Archaeological Zelliges of Meknes (14th-century): Physical measurements of the colour and identification of colouring agents

Abstract

Two series of Zelliges belonging to the Filalia and Bou-Inaniya Medersas (14th-century) in Meknes city have been studied in order to describe precisely the colour of the glazes and to identify the chromogen agents responsible for these colours. The glaze colours are physically studied by the determination of their chromatic coordinates using chromametry method. These coordinates are represented in the conventional Yxy and L*a*b* spaces. Furthermore the chromogen ions, responsible for the different colour shades, are identified by optical absorption spectrometry (OAS) and by electron paramagnetic resonance (EPR) methods. These ions are the classical ones: copper (Cu 2 + ) for the green, cobalt (Co 2 + ) for the blue, iron (Fe 3 + ) for the honey colour and iron (Fe 3 + ) in association with manganese (Mn 3 + ) for the black.