Underneath the “Old Man in Military Costume” painted by the Dutch artist Rembrandt in the years 1630/31, investigations spotted another portrait which was only faintly distinguishable with all applied technologies. An international team of scientists now used a detailed mock-up to test different methods to look beneath the original painting at DESYs X-ray source DORIS and at the National Synchrotron Light Source [NSLS] of the Brookhaven National Laboratory [BNL] in the United States, as well as with a mobile X-ray scanner. The results are published as the cover story of the “Journal of Analytical Atomic Spectrometry” [JAAS] of the British Royal Society of Chemistry…