4 Principle
The product or system under test is applied at uniform thickness to flat panels of uniform surface texture.
After drying/curing, the pencil hardness is determined by pushing pencils of increasing hardness over the paint film,
with the panel in a horizontal position.
During the test, the pencil is mounted so that it presses down on the paint surface at an angle of 45° with a load of
750 g.
The hardness of the pencils is increased in steps until the coating is marked by defects of the kind defined in 3.1.