Methodology for the study of archaeological rendering mortars

In the study of an archaeological wall painting, the analyze of its support, the mortar, has a great importance. In this paper, the methodology followed for the comparative study of mortars from various examples of wall painting whose chronology ranges from roman to caliphate times is shown. For the examination of the mortars a visual analysis and a sampling have been carried out; the selected samples have been studied with different instrumental methods: stereoscopic microscopy, optical microscopy, scanning electron microscopy (SEM-EDX) and X-ray diffraction. In addition, because of the similarity of the results obtained in these first analyses, a study was also carried out to establish the distribution of the aggregate and the relationship between binder and aggregate. All this has allowed the characterization of the different layers of mortar as well as establishing differences and similarities between the mortars belonging to the different chronologies.