Ultramarine

Ultramarine is a blue pigment historically derived from lazurite, a mineral found in lapis lazuli. The name, from Latin ultramarinus meaning beyond the sea, reflects its origin in long-distance trade routes bringing the material from regions such as Afghanistan to Europe.

Natural ultramarine was highly valued in antiquity and the Middle Ages for manuscripts and paintings. Ground from lapis lazuli, it was expensive because the raw stone was rare and processing was labor-intensive. Its use was often limited to important works and sacred subjects, and it is still associated with a bright, luminous blue in old master paintings.

In the 19th century a stable synthetic ultramarine blue was developed, greatly reducing cost and increasing availability. The synthetic pigment, commonly designated PB29, is an aluminosilicate combined with sulfur-containing species that produce the deep blue color characteristic of ultramarine. Synthetic ultramarine can imitate the tone of the natural pigment and is now the dominant form used in art supplies.

Ultramarine is known for its vibrant, semi-translucent blue with a warm undertone and excellent covering power in thin washes. It is relatively lightfast under normal painting conditions, though long exposure to strong alkalis or intense UV light can alter its sulfur-based color centers. It can interact with certain pigments or binders to shift tone when mixed in complex palettes.

Today ultramarine remains a staple pigment in oil, acrylic, and watercolor paints, available in natural and synthetic forms. It is also produced in variants and related hues, including finely ground versions used for detailed work and film and ceramic applications.