Bathers at Asnières

This is a Sunday on the Seine, just outside Paris, at a spot where working people went to cool off. The men lounging on the bank are factory workers. Look past them to the far shore and you see the bridges and the smoking chimneys of the plants at Clichy, where some of them probably spent their week. Seurat finished this huge canvas in 1884, when he was only 24, and the official Salon turned it down. So he helped start a new independent exhibition that ran with no jury at all, and showed it there. One odd detail rewards a close look. Years later Seurat went back into the painting and added tiny dots of colour in places, the beginnings of the pointillist method he became known for. You can spot them dabbed onto the hat of the boy in the water.