Chroma – Atelier Matte Varnishish 250ml – Are water based non-toxic self-leveling and can be used either as a medium to change the sheen levels of acrylic paints or as an over-Varnishish for acrylic painting. Provide a non-tacky protective coating. Atelier Matte Satin and Gloss Medium and Varnishish are creamy mid-viscosity products made from hard acrylic emulsion. They are non-removable however they can be overpainted.