Photography is, by definition, ‘writing with light’. Getting the right amount of light, from the right direction, at the right time, has always been a fundamental concern of photographers.
With natural light, the photographer must choose his viewpoint carefully, perhaps moving the subject (or asking the model to move), or returning at another time of day or under different weather conditions, to take the best advantage of the lighting effects. Otherwise, the photographer must supply and control the light; and controlled lighting may be divided into three parts: key, fill, and effects.
The key light determines the shadows, and is (as its name suggests) the ‘key’ to the whole lighting plot. The key may be broad or small, hard or soft, but it must be the only light that creates shadows: ‘crossed shadows' such as a double nose shadow are the token of a sloppy lighting technician. Out of doors, during the day, the key is the sun. The crudest form of artificial key light is on-camera flash.
The fill determines the ratio of the shadows to the highlights. Again it may be broad and soft, or small and hard, but it must never cast a visible shadow on the principal subject. Out of doors, during the day, skylight provides the fill: a wide lighting ratio on a bright, clear, sunny day, or a very small ratio (completely ‘flat’ lighting with no strong shadows) on an overcast day. When so-called ‘fill’ flash is used, it often functions as the key, with daylight or other available light supplying the fill.
Effects lights, sometimes known by their old Hollywood name of ‘kickers’, have no real counterpart in nature; they are used in photography to mimic the way in which the human eye scans a subject, lingering here, skipping there, and adjusting in sensitivity to see into the shadows or to avoid being blinded by highlights. Classic examples include the hair light; the catchlight in the eyes; or lights that draw attention to (for example) jewellery or clothing.
Another useful distinction in lighting is the difference between chiaroscuro, the interplay of light and shade that has been the staple of European painters since Caravaggio and Joseph Wright of Derby, and notan, the ‘flat’ style familiar from Japanese woodblock prints.
Some photographers pride themselves on being able to light a portrait or a still life with a single light; others pride themselves on being able to handle numerous lights while still retaining a naturalistic effect. However, the distinction is somewhat unreal, since skill in lighting lies in being able to create the desired effect, regardless of whether it takes one lamp or a dozen.
The earliest purpose-built
To overcome the limitations of climate, and to extend photography beyond the hours of daylight, electric lighting became increasingly popular towards the end of the 19th century; more popular, it seems, than gas, because ‘half Watt’ lights (as they were often known) were much easier to move than gas. This was not just because they relied on a cable rather than a rubber hose: the mantle of a gas lamp is very fragile, and becomes more so with age. As well as incandescent lamps (first demonstrated publicly in 1840, four decades before Edison's patent), arc lights were also used; these had been demonstrated as early as 1808, but they remained tricky to use and noisy, and because of the very high UV output they could give rise to a painful condition that amounted to sunburn of the retina, an affliction known in the early days of Hollywood as ‘Klieg eye’ after a leading manufacturer. Another option, popular on location, was pyrotechnic lighting, via either ‘flashpowder’ or (only slightly less dramatically) magnesium ribbon; the latter was sometimes woven into a mat for speedier combustion. From 1929, the flashbulb (where the combustible material was sealed into an oxygen atmosphere inside a glass ampoule) increasingly supplanted flashpowder; not until the 1960s did small, portable electronic flash provide a workable alternative, albeit with vastly smaller light output.
As long as black-and-white reigned supreme, the colour of the light was not important, and indeed, mercury vapour lamps (the modern high-efficiency version dates from 1934) were often touted in photography books before the Second World War; how much this reflects actual usage, rather than a typically photographic obsession with technology, is unclear.
When colour became important, there were three choices. First, the film could be matched to the colour temperature of the lighting: so-called Type A and Type B films were matched to 3, 200 K and 3, 400 K respectively. Second, a filter could be used to bridge the discrepancy, either over the lighting or over the camera lens. Third, the lighting could be made to match the sensitivity of daylight film, as was first done with electronic flash, and later with a variety of continuous lights: HMIs, ‘daylight’ flicker-free fluorescents, and integrally filtered tungsten.
The earliest successful commercial electric flash units appeared after the Second World War. Well into the 1970s, however, studio flash tended to be massive, barely transportable, and by later standards very low powered: 5, 000 watt-seconds was regarded as a lot of power, and a 5 kW-s power pack and ‘northlight’ (big soft box) together might weigh the best part of half a tonne. Multiple ‘pops’ were often necessary when shooting still lifes including, for example, cars. From the 1970s onwards, however, ‘monobloc’ heads became increasingly popular, incorporating both the power pack and the flash head in a single compact unit. Again, power was low in the early days—200 W-s was regarded as a lot—but by the 1990s, 1, 000 W-s and more per unit was commonplace. Separate generator-head units remained in production, but were much smaller: typically 2, 000 W-s packs, supplying up to three heads per pack. By the early 21st century, 10 to 20 kW-s was regarded as quite modest in a big commercial studio.
Regardless of the lighting medium, positioning is the real skill. The ‘lighting stand’, effectively a tripod with a very tall centre column, is the basic light support but there are also floor mounts, boom arms, and overhead railway systems. The last often incorporate complex pantographs for height adjustment.
All lighting media have their own ‘look’: it is very difficult, for example, to recreate the Hollywood film-star look of the 1930s and 1940s without generous amounts of ‘hot’ or tungsten lighting. Many lighting plots are, however, surprisingly formulaic: ‘Paramount’ or ‘Butterfly’ lighting (the latter from the shape of the nose shadow) relies on a key that is high and to one side of the camera, and a fill that is low and to the other side. Nor can lighting be considered in isolation. Again taking Hollywood portraits as an example, the use of large formats (normally 20.3 × 25.4 cm (8 × 10 in) ) was very important, as was in the early years the tonal rendition of orthochromatic (as distinct from panchromatic) film-stocks.
— Roger W. Hicks
Bibliography
- Keppler, V., Man + Camera (1970).
- Life Library of Photography: Light and Film (1971)
Bibliography
- Kerr, N., Lighting for Imaging (1994)
