I really enjoyed seeing this progress on the WetCanvas site, you asked if anyone had any ideas on how to maintain a straight line, without using masking tape. I wonder if you could use a sheet of masonite or plywood, held off of the surface of the canvas 1/4-inch or so as a pattern, generally masking areas from that paint. When you apply the paint you would want to direct the stream from the center of the masonite pattern toward the canvas, so the flow of paint would not by inertia be driven under the pattern. I think you could get generally straight lines or shapes, kind of like dodging in photography.
