The sky sweep.

In early September 2007, Holly Strauss "faux-finisher-extra-ordinAIR" began painting our sky. Layer after layer. With a little brush and a big brush. A flat brush and a round brush.
But no air brush? She finished in a couple days, adding small details along the way.
We rolled an enormous canvas over a corner of the studio. We made the backing from thin (1/8th inch) bendable plywood which we mounted on 2x4 bracing. The canvas was clipped on, so as the paint dried, it began tightening, hugging the backing, and taking on the smooth curve.