Sealing and Varnishing Your Work
You have two choices when you paint in watercolors on an alternate support such as clayboard or watercolor canvas: you can frame behind glass as with a traditional watercolor, taking the same precautions that the painting itself does not come into direct contact with the glass and that there is a space between the artwork and the glass or you can seal your work and frame as an oil or acrylic painting. Because paint lifts so easily off of these surfaces, for my part, I feel safest sealing and varnishing.
The later definitely has some advantage. If you paint on large surfaces, a matted painting framed behind glass can be an expensive purchase and a heavy one for hanging. Some artists have remarked that paintings on the larger sized watercolor canvas sealed and varnished sell better because of they are easier to frame and the frames, lighter without the glass. There is a school of thought that also recognizes the fact that oils sell at higher prices than watercolors. Perhaps it’s the long tradition of oil painting that adds a certain mystique to the works. Or perhaps it is the advantage of being able to frame without glass. Victorian watercolorists took great pains using bodycolor and gum arabic to “heighten” a painting to make it look like an oil in order to get higher prices for their work. For me, I looked at framing without glass as a means to transport works easier for shows, to say nothing of it being safer.
I experimented with several different approaches to come up with a sealing method that I use now. Now I must say that I like a glossy finish, so the products I mention are all about accomplishing this goal. For clayboard and canvas paintings, I first begin with the clayboard fixative. I use about three coats, allowing ample time to dry between coats. After this, I use the Krylon Triple-Thick Clear Glaze. The “triple-thick” refers to the fact that one coat of this product equals three coats of other clear acrylic fixatives. I will apply at least two coats until I achieve the finish I’m after. I follow this with a UV resistant varnish, also by Krylon. I typically will spray six thin coats to complete the process. There are a couple of things to bear in mind when doing this: first of all, make sure you have a big space that is covered to do the actual spraying. Make sure nothing is near by that may get a bit of the spray. You will want to take off your glasses, if you wear them. Found that out the hard way. Make sure the room is well-ventilated. There will be lots of spraying going on, so be sure and take that precaution.
Another approach is recommended by Golden for varnishing acrylics. This method requires an isolation layer so that this layer would protect the acrylic should the varnish need to be removed. The isolation layer is the Golden soft gel gloss, mixed two parts gel to one part water and brushed on. I applied this layer onto watercolor canvas. Despite being the glossy finish, it wasn’t as glossy as I liked, but maybe if you’re looking for more of a matte finish, you may appreciate the look. I didn’t like applying this with a brush either. The mix is quite watery and brushes easily, but I preferred spraying. This layer is followed up by the MSA Archival Varnish. For prints, this is up to eight thin layers. I do at least six layers for paintings and prints. It’s an easy precaution to take to protect your work. Since I’ve used the MSA Archival Varnish for prints, I have now taken to use it instead of the Krylon varnish.
I have tried both of these approaches with watercolor works on paper. I mounted the work on matboard before beginning. I can’t say I was happy at all with the results and will just still to using this for alternate supports. The nice thing about varnishing your works is that you get a really nice looking product when you’re done. I find the gloss finish really adds a lot and the painting looks like the watercolor when the paints were first applied, juicy and wet.