Technology of production of polychrome lustre

Lustre is a decoration consisting of a few hundreds of nanometres thick surface layer of silver and copper metal nanoparticles incorporated into the glaze. Polychrome lustreware with several combinations of colours and shines was produced in Abbasid Iraq in the 9th century AD. Three colour combinations, black plus red, white-silvery plus red-coppery and yellow-golden plus red-coppery, have been studied, and the materials and methods of production determined. Two separated firings the first for the copper and the second for the silver lustre were performed. The black, white, yellow and green colours of the silver lustres are associated with the different sizes of the nanoparticles and to their distribution in the layer. Although the addition of lead and tin in the initial mixture is demonstrated, their incorporation in the glaze has been found to be the key factor in the production of the red-coppery and yellow-golden lustre.