Multi-modal approach for the characterization of resin carriers in Daylight Fluorescent Pigments

The light aging behavior of daylight fluorescent paints: a colorimetric, photographic, Raman spectroscopic and fluorescence spectroscopic study

Daylight fluorescent pigments with their intense color effects have attracted great interest among artists since their market launch in the mid-twentieth century. Since then they have been widely used in the visual arts. The pigments are mainly compositions of organic fluorescent dyes and optical brighteners diluted in an insoluble resin. Due to the susceptibility of the dyes to visible and UV radiation, their lightfastness is comparatively low. This paper presents a comprehensive study of the color and fluorescence changes of daylight fluorescent paints upon exposure in visible light and ultraviolet radiation conducted on mock-ups of commercial daylight fluorescent pigments. The different aging characteristics of the pigments depend on the color tone. They were recorded by means of photographic and colorimetric documentation. In addition, Raman spectroscopy was used to identify the main dyes of the various pigments, even in the complex system of paints, consisting of primer, binder, resin and dyes, and to determine their degradation during aging. Fluorescence spectroscopy revealed that the change in fluorescent color may not only be due to the decrease in dye concentration, but also to the transformation of the original dyes into other fluorescent compounds during light aging. Finally, this paper provides recommendations for the presentation of artworks containing daylight fluorescent pigments.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s40494-022-00812-4.

Assessing the (In)Stability of Urban Art Paints: From Real Case Studies to Laboratory Investigations of Degradation Processes and Preservation Possibilities

Urban art as a shared expression of street art between artists, citizenship and municipalities has always had an important role in the social life and appearance of modern cities. However, the durability of urban and street artworks is susceptible to the degradation processes that the employed commercial paint formulations undergo once outdoors. These are complex mixtures of compounds, differently sensitive to environmental agents according to their chemical nature. Starting from the colorimetric analysis of murals created in 2010, 2011 and 2018 in Reggio Emilia, Italy, documenting their degradation already after a few months, this study aimed at understanding the stability of the most unstable paints used by the artists in these artworks. A multi-analytical approach evaluated the commercial products under the chemical point of view, after natural and accelerated ageing. Additionally, two manufactured anti-UV varnishes were evaluated for their possible use as coatings. The results pinpointed the weaknesses of the selected paints and highlighted how the application of an anti-UV coating might slightly affect the visual aspect of the artwork, though ensuring a greater resistance to the outdoor conditions due to their minor chemical sensitivity to environmental agents.