imaging radiation and mechanical locking of the imaging layer to one or both adjacent layers. The scattering material may also be chosen also for its ability to chemically bind with an adjacent layer to increase intercoat adhesion.

Abstract: The invention provides a lithographic printing for precursor having an imagable coating on an aluminum support, wherein the imagable coating comprises a polymeric substance comprising colorant groups, and wherein the aluminum support on which the coating is provided is anodized but not subsequently modified by means of a post-anodic treatment compound, and the coating does not comprise a colorant dye. The polymeric substance may also comprise pendent infra-red or developer dissolution inhibiting groups, and these groups may also be the colorant groups themselves.

Abstract: This patent describes on-press ink and/or fountain solution development of lithographic plates having on a substrate a thermosensitive layer capable of hardening or solubilization upon exposure to an infrared laser radiation. The plate can be imagewise exposed with an infrared laser and then on-press developed with ink and/or fountain solution by rotating the plate cylinder and engaging ink and/or fountain solution roller. The developed plate can then directly print images to the receiving sheets. The imagewise exposure can be performed off the press or with the plate being mounted on the plate cylinder of a lithographic press.

Abstract: A water-developable, photosensitive resin plate for letterpress printing which comprises a photosensitive resin layer and a protective film contacting therewith, wherein the protective film consists of at least two layers, of which one is a surface layer containing a resin having a water absorption of 5% by weight or less and the other is an intermediate layer containing a water-soluble resin in contact with the photosensitive resin layer.

Abstract: An improved offset printing press has a single plate blanket image (PBI) cylinder for holding an image formed on a thin film printing plate affixed thereto. The plate may be from 0.5 to 25 microns thick and has a thin layer of ink repelling material coated thereon. The plate is imaged, after being affixed to the PBI cylinder, by ablating selective portions of the ink repelling coating. The PBI cylinder is constructed to hold the printing plate by vacuum techniques, and apparatus to load and unload the plate is associated with the PBI cylinder. Because of the thinness of the printing plate, the PBI cylinder is a compliant surface, capable of printing on an inelastic media covered impression cylinder. In addition, unique inking apparatus is provided to transfer ink to the imaged printing plate. Variations of the press include a four color press utilizing a single PBI cylinder.

Abstract: A method for preparing a lithographic plate which can react with an imaging fluid to form an image, including providing a hydrophilic support; forming a fluid-receiving layer that includes a water-soluble material which is chemically reactive with the imaging fluid; imagewise applying the imaging fluid to the fluid-receiving layer; and drying or curing the applied fluid to form an image in the fluid-receiving layer.

Abstract: A printing plate is prepared by the method comprising: (a) providing a substrate; and (b) applying by ink jetting to the substrate a fluid composition comprising an acidic polymeric compound, in which the acid groups of the acidic polymeric compound are at least partially neutralized with base, providing a printing plate that is ready-to-use on a press without having to develop it. The printing plate of this invention is capable of extended press run length and advantageously avoids the need of chemical development.

Abstract: A method of making a printing plate in which the uncoated surface of a substrate is treated with a pre-treatment solution prior to the deposition of ink on the surface. The pre-treatment liquid comprises a polyvalent metal salt, and at least one of an organic swelling reagent and/or a coalescence reagent. The pre-treatment liquid is applied to form a thin, homogenous layer of approximately 4 &mgr;m to the entire upper surface of the recording plate. The swelling reagent and/or the coalescence reagent and the polyvalent metal cations are physically well localized in the porous structure of the plate's surface. After partial drying of the pretreated anodized aluminum plate, CTP liquid is deposited onto the surface to form an image. The CTP liquid solids react with the pre-treatment liquid and are, therefore, chemically bound to the surface. This allows all data to be deposited in a single pass of the inkjet head without the problem of clustering.

Abstract: A radiation-sensitive composition comprises: (i) at least one component capable of absorbing IR radiation; and (ii) a diazonium polycondensation product soluble in an organic solvent; with the proviso that the composition does not contain components capable of reacting with decomposition products produced from IR radiation exposure of the diazonium polycondensation product. The composition may additionally comprise a polymeric binder of the type useful for conventional negative-working printing plates. The composition is suitable for preparing thermally imageable printing plate precursors and printing plates and may also be used in a method for providing an image on such plate precursors and printing plates.

