Realizing sensations: analyzing Paul Cezanne’s watercolors and assessing their light sensitivity with microfade testing

The exhibition Cézanne Drawing at The Museum of Modern Art (MoMA) brought together an exceptional group of works on paper from public and private collections across the globe. Recognizing the inherent light sensitivity of both the paper and watercolors, controlling, and tracking light exposure was central to the exhibition planning. This concern also led to a systematic study of three watercolors in the museum’s collection, Foliage (1895), Study of Trees (1895), and Mont Sainte-Victoire (1902-06), to characterize the watercolor paints used by Cezanne in these works and their sensitivity to light exposure, and to better understand the condition of the drawings based on the palette’s chemistry. Examination and analysis were undertaken non-invasively and micro-invasively with the following techniques: Infrared Reflectography (IRR), Ultraviolet Fluorescence Photography (UVF), Raman and surface-enhanced Raman (SERS) spectroscopies in addition to X-Ray fluorescence analysis on small spots and large areas using portable (p-XRF) and XRF scanning, respectively. The palette for these three watercolor drawings includes lead white, bone black, vermilion, yellow ochre, chrome yellow, emerald green, viridian, cobalt blue, and synthetic alizarin and carmine lakes. Microfade testing (MFT) was performed on the paper support and spots with each identified pigment, and the data acquired was evaluated both for color change (ΔE 00 ) and rate of color change ( ∂ΔE_00/∂ t ). Together these techniques inform the future display and loan of these and similarly fugitive watercolors in Cézanne’s oeuvre.