ABOUT VARNISHING WATERCOLORS
...has deep artistic roots. Artists have been varnishing watercolors since the Italian Renaissance, or earlier. The ceiling of the Sistine Chapel is varnished watercolor.
My varnished watercolors are mounted on wood panels. They need neither frame, mat, nor glass. The addition of varnish makes the painting, technically, a "mixed media" piece, as the paint absorbs the varnish.