MM19 Polyurethane Gloss Varnish is specially formulated for use in folk art techniques, this water-based finishing varnish provides a clear high gloss non-yellowing finish. For a protective surface coating use direct from bottle. Do not dilute with water. Allow at least 6 hours drying time between coats. Do not use Matisse MM19 Poly-U-Gloss Varnish over oil-based paints or oil-based antiquing finishes. Do not use on paper, canvas or other flexible substrates. Water-resistant, heat-resistant, quick drying, and flexible. Varnishing A varnish is a clear coat applied over the top of an artwork. It has two main functions - to give an even sheen to the work, which will in turn help to bring out the full intensity and beauty of the pigments, and to protect it from several different areas of attack such as wear and tear and airborne grime and chemicals.