Carbonation of fresco mural paintings with a dolomitic mortar

An innovative approach involving a collection of experiments to mimic and assess the different conditions (at selected time-pH-[Mg2+]-humidity) existing during carbonation process in dolomitic mortars is proposed with combination micro-analytical imaging techniques, namely: optical electron microscopy, micro-Fourier-Transform Infrared spectroscopy, Raman spectroscopy synchrotron-based micro X-ray diffraction. The was studied from short time scale long simple aqueous saturated solutions fresco mock-up samples. These techniques allowed identifying both crystallized amorphous components revealing their in-depth distribution multi-layered systems. presence Mg2+ influences microstructure composition mortars, resulting aragonite concurrent calcite. In later stages, i.e. once Ca2+ has transformed into carbonate, brucite can lead formation magnesium carbonates hydroxycarbonates. results contribute explaining lability old observed historical paintings.