Abstract: A fluid composition suitable for ink jetting upon a substrate, which includes a copolymer having a low surface energy and a plurality of tertiary amine sites, where the tertiary amine sites are at least partially neutralized with an acid; a nonionic or cationic surfactant; and water. The fluid composition may be used to prepare a printable media comprised of a substrate and an ink receptive thermoplastic image layer supported on the substrate; where the ink receptive layer contains a copolymer having a low surface energy and a plurality of tertiary amine sites, the amine sites being at least partially neutralized with an acid.

Abstract: A method of preparing a printing member or a printing member precursor involves contacting a substrate with an aqueous formulation comprising a polyester having pendent hydrophilic groups wherein said polyester has optionally been combined with a second compound. Said pendent hydrophilic groups may be selected from alkvleiie oxide moieties, carboxyl groups, amino groups, sulphonic groups, phosphoric groups, sulphuric acid ester salts, hydroxyl groups, salts of any other aforesa-id and quaternary immonium salts in general. Said printing member is preferably a lithographic printing member. It may be for use in wet or dry printing.

Abstract: A printing plate is prepared by the method comprising: (a) providing a substrate; and (b) applying by ink jetting to the substrate a fluid composition comprising a compound which comprises at least one nitrogen-containing heterocyclic moiety, providing a printing plate that is ready-to-use on a press without having to develop it. The printing plate of this invention is capable of extended press run length and advantageously avoids the need of chemical development.

Abstract: Lithographic plate constructions include imaging layers having dispersed therein a radiation-scattering material and a radiation-absorbing material, both of which cooperate to increase the overall absorption of radiation in that layer. The radiation-scattering material may be in particulate form, the particles reflecting the imaging radiation from their surfaces. The use of particulate scattering material within the imaging layer creates a highly porous matrix that favors deep penetration of the imaging radiation and mechanical locking of the imaging layer to one or both adjacent layers. The scattering material may also be chosen also for its ability to chemically bind with an adjacent layer to increase intercoat adhesion.

Abstract: A direct drawing type lithographic printing plate precursor comprising a water-resistant support having provided thereon an image-receiving layer comprising inorganic particles and a binder resin, wherein the inorganic particles comprise at least one kind of particles selected from: (i) metal oxide particles having an average particle size of from 0.01 to 5 &mgr;m and comprising a metal atom selected from Mg, Ba, Ge, Sn, Zn, Pb, La, Zr, V, Cr, Mo, W, Mn, Co, Ni and Cu; and (ii) double oxide particles having an average particle size of from 0.01 to 5 &mgr;m and comprising at least one metal atom selected from Mg, Al, Si, Ti, Zr, Cr, V, Mo, Sn, W and Nb, and wherein the binder resin comprises a complex comprising: a resin containing a bond in which a metal atom is connected with an oxygen atom; and an organic polymer containing a group capable of forming a hydrogen bond with the resin and at least one polar functional group selected from a carboxy group, a sulfo group and a phosphono group.

Abstract: A method of preparing a printing plate for printing comprises applying a fluid composition by ink jetting to a substrate, and thereafter curing the fluid applied to the substrate. The fluid composition is jetted onto the substrate at a jetting temperature T2. The substrate is at a temperature Ts. The viscosity of the fluid composition at temperature Ts is about at least 300 times greater than the fluid's viscosity at temperature T2. The invention minimizes the dot spreading which otherwise occurs when a substrate is imaged via ink jetting to prepare a printing plate.

Abstract: According to the present invention there is provided a heat-sensitive imaging element for making lithographic printing plates. The heat-sensitive imaging element comprises an image-forming layer comprising hydrophobic thermoplastic polymer particles having a specific particle size and polydispersity for obtaining printing plates with an improved sensitivity, excellent developability, high throughput and less scumming.

Abstract: Provided is a lithographic printing machine comprising a plate cylinder for imaging, a blanket cylinder, an impression cylinder, and a film-coating unit, a film-hardening unit, an imaging unit and a cleaning unit each unit of which is adjacent to the plate cylinder for imaging, wherein an image-forming layer containing a polymer having a functional group which is crosslinked by light or heat before imaging and a functional group which is converted from hydrophilic to hydrophobic by the heat generated by infrared ray irradiation is formed by the coating unit. A lithographic printing method using the lithographic printing machine is also provided.

Abstract: A process for making lithographic sheet material suitable for imaging by laser radiation. A metal substrate is electrocoated in a bath containing a polymeric resin and laser-sensitive particles, thereby depositing a laser ablatable layer on a principal surface of the metal substrate. In one embodiment, the laser-ablatable layer is treated with a corona discharge for a time sufficient to render the layer non-ink wettable. In other preferred embodiments, the laser-ablatable layer is overcoated with an overlayer such as a non-ink wettable silicone layer or a water-wettable layer comprising an organophosphorus polymer, preferably a copolymer of acrylic acid and vinylphosphonic.

