Chroma Atelier Binder Medium is a water-based acrylic emulsion that can be used for preparing and sealing surfaces. Use the Binder Medium straight from the bottle or mix 1:1 with water to seal and size canvas prior to painting as it promotes good adhesion of paint and prevents moisture loss into the substrate. It is also used for isolation and barrier coats between layers between dried layers of acrylic. Dries to a glossy finish.