Hints, Tips & Techniques for Water Colour - Framing
For protection, a water colour painting should be displayed behind glass, using a mount to ensure the work is not directly against the glass. When choosing mounts, small pictures generally suit larger mounts whilst larger pictures will look good in smaller mounts.
Remember to use acid free mounts and backings; without them your painting will discolour in the frame.
NB. Varnishing water colours is generally not recommended because it alters the tones of the painting. A varnish will also sink into the paper, discolouring and embrittling it.