Characterisation and study of degradation of daylight and UV-light fluorescent pigments in modern art through non-invasive methods

Artists started to experiment fluorescent colours shortly after the discovery of daylight pigments by the Switzer brothers in the 1940s. It is a new way of expression for painters from the 20th century such as Andy Warhol, Martial Raysse, Keith Haring and Pierre Alechinsky. More recently, artists from the 21st century use the daylight colours through new technics like aerosol spray paint [1].
It is well known that some fluorescent pigments are unstable. Indeed, phenomena of discolourations and fluorescence losses are often observed. The companies that provide this type of pigments kept secret the composition of their paints and aerosols. Moreover, knowledge of materials used by artists is so important for the history of the art of techniques but also for conservation issues.
The aim of the study is to characterise and found identification markers from distinct fluorescent colours, from different manufacturers, using non-invasive methods namely Raman [2] and FT-IR spectroscopy, macro-XRF, X-ray diffraction and hyperspectral imaging. In a second step, after an artificial aging, the goal will be to observe how each pigment evolve to discern which are the most subject to the fading phenomenon.
The final step of this study is to find the most optimal analytic strategy for the analysis of works of art, preserved at the Royal Museums of Fine Arts of Belgium, to identify pigments that are more susceptible to fade and enforce preventive conservation for this one.
References
[1] A. Colombini and C. Valageas, Technè, 38 (2013) 34-38
[2] W. Fremout, in: Conference paper from IRUG 11. (Boston, MA) (2014)