Abstract: A heat-sensitive precursor of lithographic printing plates, which comprises a hydrophilic layer provided on a substrate having an ink-receptive surface or coated with an ink-receptive layer; the printing plate precursor further having a water-soluble overcoat layer on the hydrophilic layer, and the hydrophilic layer being a three-dimensionally cross-linked hydrophilic layer, the heated area of that is easily removed by a fountain solution or ink when subjected to printing operations.

Abstract: According to the present invention there is provided a heat mode imaging element for making a lithographic printing plate having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer which top layer is IR-sensitive and unpenetrable for an alkaline developer wherein said first layer and said top layer may be one and the same layer; characterized in that said top layer contains a polymer that lowers the dynamic friction coefficient of the top layer to less than 0.37, and wherein said polymer in the top layer is polytetrafluoroethylene.

Abstract: A heat-sensitive composition, for example a coating on a lithographic printing plate, comprises a carboxylic acid derivative of a cellulosic polymer. The composition may contain a radiation absorbing compound and suitable electromagnetic radiation, preferably infra-red radiation, may be used to heat the composition imagewise. The presence of the cellulosic polymer enhances resistance to certain organic liquids.

Abstract: A support for a printing plate is disclosed, comprising a substrate having thereon at least one component layer contains porous particles. The component layer further contains a flaky inorganic particles or a material having the function of converting light to heat. A printing plate comprising the support is also disclosed, having on the support an image forming layer containing a thermally fusible particles.

Abstract: Lithographic imaging using non-ablative printing members combines the benefits of simple construction, the ability to utilize traditional metal base supports, and amenability to imaging with low-power lasers that need not impart ablation-inducing energy levels. A representative printing member has a hydrophilic metal substrate and, thereover, first and second layers. The first layer has a thickness and an exposure surface and comprises a material that absorbs imaging radiation. The second layer overlies the first layer and is oleophilic and substantially transparent to imaging radiation. Exposure to imaging radiation causes the first layer and the substrate to irreversibly detach without substantial ablation, thereby facilitating removal, by subjection to the cleaning liquid, of the first and second layers where detachment has taken place.

Abstract: A printing plate useful in lithographic printing is prepared by the process comprising: (a) applying an alkali soluble composition comprising at least one polymer composition to a hydrophilic surface on a substrate to provide the surface face with at least one layer which is alkali soluble at a pH in the range of about 6.0 to 14.0; (b) imaging the coated substrate electrostatically with a toner composition; (c) heating the imaged substrate a first time to a temperature greater than the glass transition temperature of the toner composition; (d) contacting the imaged substrate with an aqueous alkaline solution having a pH in the range of about 6.0 to about 14.0; and (e) heating the imaged substrate a second time to a temperature greater than the glass transition temperature of the toner composition. This printing plate is capable of long runs on press with good image quality and advantageously minimizes the occurrence of undesirable background toner “specking” on press.

Abstract: Lithographic imaging using non-ablative printing members combines the benefits of simple construction, the ability to utilize traditional metal base supports, and amenability to imaging with low-power lasers that need not impart ablation-inducing energy levels. A representative printing member has a topmost layer that is ink-receptive and does not significantly absorb imaging radiation, a second layer thereunder that is hydrophilic and does absorb imaging radiation, and a metal substrate under the second layer. The printing member is selectively exposed to laser radiation in an imagewise pattern, and laser energy passes substantially unabsorbed through the first layer and is absorbed by the second layer. Heat builds up in the second layer sufficiently to detach the first layer, which is formulated to resist reattachment. But the first layer and, more significantly, the third layer act to dissipate heat from the second layer to prevent its ablation.

Abstract: A process for making printing plate material suitable for imaging by laser radiation. A metal substrate is electrocoated in a bath containing a polymeric resin and laser-sensitive particles, thereby depositing a laser ablatable layer on a principal surface of the metal substrate. In one embodiment, the laser-ablatable layer is treated with a corona discharge for a time sufficient to render the layer non-ink wettable. In other preferred embodiments, the laser-ablatable layer is overcoated with an overlayer such as a non-ink wettable silicone layer or a water-wettable layer comprising an organophosphorus polymer, preferably a copolymer of acrylic acid and vinylphosphonic acid.

