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.
Copper Green is the appellation of a class rather than of an individual pigment, under which are comprehended Verdigris, Verditer, Ma-hichili' mineral green, Green bice, Scheie's green, Schweinfurt or Vienna green, Hungary green. Emerald green, true Brunswick green, green Lake, Mountain green, African green, French green, Saxon green, Persian green, Patent green, Marine green, Olympian green, etc.; and old authors mention others under the names of individuals who prepared them, such are Verde de Barildo, etc.
The general characteristics of these greens are brightness of colour, well suited to the purposes of house-painting, but not adapted to the modesty of nature in fine art. They have considerable permanence, except from the action of damp and impure air, which ultimately blacken them; to which shade they have also a tendency by time. They have a good body, and dry well in oil, but, like the whites of lead, are all deleterious substances. We will particularize the principal sorts.
Verdigris,Or Viride Æris, is of two kinds, common or impure, and crystallized or Distilled Verdigris, or more properly refined verdigris. They are both acetates of copper, of a bright green colour inclining to blue. They are the least permanent of the copper greens, soon fading as water-colours by the action of light, 4c, and becoming first white, and ultimately black, by damp and foul air. In oil verdigris is durable with respect to light and air, but moist and impure air changes its colour, and causes it to effloresce or rise to the surface through the oil. It dries rapidly, and might be useful as a siccific with other greens or very dark colours. In varnish it stands better; but is not upon the whole a safe or eligible pigment, either alone or compounded. Vinegar dissolves it, and the solution is used for tinting maps, etc. The addition of refined sugar, with gentle boiling, facilitates the solution and improves the colour.
Green Verditer is the same in substance as blue verditer, which is converted into green verditer by boiling. This pigment has the common properties of the copper greens above mentioned, and is sometimes called Green Bice.
Emerald Green is the name of a new copper green upon a terrene base. It is the most vivid of this tribe of colours, being rather opaque, and powerfully reflective of light, and appears to be the most durable pigment of its class. Its hue is not common in nature, but well suited for gems or glazing upon. It works well in water, but difficultly in oil, and dries badly therein. The only true emerald green is, however, that of chrome, with which metal nature gives the green colour to the emerald.
Mineral Green is the commercial name of Green Lakes, prepared from the sulphate of copper. These vary in hue and shade, have all the properties before ascribed to copper greens, and afford the best common greens; and, not being liable to change of colour by oxygen and light, stand the weather well, and are excellent for the use of the house-painter, etc.: but are less eligible in the nicer works of fine art, having a tendency to darken by time and foul air.
Mountain Green is a native carbonate of copper, combined with a white earth, and often striated with veins of mountain blue, to which it bears the same relation that green verditer does to blue verditer; nor does it differ from these and other copper greens in any property essential to the painter. The Malachite, a beautiful copper ore, employed by jewellers, is sometimes called mountain green, and Green bice is also confounded therewith, being similar substances and of similar use as pigments. It is also called Hungary Green, being found in the mountains of Kernhausen, as it is also in Cumberland.