Now take The Dance Class, a picture Degas painted in 1874, the same year as (what would become known as) the First Impressionist Exhibition.
It shows a dance studio full of ballerinas paying scant attention to their elderly ballet master, who is standing, supported by the long pole he uses to mark time by tapping the floor.
The young dancers are standing, leaning and stretching along the studio wall.
All are dressed in white tutus, with a variety of coloured sashes tied in bows around their waists.
A small dog peers round the ankles of the ballerina standing in the foreground to the left of the picture: she has her back to the viewer and is sporting a large red hairclip.
On her left, at the edge of the composition, is the most inattentive dancer, who is scratching her back, eyes closed and chin raised in momentary relief.
For those of you who, like me, have worked backstage in a theatre and watched ballet dancers rehearse, it is a wonderfully accurate, evocative painting.
It captures the feline nature of ballerinas, at once lazy and distant, while at the time emitting a poised physicality that is both sensuous and powerful.
Degas has pulled off a great representational feat.
He has done so by ignoring the traditional rules of the Academy and instead mimicking the compositional techniques of Japanese woodcut artists.
Much thanks to Will Gompertz’s book What Are You Looking At….some of the blog is directly taken from this fantastic book.