Ultramarine Blue (Red Shade) Pigment

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 Blue (Red Shade)

Origin and History

In 1814, Tassaert observed the spontaneous formation of a blue compound, very similar to ultramarine, if not identical to it, in a lime kiln at St. Gobain, which caused the Societé pour l'Encouragement d'Industrie to offer, in 1824, a prize for the artificial production of the color. Processes to make the artificial pigment were devised by Jean Baptiste Guimet (1826) and by Christian Gmelin (1828). Still, while Guimet kept his process a secret, Gmelin published his and thus became the founder of the "artificial ultramarine" industry.

Source

Ultramarine is a blue pigment consisting of a double silicate of aluminum and sodium with sulfide, occurring in nature as a component of lapis lazuli. The Colour Index designation is Pigment Blue 29, and the Colour Index number is 77007. Ultramarine is one of the most complex mineral pigments, a sulfur-containing compound of sodium-silicate, essentially a mineralized limestone containing a blue cubic mineral called lazurite (the major component of lapis lazuli). The term ultramarine designates both the natural mineral and the artificial pigment, although today, most distinguish the natural mineral by its name, lazurite, or the rock containing it, lapis lazuli.

Permanence and Compatibility

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.

For a detailed explanation of the terms in the table above, please visit Composition and Permanence.