![Crop of patent 636492](https://upload.wikimedia.org/wikipedia/commons/2/20/Crop_of_patent_636492.png)
The electric flash-lamp uses electric current to start
flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and produces a loud noise regardless of confinement. It is widely used in theatrical pyrotechnics and fireworks (namely salutes, e.g., cherry ...
burning, to provide a brief sudden burst of bright light. It was principally used for
flash photography
A flash is a device used in photography that produces a brief burst of light (typically lasting 1/1000 to 1/200 of a second) at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a ...
in the early 20th century but had other uses as well. Previously, photographers' flash powder, introduced in 1887 by
Adolf Miethe
Adolf Miethe (; 25 April 1862, Potsdam – 5 May 1927, Berlin) was a German scientist, lens designer, photochemist, photographer, author and educator. He co-invented the first practical photographic flash and made important contributions to the p ...
and Johannes Gaedicke, had to be ignited manually, exposing the user to greater risk.
Invention
The electric flash-lamp was invented by
Joshua Cohen (a.k.a. Joshua Lionel Cohen of the
Lionel toy train fame) in 1899, and by
Paul Boyer in France. It was granted U.S. patent number 636,492.
[Patent No. 636,492](_blank)
/ref> This flash of bright light from the flash-lamp was used for indoor photography in the late nineteenth century and the early part of the twentieth century.
Joshua Lionel Cohen's flash-lamp patent 636,492 reads in part,
The principle of operation of the electrical flash-lamp is linked to the shutter of an early box camera
A box camera is a simple type of camera, the most common form being a cardboard or plastic box with a lens in one end and film at the other. They were sold in large numbers during the late 19th and early 20th centuries. The lenses are often singl ...
: tripping the shutter ignites the flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and produces a loud noise regardless of confinement. It is widely used in theatrical pyrotechnics and fireworks (namely salutes, e.g., cherry ...
and releases the potential energy
In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors.
Common types of potential energy include the gravitational potentia ...
of the exploding powder causing a bright flash for indoor photography.
Uses of flash-lamp
The main purpose of Cohen's invention was as a fuse to ignite explosive powder to get a photographer's flash. One of the first practical applications, however, for Cohen's flash-lamp was as underwater mine detonator fuses for the U.S. Navy.[Aboutdotcom](_blank)
''Cowen was an inventor of sorts; he developed a fuse to ignite photographic flash powder. Though the invention failed in its intent, the U.S. Navy bought up the fuses to use with underwater explosives.'' In 1899, the year the invention was patented, the government awarded Cohen a $12,000 contract for 24,000 naval mine
A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, any ...
detonator fuses.[Joshua Lionel Cowen at a glance](_blank)
/ref> The use of the flash for photography was dangerous, and photographers could get burned hands from the flash.
Electric apparatus applications
A 1910 brochure for the Nesbit High Speed Flashlight Apparatus says,
See also
* Valentin Wolfenstein
Valentin Wolfenstein (19 April 1845 – 3 February 1909) was a Swedish-American photographer who worked both in Stockholm and Los Angeles, California. He was one of the first photographers to use flash-lamps for photography.
He owned the firs ...
* Flash (photography)
A flash is a device used in photography that produces a brief burst of light (typically lasting 1/1000 to 1/200 of a second) at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a ...
* Flashlight
A flashlight ( US, Canada) or torch ( UK, Australia) is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the ...
Footnotes
Bibliography
*Beyer, Rick, ''The Greatest Stories Never Told - 100 Tales from History to Astonish, Bewilder & Stupefy,'' The History Channel, 2000, {{ISBN, 0-06-001401-6
*
Photographic lighting
1899 introductions
Obsolete technologies