Lampblack

Lampblack is the soot or amorphous carbon obtained by burning bodies rich in that element, such as resin, petroleum, and tar, or some of the cheap oily products obtained from it. The supply of air is limited or controlled so as to produce a smoky flame, and the smoke passes into a chamber with some arrangement for receiving the abundant deposit of soot. For some of the finer qualities of lampblack this soot or carbon is purified by heating it in closed vessels. A large quantity of lampblack has been made in the United States by the imperfect combustion of natural gas. Lampblack is a useful pigment for artists both in oil and water colour, a coarser kind being employed by house-painters. It is the chief ingredient in Indian Ink (q.v.), and along with boiled linseed-oil forms printing-ink. Of it is formed the pigment for the carbon paper used in the Autotype Process (q.v.). Lamp-black is also employed in the preparation of some kinds of leather, and for other purposes.