Scientists solve white mark mystery in The Scream

One of the great mysteries of the art world has been solved, and while the identity of the woman in the Mona Lisa remains unconfirmed, scientists have discovered what the white mark next to the figure in The Scream is.

For more than 100 years art enthusiasts have puzzled over what the mark next to the figure in Edvard Munch's infamous painting is, with it being widely believed that the mark was bird muck.

Munch painted four versions of The Scream, with one selling for almost £91 million in 2012, but the most renowned version is the painting which is part of the collection of the Norwegian National Museum. This version differs from the others as it has a series of white splatters on the surface.

It is known that Munch painted several of his large drafts outdoors and that he liked to expose his work to the forces of nature. And it was a force of nature - or excrement from a passing bird - that was thought to be the cause of this white mark.

Others dismissed this view, believing instead that it was either paint or chalk which had dripped onto the work while Munch worked in his studio.

In May Professor Tine Frøysaker from the University of Oslo invited a team from the University of Antwerp to shed some light on the painting - such as characterising the painting materials and techniques used by Munch, not necessarily just working out what the white mark was.

After submitting the artwork to a Macro X-ray fluorescence scanner and testing a small sample of the unknown white substance the team discovered that it was wax.