Eugène Delacroix

Delacroix argued for colour the way other painters argued for drawing, and the fight defined French painting for fifty years. Ingres led the opposition. Delacroix put complementary colours side by side so they intensified each other, a method the Impressionists took straight from him.

Liberty Leading the People, painted in 1830, is the picture everyone knows, though it was kept out of public view for years afterwards because the government found it inflammatory.

Morocco in 1832 changed his palette permanently. He filled notebooks with watercolours of horses, streets and light, and drew on them for the rest of his career. His journals, kept over decades, are among the best things ever written by a painter about painting. The Saint-Sulpice murals, finished shortly before his death in 1863, are where Van Gogh and Cézanne both went to look.