Abstract: A heat-sensitive lithographic printing plate precursor which comprises a substrate having thereon an anodic oxidation layer, with the printing plate precursor comprising a hydrophilic layer containing at least one kind of fine particles selected from the group consisting of heat-fusible hydrophobic thermoplastic fine particles, finely divided polymers having thermally reactive functional groups and microcapsules in which compounds having heat-reactive functional groups are encapsulated, and with the anodic oxidation layer having a surface over which micropores having an average pore size of 6 to 40 nm are uniformly distributed.

Abstract: Provided is a lithographic printing plate comprising a support substrate having disposed thereon an ablative-absorbing layer and, optionally, a durable, ink-accepting surface layer that is not ablative-absorbing. The ablative-absorbing layer may contain a high weight per cent of an organic sulfonic acid component. The printing plate may further comprise a hydrophilic polymeric layer interposed between the ablative-absorbing layer and the substrate. The printing plate also comprises a primer layer underlying the ablative-absorbing layer with an adhesion-promoting agent, such as a zirconium compound, present in the primer layer. Also provided are methods of preparing such lithographic printing plates, and methods of preparing imaged lithographic printing plates from such lithographic printing plates by imagewise exposure to a laser and a subsequent cleaning step with water or with a cleaning solution.

Abstract: Cleaning compositions for ablation-type lithographic printing plates include solvent, non-solvent and lubricating components, the vapor pressures and concentrations of the various components being chosen such that the mixture never becomes too rich in solvent. In this way, the solvent's effect is directed primarily at thermal byproducts, which, because they are exposed and already partly decomposed, are more vulnerable to solvent action than the intact, anchored plate constituents in unimaged regions. The compositions are used in conjunction with mechanical rubbing of the plate surface following imaging.

Abstract: According to the present invention there is provided a method for making a lithographic printing plate including the steps of dispensing in a predetermined pattern a latex of particles of a hydrophobic polymer onto an optionally modified hydrophilic surface of a lithographic base, characterized in that the hydrophobic polymer and the optionally modified hydrophilic surface of the lithographic base have mutually reactive groups.

Abstract: Printing and printed circuit board members and a method for producing printing member from a member is provided. The printing member includes a topmost protective layer, an IR ablatable layer, a substrate and a wash-off layer. The wash-off layer is washed with a solvent after imagewise ablation of the topmost protective layer so as to expose the substrate, so that the printing member is produced.

Abstract: This invention provides a directly imageable planographic printing plate precursor with excellent image reproducibility without requiring any complicated process after irradiation with a laser beam. To solve the above problem, this invention is constituted as describe below. A directly imageable waterless planographic printing plate precursor, in which at least an ink acceptable layer and a silcone rubber layer are laminated in this order on a substrate, wherein when the printing plate precursor is measured by TG-GC/MS in a hellium current at a heating rate of 10° C./min, a decomposition product is generated in a temperature range of 100° C. to 200° C. by 0.001 g/m2 to 1 g/m2 per plate area.

Abstract: A printing system which uses a single-layer printing member coated on to a cylinder is provided. For waterless offset application, the single-layer printing member may comprise an oleophobic imaging layer containing an oleophobic resin, coated on an oleophilic cylinder. The single-layer printing member is composed of a resin having either oleophobic or oleophillic properties, to which an infrared absorbing component or components may be added.

Abstract: A lithographic imaging member is prepared by applying an ink jetable fluid to a fluid-receiving element that includes a clay-containing fluid-receiving surface layer. This layer also includes a water-soluble binder and a silane hardening agent. The applied fluid is an aqueous solution of a silane having multiple hydroxy, alkoxy or acetoxy groups that is readily absorbed in the clay-containing surface, and dried to provide an oleophilic image.

Abstract: A structure for pattern formation adapted for optically forming a pattern, characterized by comprising: a photocatalyst-containing layer provided on a substrate, the photocatalyst-containing layer containing a material of which the wettability is variable through photocatalytic action upon pattern-wise exposure.

Abstract: The effects of interfacial transition between organic and inorganic layers of a lithographic printing member are ameliorated by incorporating an inorganic component within the matrix of the organic layer. In a first aspect, a lithographic printing plate having adjacent organic and inorganic layers is fabricated by depositing a curable polymer, softening the polymer, and integrating an inorganic material therewith. The polymer is then cured to immobilize the integrated deposition material, and the desired inorganic layer is applied over the deposited inorganic material (and any exposed portions of the polymer). In a second aspect, a graded structure is built up on a substrate in successive deposition steps. Both polymer precursors and an inorganic filler material are deposited in stages, with each stage containing a desired ratio of polymer to filler.

