Watercolor Painting Frames
Watercolor paintings must be framed under glass no matter what. Photo mats are often a great way to give them a little extra something. Good quality picture glass should be a serious consideration, as watercolor can fade under the slightest climate change, and the chemical makeup of the paper can be altered.
Watercolors are not mounted, but should be tacked on to an acid free paper backing with proper adhesive. The reason watercolors aren't mounted is so the artwork can hang naturally, with the inherent waves of the paper being part of your watercolor's charm.
Do not underestimate the life span of a watercolor painting. With proper care and treatment, they have the potential to survive decade after decade.