Pigment Ultramarine Blue

Ultramarine is a blue pigment composed of sodium aluminosilicate and three sulfur atoms in the form of sulfide or sulfate, the unpaired S3-anion originating from the blue. It is prepared from inexpensive modifier components such as kaolin, sodium carbonate and sulfur. Synthetic ultramarine does not show vivid blue as much as natural ultramarine, due to even particle size, diffusing light more uniformly. Synthetic dark blue can be affected by light, oil or lime. Ultramarine has heat and alkali resistant properties. It is used as a colourant and optical brightener for plastics, rubber, inks, paints, cosmetics, detergents, cement, textiles and paper.

 Ultramarine blue is a saturated, semitransparent, dark, violet-leaning blue. It makes clean violet mixes with cool reds and magentas and is nicely neutralized with siennas or raw umber. Ultramarine's unique property of flocculation—the tendency of its particles to clump up together—give it a lively granulating texture in washes. Interesting effects can be achieved when mixing ultramarine with a micronized pigment, as some of the heavier blue particles will sink a bit while the lightest particles will float above.