Recherche d'indices sur les techniques de fabrication de zelliges du XIVe siècle (Chellah, Maroc).

Abstract

The art of zellige and the buildings they decorate are an integral part of life and cultural heritage in Morocco. The architects confronted with the problems of restoration of these buildings and the zellige decorations are often forced to envisage the replication of disappeared elements. But the techniques, the texture and the composition of the material are not or badly known. Here we are interested in searching the physical characteristics of zelliges coming from the site of Chellah, in Rabat, and dating from the XIVth century. We look for some indications on one or several techniques of their manufacture. The analyse concerned the colours, by optical absorption spectrometry and chromametry, the texture, by cathodoluminescence and scanning electron microscopy, and the elementary composition of the different phases, by energy-dispersive X-ray spectrometry. Colouring agents, used to colour the glazes, were identified (iron, copper and manganese). The determination of the chromatic coordinates of the colours of the glazes and their representation in the conventional spaces Yxy and L*a*b * supplies a norm repository. That can be used to direct and control the attempts of replication in purpose of restoration. We notice the presence an abundance of devitrification crystals in the glaze/body interface, probably meaning the application of the glaze suspension on an unfired calcareous body. For all the examined samples, transparent lead and tin-opacified lead glazes have been used. These data will be useful for some replication experiments in association with the local craft. It establishes a first repository system useful to compare with other from various periods, and from other Moroccan buildings.