The Channel of Gravelines, Grand Fort-Philippe

Painted in 1890 and now at the National Gallery in London, 'The Channel of Gravelines, Grand Fort-Philippe' belongs to the final series of Seurat's coastal paintings, produced at the Channel ports near the Belgian border during his last productive summer campaign before his sudden death in 1891, aged 31. The Gravelines channel series of 1890—four major canvases and several studies—represents the ultimate refinement of his divisionist coastal method: an absolute geometry of water, sky, and harbour wall rendered in pure colour. The four main Gravelines canvases are regarded as among his supreme achievements in terms of technical mastery and formal purity.

The composition is structured with near-geometric rigidity: the horizontal channel, the vertical harbour structures, and the vast sky above. Every element is built up from systematically applied dots of colour calculated for optical mixing. The painted border of warm-cool contrasting dots frames the image according to Seurat's framing theory.