High lightfastness and smoothness. Can be blended and layered for various effects. Pigments chosen for purity-intensity and resistance to UV. The Caran d’Ache Luminance 6901 40 piece colour pencil set is a combination of the highest lightfastness and the smoothness of a permanent lead. Every shade has been formulated using finely-ground pigments chosen for their purity, intensity and resistance to UV. Colours can be blended, burnished and layered on a variety of surfaces. The casing is made of California Cedar from managed forests. The smoothness of the Luminance 6901 leads require the use of a well-sharpened pencil sharpener. The pencil cap indicates the colour of the pencil lead.