Constable’s sketches, many created outdoors, are the most spontaneous and innovative of his works. He knew the value of these studies and rarely parted with them, saying that ‘he had no objection to part with the corn, but not with the field that grew it.’

Seated on a stool, he worked with a wooden paintbox on his lap – a kind of portable easel. On its lid, he pinned a sheet of paper, canvas, or millboard. He worked quickly, painting an impression of the scene before him in about an hour.

Constable prepared batches of paper sheets in advance, covering them with a range of grounds (even-toned paint layers). These grounds gave an overall background colour, acted as an absorbent layer between paper and paint, and increased the paper’s surface strength.

Several British artists before Constable had made oil sketches outdoors from nature. But these artists generally conceived of their sketches only

as raw material, to be transformed into pictures that had little relation to their fieldwork. Constable’s sketches are more experimental, and his sketching style is more diverse. There is greater continuity between his sketches and his exhibition pieces.

Although naturalistic oil sketches became popular in Britain around 1810, Constable alone made sketching central to his painting.