Photoflash

Photoflash (pronounced foh-tuh-flash)

(1) An alternative name for a flashbulb (mostly archaic), a lamp which emits a brief flash of bright light; used to take photographs in a dark environment.

(2) Of or relating to flash photography (industry use only).

(3) The precise point at which a flashbulb illuminates.

1925–1930: The construct was photo- + flash.  Photo (phot- the prevocalic) was a clipping of photograph.  Photo was from the combining form φωτω- (phōtō-) of Ancient Greek φῶς (phôs) (light).  The –graph suffix was from the Ancient Greek suffix -γραφω (-graphō), from γράφω (gráphō) (to scratch, to scrape, to graze), probably best known in the derived from -graphy.  Flash was from the Middle English flasshen, a variant of flasken or flaskien (to sprinkle, splash), which was probably of likely of imitative origin.  In the sense use in photography, it was probably of North Germanic origin and akin to the Swedish dialectal flasa (to burn brightly, blaze) and related to flare.  The Icelandic variation from the Germanic was flasa (to rush, hastily to go).  The word photoflash has a long history as a technical term in photography and the manufacture of photographic equipment but three syllables was just too much for general use and the public used “flash” for just about all purposes, the odd necessity like “flashbulb” embraced to avoid confusion.  Photoflash is a noun; the noun plural is photoflashes.

The industry however needed to be more precise so photoflash became a frequent modifier, required because of the modular nature of the flash equipment, originally not part of the camera assembly proper and even at the tail-end of mass-market analogue photography, not all cameras featured built-in flash-lamps.  A photoflash unit was the whole, packaged flash assembly which included the flash-lamp, housing and mounting bracket which attached the unit to the camera body.  Originally the units were designed to accommodate replacement lamps but in 1960s, single-use units were developed, styled usually as rotating cubes which permitted use for four shots.

The photoflash capacitor is not used only in cameras.  It is an electrolytic capacitor designed specifically to provide a pulse of high-voltage energy for a very short duration and as well as the use in conventional photography, they’re installed also in devices using solid-state laser power supplies including optical readers and some printers.  Whatever the hardware to which they’re attached, the purpose is always a brief illumination.  Because of the requirements for feeding a very high current for a precise length of time, the greatest challenge during the development process was to ensure a reliable high discharge pulse without excessive heat generation and thus the physical expansion of components.

Three-frame spread of Lindsay Lohan being photographed at the point of photoflash.

Photoflash composition has two meanings: (1) The pyrotechnic material which, when loaded in a suitable casing and ignited, produces a flash of sufficient intensity and duration for photographic purposes and (2) the collections of techniques used by professional photographers when shooting in light conditions where the use of a photoflash is required.  This involves considering things like the available ambient light, distance, the angles of surrounding surfaces & their reflective properties and the need for any filtering.  For professionals, photoflash devices (known variously as flashes, speed-lights, studio strobes and a number of other terms) are adjustable to an extent those used on consumer lever cameras typically are not, the relevant metric a product of the relationship between the distance between the subject & light source and what is called the focal length (dictated essentially the lens aperture).

RAF 4½ inch (114 mm) Photoflash Bomb (the only fundamental design change was the use of narrower fins on the Mk II version).  The cardboard tubular body was closed at the tail by a dome while the nose was sealed by a diaphragm with a bush, into which was inserted the fuse.  A defined measure of flash composition was loaded between the front and the rear diaphragm while a central tube extended between each, filled with gunpowder.  As soon as a fused flashbomb was released from an aircraft, the fuse was operative, triggering the gunpowder at the desired height which burst the body of the photographic flash, simultaneously igniting the flash composition.

Photoflash composition was of critical importance in the photoflash cartridges used in photoflash bombs which were specialized forms or ordnance perfected during the early years of World War II (1939-1945).  Dropped from aircraft passing over enemy territory, they were fitted with a photoflash cartridge timed to detonate at a height chosen to optimize the spread of light over the area of interest.  The development of the devices had been encouraged by research which confirmed only a small fraction of the bombs dropped by the Royal Air Force (RAF) were coming within miles of hitting the target zone.  For many reasons, the inaccuracy was understandable given that night bombing over distance was a new aspect of war, carried out by inexperienced aircrew in the cold and dark of night, while under fire from night-fighters and ground-based guns, all while trying to locate blacked-out targets.  In the early days, for navigation the crew could rely on little more than maps, mathematics and the visual recognition of physical ground-features.

RAF photograph taken from Vickers Wellington, Berlin 1941.  The ground is illumined by the flash while the unusual light patterns are from ground-based searchlights, the shapes a product of the camera's exposure length.

There would later be electronic innovations such as devices designed to let bombardiers “see through” cloud but the photoflash bomb (always in the RAF known as “flashbombs”) was a relatively simple approach which scaled-up existing technology, the flashbombs essential huge versions of the flashbulbs used on cameras.  Given their size, they were capable for short periods of producing intense light of sufficient dispersal and luminosity to permit either a pilot accurately to position his craft for a bombing run or for surveillance aircraft to take aerial reconnaissance photos at a safe height.  Of great utility at the time, flashbombs are no longer part of the military inventory because of improvements in night-vision optics, radar and satellite imagery.

RAF photograph taken from De Havilland Mosquito (pathfinder), Hamburg 1943.  The shape at the bottom-left of the photograph is the flashbomb exploding. 

The allies used a variety of flashbombs during WWII all with basic but effective engineering and a method of construction which would have been familiar to fireworks makers.  Typically, a flashbomb was a cardboard tube, capped on both ends with metal stoppers and filled a flash powder charge and a fuse set to trigger after a certain time, the length of the fuse determining the detonation height.  Being a camera’s flashbulb writ large, the flash lasted only around 200 milliseconds but this was ideal for aerial photography and could be enough for a pilot’s visual orientation although flashbombs were often dropped in staggered clusters, providing an extended duration of visibility.