Joseph Mallord William Turner

A soft, rather blunt graphite pencil and watercolour have been used on white paper to create this composition. The pencil drawing for this painting is quite detailed, and in parts the pencil sketches of trees, the building etc. have been filled in with a wash of watercolour applied to dry paper. The cornfield in the foreground, and the sky, have both been given some sketchy form by applying a wash of a single pigment to dry paper so as to make it somewhat uneven. This is a highly economical method of creating rather non-specific detail that need not correspond to the initial drawing, which is very sparse in these areas, without taking much time to paint it. The cornfield was coloured in leaving the pencilled figures more or less blank: they do not appear to have been washed out by the use of a wet brush, or scraped off the paper; both were equally economical methods which Turner often employed at the moment when he began to create specific details in a sketchy landscape.

Examination at moderate magnification, up to x40, made it clear that the blue and yellow colours were each painted using a single pigment. The identifications of these materials were in fact confirmed by removed 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. Since it is already known that the washes are pure colours, it is then possible to work out exactly which pigment was used in each case: Prussian blue for the sky and yellow ochre for the cornfield. One or more earth colours were used to paint the building, the shadowed land next to it, and the brown details of the figures. Localised Prussian blue washes applied over the yellow ochre and brown earth pigments combine with them to depict the trees, while the blue costumes of the figures were painted with the same material.