Umbers are one of the oldest pigments used by mankind. These natural Iron-Oxides are known for their durability and are considered a permanent pigment. Burnt Umbers build on the lightfast and chemical resistance of Raw Umber and add improved heat stability. Raw Umbers are naturally occurring Iron-Hydroxides, which convert to Burnt Umbers, or Iron Oxides upon heat treating. Hoover 503BU in one of the highest quality Burnt Umbers on the market today. It combines ease of dispersion with high color strength.