Joseph Mallord William Turner

This work on cream coloured wove paper is composed of rapidly superimposed washes of colour which have been tested out on the edges of the sheet. Turner’s brush-strokes overrun the edges of the sheet in some cases. Many Turner Bequest watercolours have been trimmed in the past, and it is impossible to know now how typical this sheet is of his working practice.

This sketch must have taken longer to complete than usual, since many of the horses and figures are developed in some detail. The application of dense black washes made form black pigment only is rather uncharacteristic of Turner, but entirely appropriate to the subject. Much of the paper is covered with multiple watercolour washes, while washing-out and small amounts of gouache were used for highlights.

The identification of the colours at the edges was done by removing tiny samples the size of a pin-point, and placing them in the sample chamber of a scanning electron microscope, under an X-ray beam. This beam interacts with the elements that make up each pigment, and the resulting spectrum makes it possible to work out which elements are present, and therefore which pigments are likely to be present. Sometimes the lack of detectable elements, in combination with surface colour and appearance in ultraviolet light, can serve in combination to identify a material. For example, the traditional and fast-fading watercolour pigment gamboge (deep yellow) is likely to be present in yellow areas where no elements were detected, while in other yellow areas the detection of chromium and lead indicate that chrome yellow is definitely present. Lime green was created by mixing gamboge and black, an unusual combination for Turner, though for this subject black must have been abundantly available on his palette already. (More than one white ceramic watercolour palette of Turner’s has survived, none linked to any particular painting or period of his life.) Vermilion, Prussian blue, and brown ochre were also confirmed in this sketch. These analyses give more confidence to visual judgements on the materials that Turner was using at this time in other watercolours.