This color contains the following pigments:
Fe2O2 or Fe2O3 • H2O
Mars Orange is a bright, extremely light red and appears almost pinkish in contrast with darker colors. It has incredible tinting strength and opacity. The synthetic form of Mars Orange is made from iron oxides and is cleaner, brighter, and denser than its ochre-based counterparts.
Mars Orange has excellent permanence and lightfastness.
Mars Orange has no significant hazards.
The word Mars refers to the Roman god of iron and war. Mars Orange has been manufactured as a pigment since the 17th century.
hydrated iron oxide
α-FeO3+(OH) or Fe2O3
Raw Sienna is a moderately dull deep earth yellow with medium tinting strength and excellent transparency. It is one of the basic permanent artists' pigments and is made from a form of limonite clay whose yellow-brown color results from ferric oxides. Raw Sienna is preferable to Yellow Ochre for creating flesh tones, due to its higher subtlety of color when mixed with white. It creates a bright Ochre when mixed with Cadmium Yellow and creates greens and grays when mixed with Ultramarine. Raw Sienna dries quickly.
Raw Sienna has good permanence.
Raw Sienna has no significant hazards.
Raw Sienna has been used as a pigment since prehistoric times, although its current name came about during the Renaissance. It comes from the city of Siena, in Italy, and is short for terra di Siena, meaning earth of Siena. Sienna was famous for the mining and production of earth pigments from the Renaissance until World War II. Due to the depletion of clay deposits in Tuscany, Italian siennas now come from other areas, including Sicily and Sardinia.