Pure Orange

Synonyms:

pure orange, marigold, alizarin yellow, alizarin orange

Under the above names a pigment of great richness and beauty has been introduced. It is a kind of lake, and consists of a coal-tar colour known to chemists as β-nitro-alizarin thrown down upon an aluminous base. Nitro-alizarin, as its name implies, is a derivative of alizarin, one of the least changeable of all organic pigments, and the chief tinctorial product of madder. There is no doubt about the beautiful hue of this paint, a deep brownish gold: the trials first made as to its permanence in oil promised well, but on continuing the exposure to light of this pigment ground in oil it became evident that it suffered considerably. The deterioration was more marked when the paint had been mixed with flake white, but even as a glazing colour it is not safe.