Universal Medium/Varnish The Universal Medium is a medium and varnish rolled into one. As a medium, use as a fast medium for layering Small additions to the paint reduce viscosity sharply and layers dry faster. As a water based varnish, it is comparable to solvent varnish. It is very easy to apply. It gives the colour saturation and enhancement of a good solvent based varnish. By adding water to the concentrate, different levels of sheen can be created between low sheen and high gloss. Artists should experiment with colour swatches to decide on the finishes that they prefer, as it is non removable. (For a removable varnish, see Chroma Solvent Finishing Varnishes. Directions: Apply a seal coat of one part varnish: one part water. This allows the varnish to penetrate and seal the paint layer so that a more concentrated varnish can be spread easily when the seal coat is dry. Use full strength for a gloss finish or thin with water for a satin finish.