Japanning. The art of coating surfaces of metal, wood, etc., with japan or varnish to produce a high black luster. Japanning liquid is made by cooking gum shellac with linseed oil in a varnish kettle. The articles to be coated, such as hair pins, pants buckles, buttons, etc., are immersed in the liquid and then dried and hardened by means of a high temperature in stoves or hot chambers.