FAS Gesso Primer is a fast-drying waterproof primer that is applied prior to painting. It is used for both oils and acrylics. It seals absorbent surfaces, prevents uneven appearance and excessive fast drying, resulting from paint penetration. In an undiluted form, Gesso may be textured. Dilute with a little water if only sealing is required. This primer is recommended for surface preparation and sealing canvas, linen and board. It offers texture or 'tooth' to the painting surface.