Ultramarine Blue Pigment

Ultramarine Blue has a fabled history. It is naturally derived from the semiprecious gemstone lapis lazuli. It gets its name from the Latin, meaning beyond the sea, since the best source of lapis was in the northeastern corner what is now Afghanistan.

from the Wilton Diptych c. 1395

Lapis was not used as a pigment in Western art until the early Christian era. It played a role of major importance in later Medieval Art later when blue acquired a symbolic significance, particularly for the clothing of the Virgin Mary.

The difficulty of obtaining lapis, however, was compounded by the difficulty of converting it into a pigment. The lapis had to be crushed then mixed with linseed oil, pine rosin and mastic resin into a dough. The dough was then wrapped in linen and soaked in a mild solution of lye. The lye leached out the ultramarine blue from the matrix.

The first blue that settled out was the purest and highest quality. The dough was then transferred to a 2nd bowl of lye until more blue leached out. The process continued until the last extraction in which a very pale blue called ultramarine ash was produced.

In the Middle Ages, ultramarine was as valuable as gold. The two colors were often used together in devotional paintings that expressed the richness of the gift of piety by the wealthy patron.

Ultramarine Blue Paint

What is it that constitutes this gorgeous deep blue? The surprise, as with most pigments, is that its components are not in the least bit blue or exciting to the eye. The chemical composition of ultramarine blue was analyzed by two French chemists in 1806.

Sodium, Aluminum, Sulfur, and Silica

Learning the ingredients – sodium, aluminum, sulfur, and silica – spurred the French “National Society for the Encouragement of Industry” to offer a prize for developing an inexpensive synthetic ultramarine blue. This was achieved by 1830 and ultramarine blue was able to enter the palette of the every-day artist. The term “French ultramarine” simply refers to the fact that it is the synthetic, but it has the same ingredients as genuine lapis lazuli.

Tags: aluminum, art, art and chemistry, artist materials, chemistry of paint, chemistry of pigment, Encaustic, encaustic in mixed media, French, genuine lapis lazuli, lapis blue, Middle Ages, oil paint, oil sticks, Oilstick, Paint, Pigment Sticks, R&F, R&F encaustic, R&F Handmade Paints, silica, sodium, sulfur, ultramarine blue, Virgin Mary, Wilton Diptych

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