Lacker, or Lacquer, is a kind of varnish, applied to brass, tin, and other metals, in order to improve their colour, and to prevent them from tarnishing.

The best lacquer is prepared from rectified spirit of wine, and seed-lac, in the proportion of three ounces of the latter to one pint of the former. The mixture is digested for some hours in a moderate heat; when the liquor is strained, and left to subside. In this state, it is ready to receive the shade required, by adding gamboge, an-notto, or other tinging drugs.

With a view to impart a golden colour to metals, two parts of gamboge are usually added to one of annotto; but, a better method is, to dissolve those substances separately, and to ascertain the particular shade, by mixing different proportions of the two solutions. If silver or tin are to be lacquered, it will be necessary to employ a larger quantity of the colouring matters than is required, when this kind of varnish is to be applied to brass.