High voltage photography
Julien Maire reconfigured a 3D printer into an image making device. Next to the nozzle, a spark plug is installed. The printer draws a contour while the sparkplug fires loudly. An analog camera with it’s shutter wide open collects the light and adds each consecutive contour to one threedimensional-looking image. It takes from one to ten hours for a ghostly object to appear, shapen by blue-white light from electric discharges.
More info on julienmaire.blogspot.com