Nuclear forensicsNuclear physicists prove a Peggy Guggenheim Collection painting is a fake

For more than forty years now, art experts and researchers have been trying to determine whether a painting in the Peggy Guggenheim Collection in Venice was a genuine painting which the French artist Fernand Leger produced between 1913 and 1914 as part of his “Contraste de Formes” series.

Because Leger experts were not sure, the painting had been kept in storage.

News Daily reports that now, scientists from the Instituto Nazionale di Fisica Nucleare (INFN) in Florence have used, for the first time in the art world, a brand new carbon 14 dating method, the so-called “bomb peak” curve, to ascertain the painting’s provenance.

An INFN release reported that “It is now a certainty that the painting is a fake. The enigma has now been solved.”

“The researchers measured the radiocarbon content in a minute fragment of unpainted canvas of the work, believed to be part of the Contraste de Formes series… then plotted their results against the so-called ‘bomb peak’ curve,” the release noted.

“This comparison, used for the first time to ascertain the authenticity of a painting, demonstrated with absolute certainty that the canvas support was produced after 1959, at least four years later than Leger’s death in 1955,” it added.

News Daily notes that the “bomb peak” is based on radiocarbon levels released during a series of nuclear tests conducted during the cold war, after 1955. INFN says that a secondary effect of the series of nuclear tests conducted in the atmosphere by the United States and Russia – joined by France in 1960 and China in 1964 – was the significant increase in the level of radiocarbon (C-14) in the earth’s atmosphere.

The Limited Test Ban Treaty (LTBT), which came into effect in fall 1963, banned nuclear tests in the atmosphere, and as a result the levels of C-14 began to fall.

“Scientists call this phenomenon the ‘bomb peak,’” the INFN release said. “Con l’aumentare del radiocarbonio in atmosfera aumentava, conseguentemente e con uguali valori, anche quello di tutti gli organismi viventi, tra cui anche le piante di cotone o lino da cui si realizzano le tele da pittura” (As the level of radiocarbon in the atmosphere increased, it also increased at a corresponding rate in all living organisms, including the cotton and linen plants used to make canvases for artwork).

News Daily says that the Guggenheim Collection sent a small sample from a folded, unpainted edge of the canvas of the painting to the Italian scientists in Florence for analysis using accelerator mass spectrometry. The scientists measured the level of radiocarbon to determine the date of the canvas — based on when the crops used to produce the canvas were harvested — by comparing the level of radiocarbon in the fabric with radiocarbon level during the bomb peak period.

The meticulous analysis established beyond doubt that the canvas for the painting was produced in 1959, four years after Leger’s death in 1955.

Pier Andrea Mando, head of the INFN Florence division, said: “E’ la prima volta che una misura di radiocarbonio viene usata per scoprire un falso pittorico di arte contemporanea, sfruttando il confronto con le concentrazioni atmosferiche di quell’isotopo negli anni del bomb peak” (it was the first time radiocarbon dating has been used to reveal a forgery in contemporary art, by comparing levels of that isotope in the atmosphere during the bomb peak period).

— Read more in L. Caforio et al., “Discovering forgeries of modern art by the 14C Bomb Peak,” European Physical Journal Plus 129, no. 6 (January 2014) (DOI: 10.1140/epjp/i2014-14006-6)