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

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 weak acids, so avoid using it with acidic mediums and supports and in outdoor applications where it may be exposed to acid air pollution and rain.

Ultramarine blue absorbs a moderate amount of oil (38 to 42 grams of linseed oil 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 because of its poor wetting properties, although it easily disperses in water.

Toxicity

Ultramarine blue is not considered toxic, but care should be taken when handling the dry powder pigment to avoid inhaling the dust. 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.