The French painter Georges Seurat (1859-91) was among the most influential figures of the generation following the Impressionists. He combined the Impressionists' celebration of atmospheric light and colour with his own 'scientific' system for achieving this effect. This involved building up an image from small patches of contrasting colours, rather than mixing colours on the palette - a method based on an optical theory that Seurat termed 'divisionism' but which is now known as pointillism. This film sets Seurat's creative development in the context of late nineteenth-century France, showing how his exhaustive pursuit of a 'rational' technique for reproducing the myriad effects of light dominated his short career. Seurat's command of composition is traced to his study of ancient art and the Renaissance master Piero della Francesca, and his focus on the working-class or lower bourgeois social arena is related to the influence of Millet. His modern legacy is illuminated in discussion with Henry Moore and Bridget Riley, who testify to Seurat's continuing power to open insights into the nature of visual creation.