This part of EN 13523 describes the procedure for determining the relative hardness of an organic coating on a metallic substrate, by means of pencils of known hardness. Smooth surfaces will give more accurate results but the method is also applicable for textured surfaces.
DS/EN 13523-4:2001 history
2001DS/EN 13523-4:2001 Coil coated metals - Test methods - Part 4: Pencil hardness