Have you seen Munch's 'The Scream' in person? You may be partly responsible for its fading colours

A new study shows that the low-quality pigments the artist used for his 1910 masterpiece are susceptible to humidity and moisture

People who have viewed 'The Scream' in person may be responsible for its fading colours. AFP

Why is Edvard Munch's The Scream fading? The question was one of the art world's most persistent mysteries – right up there with trying to establish the identity of the Johannes Vermeer's Girl with a Pearl Earring – and we may finally have an answer.

And if you’ve ever seen the 1910 masterpiece in person at the Munch Museum in Oslo, Norway, you may be part of the blame as well.

An international group of scientists, working in collaboration with the museum, have published their findings in the Science Advances journal, in which they say the main cause of the deteriorating colours is the cadmium-sulfide paint Munch used for the work.

The pigment is susceptible to moisture, and the study reveals that even the humidity formed by human breath can cause its colours to fade.

There are actually several versions of the illustrious image, including two paintings, two pastels as well as a handful of drawings and sketches. However, the one that is most famous is the 1910 version –the one that experts examined in their study.

The study showed that the yellow pigment that Munch used to create the harrowed and instantly-recognisable figure, the swirling sunset sky and its reflection on the lake has been deteriorating for years.

"It turned out that rather than use pure cadmium sulphide as he should have done, apparently he also used a dirty version, a not very clean version that contained chlorides," Koen Janssens, a professor at the University of Antwerp who worked on the study, 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.”

It used to be thought that exposure to light was causing the painting’s colours to fade. However, during the study, experts examined the painting under ultraviolet light to determine which parts of the painting had degraded and reached the conclusion that the culprit was humidity, not light.

The painting suffered further damage when it was stolen in 2004, alongside the artist's Madonna painting. Both canvasses were recovered in 2006 and the 1910 version of The Scream has since been housed in a storage unit with light and temperature control.

The Munch Museum is expected to reopen sometime later this year, setting up a new location near Oslo's opera house. Curators will now try to overcome the challenge of how to safely present the painting to the public, and trying to ensure our foggy breaths don't cause The Scream to fade.