Atelier - Acrylic Varnishes - 250ml - Satin Medium & Varnish - Atelier Interactive Satin Medium Varnish is 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-varnish for acrylic painting. Atelier Satin Medium provides a non-tacky protective coating. Atelier Satin Medium Varnish is creamy, mid-viscosity. Product made from hard acrylic emulsion. Satin Medium is non-removable, however it can be overpainted.