Physico-chemical and analytical studies of the mural paintings at Kariye Museum of Istanbul.

Optical (OM) and Scanning Electron Microscopy (SEM-EDS), [mu]FT-IR spectroscopy and Gas Chromatography-Mass Spectrometry (GC-MS) have been used to ascertain, at molecular, nano- or micrometric level, the state of conservation of the mural paintings at the Kariye Museum in Istanbul. The characterization of the original organic and inorganic materials used in the painting preparation and plaster layers allows to define the painting techniques. Furthermore, the nature and the extent of the degradation phenomena and the materials used in subsequent restorations have been identified. The poor state of conservation of the pictorial cycle, due to quite severe deterioration processes, noticeable detachments, presence of salts, etc., strongly calls for a prompt intervention, guided by an exhaustive and appropriate scientific approach. The present study offered the possibility to compare the results obtained by different techniques on the same samples, in order to evaluate performance, advantages, limits of each of them