Ro-iro Urushi: Black Lustre Lacquer, Raw Lac Blackened with Haguro Iron Vinegar (after Rein 1889)

Japanese black lacquer is not coloured with a black pigment. The lacquer makers added iron, dissolved in vinegar, to filtered raw lac and stirred off the water: the iron turns the lac a deep, lustrous black. The same iron vinegar, haguro, was used to blacken teeth. Result: Ro-iro-urushi, the best black lustre lacquer, 0.5 to 2 % iron. Source: J. J. Rein, The Industries of Japan (1889), pp. 350-353. Not given: how much haguro (set by the colour). Picture drawn by Youblob.