Imaging the paintings under the paintings of the Old Masters

Speaking at the 241st National meeting & Exposition of the American Chemical Society, an international team of scientists have now described use of a new technique to see the paintings under the paintings of Rembrandt, Caravaggio, Rubens, and other 17th Century Old Master painters. The report by scientists in Belgium, The Netherlands and the United States was among almost two dozen studies presented as part of a symposium on chemistry and art titled "Partnerships and New Analytical Methodologies at the Interface of Chemistry and Art," presented on March 29 in Anaheim, California.

"The underpainting was the first and most important step in creating a work of art," explained lead scientist Matthias Alfeld, who is with the University of Antwerp in Belgium. "It was the sketch that guided the artist through the creative process. The Old Masters generally used to roughly indicate light, shade and contours. Observation of the underpainting would allow us to see the first execution of the artist's vision of the painting. It's a more detailed look over the shoulder of the artist at work. But the underpainting has virtually escaped all imaging efforts. So far, our methods to visualize the underpainting, except in localized cross sections, have been very limited."

Alfeld and colleagues described use of a powerful new technique called scanning macro X-ray fluorescence analysis that allows more detailed imaging of the composition of underpaintings. It is portable enough for use on-the-scene in museums and does not harm priceless artwork. The technology already has provided new insights into the nature of the paint that some Old Masters used in their underpainting.

An analysis of paintings from the workshops of Rembrandt and Caravaggio, for instance, led them to the conclusion that the Old Masters were more frugal than fussy about the paint used for the underpainting. The analysis suggested that this brown pigment mixture in underpaintings actually consisted of recycled leftovers from the artist scraping his palette clean.

"Using the new technique, we hope to disperse doubts about the authenticity of several paintings or to confirm that these paintings were not by the painter they have been attributed to," Alfeld said. "It is nice to show that the world of art can intersect with chemistry. Chemistry is such an all-encompassing science. Imagine, chemistry isn't just about molecules and reactions, but it also involves also the study of something as beautiful as great works of art."