Atelier Interactive Matte Medium & Varnish is a water based, non-toxic, self-leveling Medium & Varnish and can be used either as a medium to change the sheen levels of acrylic paints or as an over-varnish for acrylic painting. Provide a non-tacky protective coating. Atelier Matte, Satin and Gloss Medium & Varnish are creamy, mid-viscosity products made from hard acrylic emulsion. They are non-removable, however they can be overpainted.