This document specifies a test method for determining, under defined conditions, the resistance of a single coating or a multi-coat system of paint, varnish or related product to penetration, by scratching with a scratch stylus loaded with a specified load. The stylus penetrates to the substrate, except in the case of a multi-coat system, in which case the stylus can penetrate either to the substrate or to an intermediate coat.The method specified can be carried out:a) either as a “pass/fail” test, by testing with a single specified load applied to the stylus to assess conformity with a particular specification; orb) as an assessment test by applying increasing loads to the stylus to determine the minimum load at which the coating is penetrated.NOTE Neither this document nor ISO1518-2 specifies a method using a curved stylus, which is specified in ISO12137. The choice between the three methods depends on the particular practical problem.