It's not designed to take a darkslide, it's a one-shot device. The camera is in the form of 2 boxes, one (which carries the pinhole) slides inside the other & retains the 5x4" paper (or film) flat at the film plane. They're held firmly together with a couple of little built-in magnets. It's very well designed & slick, but you've got to get the decisive moment! (Or carry a changing bag).