Edvard Munchs iconic painting, dubbed «the Coca-Cola of the art world», has intrigued conservators, curators and art historians for years.
The version of «The Scream» that's on display in Norway's National Gallery features a prominent white stain on the arm of the painting's screaming subject.
Thus far, no one has been able to provide a definitive explanation of what the stain is, and whether it was left there deliberately by the artist.
A thorough scanning with X-ray technology has revealed that the stain consists of candle wax, most likely stemming from someone blowing out a candle close to the painting.
Previously, experts had theorised that the stain consisted of bird droppings. Munch famously mistreated his paintings, often leaving them outdoors to be weathered by the forces of nature.
Professor Tine Frøysaker, an art scholar at the University of Oslo, says bird droppings were ruled out after examining the stain under a microscope.
– We initially examined the painting through a powerful microscope. We saw that the stain in no way looked like animal excrement, says Frøysaker, explaining that bird guano would have bled into the paint.
In addition to solving the mystery of the stain, the deep scanning has provided researchers with valuable insights into Munchs painting technique, aiding future conservation efforts.
The painting in The National Gallery's collection was Munchs first version of the famous image, painted in 1893 with tempera and pastels on cheap cardboard. It was famously stolen in a break-in in 1994, but was recovered only months later.
A later version, painted with tempera on cardboard in 1910, made international headlines when it was stolen from the Munch Museum in Oslo in an armed robbery in 2004. It turned up two years later and had to undergo a lengthy restoration process.
The famous image has in later years become something of a pop cultural icon, appearing on mugs, T-shirts and posters around the world, as well as being represented by its own emoji.