Three days later, on the evening of 28 May, Pia returned for a second session at about 9:30 pm and took a few more exposures. Based on his experience of 25 May, he varied the exposure times and the lighting. At around midnight the three men went back to develop the plates. Pia later said that he almost dropped and broke the photographic plate in the darkroom from the shock of what appeared on it: the reverse plate showed the positive image of a man and a face in a detail that could not be seen with the naked eye.