TY - JOUR
T1 - Photo-catalytic degradation of binding media of ultramarine blue containing paint layers
T2 - A new perspective on the phenomenon of “ultramarine disease” in paintings
AU - de la Rie, E. René
AU - Michelin, Anne
AU - Ngako, Manuela
AU - Del Federico, Eleonora
AU - Del Grosso, Chelsey
PY - 2017/10/1
Y1 - 2017/10/1
N2 - Failure of ultramarine blue paint layers in historic as well as modern paintings has been reported in the literature many times and is often referred to as “ultramarine disease” or “ultramarine sickness.” The pigment itself is known to degrade hydrolytically when exposed to acids, but whether this is the primary cause of the failure remains unclear. This paper describes a study in which ultramarine blue paints using linseed oil and a urea-aldehyde resin as binding media were aged under simulated indoor conditions. The paints were analyzed using reflectance spectroscopy, scanning electron microscopy, and Raman and nuclear magnetic resonance spectroscopy. The urea-aldehyde resin binding medium was analyzed using size exclusion chromatography and Fourier-transform infrared spectroscopy. The study provides evidence of photo-catalytic degradation of binding media of ultramarine blue paint layers via free-radical processes, causing changes in reflectance while the pigment itself remains intact. It is believed that this is the primary process behind the degradation of ultramarine blue paint layers in paintings.
AB - Failure of ultramarine blue paint layers in historic as well as modern paintings has been reported in the literature many times and is often referred to as “ultramarine disease” or “ultramarine sickness.” The pigment itself is known to degrade hydrolytically when exposed to acids, but whether this is the primary cause of the failure remains unclear. This paper describes a study in which ultramarine blue paints using linseed oil and a urea-aldehyde resin as binding media were aged under simulated indoor conditions. The paints were analyzed using reflectance spectroscopy, scanning electron microscopy, and Raman and nuclear magnetic resonance spectroscopy. The urea-aldehyde resin binding medium was analyzed using size exclusion chromatography and Fourier-transform infrared spectroscopy. The study provides evidence of photo-catalytic degradation of binding media of ultramarine blue paint layers via free-radical processes, causing changes in reflectance while the pigment itself remains intact. It is believed that this is the primary process behind the degradation of ultramarine blue paint layers in paintings.
KW - Acid hydrolysis
KW - Binder
KW - Free radical process
KW - Hindered amine light stabilizer
KW - Linseed oil
KW - Paint
KW - Painting
KW - Photo-catalytic degradation
KW - Ultramarine disease
KW - Urea-aldehyde resin
UR - http://www.scopus.com/inward/record.url?scp=85026834858&partnerID=8YFLogxK
U2 - 10.1016/j.polymdegradstab.2017.08.002
DO - 10.1016/j.polymdegradstab.2017.08.002
M3 - Article
AN - SCOPUS:85026834858
SN - 0141-3910
VL - 144
SP - 43
EP - 52
JO - Polymer Degradation and Stability
JF - Polymer Degradation and Stability
ER -