Gesso

Gesso (Italian:ˈdʒɛsːo "chalk," from the Latin gypsum, from the Greek γύψος) is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these. It is used in artwork as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it.