Art experts have long known that The Bedroom isn’t the same painting it once appeared to be. In 1888, van Gogh described it in a letter to his brother Theo, saying, “The walls are of a pale violet. The floor—is of red tiles.” Those exact pigments have since vanished after more than a century of fading, but conservation scientists at the Art Institute of Chicago set out to prove they weren’t lost for good.
Using a macro x-ray fluorescence scanner, Francesca Casadio and her colleagues were able to determine the elements and minerals in the paint. They also used a process called surface-enhanced Raman spectroscopy that makes molecules vibrate in a distinct way under laser light. But their biggest breakthrough came from something surprisingly simple: After flipping over a tiny sample of the painting under a microscope, a blue paint chip was revealed to be pale purple on the underside.
via Mental Floss
Image: ART INSTITUTE OF CHICAGO
