AIC's 53rd Annual Meeting

Beginning with his Nocturnes, Whistler began diluting his oil paint with a secondary medium he referred to as his “sauce.” Such a fluid medium allowed the artist to work wet-in-wet, and facilitated scraping, rubbing, and scumbling. While there are primary source references to copal being used in his “sauce,” there have been no technical studies that have identified copal as an ingredient that Whistler employed. In the 1980s and 1990s, Stephen Hackney and Joyce Townsend collaborated on a series of technical studies on paintings by Whistler in the Tate, National Gallery of Art, and Hunterian Art Gallery, among others. Their research did not find any evidence of copal, instead determined that turpentine and mastic varnish were added to the oil paint to create the sauce.

The four Nocturnes in the Harvard Art Museums’ collection (1943.171, 1943.172, 1943.173 and 1943.176) were completed over the course of the 1870s. The paintings are significantly understudied, largely due to their inclusion in the Winthrop collection, which stipulates their continuous display in the galleries and prevents their travel. The closure of the museum during the pandemic provided a rare opportunity to study the paintings. This research aimed to contribute up-to-date material analysis to compare with primary sources and build on the work of both Hackney and Townsend.

A small set of samples were taken from each painting and were either prepared as a cross-section or analyzed by thermally assisted hydrolysis and methylation pyrolysis-gas chromatography mass spectrometry. A comparison of the data has revealed some insight into Whistler’s painting materials and technique for this set of paintings. In darker compositions (1943.171 and 1943.173) multiple layers of media rich paint, some of which were unpigmented and all varying in thickness, were applied. This is in contrast to lighter compositions (or areas, 1943.172 and 1943.176) where single, relatively thick, pigment rich layers were applied. In these layers the addition of organic media was observed, in patches or waves, suggesting incomplete mixing. Pinaceae resin, may at the very least be suggested to be part of Whistler’s ‘sauce’ based on the analysis conducted here. Using written accounts as a guide the use of turpentine could be suggested, which would result in a more fluid paint medium which is a characteristic of Whistler’s paint. Analysis also suggests the recipe for Whistler’s sauce was not fixed, with evidence found for the incorporation of bleached shellac (1943.171) and perhaps mastic (1943.172) into the paint in some but not all of the nocturnes.