This is a beautiful transparent colour, which, in some fine manuscripts of the fifteenth century, is used as a transparent glaze over burnished gold, the effect of which is very magnificent, as the metallic gleam of the gold shines through the deep transparent red of the over-painting. Lake was also used as an opaque, solid pigment by mixing it with white, which at once gave it "body," and destroyed its transparency.

Purple of a very magnificent tint was occasionally made by a mixture of ultramarine with the carmine-red of the kermes beetle; this was specially used by the illuminators of the fourteenth and fifteenth centuries.

Yellows.

Yellows.Yellow ochre, a fine earth pigment coloured by iron, was the principal yellow of the illuminators.

In late manuscripts orpiment (sulphuret of arsenic), which is a more brilliant lemon-yellow, was occasionally used; see Cennino Cennini, § 47.

Litharge yellow, an oxide of lead, was another important colour, but more especially for the painter in oil, who used it very largely as a drier[[278]].

Another fine ochreous earth of a rich brown colour was the terra di Siena or "raw Siena"; the colour of this was made warmer in tint by roasting, thus producing "burnt Siena."

Use of white.

Use of white.White pigments were perhaps the most important of all to the illuminator, who usually only used pure colours for his deepest shadows; all lights and half tints, both in miniature pictures and in decorative foliage, being painted with a large admixture of white. The use of this system of colouring by Fra Angelico and many painters of the Sienese school has been already referred to; see page [190].

For this reason it was very important to use a pure and durable white pigment which would combine well with other colours.