From the early days of photography it was obvious that artificial light would be indispensable; freed from the vagaries of the sun, pictures could be taken where natural light was lacking or on dull days when studio work became impossible.
Naturally, it was thought that bright lights would reduce exposure times and photographers turned to chemicals. Limelight was produced by heating a ball of calcium carbonate in an oxygen flame until it became incandescent but, though L. L. B. Ibbetson, J. F. Goddard (1795-1866), and Antoine Claudet used it in 1840, the results were poor: chalk-white faces peered from the harshly lit picture, an effect created by the proximity of the light source and the dissimilar reflectance of different parts of the scene. However, attempts using limelight and other chemical sources (such as Bengal light, a pyrotechnic compound made briefly popular by John Moule under the name of photogen in 1857) were doomed to failure, either because they did not contain the rich blue, actinic wavelengths that the orthochromatic plates of the day required (limelight), or because of their low intensity and the copious clouds of fumes they released (Bengal light).
There was one exception: magnesium. In 1862 Edward Sonstadt began experiments to prepare the metal on a commercial basis and by 1864 magnesium wire was placed on sale, though at a colossal price—more than double that of silver. Following a demonstration in February that year Alfred Brothers (1826-1912), a member of the Manchester Literary and Philosophical Society, produced a photograph in a darkened room in only 50 seconds. The highly actinic light proved ideal for photography.
Magnesium was burned as a wire or ribbon (the larger surface area of the latter aiding combustion), either twisted into tapers or in clockwork lamps with a reflector. Lamp designs were many and varied: powdered magnesium, blown into the naked flame of a spirit lamp, produced a vivid flash, and multiple-headed lamps could fire more powder at a time, but burning was often incomplete and unpredictable. Exposures varied considerably and the air remained laden with grey, opaque fumes, making the metal unsuitable for studio use. Nevertheless, magnesium lamps gained in popularity through the 1870s and 1880s despite the expense.
Flashpowder
Producing a shorter, more predictable flash became the goal. Charles Piazzi Smyth, experimenting in the pyramids at Giza, Egypt, in 1865, had attempted to ignite magnesium filings mixed with gunpowder. The resulting picture was poor but the principle was sound: combining magnesium with an oxygen-rich chemical would sustain combustion. In November 1865 J. Traill Taylor used such a mixture, thereby sometimes (wrongly) being credited as having invented flashpowder.
Perhaps due to the conflagration that these and other early powders produced, they were treated as no more than novelties. Then, in Germany in 1887, Adolf Miethe and Johannes Gaedicke mixed fine magnesium powder with potassium chlorate to produce Blitzlicht—the first widely used flashpowder. The ability to produce ‘instantaneous photographs’ at night, or arrest moving objects with the relatively short-duration flash, caused great excitement, and there was an upsurge in artificial-light photography. In February 1888 a reporter for the New York Sun, Jacob Riis, recorded wretched immigrants in the city slums by firing magnesium cartridges in pistol-like flashguns (which caused great fear) or casually throwing a match into a heap of flashpowder in a frying pan, on one occasion almost burning down a hovel and setting light to his own clothes.
Flashpowder is effectively an explosive, with almost twice the power of gunpowder, and such accidents were common. Photographers generally prepared flashpowder by grinding the components in a mortar and pestle, but often forgot that they should grind them separately before mixing. There were a number of incidents; in Philadelphia three photographers died in separate accidents and the ‘blinding, smoke-belching, evil-smelling’ powder acquired a fearsome reputation. By the early 1900s flashpowder formulations had been refined so that flashes lasted only 10 ms, an improvement which aided portraiture, as subjects no longer closed their eyes during the exposure. However, a convenient ‘smokeless’ light continued to elude science, though there were many ingenious attempts, for example by burning magnesium in muslin bags.
Flashbulbs
In his experiments in underwater photography in the 1890s, Louis Boutan used a cumbersome magnesium lamp devised by the engineer Chauffour. Powdered magnesium, sealed in a glass jar fixed to a lead-weighted barrel to supply oxygen during burning, was ignited by means of an alcohol lamp (and, later, electrically). Paul Vierkötter used the same principle in 1925, when he ignited magnesium electronically in a glass globe. In 1929 the Vacublitz, the first true flashbulb made from aluminium foil sealed in oxygen, was produced in Germany by the Hauser Company using Johannes B. Ostermeier's patents. It was quickly followed by the Sashalite from the General Electric Company in the USA.
Traditionally, in dim light photographers removed the lens cap from a tripod-mounted camera (or, after shutters were introduced, used the ‘B’ setting) while the flashpowder was lit. Flashbulbs, however, weighed little, were easily fired electrically (the current heated a filament, which ignited a primer paste and burned the aluminium), were extremely powerful, and far more convenient. For safety a chemical spot changed colour if the bulb was cracked or leaking, and lacquer both prevented shattering and could be coloured to match the sensitivity of the new colour films. Mass-market cameras were soon fitted with integral flashguns or synchronizers to fire a bulb when the shutter opened. The freedom this conferred, coupled with predictable exposures, was immense and by the 1950s bulbs had virtually supplanted powder. Bulb manufacturers proliferated and produced literally hundreds of types up to the 1970s, by which time they had decreased from the size of a domestic light bulb to the diminutive AGI series at only 3 cm (1.2 in) high. Refinements such as flashcubes (made from four AG1 bulbs), Magicubes, Flashbars, and Flip Flashes all increased amateur convenience.
Electronic flash
Electronic means of creating light eventually superseded chemicals. In June 1851 Henry Talbot recognized that if a moving object was lit by a bright enough light for a short enough duration it would ‘freeze’ its motion; he reputedly pinned a page from The Times to a revolving plate and lit it with the discharge from a series of Leyden jars (effectively a crude capacitor): the first flash photograph (and, incidentally, the first high-speed photograph).
Experiments with discharge tubes, which produce a short-duration flash, were conducted in the 1870s and 1880s by Crova, Anschütz, and others, as well as the Seguin brothers in the 1920s. However, Harold Edgerton's work in high-speed photography during the 1920s and 1930s proved that when a short-duration flash was powerful enough he could—to the public's delight—arrest the motion of a speeding bullet. Edgerton's designs led to the production of Kodak's 1939 Kodatron flashlamp and, subsequently, smaller, portable flashguns which—with a flash of less than 1/10, 000 s—could freeze any subject that photographers normally encountered. By the 1950s pictures of leaping dancers and icelike flowing water were common in amateur exhibitions. The miniaturization of electronic flash relied as much upon improvements in battery technology as the introduction of small, powerful capacitors. A capacitor was used to store an electric charge, which could be released to fire a flashbulb. In the case of electronic flash the dangerously high voltages involved required that the flashgun design used a low-voltage charging circuit to protect the user.
Photographic flash has moved through chemical and electronic phases, driven by a desire to shorten duration and increase intensity. Refinements lie with automatically quenching the flash when a sensor either in the flashgun or within the camera detects that enough light has reached the film (‘auto’ flash), and using an infrared pre-flash to set distance and aperture on automatic cameras. Disadvantages lie only with unequal lighting in subjects at dissimilar distances from the source of the principal flash and the harsh shadows produced by the generally smaller reflector, a consequence of miniaturization.
— Chris Howes
Bibliography
- Martin, R. (ed.), Floods of Light (1982).
- Howes, C., To Photograph Darkness (1989).
- Bron, P., and Condax, P. L., The Photographic Flash: A Concise Illustrated History (1998)
