To refine what can be seen during the restoration of damaged and faded works of art, a team of Italian researchers has developed an imaging system that can capture features not otherwise detectable with the naked eye or current imaging techniques.
The system, known as Thermal Quasi-Reflectography (TQR), is able to create revealing images using reflected light from the mid-infrared part of the spectrum.
Researchers from the University of L'Aquila (L'Aquila, Italy), the University of Verona (Verona, Italy), and Italy's National Institute of Optics (Florence, Italy) successfully demonstrated the effectiveness of the TQR system on two famous works of art: the Zavattari frescos in the Chapel of Theodelinda and "The Resurrection" by the Italian Renaissance artist Piero della Francesca.
In its first test on a small section of the Zavattari frescos in the Chapel of Theodelinda, the TQR system revealed details that were missed by earlier optical and near-infrared studies.
When used to analyze "The Resurrection", the TQR system identified features such as highly reflective retouches from previous restorations, all while operating during normal museum hours. The most surprising feature was an area around a soldier's sword that was painted by using two different fresco techniques. The subtle distinction was not detected by near infrared photography.
The researchers are currently conducting tests to determine if the TQR system can also identify the pigments used in paintings, which is important in determining how best to protect and restore artwork.
The researchers' work was published recently in Optics Expresshere.
-- by Dave Wilson, Senior Editor, Vision Systems Design