Infrared Multispectral Reflectography


Infrared reflectography is a non-invasive imaging-based technique which employs a detector working in the near infrared range of the electromagnetic spectrum. At these energies the light is penetrating below the painting surface thus revealing the presence of underdrawings or preparatory designs, as well as possible composition changes. For the project, an Infrared Multispectral Scanner developed by the National Institute of Optics (INO-CNR) in Florence is being used.

The scanner employs a probe of 15 fibre optics recording three bands in the visible range (red, green and blue) as well as 12 bands in the infrared. Each band in the infrared is between 60 and 100 nm wide and is centred at the following wavelengths: 952 nm, 1030 nm, 1112 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1820 nm, 1930 nm, 2265 nm. The spatial resolution of the acquired images is 4 pixels/mm, 16 pixels/mm2. Images are perfectly superimposable and are free from aberrations associated with the use of objectives or lenses as in conventional photography. The high resolution allows to locate specific details with great precision with the possibility to compare the images obtained at different wavelengths. While running, the scanner follows a boustophedonic path, and has a built-in autofocus, and can cover an area of 95×95 cm2. 


Fontana, R.; Bencini, D.; Carcagnì, P.L.; Greco, M.; Mastroianni, M.; Materazzi, M.; Pampaloni, E.; Pezzati, L., Multi-spectral IR reflectography, proceedings of SPIE, 2007, 6618.

Bonifazzi, C.; Carcagnì, P.L.; Fontana, R.; Greco, M.; Mastroianni, M.; Materazzi, M.; Pampaloni, E.; Pezzati, L.; Bencini, D.,  A scanning device for VIS-NIR multispectral imaging of paintings, «Journal of Optics», 2008, 10 (6).

Daffara, C.; Pampaloni, E.; Pezzati, L.; Barucci, M.; Fontana, R.,  Scanning Multispectral IR Reflectography SMIRR: an Advanced Tool for Art Diagnostics, «Accounts of Chemichal Research», 2010v 43 (6).