Abstract: A printing system which uses a single layer printing member coated on to a cylinder is provided. For waterless offset application, the single layer printing member consists of an oleophobic imaging layer containing an oleophobic resin, coated on an oleophillic cylinder. For wet application, the single layer may either be hydrophilic, coated on a oleophillic cylinder; or vice versa. The single layer printing member is composed of a resin having either oleophobic, hydrophilic or oleophillic properties, to which an infra red absorbing component or components may be added.

Abstract: A substrate is coated with a first material which is soluble in a first solvent, whereupon a second material which is strongly adherent to the first material and insoluble in the first solvent is selectively applied by an ink jet printer. The substrate is then developed in the first solvent to establish the image. In a preferred embodiment the substrate is hydrophilic, the first material is a negative working photosensitive material, and the second material is a transparent adhesive, which permits curing the first material by exposure to actinic light after the development step. The adhesive is then removed. In an embodiment directed to a waterless plate the substrate includes a surface coating of silicone, and the first material is a primer which promotes adhesion of a second material in the form of an oleophilic adhesive which is selectively applied. The primer is then developed to expose the silicone on the non-image areas.

Abstract: A printing plate precursor for direct receipt of an image-wise applied ink receptive layer the precursor having a desorbable surfactant adsorbed on at least one surface in an amount effective to improve the resolution of the subsequently image-wise applied ink receptive layer. The printing plate precursor can be used to prepare a printing plate having improved resolution. The printing plate may be prepared by (a) applying a desorbable surfactant to at least one surface of a printing plate substrate, (b) removing non-adsorbed surfactant from the surface, (c) applying a fluid composition containing an ink receptive material onto at least a portion of the surface in the form of a desired image, thereby providing an ink receptive image layer; and (d) removing the desorbable surfactant from any area of the surface which does not form part of the desired image.

Abstract: A positive-working lithographic printing plate which is imageable by dual infrared lasers has a substrate which absorbs modulated, imaging infrared laser radiation of one wavelength to heat the substrate and an adjacent coating. The substrate has a coating which is a material which will react and form gaseous reaction products which ablate or propel the coating from the substrate upon reaching a threshold reaction temperature. The coating is transparent to the infrared radiation of the one wavelength and contains a dye which absorbs unmodulated, non-imaging infrared laser radiation of another wavelength to heat the coating. The unmodulated, non-imaging infrared laser radiation heats the coating in the imaged areas to a temperature below the threshold temperature and the heat from the substrate further heats the coating to a temperature above the threshold temperature and ablates the coating in the imaged areas.

Abstract: A direct-to-plate method of lithographic printing is disclosed which enables to recycle the lithographic substrate of the printing master.

Abstract: A negative working non-ablative lithographic printing plate precursor is provided which includes a metal support such as an anodized aluminum plate and provided thereon a layer or a stack of layers, wherein at least one layer includes a near infrared light absorbing compound which is the main component of the layer(s). As the amount of other reactive compounds besides the near infrared light absorbing compound is less than 20% by weight, excellent-storage stability is obtained. In a highly preferred embodiment the layer or stack of layers is substantially free from the other reactive compounds. The material is very suitable for computer-to-plate and computer-to-press applications as it can be used as a printing master directly after exposure or may be processed by rinsing with plain water.

Abstract: Heat-imagable negative working lithographic printing forms employ negative working heat sensitive compositions comprising a water soluble binder and particles of pigment in association with a thermoplastic resin. Heat causes fusion of the particles to the binder. Heated regions are thereby rendered insoluble to aqueous developers. Unheated areas are soluble in developer or fount solutions, so development may take place “on-press” during the initial phase of a print run.

Abstract: A method is provided for preparing a negative working lithographic printing plate precursor by applying a dry powder, containing a light absorbing compound in an amount not less than 50% by weight, on a metal support such as an anodized aluminum plate. The light absorbing compound is preferably carbon, soot or an infrared dye. In one embodiment of the invention, the dry powder may be rubbed in on the surface of the metal support. In another embodiment a layer of soot is applied on the metal support by contacting the surface of the support with a flame. In still another embodiment, a metal support is contacted with a transfer material consisting of a support and a dry layer of a light absorbing compound such as carbon. By applying heat or light, the dry powder is converted into a hydrophobic substance at the printing areas of the plate.