Spectroscopic Investigation of Wall Paintings in the Alhambra Monumental Ensemble: Decorations with Red Bricks

The Alhambra Monumental Ensemble (Granada, Spain) is a unique well-preserved palatine city from the medieval Islamic period, and it constitutes best example of Nasrid architecture. In this work, we focus on study one its most unknown decorations: Wall paintings with appearance red bricks. These faux-brick decorations are found in many different locations within complex, including both exterior interior walls, arches vaults. We have considered reigns to gain information about their characteristics terms materials, execution techniques conservation state. They been studied combining non-invasive methodology using portable equipment (X-ray fluorescence (XRF) Raman spectroscopy) complementary studies selected samples (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS) microimaging). general, those located poorly preserved, contrast good state motifs. rectangles these were painted over white finishing layer, which acted also as edge lines between false colour was always due hematite (?-Fe2O3), revealed by characteristic bands. use natural ochre pigment (very abundant region) could be hypothesised considering XRF SEM-EDS results. layer made lime mortar presence CaCO3 painting layers suggests lime-based (either fresco or mezzo fresco). Only indoor locations, technique, based gypsum (CaSO4·2H2O) plaster, used. identification calcium oxalate location, form weddellite (CaC2O4·2H2O), can interpreted result organic binder degradation. Furthermore, superficial contamination detected outdoor locations.