Product Description R&F has long used Stil de Grain in some of their mixes and are now introducing it on its own. It is to Raw Sienna what R&F’s Brown Pink is to Burnt Sienna – like a Sienna on steroids. Raw Sienna is a natural earth, so both its top and undertones are muted. Stil de Grain, being a synthetic iron oxide, has a clean top tone, and its undertone is golden yellow. The French name is a revival of the long obsolete impermanent color made from buckthorn berries.