SIMS studies of the material aspects in grounds and paints in paintings by van Gogh

Imaging Secondary Ion Mass Spectrometry (SIMS) is used to analyse the composition of ground and paint layers in paintings by Van Gogh. The mapping capabilities of Secondary Ion Mass Spectrometry (SIMS) were employed to identify potential discriminating features in paint cross-sections from two selected grounds (painting F216 and F294) and a baryte containing paint from F377 (Sunflowers Run to Seed, August/September 1887). The samples from F294 and F377 contain barytes with substantial amounts of strontium. The strontiobaryte particles have overlapping SIMS maps for sulphur, barium and strontium, a feature that will be used in tracing the natural source material. The ground of F216 contains siliceous opal (chert) particles, in which the distribution of magnesium (m/z 24) and silicon (m/z 28) overlaps. This is a feature that distinguishes this ground from related leadwhitechalk grounds.