A few weeks ago, six artists began turning a former jet hangar at the El Toro Marine Corps Air Station in Irvine into a really huge pinhole camera, not surprisingly the world’s largest. They drilled a three-quarter-inch hole in the front of the building, then sealed the walls and roof with black plastic and foam to block other light. For film, they’ll be using a sheet of muslin three stories high and 111 feet long, coated with light-absorbing chemicals and hung from the ceiling of the hangar. The project has been undertaken to take a photograph – again, the world’s largest – of the air station for posterity, now that it’s being converted into a 1,300-acre regional park. One of the requirements of a pinhole camera is a very long exposure time – in this case, the aperture will be open for 10 days.