rally substitute a mixture of ivory-black, and the common blue used for dyeing cloths.
Indian-ink is an excellent black for water-colours, and consists of an equal mixture of lamp-black and common glue. Ivory-black, or charcoal, may be substituted for lamp-black; but it is seldom employed, on account of the great trouble of levigating it to a sufficient degree of fineness.
2. White, of which there are several kinds; as flake-white, white-lead, calcined hartshorn, pearl-white, Spanish-white, egg-shell-white, and magistery of bismuth.
Flake-white, and white-lead, are the produce of the same metal. The preparation of the former is kept secret by colour-makers; but the latter is made, by forming thin plates of lead into rolls, and placing them so as to imbibe the fumes of vinegar contained in a vessel, over a moderate fire. Nearly the whole is thus converted into a white calx, which is collected, ground up with water, and formed into little cakes. (See White-Lead.)—These two are the only whites that can be used in oil; all the rest being transparent, unless laid on with water.
Calcined hartshorn is the most useful of the earthy whites, as it contains the least proportion of alkali.
Spanish white is only chalk, very finely prepared.
Pearl-white is made from oyster-shells, as egg-shell-white also is from those of eggs. All these, from their attraction for acids, necessarily destroy those colours which are compounded with any acid or metallic salt.
The magistery of bismuth is apt to turn back, as well as flake-white, and white lead, when employed for a water-colour.
3. Red. The principal red colours used in painting, are carmine, rose-pink, vermillion, and red-lead.
Carmine is the brightest and most beautiful red colour known at present.—(See vol. i. p. 436).
Rose-pink is a very delicate colour, inclining more to purple than scarlet. It is prepared from chalk, coloured with a decoction of brasil-wood, heightened by an alkaline salt, which renders it very liable to fade, and of little value. This colour might be made more durable, by employing for its basis the white precipitate of lead; and by brightening it with a solution of tin.
Vermillion consists of sulphur and quicksilver, the former of which is melted, when the quick-silver is stirred in, and the whole is converted into a black mass.—See Cinnabar, vol. i. p. 527.
Red-lead is a calx, of a lively yellowish colour, which it acquires by slow calcination. Both these colours are very durable; the former, however, is the best red for oil-painting, but does not answer with water; the latter inclines to an orange; and, like other preparations of lead, frequently turns black.
4. Orange. The genuine orange-coloured paints are, red orpiment, and orange-lake. the first of these is a sublimate formed of arsenic and sulphur; the other may be prepared from turmeric, infused in spirit of wine, having its colour struck upon calx of tin, and brightened by a solution of that metal. The different shades of orange may, however, be pre-
