Caran d'Ache Luminance colored pencils are the highest quality colored pencils and are manufactured in Switzerland. They have the same lightfastness as a high grade oil paint. Luminance pencils conform to ASTM D-6901. 80% of these pencils are rated LF1 and 20% are rated LF2. This level of lightfastness was achieved by using the finest pigments. Luminance pencils will not form wax bloom. The texture and hardeness of Luminance pencils are extremely uniform with an 8B hardness for all colors.