In Part One, I discussed foundation options you may choose to paint upon. In this post, I’ll focus on points to consider when deciding whether to use canvas or board. I’ll also discuss protecting the finished artwork depending on the surface and media used.
Should you work on stretched canvas, unstretched canvas, or on boards? This is a personal decision. I recommend you try both and decide what feels and works best for you. Canvas has a give and take which many artists, including me, love. Board has a smoother finish which allows the brush and the paint to glide over the surface.
An intermediate solution could be canvas panels, where canvas is stretched and adhered to a rigid panel of either wood, metal, or cardboard. This option gives the rigidity of board and the texture of canvas.
Canvas works can be removed from their stretchers and rolled to make shipping less costly and easier. When working on board, size and weight can become factors. Due to weight, many artists prefer to use panels of 18 x 24 inches or less. If your work involves a lot of impasto or built-up surface either through the use of mediums of the adherence of materials onto the surface, a rigid surface such as canvas panels or boards are best suited to your work. These types of works may crack or delaminate with time if painted on stretched or unstretched canvas. If you paint lean or use washes in your work, any of the surfaces mentioned will work for you.
Protecting the finished work
Once your painting is complete, it is best to protect the painting from dust, smoke, and other materials which can affect the surface and eventual cleaning and restoration. For oil paintings, varnishing is recommended. For acrylic paintings, applying an isolation layer over your work and then varnishing is best. For watercolor works, appropriate framing with mats and either glass or Plexiglas (UV protective for both) is best.
I just mentioned an isolation layer. I learned of isolation layers while preparing my work for a large museum exhibition. I began by applying varnish directly onto the finished works and noticed that the varnish reacted differently depending on the brand and color of paint used. Because I use both Golden and Liquitex Heavy Body acrylics in my works, the surface appeared mottled with gloss and matte areas once dry.
I reached out to Gamblin, the makers of Gamvar varnish, and they suggested removing the varnish with their Gamsol product, applying an isolation layer, and then revarnishing the work. The isolation layer serves to create a common base across the entire surface while also protecting the painted layer from the varnish and any restoration solvents which may be used in the future. The isolation layer solution is comprised of acrylic medium and water. Golden now sells a pre-mixed isolation coat product. If you wish to mix your own, use a 2:1 ratio of Golden Gel Medium (gloss) to water. I mix mine in a large glass container which can be sealed. You don’t want bubbles in the mixture so it’s best to let it set overnight. You may brush or spray the isolation coat onto your painting.
The layer may need to be applied in one or more coats. Once applied, let the surface dry completely and then look at the painting. If you see an uneven sheen, apply another coat perpendicular to the original coat and let dry. Don’t apply the layers too thickly. The layer may not dry clear when it dries.
Once satisfied, let the isolation layer dry thoroughly and gas out before applying your varnish. The varnishes I use are Gamvar Gloss, Matte, and Satin, depending on the painting. I’ve heard of artists mixing a 50/50 blend of gloss and satin, or satin and matte depending on the need. Apply the varnish in the same manner as mentioned above for the isolation layer and let dry thoroughly. If interested, I noticed last week that Gamblin has now produced its own line of varnish brushes intended to be used with their varnishes.