isolation coat

The purists would answer that watercolour paintings should be behind museum quality, anti-reflective, conservation UV filtered glass, and confined within a frame. And most watercolour paintings are, as this used to be the only option for exhibiting your watercolour artwork. However there are many more presentation options for watercolour artists to consider once their work has a protective varnished final layer. 

Firstly your artwork must be completely dry. Leave for at least 7 days up to 4 months. Always give yourself plenty of space in a dust free studio.