Flashes were first used in the late 1800's in the form of a stick with magnesium on the top that when burned would produce very bright light (the stick was held in the air, and the camera shutter released at the same time), later camera flashes used a special type of light bulb known as a flashbulb, and modern flashes use LED's or a special type of tube which emits a flash of mostly blue light when electricity is applied to it from the flash capacitor (known as a xenon flashtube).