HISTORICAL OVERVIEW

In 1794, the Frenchman Nicholas-Jaques Conté discovered almost at the same time as the Austrian Josef Hardmuth, that by mixing graphite with clay it was possible to produce leads with different degrees of hardness, which would accomodate a variety of applications and also preserve the graphite deposits. 

In 1839, Lothar von Faber succeeded in significantly improving the graphite-clay mixing process. It was at that time that the hardness grade scale was established and it remains valid today.