The breakthrough in color accomplished by Cezanne, Pissaro, Bonnard, and Picasso came from a palette of colors created by Gustave Sennelier. These artist's watercolors are still made using the company's original turn-of-the-century techniques. Sennelier uses only the purest pigments which are cold ground on porcelain grindstones - this avoids heating the pigments which can alter the color's shade.