Spotlight on ultramarine

The word ultramarine comes from the Latin ultra, meaning beyond, and mare, meaning sea; this was how the semi-precious stone the pigment was extracted from first arrived in Europe. That stone, lapis lazuli (“the blue stone” in Latin) came via foot and donkey on the Silk Road from Afghanistan and was loaded on to ships in Syria sailing to Venice, from where it was traded throughout other parts of Europe. One of the oldest blue pigments, early evidence of ultramarine’s use can be found in Afghanistan in the cave temples of Bamiyan in 6th and 7th centuries AD.

Lapis lazuli is a mix of the minerals lazurite, silicate and pyrite, and while this mined stone was used for decoration purposes in ancient Egypt and Sumer, the blue pigment was not extracted until much later. There’s evidence of it used in Chinese paintings from the 10th and 11th centuries, in Indian mural paintings from the 11th, 12th, and 17th centuries, and Anglo-Saxon and Norman illuminated manuscripts from c1100. In the 15th century, the artist Cennino Cennini described ultramarine in his Il Libro dell’Arte as a “glorious, lovely and absolutely perfect pigment beyond all the pigments”.

But to produce genuine ultramarine pigment from lapis lazuli a complex and time-consuming process is needed. The mineral mined was ground and mixed with resin, linseed oil or wax, then heated to form a dough-like mixture. This was kneaded like bread and placed in a lye solution, allowing blue flakes to separate, sink and dry, with the final result a fine blue powder pigment. The process would then be repeated to produce a finer grade of pigment each time, meaning that a comparatively small amount of ultramarine pigment could be extracted from the stone.

Nonetheless, the intensive extraction process created a high-quality blue pigment free from the invisible impurities which lay in the rock and damaged the paint colour. The time taken, along with the distances travelled from the East, made natural ultramarine a very expensive pigment. Gram per gram, it was once considered more precious than gold.

The preciousness of the pigment dictated how it was used in painting. Artists employed it sparingly and had to account for the cost of this pigment, which was sold at the best quality and price in Venice.

From 1400, ultramarine was often used for the robes of the Virgin Mary, to illustrate her divinity.

Ultramarine remained an expensive pigment until a synthetic version was invented. In 1817, the Royal College of Art in England offered a prize to anyone who could produce do this. The French Government’s Société d’Encouragement pour l’Industrie Nationale then offered a larger reward of 6,000 francs, and in 1828 the French chemist Jean-Baptiste Guimet was successful. His pigment, French ultramarine, was made from a mix of clay, soda, charcoal, quartz and sulphur, heated to produce a green ultramarine substance which was then ground, washed and re-heated to convert it to a blue pigment. French ultramarine was chemically identical to the prohibitively expensive ultramarine pigment it took its name from.

JMW Turner was the first accredited artist to use synthetic ultramarine, in 1834. In 1957, Yves Klein developed a version called IKB (International Klein Blue) which he registered as a trademark colour and made 200 monochrome paintings from.

Winsor & Newton produces a French Ultramarine and a cooler Ultramarine (Green Shade).