Lead Pigments.—The principal pigments of lead are white, yellow, and red.
White Pigments:—
White Lead, Flake White Ceruse, Mineral White, are so many different names for the carbonate of lead already described.
Newcastle White is white lead made with molasses vinegar.
Nottingham White.—White lead made with alegar (sour ale), often, however, replaced by permanent white, i.e., sulphate of baryta.
Miniature Painters’ White, White Precipitate of Lead, is simply lead sulphate.
Pattison’s White is an oxychloride of lead, PbCl2PbO.
Yellow Pigments:—
Chrome Yellow may be a fairly pure chromate of lead, or it may be mixed with sulphates of lead, barium, and calcium. The pigment known as “Cologne yellow” consists of 25 parts of lead chromate, 15 of lead sulphate, and 60 of calcic sulphate. The easiest method of analysing chrome yellow is to extract with boiling hydrochloric acid in the presence of alcohol, which dissolves the chromium as chloride, and leaves undissolved chloride of lead, sulphate of lead, and other substances insoluble in ClH. Every grain of chromate of lead should yield 0·24 grain of oxide of chromium, and 0·4 grain of chloride of lead.
Turner’s Yellow, Cassella Yellow, Patent Yellow, is an oxychloride of lead (PbCl27PbO) extremely fusible.