The Color Blue

The Marquise de Seignelay and two of her sons

by Pierre Mignard

If the Virgin Mary had paid for even one of her portraits showing her in celestial blue robes, she would have needed the income of King David instead of her carpenter husband Joseph. That's because painters created the ultramarine pigment first used in the 13th century to portray her from the mineral ultramarine, extracted from lapiz-lazuli  stone and imported at sky-high expense only from Sar-e-Sang in modern-day Afghanistan. this convoluted import system often made the pigment costlier than gold.

Even 700 years ago, contracts were extremely specific about the amount and qualty of the ultramarine used because it was so expesive. the color- and it associations with purity and divinit- became popular with wealthy women sitting for portraits.

In the 16th centuty, painters thought they had found a cheaper, identical color in smalt, created from adding cobalt oxide to potash-rich glass that was crushed. but the bright blue turns gray in about a century when combined with oil paint.  Those 'gray' skies in Dutch landscapes were meant to be sunny blue- a fact scholars only learned in the 1970's and 1980's and still unknown to most museum visitors.