Cadmium fading and yellow color damage is mostly caused by water, study finds
New information on color conservation will help “The Scream” re-show its face to the public.
Edvard Munch’s 1910 version of this iconic work of art has rarely been shown since 2006 because the cadmium sulfide pigments in the painting are very fragile. The cadmium yellow brushstrokes in the sky and the central figure are lost in the cream and the thick paint on the lake peels off. To avoid further damage, the Munch Museum in Oslo almost always stores “The Scream” under careful lighting control and at around 50% humidity.
A chemical analysis of the paint now shows that humidity is the main cause of deterioration, while light plays only a minor role. Letizia Monico, chemist at the Italian National Research Council in Perugia, and her colleagues will report on the progress online on May 15 in Science.
Researchers examined microscopic flakes of paint from “The Scream” as well as samples of paint with a similar composition of chemicals artificially aged in the lab.
X-ray examinations of the stained samples showed cadmium sulfate, a decomposition product of cadmium sulfide, in the colored spots of “The Scream”. Cadmium sulfate has also appeared in artificially aged paints exposed to at least 95% humidity in both light and darkness. However, similar samples exposed to a light humidity of 45 percent did not show signs of deterioration. This indicates that humidity is the main contributor to the aging of the Scream, and while the paint can be fine with normal lighting, it should be kept at 45% or less humidity.
The new understanding of the artwork could affect the preservation of other paintings by Munch’s contemporaries, such as Matisse and van Gogh, which also contain decaying pigments of cadmium sulfide. However, Monico cautions that each painting is a unique and complex chemical scene. Therefore, precautionary strategies must be developed in each case.