In 2013 the art historian Lindsay Stainton rediscovered photographs of the Royal Collection drawings as she packed for a house move. A scholar of British drawings, she had been sent the photographs 20 years earlier as part of the cataloguing of the Windsor collection, but had not been able to identify them at that time. Looking through them again, she suddenly realised that one of the drawings was a study for Gainsborough’s most celebrated landscape painting, Cornard Wood.

The artist had ruled a squared grid over the drawing, a common technique that artists used for transferring a composition square by square from a study sheet onto a larger canvas. Numbers pencilled along the lower edge of the sheet allowed Gainsborough to keep track of the transfer process, and small oil stains suggest that he had the drawing close to hand while working on the painting.

Drag the slider to compare the drawing with the painting