The Rainbow: Study for 'Bathers at Asnières'

Painted in 1883 and now at the National Gallery in London, this small panel with a rainbow is one of the most unusual of Seurat's preparatory studies for 'Bathers at Asnières.' The rainbow—an optical phenomenon that dramatically validates Newtonian colour theory—was clearly of scientific interest to a painter who based his method on the physics of light. Whether the rainbow appeared in the preparatory studies through direct observation or was a deliberate compositional experiment, it demonstrates Seurat's sustained engagement with the full range of natural optical effects he was seeking to systematise.

The rainbow arc is rendered through careful chromatic sequencing—from red through orange, yellow, green, to violet—applied in regular strokes against the sky. The landscape below is painted in the warm greens and sandy tones typical of the Asnières studies. The panel demonstrates Seurat's precise colour knowledge.