A-Z of Ceramics - L is for Lustre
Lustre is a very sophisticated decorative technique in which pigment containing oxides of copper and silver is painted onto a fired glazed pot. The pot is then given a low-temperature firing in which the air-supply is restricted. This produces carbon monoxide, which hungrily extracts oxygen from every available source, forming the more stable carbon dioxide. In this reducing atmosphere, the pigments are stripped of oxygen and reduced to a microscopically thin layer of metal bonded to the surface of the glaze. The lustre thus shines with metallic glints and mother-of-pearl reflections.
First seen on glass in Egypt in the 8th century, lustre production moved to Iraq, back to Egypt, then, in the 12th century, to Syria and Iran. Shortly after, it arrived in Spain, where production continued into the 20th century.
True reduced lustre should not be confused with the less demanding and more uniform industrial technique invented in the early 19th century. In the late 19th century, true reduced lustre became a passion again among collectors and some art-potters.