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.
Blue Verditer is a blue oxide of copper, or precipitate of the nitrate of copper by lime, and is of a beautiful light blue colour. It is little affected by light; but time, damp, and impure air, turn it green, and ultimately blacken it, - changes which ensue even more rapidly in oil than in water: it is therefore by no means an eligible pigment in oil, and is principally confined to distemper painting and the uses of the paper-stainer, though it has been found to stand well many years in water-colour drawings and in crayon paintings, when preserved dry. It has been improperly substituted for Bice.
Saunders Blue, a corrupt name, from Cendres Bleus, the original denomination probably of ultramarine ashes, is of two kinds, the natural and the artificial: the artificial is a verditer prepared by lime or an alkali from nitrate or sulphate of copper; the natural is a blue mineral found near copper-mines, and is the same as.
* The late John Linel Bond, to whom his country is indebted for those noble designs, the new London and Waterloo Bridges, and other admirable structures.
Mountain Blue, found in similar situations as the above. A very beautiful substance of this kind, a carbonate of copper, both blue and green, is found in Cumberland. None of these blues of copper are, however, durable: used in oil, they become green, and, as pigments, are precisely of the character of verditers.
Schweinfurt Blue appears to be the same in substance as Scheele's green, prepared without heat or treated with an alkali. It is a beautiful colour, liable to the same changes, and is of the same habits, as blue verditer and the above ineligible pigments.