Rublev Colours Pigment Ultramarine Blue (Red Shade) - 4 oz

Ultramarine Blue is a synthetic inorganic blue pigment consisting of a double silicate of aluminum and sodium with sulfide. It occurs in nature as a component of the semi-precious stone lapis lazuli.

Ultramarine is a synthetic blue pigment rated by the American Society of Testing and Materials (ASTM International) as lightfastness category I, which is the highest lightfastness. It is compatible with all pigments but is sensitive to acids, so avoid using it with acidic mediums and supports.

Oil Absorption and Grinding

Ultramarine blue absorbs a medium amount of oil (38 to 42 grams per 100 grams of pigment), which may slow the drying of oil paint. Hence, it is a moderate-drying oil color. It is a highly refractive pigment and is difficult to grind in oil, although it easily disperses in water.

Toxicity

Ultramarine blue is not considered toxic, but care should be taken when handling the pigment. This is an FDA-compliant product recommended for food-contact products in Northern America. The pigment complies with the purity requirements in 21 CFR 73.2725.