Whistlejacket

about 1762

Oil on canvas, about 116 1/2 × 97 3/4 in. The National Gallery, London

A racehorse at life size with no rider, no saddle and no setting: an animal given the scale of a full-length portrait.

Look at

Against the even ground, the horse's outline of arched neck, lifted forelegs and long pale tail carries the whole design.
Muscle and vein are modelled in smooth gradations of chestnut, with light catching the shoulder and flank.
The rearing pose is a diagonal from the hind hoofs on the ground up to the turned head.

A chestnut Arabian stallion that won at York in 1759; painted for his owner, the Marquess of Rockingham, and always meant to be unmounted.
Kept by Rockingham's heirs until the National Gallery bought it in 1997.

Image: Wikimedia Commons (National Gallery, London image) · Public domain (faithful reproduction of a public-domain 2D work)