Method of producing aluminum support for planographic printing plate

摘要

A support made of an aluminum plate for a planographic printing plate is electrochemically roughened in an acidic aqueous solution in an electrolytic apparatus with plural cathodes and anodes arranged alternately on one side of the plate by applying a DC voltage. A soft starting zone which comprises at least one electrode connected to an electric power supply, which is separate from a main electric source, is provided. A current density of 0.01 to 100 A/dm2, which is lower than the current density used in any subsequent main roughening, is provided in the soft starting zone.