 Franschen was working in his lab in Germany, trying to replicate the experiments of other scientists with an electrified cathode tube, when he noticed some barium-painted cardboard nearby fluorescing. Puzzled, he turned off the lights, but it continued to glow. He realized the cathode tube was emitting something other than light. When he went to move the barium board, he noticed a lead plate cast a shadow on it. He began to try to create images, placing objects between the tube and the cardboard.