Atelier Binder Medium can be used as a medium for acrylic paint or as a sealer. When used as a medium, it will speed up the drying time of your paint when you need multiple layers in a short space of time. Use, on its own, to seal porous surfaces where minimal tooth is required. Atelier Binder Medium will increase gloss when mixed with acrylic paint. It is water based and dries to flexible film.