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 several of the plein-air painters, describes the pigments they used, and includes short excerpts by the scientists whose work was the foundation of the new painting - complementary colors, optical mixing, and the pigment-color correspondences. It closes with color swatches of the pigments, provided by the London artists' colormen, L. Cornelissen & Son. This book will be of interest to art historians, collectors, students, conservators, and museum-goers.