Coating hardness is the capacity of a coating to resist scratching, marring or gouging of foreign objects. The pencil hardness test, also commonly known as the Wolff-Wilborn test, uses the varying hardness of standardized pencil sets to determine a coating’s overall hardness and scratch resiliency. The chosen pencil with a corresponding hardness level is placed on a tool to be run across the coating surface with a standardized force. If the coating resists permanent scratching, the pencil with the next hardness level is used and the procedure repeated until permanent scratching occurs, thereby determining the coating's hardness.
