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The employment of synchrotron techniques complemented by conventional laboratory systems has allowed us to deepen and improve our knowledge of Roman wall painting procedures. The palette identified in wall paintings from Pompeii and Herculaneum from the second century BC includes goethite, hematite, cinnabar, glauconite, Egyptian blue, and other components such as calcite and aragonite. Proof of the use of organic binders is provided by FTIR and PY-GC/MS. Therefore, the possibility of the use of 'a secco' techniques cannot be ruled out. Pigments in wall paintings are usually found in small percentages and conventional X-ray diffractometers do not detect them. Synchrotron radiation -high-resolution X-ray powder diffraction has allowed identification with only a few micrograms of sample.a rcm_478 286..307

Illuminated Arabic manuscripts have been studied, employing two laboratory-made X-ray diffraction (XRD) systems developed recently in the C2RMF laboratory. The validity of the micro-XRD and XRD portable systems for the study of this type of artworks has been demonstrated. A common observation in all the analyses is the presence of calcite and rutile; also, hematite, goethite, cinnabar, brass, anatase and barite were detected in the various colours. Differences between the results obtained by both techniques due to acquisition mode are discussed. In addition, other techniques such as X-ray fluorescence (XRF) and micro-Raman were used for the complete characterization of the manuscripts.

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Abstract.It has been observed that the partially or totally dehydroxylated pyrophyllite suffers a partial reversible rehydroxylation when cooled down at room temperature. This rehydroxylation was substantiated by thermogravimetric measurements by a mass increase, while IR spectroscopic studies have shown that during the rehydroxylation the intensity of some OH bands increase as two new bands appear. This rehydroxylation process is also very much influenced by the particle size of the pyrophyllite.