Four hours later, as the sun continues to climb through a cloudless sky, a thin stream of acrid smoke begins to issue from McCaw’s giant camera. Like a kid’s magnifying glass held over an anthill, the lens focuses the sun’s rays, making them strong enough to scorch the paper. McCaw is ready. He opens a small slit in the side of the camera’s bellows and activates a solar-powered fan (the kind normally used to cool computer CPUs) to help vent the contrast-killing smoke. At the end of his first exposure, McCaw quickly closes the lens, repositions the camera and deftly swaps in a new sheet of paper for the next. Apart from that, he waits, making sure his art is only ever so slightly on fire.