With the help of the brilliant X-ray radiation from DESY's research light source PETRA III,scientists own solved a decades-dilapidated mystery from the world of art: A team led by Dr. Geert Van der Snickt of the University of Antwerp unravelled the nature of mysterious white spots on the famous portray "The Scream" by the Norwegian artist Edvard Munch. opposite to popular assumption the stains are not bird droppings - and neither simply white color. Instead, the X-ray examination shows that the patches are made of wax, and which probably dripped from a candle in Munch's studio on the portray.
Source: phys.org