Supreme professional quality. A virtually perfect color range; many are truly unique, such as the high transparency colors (transparent oxides, Rembrandt Rose, etc.). Each color is made from the best and purest pigments, ground to extreme fineness in pure linseed oil from the first pressing. Poppy oil is used for white and a few light shades to deter yellowing. The raw materials are admitted to the production process only after stringent laboratory monitoring. The colors are ground to their optimal fineness, depending on the properties of the pigments. Thoroughly tested for brilliance, fineness, drying time, elasticity, viscosity and surface adhesion.