AIC's 46th Annual Meeting

In this talk we will discuss the progress of finding a new method for the integrated inpainting of fluorescent paint layers. During the conservation of the fluorescent, monochrome paintings of Herbert Aach’s (1923-1985) Split Infinity series (1976-77), standard retouching methods lead to negative results. So far we were able to simulate the fluorescent color under stable light conditions, but as soon as ultraviolet increases, the inpainting became more disturbingly visible. Beside these color matching difficulties, its materiality structure differed strongly from the original paint layer. Aach was an artist who made his own pigments and paint-media. The fluorescent paint layers in these series appear very dry, fresco-alike and the saturation of the fluorescent pigment in the acrylic medium is much higher than the fluorescent paints sold in art supply stores. Valuable research by Stefanie De Winter (doctoral researcher (PhD art history) KU Leuven, Belgium) describes the material-technical and the specific visual differences between fluorescent and conventional pigments. Three significant characteristics became apparent during this empiric comparison: firstly, fluorescent pigments age much faster, after 10 years they start to lose their intensity; secondly, they are very transparent, due to their organic pigment composition, which makes mixing them with other colors not possible; thirdly, there are limits in binding fluorescent pigments with media, because of their high transparency they require a very clear medium. In this study, we want to find a new retouching-method that takes into account these specific characteristics and that enables inpainting with fluorescent pigments in the monochrome, fresco-like paint layers of Aach’s works. We are currently investigating these specific pigment compositions (used in Split Infinity paintings) through pigment analysis (Raman spectroscopy). The results will be compared with the spectra on fluorescent paints researched by Wim Fremout and Steven Saverwyns (KIK, Royal institute for art patrimonium Belgium) and further analyzed with the help of specialized chemists of the University of Antwerp. We are also testing artificially pigment aging processes, to simulate the original age of the fluorescent paint layer to ensure reduction of the fluorescent intensity that is causing the disturbing effect on the total image. For the retouching-media, we are testing dry-looking mixtures, like pastel, gouache and acrylic combined with structuring techniques. In a next phase the acquired information will be used for the case-studies on inpainting of these monochrome paintings. We expect to provide new insights in the understanding of fluorescent paint. This highly needed new method for retouching fluorescent paint layers will assist conservators to better restore and preserve these very bright, high sensitive and fast degrading paint layers.