Ultramarine blue
| Ultramarine | |
|---|---|
 Color coordinates |
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| Hex triplet | #3F00FF |
| sRGBB (r, g, b) | (63, 0, 255) |
| CMYKH (c, m, y, k) | (100, 75, 0, 0) |
| HSV (h, s, v) | (255°, 100%, 100%) |
| Source | [Unsourced] |
|
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred) |
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Ultramarine is a deep blue color and a pigment which was originally made by grinding lapis lazuli into a powder. The name comes from the Latin ultramarinus, literally "beyond the sea", because the pigment was imported into Europe from mines in Afghanistan by Italian traders during the 14th and 15th centuries.
Ultramarine was the finest and most expensive blue used by Renaissance painters. It was often used for the robes of the Virgin Mary, and symbolized holiness and humility. It remained an extremely expensive pigment until a synthetic ultramarine was invented in 1826.
The pigment consists primarily of a zeolite-based mineral containing small amounts of polysulfides. It occurs in nature as a proximate component of lapis lazuli containing a blue cubic mineral called lazurite. The pigment color code is P. Blue 29 77007. The major component of lazurite is a complex sulfur-containing sodium-silicate (Na8–10Al6Si6O24S2–4), which makes ultramarine the most complex of all mineral pigments. Some chloride is often present in the crystal lattice as well. The blue color of the pigment is due to the S−
3 radical anion, which contains an unpaired electron.
The raw materials used in the manufacture of synthetic ultramarine are the following:
The preparation is typically made in steps. The first part of the process takes place at 700 to 750 °C in a closed furnace, so that sulphur, carbon and organic substances give reducing conditions. This yields a yellow-green product sometimes used as a pigment. In the second step air or sulphur dioxide at 350 to 450 °C is used to oxidise sulphide sulphur in the intermediate product to S2 and Snchromophore molecules, resulting in the blue (or purple, pink or red) pigment.
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