engleski

New and emerging nuclear techniques (NT) for the authentication of paintings

It is estimated that nowadays about 30% of items which appear on the art market are forgeries. To combat this traffic, the opinion of qualified experts in artwork authentication needs the support of scientific methods providing concrete facts and evidence. Many aspects can be addressed using different investigation techniques such as materials characterisation, absolute age determination, alteration phenomena, etc. Most challenging is the domain of paintings authentication owing to the complexity and diversity of the materials (paint layers, ground, varnish, canvas, etc.) and the preferable use of non-destructive methods. Routine techniques for this task are Vis, UV, IR and X-ray imaging, optical and electron microscopies, XRD, FTIR, HPLC and GC-MS, micro- and macro- XRF. In the present work we report on analysis of a painting obtained by new and emerging Nuclear Techniques (NT) of potential interest in the forensic investigation of paintings and other cultural heritage objects. The work was carried out in the framework of the IAEA Coordinated Research Project F11021: Enhancing Nuclear Analytical Techniques to Meet the Needs of Forensic Sciences. An ancient painting of unknown author and title, considered by art experts from its style as a French school composition of the 17th-18th centuries, was acquired at an auction for this study. Paint coupons of 2 cm x 1 cm were sampled in the sky on the right border of the painting and distributed to the participants for the application of the new NTs, rather than circulating the object. The objective was to evaluate their ability to determine the painting authenticity and to point out possible restorations or anachronic features. Following NT were applied to analyse paint coupons by different labs: direct 14C AMS dating of binder, canvas and support, Secondary Ion Mass Spectrometry with MeV ions (MeV-SIMS) of binder and pigments, full-field PIXE mapping of pigments, differential PIXE and total IBA for the determination of paint layer sequence and composition including pigment/binder ratio. Although not belonging to NT, potential of Optical Photothermal Infrared Spectroscopy (O-PTIR) imaging was also exploited. Results obtained by different techniques are presented and discussed. It is shown that the combination of above-mentioned techniques allowed to trace back the history of the test painting.

AMS-C14 dating ; MeV-SIMS ; O-PTIR imaging ; IBA ; Differential-PIXE ; Full-field PIXE imaging

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