Global Colours Gesso Medium is recommended for surface preparation and sealing. It is flexible, fast drying and permanent. Gesso Medium is best applied with a broad brush or cardboard wedge, onto a surface free from dust and grease. Dilute with 25% water to allow for absorption into surfaces of varying porosity (e.g. concrete, wood, canvas, plaster, etc.). To achieve a smooth surface apply several thin coats with light sanding in between. To achieve a smooth surface apply several thin coats with a light sanding between each coat.To prepare for oil painting, apply a minimum of 3 coats of Gesso. Allow 1-2 hours between coats, depending on the weather conditions and temperature. This medium is compatible with the range of Global Colours acrylics and other mediums, working together to create a highly versatile painting system for all artists. Not formulated for use with other brands of acrylics or mediums. This medium is available clear (Fluid Gesso Primer), heavy body, black, white, red oxide and yellow oxide. Available in 500ml jars, 1L bottles, 4L pails, 10L buckets, and 20L buckets upon request.