15th century Italian painting mastered the art of painting light in the world. As Leon Battista Alberti wrote in On Painting (1435), "light has the power to vary colour", hence a rich palette of pigments and how to mix colours was necessary to capture every nuance. Countless recipes are provided by the anonymous author of "Secrets for Colours" (c. 1450), called the Bolognese Manuscript, intended for use in fresco and in oil on panel, accompanied by instructions on how to make varnishes for paintings.