BLACK PIG′MENTS

Syn. Pigmen′ta ni′gra , L. The principal black pigments of commerce are obtained by carbonising organic substances (particularly bones), by exposure to a dull red heat, in covered ve els out of contact with the air; or by collecting the soot formed during the combustion of unctuous, resinous, and bituminous matters. Artists and amateurs also prepare, on the small scale, a variety of blacks, many of which are not procurable at the colour-shops. This they effect either by the carbonisation of substances not usually employed for the purpose, or by simply reducing to powder certain mineral productions selected on account of the peculiar shades of colour which they respectively po e . Some of the last might, however, be more appropriately cla ed with browns. The following list embraces most of these articles:—