Pencil hardness:-Resistance of the surface of a paint film to marking, or the formation of some other defect, as a result of the
action of a pencil, with a lead of specified dimensions, shape, and hardness, which is pushed across the surface
Principle:- A pencil lead with a defined geometry is pushed over the paint surface at an angle of 45°, exerting a force of
7,5 N on the surface. The hardness of the pencil lead is increased in steps until the surface of the coating is
marked by visible defects. The test result is the highest hardness at which no marking occurs.
Set of wooden drawing pencils, of the following hardnesses (see note):