The French Impressionist painters discovered new means for painting light - they used a "solar palette", the pigments matched to the colours the eyes see. They are the colours of a ray of light. This little book reproduces palettes by 8 of the plein-air painters - Cezanne, Manet, Monet, Pissarro, Renoir, Seurat, Signac, and Van Gogh. It describes the pigments they used, and includes short excerpts by the scientists whose work was the foundation of the new painting - complementary colours, optical mixing, and the pigment-colour correspondences.