Painting investigation by using non-invasive imaging techniques in the UV-Vis-IR regions Marcello Picollo1, Giovanni Bartolozzi1, Andrea Casini1, Costanza Cucci1, Marco Poggesi1, Lorenzo Stefani1, Alfredo Aldrovandi1,2 1 “Nello Carrara” Institute for Applied Physics of the Italian National Research Council (IFAC-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy; e-mail: m.picollo@ifac.cnr.it 2 Opificio delle Pietre Dure, Via degli Alfani 78, 50121 Firenze, Italy Abstract—The present communication will give an overview on the most traditional imaging techniques employed in the art conservation field as well as introduce the most recent advances in the application of imaging methodologies in this stimulating field. I. INTRODUCTION P RESENTLY, the study of artworks can be performed using invasive and/or non-invasive approaches [1]. The non-invasive methodologies are basically grouped in ‘on specific site’ (on small spot, 1-D) and ‘over area’ (on large area, 2-D) techniques focused on the diagnosis, conservation, and access to objects of art. Preliminary non-invasive investigations are always necessary at the beginning of the investigation and/or study of a work of art or before initiating any conservation procedure on valuable artworks, in order to assist curators and conservators in their decision-making process. When dealing with artefacts that can be considered as nearly flat objects, such as paintings, drawings or other graphic artworks, imaging (2-D) techniques offer an ideal approach for performing non-invasive examinations. In the field of art conservation, these imaging techniques range from well-established methodologies, such as high-resolution digital photography, to the use of visible raking light, transillumination and trans-irradiation techniques, UV reflectance and fluorescence, X-ray radiography, IR reflectography, IR false colour, etc. (Fig. 1) [2-6]. Fig. 1. Simplified stratigraphic scheme panel painting: A) varnish layer; B) paint layers; C) imprimitura layer with drawing; D) preparation layers; E) wood support. In the past decades new imaging technologies originating in remote sensing applications have been introduced in the cultural heritage field, such as multi-and hyper-spectral imaging techniques in the UV-Vis-NIR regions [7-10]. Another improvement in the field took place in 2006 when the first THz image was obtained on a canvas painting [11]. From that application, imaging devices have made it possible to expand the working range of the systems up to the Terahertz (THz) and Gigahertz (GHz) regions [12]. The present communication will give an overview on the most traditional imaging techniques employed in the art conservation field as well as introduce the most recent advances in the application of imaging methodologies in this stimulating field. ACKNOWLEDGEMENT Funding of the THz-ARTE project through the Italian Ministry of Foreign Affairs is gratefully acknowledged. REFERENCES [1]. D. Pinna, M. Galeotti and R. Mazzeo, Eds., Practical handbook on diagnosis of paintings on movable support, European Project ARTECH, Centro Di, Firenze, 2009. [2] F. Mairinger, “UV-, IR- and X-ray- imaging,” in Non-destructive microanalysis of cultural heritage materials, K. H. A. Janssens and R. Grieken, Eds., Wilson & Wilson Elsevier, Antwerp, 2004, pp.15-73. [3] J. R. 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