French term meaning wash. Term that is defined at the end of the 16th Century to indicate a painting executed with colours mixed with and gum and diluted in water. In the artistic treatises, between the 16th and the 17th Centuries, it is for the most part identified with tempera painting. Filippo Baldinucci defines the term as “a way to mix the colours with skin glue, Arabic gum, or other similar strong and adhesive things.” In the 18th Century, the interpretation and the use given by the French prevails, where the term precisely indicates a technique similar to watercolour. Differing from watercolour, gouache foresees an ample use of white (also used to lighten colours) and does not take advantage of the surface of the paper support.