Popular Science: Painting with a surprise
The work of art is currently located in the de Brecy Trust collection. Because the painting's palette was still unknown, just like its author, and the work was available for analysis, it is clear that that the inherent curiosity of the scientists would show itself.
Raman spectroscopy is a very suitable tool for pigment studies of art works, because only a minute
sample is needed for obtaining satisfying results. It has shown to be very suitable for distinguishing mineral and organic pigments and their binders. But even with the use of various techniques it is only possible to place an art work into a broad time scale because of the common usage of pigments over hundreds of years. The exposure of fakes is only realized through the identification of rogue pigments that didn’t exist at the supposed time of the creation of an art work. Chemical analyses can never fully authenticate an art work, but can expose a fake.
But let us go back to our painting of the boy. The analysis revealed remarkable combinations of pigments as well as an uncommon additive in the white colour – silica river sand and powdered glass – probably serving as a brightener. The most important discovery was the detection of a red pigment which has not yet been described in literature. It was recorded in mineralogical literature from deposits in Argentina, China and Iran in 1970 and first synthesized in 1980. So it is very unlikely that it was used intentionally in the painter’s palette. More likely it appears in nature together with other minerals commonly used for painting, such as hydrocerrusite which is used for the production of lead white. That might be a way to authenticate the author of the art work: to analyse white pigments from paintings that are known to be painted by T. Gainsborough and determine their mineralogical provenance. That could lead to supporting or undermining the assumption concerning the authorship of the painting.
Maybe we will soon learn the continuation to this story…
Edwards, Howell G. M.; Vandenabeele, Peter; Jehlicka, Jan; et al. (2014). An analytical Raman spectroscopic study of an important english oil painting of the 18th Century. SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY Volume: 118 Pages: 598-602.