Flashtube - History

History

The flashtube was invented by Harold Edgerton in the 1930s as a means to take sharp photographs of moving objects. Flashtubes were mainly used for strobe lights in scientific studies, but eventually began to take the place of chemical and powder flash lamps in mainstream photography.

Early high-speed photographs were taken with an open-air electrical arc discharge, called spark photography. 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 the gunshot.

In 1927, Harold Edgerton built his first flash unit while at MIT. Wanting to photograph the motion of a motor in vivid detail, without blur, Edgerton decided to improve the process of spark photography by using a mercury-arc rectifier instead of an open air discharge to produce the light. He was able to achieve a flash duration of 10 microseconds, and was able to photograph the moving motor as if "frozen in time."

Interest in the new flash apparatus soon provoked Edgerton to improve upon the design. The mercury lamps were only as efficient as the warmest part of the lamp, causing them to perform better when very hot but poorly when cold. Edgerton decided that a noble gas would not be as temperature dependent and, in 1930, he employed the General Electric company to construct some lamps using argon instead. The argon lamps were much more efficient, compact, and could be mounted near a reflector, concentrating their output. Slowly, camera designers began to take notice of the new technology and began to accept it. Edgerton received his first major order for the strobes from the Kodak company in 1940. Afterward, he discovered that xenon was the most efficient of the noble gases, producing a spectrum very close to that of daylight, and xenon flashtubes became standard in most large photography sets. It was not until the 1970s that strobe units became portable enough to use in common cameras.

In 1960, after Theodore Maiman invented the ruby laser, a new demand for flashtubes began for use in lasers, and new interest was taken in the study of the lamps.