Because electrical arcs could be made that were much faster than mechanical-shutter speeds, early high-speed photographs were taken with an open-air, electrical-arc discharge, called spark photography, helping to remove blur from moving objects. This was typically done with the shutter locked open while in a dark or dimly lit room, to avoid overexposing the film, and a method of timing the flash to the event to be photographed. The earliest known use of spark photography began with Henry Fox Talbot around 1850. In 1886, Ernst Mach used an open-air spark to photograph a speeding bullet, revealing the shockwaves it produced at supersonic speeds. Open-air spark systems were fairly easy to build, but were bulky, very limited in light output, and produced loud noises comparable to that of a gunshot.