Discovering forgeries of modern art by the ¹⁴C Bomb Peak

Abstract.

Exploiting the anomalous behaviour of the atmospheric radiocarbon concentration in the years after 1955 (so-called “Bomb Peak”), an alleged painting by Fernard Léger was unambiguously proven to be a fake just by dating the canvas support. Some art historians had questioned the authenticity of the painting, and their suspicions were fuelled by some scientific examinations of the paint materials (X-ray radiography, SEM-EDS), compared to those of another work unquestionably attributed to Léger. The decisive argument to prove that it was a fake was provided by the radiocarbon date obtained from a sample of canvas of the painting, using Accelerator Mass Spectrometry at the INFN-Labec laboratory in Florence. Beyond any doubt, the cotton plant from which the canvas was produced was cut no earlier than 1959, i.e. four years after Léger's death, thus definitely confirming the concerns of a fake.