Saturday, December 18, 2010


Many plein air painters like to paint on toned canvas or panels. This has the effect of removing the glaring white from the canvas, and giving a light-valued ground against which all the painting’s values can be compared. Some toned grounds are allowed to show through in the final painting, giving it an overall unity of color.

Some artists prefer to tone the canvas on location. A common method is to take a color or mixture of colors, often burnt sienna or some other warm semi-neutral, and thin it with solvent, then wipe the mixture over the canvas. The result is a thin wash-like layer of color that dries quickly in most outdoor conditions. It is even possible to rub out light areas of the painting, resulting in a toned value plan on which to build the painting. In order to use this method, it is necessary to either travel with solvent, or purchase solvent on location.

Aside from all other considerations about solvents, flying with solvent is problematic. Airline regulations prohibit flying with any flammable liquid, which is defined for airline purposes as anything with a flash point of 141 degrees or lower. Gamblin’s Gamsol, variously listed at 145 and 147 degrees, barely makes the grade as a flyable solvent. No other paint manufacturer’s product that I know of does.

Rumors abound about artists having their paints confiscated by the airline security. Maybe these artists didn’t pack their paints with the proper information. Whatever the reason, I know that most artist supply warehouses ship their Gamsol ground transport, and just avoid the issue, so I do too. I don’t pack solvent.

My preferred method is to prepare a gray-toned canvas ahead of time. This way, I can use the slower-drying oil painting ground, which according to some experts creates a stronger bond with the layers of paint above it, and which also keeps the oil from the paint from drying in, leaving the paint layer matte in texture and dulled in color.

To prepare your canvas or panel with oil painting ground, mount the canvas on boards or stretchers so that you have a stiff surface to work with. First seal the surface with a coat of PVA size. This is a thin glue-like substance that seals the canvas, keeping the oils of the ground or paint from reaching the fibers and causing their early demise from rotting. Let this dry overnight. Then, take your oil painting ground and mix in some gray or black oil paint to darken the ground to the exact value you want for your painting. Sometimes I use a black pigment, like ivory black. Sometimes I add a little quinacridone majenta to warm up the gray tone. Often I have a gray mixture of leftover paint from paintings that I can put into the mix. What you see is what you get, so balance the value carefully. Then scrape the oil painting ground over the canvas with a palette knife, and smooth the whole thing with a stiff brush, using random directions. If the canvas was previously sprayed commercially with gesso, usually one coat is enough. If it is raw canvas, two coats might be necessary. Depending on conditions, this might take up to a week to dry.  The illustration above is my canvas drying in 90 degree summer heat.  The canvas was dry the next day.

Video demonstration from Gamblin

You might prefer the simplicity and quickness of acrylic gesso. Skip the PVA step. Mix gray acrylic paint into the gesso, to reach a value at least one step lighter than the final value you would like. Acrylic paint mixed into gesso dries considerably darker than it appears when wet. Coat the canvas at least once if it is pre-primed, and at least three times if it is not. Some people recommend sanding between coats. For landscape painting, I don’t bother. Let the gesso dry overnight between coats.

If you’re joining me for the Maui Painting Retreat, pack about 4 practice pages or panels per day.  Practice panels can be prepared with the quicker acrylic gesson method.  For panels or canvas you might use for paintings, consider trying the oil painting ground.

Now, your canvas is ready. Let’s pack and go!

1 comment:

Celeste Bergin said...

thanks, Karen! Helpful information!