Earlier this year, we shared a sneak peek of the focus show currently on view in Luce Visible Storage, which highlights William Trost Richards’s watercolor practice. Before the show opened, I examined Richards’s boxes of 19th-century watercolor cakes a bit more closely. This was partly to document the condition and the organization of the watercolors within each box, which could provide clues about the artist’s working practice.
The second goal of examination involved determining whether handwritten labels on some of the individual cakes are accurate. The first label in question was written in ink on the bottom of a ceramic pan holding a medium green watercolor cake: “Emerald Green.” This caught my eye immediately, because this copper acetoarsenite green is extremely poisonous. X-ray fluorescence spectroscopy (XRF) confirmed that, indeed, the watercolor cake is full of arsenic! Plus, although the watercolor is bound in gum arabic, the long, active history of these items during use by the artist and after means that some arsenic-contaminated dust is loose within the box. All storage materials and documentation related to the box of watercolors are now labeled with warnings, and extra precaution is used for handling.
Multiband imaging (MBI) was used to quickly get a sense of whether other labels on watercolor cakes were accurate, and the results were mixed. For example, bright orange or pink luminescence in ultraviolet (UV) illumination indicates a colorant in the red lake family, such as madder or carmine. The variety of oranges and pinks visible in the UV image above means that Richards certainly used a variety of red lakes – but only some of the handwritten labels correspond appropriately.
To completely sort out the watercolor cake colors, much more analysis (and time!) would be required. It would be especially fascinating to analyze the watercolor paintings at the same time, potentially making direct connections between the art supplies and these stunning artworks.
Stop by Luce Visible Storage this spring and summer to view this lovely show.
Posted by Jessica Ford