Watercolor paintings are generally matted and placed behind glass or acrylic. Watercolour paint tends to look light and airy and it has a translucent quality. To maintain that look, avoid mats and frames that are too dark and heavy.
Watercolours are original art. They are properly preserved by using appropriate conservation grade framing materials to protect their value and their longevity.
Conservation glazing should always be selected fopr these works.