I used three colors to create this wash; pink, blue and yellow. Three is about the maximum you can do unless you want to end up with mud rather than nice blended colors. I used regular paint thinner to make a very thin soupy liquid of each color by mixing the solvent with about a tablespoon of oil paint from the tube. Paint thinner seems to make smooth, blended layers while turpentine often gives more texture where the different colors meet on the canvas. I don’t use turpentine very often mainly because I’m cheap! Paint thinner costs a lot less. But if texture was a critical issue I would definitely pop for the turpentine.
The actual wash is created by simply pouring the soupy mix onto the canvas and waiting for it to run off. Some of the best wash undercoats I’ve achieved were created by randomly pouring the paint, and then tilting the canvas to blend the colors more if I didn’t like the way they landed in the first place. Needless to say, this is a very messy process best done outdoors on a warm sunny day. It’s not particularly eco-friendly, either, so I’ll probably hear from a few environmentalists out there. Some of the bad effects can be mitigated by putting plastic under the canvas to catch the excess liquid. But it all still has to air-dry, so that’s something I haven’t found an alternative for.
The purpose of the wash is up for interpretation. I use it mainly for two reasons. First, a large canvas is a lot less intimadating to start painting on if it already has some color on it. There’s something about that huge expanse of white that can sometimes make you just sit there looking at it and wondering where to start. Second, because I paint in many transparent layers, the wash will show through when I start, and it can often influence how I use color later down the road. Sometimes I like the blending or texture of the wash so much that I just let it be and barely paint over it. Other times I’ve had its texture serve as a wonderful base for things such as stone walls, layers of leaves on the ground, or dirt paths. I never plan for those things, but often they just happen in the right places. One of the small thrills you get from time to time as an artist!