Present day carbon dating
Radiocarbon dating has the potential to answer the question of when an artwork was created, by providing a time frame of the material used.In this study we show that with two microsamples (C age gained on the paint contradicts this as it offers clear evidence for a post-1950 creation.One of those paintings, signed “Sarah Honn” and dated “May 5, 1866 AD,” imitates the American primitive folk art style and is entitled , (Fig. The painting was seized by the US Federal Bureau of Investigation.This case study was thoroughly investigated previously and numerous telltale signs of forgery were identified (23).The method, however, is invasive and in its early days required sampling tens of grams of material.With the advent of accelerator mass spectrometry (AMS) and further development of gas ion sources (GIS), a reduction of sample size down to microgram amounts of carbon became possible, opening the possibility to date individual paint layers in artworks.Therefore, identifying counterfeited artworks by relying solely on the dating of the support material is insufficient to ensure authenticity.A common approach to uncover forgeries involves discrete material analyses (19–21).
The GIS-AMS setup requires only minute amounts of material rendering the C analysis microinvasive and henceforth opening the possibility to target paint layers themselves (12).
In the lower right-hand corner, the painting is signed “Sarah Honn May 5, 1866 AD.” The blue rectangle on the left indicates the sampling location of the white paint; the one on the right indicates a close-up of the sampling location.
The blue trapezoid in dashed lines shows a previous loss in the white paint due to the nature of the artificial aging used by Trotter––the paint is literally falling off the canvas.
In cases where no pigment, filler, or binder anachronisms are identified, the judgment of degradation products arising from natural aging is inconclusive, and radiocarbon dating of the support material is indecisive, dating of the binder in the pictorial layer is indispensable.
The idea of identifying modern forgeries based on C dating of the binder was formulated with the advent of AMS (22), but suffered from practical limitation as the study was conducted on 100-mg scale sample material, an unfeasible sampling quantity for artworks.
In the case of a painting, the typical supports made of textile, wood, parchment, or paper are sampled, as they usually offer sufficient material and can provide decisive evidence in authentication issues (13, 14).