The Daler-Rowney Watercolour Mediums Watercolour Varnish provides a specialized, non-yellowing protective coat designed to seal delicate watercolour, gouache, and poster paint artworks with a single application. This high-viscosity clear liquid dries quickly to a beautiful gloss finish that deepens colour contrast and adds waterproof protection against dust and surface friction. It preserves the fine textural details of water-based designs without bleeding into the underlying paint layers, transforming vulnerable paper pieces into durable, display-ready fine art.