This document specifies a method for checking the continuity of thin anodic oxidation coatings on aluminium and its alloys by a copper sulfate contact test. The use of this method is limited to anodic oxidation coatings of thickness less than 5 ¼m, or coatings that have been deformed which includes those produced by coil anodizing techniques. NOTE The method described enables a rapid check to be made for the continuity of a thin coating of aluminium oxidation on aluminium and its alloys. In cases of doubt regarding a visible fault on the surface of a coating, the use of this method makes it possible to verify whether the fault corresponds to a local gap in the coating which exposes bare metal.