Galvanocaustics (metalworking)

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In technology, galvano-caustic or galvanic engraving is a combined etching process that includes both a chemical and a galvanic reaction. Compared to conventional etching , galvano- caustic offers the advantage that only a very weak etching liquid is used, which prevents the lines in the drawing from being eroded. A metal plate made of copper or steel is covered with a covering ground into which the drawing is etched (except for the metal). The plate is then hung in a weak vitreous copper solution or very dilute sulfuric acid and connected to the positive pole of a voltage source. The negative pole is on an iron plate (less noble metal). The metal of the copper plate dissolves in all uncovered areas of the plate and creates a depression in these areas.

The plate can then be colored using a letterpress or gravure printing process. As a rule, it is used to engrave rollers that are used for printing fabrics, rolls of wallpaper, etc.