BLUE PIGMENTS
Cobalt Blue, Cerulean Blue, Ultramarine, Ultramarine Ash, French Ultramarine, New Blue, Prussian Blue, Antwerp Blue, Cobalt Violet, Purple Madder.
Cobalt Blue is a fine colour prepared from cobalt oxide and alumina. This is quite permanent under ordinary conditions.
Cerulean Blue, made from cobalt and tin oxides, is also a permanent colour.
Genuine Ultramarine is a beautiful permanent colour obtained by grinding the lapis lazuli. Cennino Cennini, in his treatise, gives interesting particulars concerning the method then used to prepare this colour. Ultramarine Ash is a second quality of this same blue. Unfortunately the great cost of genuine ultramarine debars the majority of artists from using this colour. Happily, under the name of French Ultramarine, it is now made synthetically. By this means a good permanent colour is produced at a cheap rate. New Blue is a pale variety of French Ultramarine.
Prussian Blue is ferrocyanide of iron. Antwerp Blue is a weaker variety of the same colour containing alumina. These colours are not altogether reliable, as they are subject to change.
Cobalt Violet is a purple colour made from cobalt, and is quite permanent.
Purple Madder is usually prepared from the madder root, and is permanent under ordinary conditions. Sometimes, however, it is prepared from Crimson Lake, in which case it is fugitive.
GREEN PIGMENTS
Chromium Oxide, Viridian, Emerald Green.