Characterisation and differentiation of pigments employed on the façade of “Noto’s Valley” monuments ( Sicily)

Most of the “Noto’s Valley” monuments fac¸ades,located in different towns of Sicily such as Ragusa Ibla, Modicaand Noto, present different colours and in many cases the townsthemselves are characterized by evident chromatic variations.The knowledge of colour and in particular the characterizationof pigments is of utmost importance in the baroque Sicilianbuildings, because the peculiarity of the colour is one of the featuresthatmakes the “Noto Valley” monuments aWorld CulturalHeritage site.The present works aim is to characterise and differentiatethe pigments used on the fac¸ade of monuments and inside theplasters. In particular, we perform a micro-textural and analyticalanalysis through scanning electron microscopy (SEM) anda mineralogical investigation through the conjunction of opticalmicroscopy and fourier transform infrared spectroscopy(FT-IR). All the experimental results have allowed us to clearlyclassify the pigments into earths rich in clay minerals and earthcontaining gypsum. Furthermore, we also show that the earthsrich in clay minerals from Ragusa and Modica areas have localprovenance