A technique in Post-Impressionist painting characterized by the separation of colors into individual dots or patches, thus making the viewer’s eyes “mix” the colors. Using this technique, artists believed they could attain the maximum luminosity of color. The first artist to develop the theory of divisionism systematically was Georges Seurat (1859-1891). Web resource here.
Georges Seurat. Gravelines: Evening, Study. Oil on canvas. 1890. Musée de l’Annonciade, Saint-Tropez, France.