IN 1885, while Seurat was painting in Grandcamp, from which he brought back a number of seascapes done in low tones, full of calm and lyricism, Signac, who was working on the bank of the Seine, made the acquaintance of Armand Guillaumin. They often set up their easels side by side. It was in Guillaumin's studio that Signac, much moved, met Camille Pissarro. He interested the impressionist master in his ideas and introduced him to Seurat. The two friends explained to Pissarro why they had resolved not to mix their colors on the palette but had chosen to employ tiny brush strokes of pure colors, permitting the. mixture to be accomplished optically. They also told him of their methodical observance of the laws of contrasting and complementary colors. Convinced that their technique would make possible a more rigorous control of his sensations and feeling that it constituted a new stage of impressionism, of which he had been one of the initiators, Camille Pissarro, pupil of Corot, friend of Cézanne, Monet and Renoir, unhesitatingly accepted the audacious "divisionism" of Seurat and Signac. Pissarro's oldest son, Lucien, born like Signac in 1863, was also won over, as was his friend and fellow student, Louis Hayet.
In a letter to his dealer, Paul Durand-Ruel, Pissarro summed up the new theory which was to determine his practice from then on, stating that what he wanted was
to seek a modern synthesis by methods based on science, that is based on the theory of colors developed by Monsieur Chevreul, on the experiments of Maxwell and the measurements of N. O. Rood; to substitute optical mixture for the mixture of pigments, which means to seek to decompose tones into their constituent elements; for this type of optical mixture stirs up luminosities more intense than those created by mixed pigments.30
Now that the system had been set forth, it remained to produce paintings which by their aesthetic value would show better than any argument advanced in words the degree to which science could further the art of painting. Seurat, Signac and Pissarro set to work. Seurat began the large composition which he