Jennifer Mass: MicroXANES studies of pigment degradation in works by Henri Matisse and a Dutch golden age still life

The new painting materials used by the Impressionists, Fauvists, and Expressionists were critical components of their break with traditional modes of representation. These artists heavily exploited the synthetic organic and inorganic pigments that were newly available as a result of the industrial revolution. However, the bright and novel hues that made their way onto these artists’ palettes (and in many cases defined the movements listed above) were not always synthesized properly. Pigments in some of the greatest masterpieces of these movements have been found to be highly fugitive or rapidly discolored. These unstable materials can react with adjacent or admixed pigments, agents of degradation in the environment, and even the paint binding media surrounding them. The urgent need for preservation of these works calls for intensive materials engineering approaches to identify their mechanisms of degradation and ensure their longevity for future generations. As complex multilayered mesoscale inorganic-organic composites, these paintings present a wealth of analytical challenges.
Artists working in this period of the 1880s to the 1920s were aware of the limitations of the materials available to them, and they attempted to make choices based upon the most stable options at hand. Paint manufacturers were also aware that not all of their offerings were equally stable, and they would note the stability of the pigments offered for sale. Within this context, however, we still have monumental works from this period changing so substantially that they no longer represent the artists’ original vision. Pigments from this period that have been found to alter over time include chrome yellow (PbCrO4.PbSO4), zinc yellow (4ZnO.4CrO3,K2O.3H2O), cadmium yellow (CdS), emerald green (Cu(C2H3O2)2.3Cu(AsO2)2, eosin red (C20H8O5Br4, germanium lake), and purpurin (1,2,4-trihydroxyantrhaquinone).
Noninvasive methods for identifying these pigments (both before and after their alteration) including x-ray fluorescence, hyperspectral imaging, and ultraviolet-induced infrared fluorescence. To understand their mechanisms of degradation, however, requires microscale x-ray diffraction methods (XRD), x-ray absorption near edge spectroscopy (XANES) and mapping, and scanning transmission electron microscopy (STEM) based methodologies such as electron energy loss spectroscopy (EELS). Henri Matisse’s Le Bonheur de vivre (1905-1906) will be used as a case studies to identify highly degraded pigments, their technologies of manufacture, and their mechanisms of degradation. Adriaen de Coorte’s Still Life with Five Apricots (1704) will be discussed to probe degradation mechanisms in more traditional artists’ materials.

References:

1. Mass, J.L., Opila, R., Buckley, B. et al. The photodegradation of cadmium yellow paints in Henri Matisse’s Le Bonheur de vivre (1905–1906). Appl. Phys. A 111, 59–68 (2013). https://doi.org/10.1007/s00339-012-7418-0
2. Cotte, M., Susini, J., Dik, J., and Janssens, K. Synchrotron-Based X-ray Absorption Spectroscopy for Art Conservation: Looking Back and Looking Forward, Accounts of Chemical Research 43 705-714 (2010). https://doi.org/10.1021/ar900199m
3. Keune, K. et. al  Tracking the transformation and transport of arsenic sulfide pigments in paints: synchrotron-based X-ray micro-analyses J. Anal. At. Spectrom., 30, 813-827 (2015) https://doi.org/10.1039/c4ja00424h