A team of international researchers have identified human breath as the main reason for the deterioration of Munch's 1910 masterpiece, "The Scream," which belongs in the collection of the Munch Museum in Oslo.
Scientists from Belgium, Italy, the US and Brazil took part in the painting's investigation, which began after curators noticed that the sunset background and the neck area of the screaming protagonist had begun to fade to white.
Researchers initially believed that reducing exposure to light might prevent further deterioration, although preliminary tests revealed that this factor was not responsible for the degradation of "The Scream."
The latest findings, published in Science Advances, provide evidence that Munch had accidentally used an impure cadmium yellow paint, which can fade and flake in low humidity conditions.
"When people breathe they produce moisture and they exude chlorides so in general with paintings it is not too good to be close too much to the breath of all the passersby," Professor Koen Janssens from the University of Antwerp told the Guardian.
"I don't think it was an intentional use -- I think he just bought a not very high level of paint. This is 1910 and at that point the chemical industry producing the chemical pigments is there but it doesn't mean they have the quality control of today," he added.
These new findings will be incorporated into the display of "The Scream" at the Munch Museum, whose new location by Oslo's opera house will open to the public later this year.
While scientists hope that changing the circumstances in which the masterpiece is exhibited will slow down its degradation, "The Scream" still bears a possibly irreversible brown water mark in its lower left corner.
This damage was caused after the painting was stolen along with Munch's "Madonna" masterpiece by two masked gunmen in a daytime raid on August 22, 2004. The two paintings were recovered in a police operation in 2006.
Last March, the Munch Museum invited Norwegian poet Fredrik Høyer and Norwegian musician Bendik Baksaas for a new musical interpretation of "The Scream."
"I think it's a roar from the ground right now because the earth is in crisis. It is the planet we live on -- it cries to us, from the echo of Atlantis, that now we must begin to see the planet from the outside -- now we must listen to the voice of the heart," Høyer said of Munch's masterpiece in a statement.