Liquid coating substance that dries to a hard finish. In most lacquers resin is dissolved in a volatile solvent or a drying oil and hardens by evaporation. Urushi lacquer, however, hardens by oxidative polymerization when thin coatings are exposed to high humidities at moderate temperatures. There is also no general agreement concerning the differences between a lacquer and a varnish, particularly in modern production. Some lacquers, when sold as artists’ materials, are often called ‘varnishes’ or ‘spirit varnishes’. Urushi, which is sometimes called ‘true’ lacquer, is the Japanese name for the resinous sap of Rhus vernicifera, but in the late 20th century it became the accepted term for the saps of other species possessed of similar properties. This was done to differentiate urushi lacquers and lacquerwares from those made from other plant resins and gums or from such insect-derived resins as shellac. The various European imitations of Asian lacquer, for example vernis Martin, are all best described as ‘japanning’. Urushi is used in East and South-east Asia, and shellac in the Indian subcontinent, the Middle East and the Near East. European lacquerware employs a variety of substances and techniques but only very rarely urushi.