Detecting recent forgeries of Impressionist and Pointillist paintings with high-precision radiocarbon dating.

We report on the capacity of AMS radiocarbon dating to play a decisive role in fighting against the illicit trade in art. In the framework of a current police investigation, where previously unseen paintings were discovered in a restorer's workshop by the French Central Office for the Fight against Illicit Trafficking in Cultural Property (OCBC), we demonstrated that two paintings alleged to be by Impressionist and Pointillist artists had in fact been painted recently. Our results were based on the excess of 14C derived from atmospheric nuclear tests detected in the fibers used to make the canvas. By combining AMS 14C absolute dating and the fine precision of the post-bomb atmospheric calibration curve, we established a clear chronological context for the production of these forgeries. 14C content of the fibers revealed that the canvases were manufactured in 1956-1957 or, more likely, after 2000. As a result, absolute dating proves unambiguously that the Impressionist and Pointillist paintings are forgeries since they were not painted at the beginning of the 20th century by the alleged artists, who died in the 1940s.

New results with regard to the Flora bust controversy: radiocarbon dating suggests nineteenth century origin.

Many works of art have been attributed to Leonardo da Vinci (1452-1519), the great artist-scientist-engineer of the Italian Renaissance; however, art historians have struggled to find definitive proof to connect Leonardo to these art pieces. The Flora wax bust in the Bode Museum, Berlin, was attributed to Leonardo because her face resembles several Leonardo portraits, but this attribution has the subject of intense debate since the bust's acquisition in 1909. Using new chemical analyses and absolute 14C dating, we are able to resolve the question of authenticity. We show that the Flora wax bust is made primarily of spermaceti which was extracted from sperm whales. Therefore, 14C dating must consider the Marine Reservoir Effect. We have generated a new calibration method and dated the bust to the 19th c. This proves that the bust was not produced during the Renaissance, and thus cannot be attributed to da Vinci, and illustrates that 14C dating can be applied to unusual materials.

Unexpected presence of 14C in inorganic pigment for an absolute dating of paintings.

The absolute dating of paintings is crucial for tackling the problem of fake art. Investigations to authenticate paintings rely on an advanced knowledge of art history and a collection of scientific techniques. Radiocarbon dating is the only technique that gives access to an absolute time scale, but its application is limited to organic materials such as wood, canvas or natural binder. Extending absolute dating to inorganic pigments would make it possible to overcome the lack of available materials for dating easel and mural paintings. Here, we present a novel technique permitting paintings that contain inorganic pigment to be radiocarbon dated. We report results obtained on lead white that was the major white pigment used from Antiquity to the 20th century. We demonstrate that its manufacture is the key point for an absolute and reliable dating. We report an unprecedented use of 14C to date 14th to 16th century wall paintings. Since lead white was extensively used by the greatest artists, we anticipate that this study will open new avenues for detecting forgeries on the art market and for museums.