What it provides is continuous light, in contrast to the instant pulse of flash, and there are two types of photography where this may be better: one is where the aim is to show the movement of something as a blur, the other is where the camera needs a very great deal of light. In both cases, the relatively long exposures dictated by tungsten lighting are used deliberately to advantage.

Recording movement as a blur, or streak photography as it is also known, is a popular convention for creating the visual impression of speed and action. Often, the blur is combined with a sharp image of the object, release, or by combining flash and tungsten.

Building up the quantity of light is tungsten’s more important use. In close ups, a small aperture setting needed for maximum depth of field and a bellow extension needed for the magnification both call for more light. The practical maximum in the power output of a lamp is about 5000 joules for flash and about 2000 watts for tungsten, which frequently leaves two alternatives: several flashes fired consecutively or a long exposure with tungsten. If the equivalent flash method needs more than about four or eight pulses tungsten is usually more convenient. On a large scale, such as the lighting of a big room or a car set, where many individual lamps are needed, simple economics favor tungsten. In all these cases, however, the subject must be motionless.

Most tungsten lighting is balanced for 3200K, as in type B film, although some are rated at 3400K – slightly bluer – for use with the less common type A film. Color balance is, however, not a major issue with tungsten lighting, as it can be altered very simply by using light balancing filters over the lens or larger gels over lamps. Indeed the fine tuning of filters is standard practice.

Tungsten lamps are available both separately, for fitting into standard screw and bayonet sockets, and built into special holders. The light output is determined mainly by the wattage of the lamp, generally 275 watts and 500 watts in the case of photofloods, 850 watts and 1000 watts in the case of the smaller, more intense halogen lamps used in most professional lighting systems. The latter are filled with halogen gas, to prevent blackened deposits from the tungsten element from forming on the enveloped, which is made of a heat resistant quartz like material. Their advantage is that they are brighter and do not lower their color temperature with age, as photofloods do. They are, inevitably, expensive to replace and can be dangerously hot for some light fittings. Grease or dirt, even from handling them without gloves, shortens their life. Although photographic tungsten lamps are normally used in studios, any other form of incandescent lighting, including domestic and office lighting, has similar characteristics and can be used. The only main variable is color temperature, which can be measured with a meter and compensated for with filters.