A new digital radiography system for canvas paintings: a case study from Racconigi Castle

Within the neu_ART project (“neutron and X-ray tomography and imaging for cultural heritage”), funded by Regione Piemonte (Italy), a team of specialists in different scientific fields coming from University of Torino, Istituto Nazionale di Fisica Nucleare (INFN) and Centro Conservazione e Restauro “La Venaria Reale” is developing a new digital X-ray system expressly designed for painted canvas and panels up to 3 m × 4 m. This system is based on the usage of both linear and time delay integration (TDI) digital X-ray detectors, which allow high spatial resolution and high dynamic range. Moreover, differently from traditional X-rays and computed radiography (CR) plates based systems, scanning time is extremely fast and images are shown in real time. This system has been widely tested on several XVII, XVIII and XIX century canvas property of the Racconigi Castle and now exposed at Venaria Reale Castle: more than 20 paintings have been analyzed with this new digital radiography apparatus to optimize the acquiring and source parameters. The concrete possibility of testing the apparatus on real cases gave the chance to start the evaluation of its limits and potentialities, thanks to the constant dialogue between the scientists and the professionals involved in the activities of conservation and restoration of these works of art. Results have been also compared with other imaging techniques based on IR reflectography.