In some cases, we make checks with the analysis of micro-samples, which are taken from the work in order to identify the materials. The analysis of a sample from the mural painting from Sant Climent de Taüll has revealed traces of mecca varnished metal sheet sheeting imitating gold.

A lamina of tin (Sn), shiny like metal, is identified on top of the white mortar.

Master of Taüll, Apse of Sant Climent de Taüll [2], circa 1123. Fresco transferred to cloth.