Signac’s career as a painter started at the height of Impressionism, as the Salon tradition was being swept away and some of the Impressionists, such as Monet, were achieving critical and commercial success. However he chose the radical option, to join Seurat in his new enterprise which was more firmly rooted in the art theory expounded by Charles Blanc, and the colour science and theory of Michel Chevreul. These in turn linked with the purer science of Hermann von Helmholtz. It is often stated that the American Ogden Rood’s writings were important influences, although that is less clear; in any case Rood’s book relied largely on von Helmholtz, who definitely was accessible to the Neo-Impressionists.