Abstract: Disclosed is a process for the electrochemical roughening of aluminum or aluminum alloys useful for printing plate supports, in which a nitric acid electrolyte is employed. The nitric acid electrolyte includes at least one compound containing ammonium ions. Also disclosed is a printing plate support, roughened by the above process which possesses a particularly uniform graining structure.

Abstract: A process for producing chromium-plated, steel-based printing plate carriers comprises (A) simultaneously roughening and partially chromium-plating a substrate using alternating current in an electrolyte containing chromium, chloride, sulfate and, if appropriate, strontium ions and then, in the same electrolyte, (B) employing direct current to effect final chromium-plating. The printing plate supports produced in this manner have a uniform surface topography and peak-to-valley height values that are favorable for coating.

Abstract: In a novel process described for the image formation on reproduction layers which are optionally radiation-sensitive, an image is formed on a multi-layered material, which comprises at least one electrically conductive layer and a reproduction layer, by the action of electric current, applied via at least one electrode which can be stylus-shaped, in an aqueous electrolyte solution. Those portions of the layer which correspond to non-image areas are removed by the electrochemical treatment. An electrolyte solution is used, in particular, which has a pH in the range from 2.0 to 10.0 and which contains at least one salt in a concentration ranging from about 0.1 weight percent up to the saturation limit of the particular salt in the solution. The aqueous electrolyte solution may also contain a surfactant in a concentration range of about 0.1 weight percent to 5 weight percent.

Abstract: Disclosed is a process and an electrolyte solution for electrochemically roughening steel-based supports for offset printing plates. The treatment is carried out in a hydrochloric acid electrolyte which comprises at least one wetting agent inhibitor. As a result, a uniform surface topography of the plates is achieved, while largely avoiding the formation of scars. The roughened plates are corrosion-resistant and can be coated either directly or indirectly after first treating the plates to render them hydrophilic.

Abstract: In the electrochemical roughening of aluminum or its alloys useful for printing plate supports, an aqueous mixed electrolyte solution is employed, which contains hydrochloric acid (HCl) and hydrofluoric acid (HF), in particular in an amount of from about 0.5 to 10% by weight of HCl and of from about 0.05 to 5% by weight of HF. The very uniformly roughened support materials are used in the production of offset printing plates.

Abstract: In the development of exposed light-sensitive reproduction layers using an aqueous electrolyte developer the parts of the layer corresponding to the non-image areas are removed by electrochemical treatment. An electrolyte is used which has a pH in the range from 2.0 to 10.0 and contains at least one salt in a concentration of 0.1 weight percent up to the saturation limit of the solution for the particular salt. The electrolyte may also contain 0.1 to 5 weight percent surfactant.

Abstract: A process is disclosed for manufacturing sheets, foils, or strips which involves chemically, mechanically, and/or electrochemically roughening and anodically oxidizing aluminum or aluminum alloy surfaces, followed by two post-treatment steps. In the first step, the metal surface is treated with an aqueous alkali metal silicate solution; thereafter, the surface is treated with an aqueous solution comprising alkaline earth metal ions. The materials produced according to this process are particularly used as supports for offset-printing plates.

Abstract: Disclosed is a process for electrochemically roughening aluminum or alloys thereof, in an aqueous electrolyte, under the action of an alternating current having a frequency in the range from 0.3 to 15 Hz. The materials roughened in this way are used as supports for radiation-sensitive reproduction coatings in the field of manufacturing offset-printing plates. Also disclosed are roughened aluminum supports and printing plates produced by the above process.

Abstract: Disclosed is a process for electrochemically roughening aluminum or alloys thereof, in an aqueous electrolyte, under the action of an alternating current which is generated by superimposing at least two types of alternating current of different frequencies. The materials roughened in this manner are used as supports for radiation-sensitive reproduction coatings in the field of manufacturing offset-printing plates. Also disclosed are roughened aluminum supports and printing plates produced by the above process.