Documentation and analysis of the deformations of the panel and painted surface with 3D scanner

Pingi P., Siotto E., Palma G., Scopigno R.

Adorazione dei Magi  3D scanning  Deformation analysis  Leonardo da Vinci 

Despite what might be assumed, the surface of a painting on a canvas or a wooden panel is not perfectly flat, but rather is characterized by a complex three-dimensionality. The paint the artist lays down on the support possesses its own body and thickness, that, even on a millimeter or sub-millimeter scale, may be detected using instruments and three-dimensional measurement applications. At the same time, a wooden panel may be affected by deformations from historical or restoration changes, which may be readily revealed and documented. When analyzing a work of art subjected to an important restoration treatment, as was the case of the Adoration of the Magi by Leonardo da Vinci, a precise 3D documentation of the painted surface is thus strictly linked to the state of its wooden support. As is well-known, a panel painting is a layered structure (usually a protective varnish coating, paint layers, usually preparatory or ground layers, and the wooden panel), each with different physical and chemical compositions. Therefore, an accurate geometric 3D acquisition of the board structure and its connecting components (butterfly joins or dowel inserts) and the auxiliary support system (crossbars) may supply information to not only improve understanding of how the painting was made and its condition, but also permit it to be monitored over time or during restoration. Furthermore, the application of modern 3D computer graphics technologies is not only a valid diagnostic aid to acquiring knowledge about the work, but also a way to map information and share it (for example art historical information, technical data, and the results of chemical and physical analyses), making them easily accessible online both to experts in the sector and a wider public, thanks to specifically developed multimedia systems.1 In the case of the unfinished masterpiece by Leonardo, a complete high resolution 3D acquisition was performed in order to show and measure--at the moment during conservation treatment--a map of deviations from planarity caused by the curvature and warp of the wooden boards, permitting the documenting of the spatial deformation of the painted surface and the monitoring of its state of preservation.

Source: The restoration of Leonardo da Vinci's Adoration of the Magi - Rediscovering a masterpiece, edited by Ciatti M., Frosinini C., pp. 281–286. Firenze: Edifir - Edizioni Firenze s.r.l., 2021

Publisher: Edifir - Edizioni Firenze s.r.l., Firenze, ITA