Pencil Test (Wolff Wilborn)- Set 20 pencils

It is used to determine the resistance of coating materials or lacquers applied to a plate substrate to scratch effects on the surface. In the Wolff-Wilborn Test, pencils of various degrees of hardness are moved over the surface under a fixed pressure and angle to the surface. Set of 20 Koh-i-noor pencils. The degree of hardness of the pencil which damages the surface is taken as a measurement of scratch hardness.