Why synthetic emerald-green pigments degrade over time

Summary

Perhaps most relevant to this current paper is a 2020 study in which scientists analyzed Edvard Munch’s The Scream, which was showing alarming signs of degradation. They concluded the damage was not the result of exposure to light, but humidity—specifically, from the breath of museum visitors, perhaps as they lean in to take a closer look at the master’s brushstrokes. Let there be (X-ray) light Co-author Letizia Monico during the experiments at the European Synchrotron. ESRF Co-author Letizia Monico during the experiments at the European Synchrotron. ESRF Co-author Annelies Rios Casier (University of Antwerp) performing a micro-sampling from a green area of The Intrigue. Lies Vanbiervliet Co-author Annelies Rios Casier (University of Antwerp) performing a micro-sampling from a green area of The Intrigue. Lies Vanbiervliet Photomicrographs of paint fragments taken from two altered emerald-green areas of The Intrigue, analyzed using vibrational spectroscopy techniques and advanced synchrotron technique methods. Miliani et al., 2025 Photomicrographs of paint fragments taken from two altered emerald-green areas of The Intrigue, analyzed using vibrational spectroscopy techniques and advanced synchrotron technique methods. Miliani et al., 2025 Co-author Annelies Rios Casier (University of Antwerp) performing a micro-sampling from a green area of The Intrigue. Lies Vanbiervliet Photomicrographs of paint fragments taken from two altered emerald-green areas of The Intrigue, analyzed using vibrational spectroscopy techniques and advanced synchrotron technique methods. Miliani et al., 2025 Emerald-green pigments are particularly prone to degradation, so that’s the pigment the authors of this latest paper decided to analyze. “It was already known that emerald-green decays over time, but we wanted to understand exactly the role of light and humidity in this degradation,” said co-author Letizia Monico of the University of Perugia in Italy. The first step was to collect emerald-gr...