Should you varnish a watercolour painting?

There are a few things to think about when you are considering whether or not to varnish a watercolour painting. The addition of varnish to a watercolour painting will change the look and feel of the work, some types of varnish will do this more than others. Because paper is highly absorbent, any varnish applied to the surface will soak into it and become a permanent, non-removable addition to the piece. Adding a varnish could re-categorise the watercolour as a mixed media piece and potentially exclude it from being considered a watercolour by some societies, museums, collectors, and conservators.