Shortly after the discovery of a portrait “hidden” under Still Life with Bread and Eggs (1865) by Paul Cézanne (1839–1906), we applied to the Center for Scientific Studies in the Arts, a research partnership between the Art Institute of Chicago and Northwestern University, and proposed our still life as one of their projects. As a result, last month, three Northwestern scientists brought their highly specialized scanning and imaging equipment to the museum and spent a week in our Paintings/Objects lab examining the painting.

The most important piece of equipment they brought was an X-ray fluorescence (XRF) macro-scanner, shown here in action. It uses X-rays to detect the presence of chemical elements in individual spots in the painting. Different pigments contain different elements which can identify specific colors and paint mixtures. The XRF macro-scanner collects data points and plots them on maps of elements present in the painting. Using these maps, we can get a good idea of what colors the artist used and where they appear in the painting.

The full scan of Still Life with Bread and Eggs took seven hours and thirty-six minutes, recording data from 278,160 spots. Additionally, the scientists did a few partial and even slower scans to collect finer details. We are hoping to map the paints in the portrait under the still life and get a better idea of who the sitter might be. But as you can imagine, that is a lot of data to analyze, so it may be some time before we get the results. Stay tuned!