@misc{10481/72274,
year = {2021},
month = {12},
url = {http://hdl.handle.net/10481/72274},
abstract = {Photo-induced darkening of red cinnabar (HgS) has attracted the interest of many
researchers as it drastically impacts the visual perception of artworks. Darkening has commonly
been related to metallic mercury (Hg0) formation in the presence of chlorides. Based
on the study of UV-aged cinnabar pigment and tempera paint we propose an alternative
pathway for the blackening reaction of cinnabar, considering its semiconductor properties
and pigment-binder interactions. We demonstrate that darkening is caused by the oxidation
of cinnabar to mercury sulfates and subsequent reduction to Hg0 via photo-induced electron
transfer without the involvement of chlorides, and provide direct evidence for the presence of
Hg0 on UV-aged tempera paint. Photooxidation also affects the organic binder, causing a
competing depletion of photo-generated holes and consequently limiting but not impeding
mercury sulfate formation and subsequent reduction to Hg0. In addition, organics provide
active sites for Hg0 sorption, which is ultimately responsible for the darkening of cinnabarbased
paint.},
organization = {European Commission	P12-FQM-1889},
organization = {University of Granada	RNM-179},
organization = {Unidades Cientificas de Excelencia (University of Granada)	UCE.PP2016.05	
UCE.PP2018.01},
publisher = {Nature},
title = {Direct evidence for metallic mercury causing photo-induced darkening of red cinnabar tempera paints},
doi = {10.1038/s42004-021-00610-2},
author = {Elert, Kerstin and Pérez Mendoza, Manuel José and Cardell Fernández, Carolina},
}