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 color", hence a rich palette of pigments and how to
mix colors 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.