Lacquer

Lacquer gives an object a deep reddish-brown sheen. It does not harden by drying out: it sets by oxidation and polymerization in a warm, humid environment, so finished pieces are kept somewhere damp. Rather than one thick coat, it is applied in many thin ones: raw lacquer for the base, and on top coloured lacquer mixed with pigment, black lacquer mixed with iron, and others. Shell cut into patterns, laid on and then lacquered and polished again layer by layer, makes mother-of-pearl lacquerware. The oldest traces of lacquer on the Korean peninsula are on a Bronze Age mandolin-shaped bronze dagger from the Jeokryang-dong site in Yeosu. Fresh lacquer inflames the skin, so it is handled with great care.

Look at the light across the surface at an angle and notice how deep the colour is; where there is mother-of-pearl, shift your angle and watch the shell change colour.

Was this sheen painted on, or polished out?