Mention has already been made of the great confusion prevailing in the nomenclature of pigments, and that many of these are put on the market under a variety of names taken from different languages.
Although the number of the earth colours is far smaller than that of the artificial colouring matters, the nomenclature is in a no less confused condition.
Most frequently, earth colours are named after the localities where they are either discovered or prepared, in combination with the word indicating the colour of the product—for example: Cologne white, Vienna white—or the term “earth” (Verona earth, Veronese green, etc.). Whilst these names give, to some extent, an indication of the nature of the pigment, others have no reference to it at all; such as colcothar, bole, umber, etc. Finally, a number of other names in use are calculated to produce the impression that the earth colours in question are of an entirely different nature to their real one. As an example, we may cite the name “French chalk,” which is not a chalk at all, but consists of the mineral talc. Black chalk, again, is not chalk (calcium carbonate), but a black shale; and graphite is often termed blacklead, although it contains no lead at all, and the name is merely a survival from the time when pencils of metallic lead were used for drawing.
In order to bring some kind of order into the various names which are applied to the earth colours, a list of those in current use is appended. Many of these names, it may be stated, have been selected in a purely arbitrary manner, some manufacturers, for instance, selling ordinary chalk under a variety of foreign names, for the purpose of thereby obtaining higher prices. These borrowed names would seem to be superfluous, to say the least. Pure and properly levigated chalk is the same article everywhere, whether prepared from English, French or German limestone; and in all cases the simple name, “chalk,” with an explanatory “single,” “double,” or “triple” levigated, should be quite sufficient.
In the case of earth colours that are really obtained of special quality in certain localities, such as terra di Siena, green earth from Verona, or the like, the corresponding name might be retained, even if the pigment did not originate from the locality in question, as a generic term for a pigment possessing certain properties and of a certain composition.
In the following classification, the names of the earth colours are given in accordance with their colour and chemical composition.
White Earth Colours
Carbonate of Lime:
Chalk; levigated chalk; Vienna white; Spanish white; marble white; artists’ white; Bougival white; Champagne chalk; Paris chalk; Cologne chalk; Mountain chalk; craie; blanc minéral; Blanc de Champagne; Blanc de Meudon; Blanc de Bougival; Blanc de Troyes; Blanc d’Orleans; Blanc de Rouen; Blanc de Briançon.
Basic Carbonate of Lime: