This section is from the book "Chromatography; Or, A Treatise On Colours And Pigments, And Of Their Powers In Painting", by George Field. Also available from Amazon: Chromatography, or A Treatise on Colours and Pigments, and of Their Powers in Painting.
Prussiate Of Copper differs chemically from Prussian blue only in having copper instead of iron for its basis. It varies in colour from russet to brown, is transparent and deep, but, being very liable to change in colour by the action of light and by other pigments, has been very little employed by the artist.
There are several other pigments which enter imperfectly into, or verge upon, the class of russet, which, having obtained the names of other classes to which they are allied, will be found under other heads; such are some of the ochres and Indian red. Burnt carmine and Cassius's precipitate are often of the russet hue, or convertible to it by due additions of yellow or orange; as burnt Sienna earth and various browns are, by like additions of lake or other reds.