A scanning device for wide band infrared reflectography

Diagnostics in the cultural heritage field is an important resource to investigate art history, issues, execution techniques, materials and state of conservation of an artwork. In this field the main concern is preservation and, for this reason, new non-invasive and non-destructive technologies have been developed. At the Department of Physics in Ferrara, imaging for cultural heritage, using electromagnetic radiation, from visible light to X-rays is applied and studied. A diagnostics protocol has been defined to standardize the study approach on paintings considering that each painting is a particular case, and the protocol must be adapted to the needs that the artwork itself requires. This work consists in the development of a scanning devices for wide band infrared Reflectography, to extend the applications of the reflectographic technique, and how it is inserted in the diagnostic protocol. Infrared reflectography use the electromagnetic radiation of Near-IR to investigate the underdrawing in paintings. The success of IR Reflectography to reveal the underdrawing in paintings since XIV up to XVI century depends on the peculiar technique of painters in that period. Thin and uniform pictorial layers, covering high contrast drawings on white priming allow a good detection of underdrawing details. Paintings of late sixteenth century have dark preparations and thick paint layers, so Reflectography doesn’t get the same good results. Extension of the spectral band to longer wavelengths, up to 2,5 μm, is a tool to improve reflectographic capability.