I recently attended a workshop on framing watercolours without glass. The basic idea is to mount the finished watercolour on a wooden cradle and then finish the surface with varnish or an equivalent. The painting can then be hung without a frame (on a deep cradle) or framed like an acrylic or oil i.e., without a mat or glass.
Step one is to "glue" the watercolour to the wooden cradle, using acrylic polymer gloss medium, with or without GAC100 added. These are all archival materials. Once the watercolour is glued in place, its edges are trimmed to match the size of the wooden panel. At that point there are two options:
1. Dorland's cold wax can be spread over the surface, dried, then buffed. This protects the surface (in lieu of varnish). Photo below, the painting on the top right - here it is drying and not yet buffed up.
2. The surface can be painted with more acrylic gloss medium (enough coats to create an even sheen), then once dry, an archival spray varnish can be sprayed over this separation coat. Photo below, bottom painting.
The sides of the cradle are painted using acrylic full body paint.
The result is attractive and it keeps costs down substantially as framing costs can be reduced or even eliminated.