I was actually able to view an artist like this in person. It was on the strip in Vegas. They have to work really fast so they can get the right colors. Usually they lay their canvas onto fanned tables of some sort to help the paint to stay moist. Was pretty cool they way he used newspaper and stencils.
now that was really really cool. i've always wanted to do art with spray paint, whether it be graffiti or something like that. nice find.