PIGMENTS
Naples Yellow (antimony yellow) is essentially lead antimoniate
which may be considered to be chemically combined lead and antimony oxides.
It varies in color from sulphur-yellow to orange-yellow, depending upon the pro-
portion of the two materials. It is made in various ways: from the prolonged
roasting of the mixed oxides of lead and antimony, or from salts of those metals,
like tartar emetic (potassium antimonyl tartrate) and lead nitrate with sodium
chloride (see De Wild, p. 56; also Rose, pp. 306-310). The pigment is homo-
geneous and finely divided, and it has good hiding power. It resembles massicot
in its microscopic character, and De Wild says (p. 57) that no crystalline form
can be detected, even at high magnification. Chemically, it is quite stable; it is
little affected by alkalis or by dilute and concentrated nitric or hydrochloric acids.
It fuses only at a high temperature but turns permanently dark brown. Since
it is a lead pigment, it is darkened by hydrogen sulphide; hence, it is more useful
in oil than in water color medium.
The history of this pigment is rather obscure. A compound of antimony and
lead seems to have been used in Babylonia and Assyria in the production of
yellow ceramic glazes (see Partington, pp. 256, 283, and 292), It was found
(Partington, p. 292) in cake form among other pigments in Sargon IPs palace
at Khorsabad. Lucas (p. 125) found lead and antimony in a specimen of Egyptian
glass of the XIX Dynasty. Little is known about its early history in Europe.
Naples yellow has been vaguely connected by some with the gialtorino of Cennino
Cennini (see Thompson, The Craftsman's Handbook, p. 28, and The Materials of
Medieval Painting, pp. 179-180), but the identity of that yellow is still uncertain.
R. Jacobi has reported (c Uber den in der Malerei verwendeten gelben Farbstoff
der Alten Meister,* Angewandte Chemiey LIV [1940], pp. 28-29) on specimens of
a yellow pigment used in paintings from the XVIII century, particularly in
northern Europe which, on the basis of spectroscopic studies, were found to be a
compound of lead and tin oxides. Recipes for the preparation of lead antimoniate,
as it is now known, first appeared around the middle of the XVIII century (see
Guignet, p. 105, and De Wild, p. 56). Rose says (p. 307) that the first recipes are
given by Passeri in 1758. De Wild (p. 58) does not believe that it was used by the
old masters. Doerner (p. 62) thinks, however, that it was used by Rubens. Only
careful chemical analysis could distinguish it, on paintings, from massicot. Naples
yellow is still used as a ceramic pigment, but not much by artists, although it can
be got from a few colormen. Several substitutes, which are sold under that name,
are mixtures like cadmium yellow, zinc white, Venetian red, etc. The name has
come to indicate a shade of yellow rather than a definite chemical compound.
Natural Pigments are those which are mineral, vegetable, or animal in origin.
They are the pigments most generally used in the early history of painting. In-
cluded are many of great stability and usefulness, like ochres and umbers. Some
are of fine quality, like azurite, malachite, and ultramarine. A few of the natural
animal and vegetable colors, like indigo and madder lake, are moderately stable,
but many, like saffron and carmine, are fugitive. Natural mineral pigments are