The purpose of scratch hardness tests is to determine the resistance of coating materials to scratch effects on surfaces.
In the Wolff-Wilbon Test, pencils of various degrees of hardness are moved over the surface under a fixed pressure and angle to the surface. The degree of hardness of the pencil which damages the surface is taken as a measurement of scratch hardness e.g. “3H” hardness.
This test comlies with ASTM D3363, ECCA-TA-1