Tracking old and new colours: Material study of 16th century mural paintings from Évora Cathedral (Southern Portugal)

Abstract

This article describes the results of a multi-analytical research carried out on the mural paintingsfromEvora Cathedral, one of the oldest and most promi-nent monuments ofEvora city. The paintings were a late16th Century addition to the cathedral’s northern tran-sept chapel and are attributed to the painter JosedeEscovar, whose painting workshop was remarkably activein the so-called golden age of mural pai ntings in south-ern Portugal. The aim of the study was to reconstruct thepaintings’ life story through a material s science perspec-tive by discerning the material characteristics of the orig-inal and overpaint campaigns. The analytical setupcomprised technical photography (TP) in the visible andUV light, Vis-Spectrophotometry, optical microsc opy(OM) complemented with scanning electron microscopywith energy dispersive X-ray spectrometry (SEM-EDS),micro Fourier transform infrared spectrometry (mFT-IR)and pyrolysis–gas chromatography (Py-GC/MS) analysesof the collected samples. Results show that the originalpaint layers were executed with a combination of frescoand secco techniques, using a very simple chromatic pal-ette composed of earth pigments, mercury sulphide, cal-cium carbonate and green copper based pigments. Thepaintings were heavily retouched and overpainted usingearth pigments, smalt, Prussian blue, zinc white and leadwhite. Furthermo re, the analyses of the cross-sectionstaken from the stuccoed frames revealed a first decora-tive campaign made with gold and silver alloy