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Since the end of the 20th century, the a-, band «-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide useful technical and chronological information for the study of works of art. Although when a CuPc blue pigment is identified, its crystalline structure often remains unspecified despite the interest for conservation science. In this study, X-ray powder diffraction, attenuated total reflectance micro-Fourier transform infrared spectroscopy and micro-Raman spectroscopy analyses have been carried out on 15 dry pigment samples of CuPc and acrylic, vinylic, alkyd, arabic gum and oil-based artists' paints. By using the polymorphic markers underlined for dry pigments, the CuPc crystalline structure has been successfully identified for most of the analysed artists' paints. However, according to the analytical technique used and the investigated paint sample, the obtained results largely differ.

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com". Abstract In this study, Monte Carlo (MC) simulations combined with energy dispersive X-ray fluorescence (EDXRF) spectroscopy have been used to characterize nondestructively a collection of Cu-based artifacts recovered from two archeological sites in southern Portugal: (a) the Chalcolithic E.T.A.R. site of Vila Nova de Mil Fontes and (b) the Middle Bronze Age site of Quinta do Estácio 6. The metal artifacts show a multilayered structure made up of three distinct layers: (a) brownish carbonate soil-derived crust, (b) green oxidized corrosion patina, and (c) bulk metal.In order to assess the reliability of the EDXRF-based Monte Carlo simulations to reproduce the composition of the alloy substrate in archeological bronze artifacts without the need to previously remove the superficial corrosion and soil derived patinas, EDXRF analysis together with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) was also performed on cleaned and patina-/crust-coated areas of the artifacts. Characterization of the mineralogical composition of the corrosion products in the surface patinas was further determined by means of X-ray diffraction (XRD). Results suggest that the adopted EDXRF/Monte Carlo protocol may represent a safe and fast analytical approach in the quantitative characterization of the bulk chemical composition of Cubased metal artifacts even in the presence of fairly thick corrosion patinas and/or soil-derived encrustations at the surface of the archeological objects.

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