Two types of reflectors are of importance in photography. They are the lamp reflector and the plane reflector. The first type, the lamp reflector, is used with artificial light sources-tungsten, tungsten-halogen, fluorescent, and electronic flash lamps to direct the light. The second type, the plane reflector, is used to redirect light from any kind of light source into shaded areas to soften or lighten shadows. (While it is true that mirrors are also reflectors, reflector is used in photography as a more general term. Mirrors always reflect specular light; and reflectors reflect either specular or diffused light.)

LAMP REFLECTORS. Light emitted by the filament of a lamp is dispersed in all directions. This is useful when the lamp is for general illumination, such as one suspended from the ceiling to light a room. As a photographer, however, you are usually interested in illuminating only a given area, and it is, therefore, to your advantage to concentrate the light emitted by a lamp onto the area of interest. You can do this by mounting the lamp in a concave reflector that reflects almost all the light onto the area to be photographed (fig. 1-13). Lamp reflectors generally have a satin or matte finish to diffuse the reflected light to prevent hot spots that could result if the reflector surface were highly polished.

Reflectors of electronic flash units vary considerably in their efficiency and covering power at

Figure 1-14.-The position of the discharge tube in relation to the reflector.

different distances from the subject. Generally, they are designed to provide maximum efficiency at distances of from 6 to 12 feet from the subject. Professional type of electronic flash units may have a dual reflector system-one position for a normal angle and the other for a wide angle (for a wide-angle lens); others may have a zoom system to provide optimum light distribution for any lens within a wide range of focal lengths. Depending on the position of the discharge tube in relation to the reflector, the unit can be used as a spotlight or floodlight (fig. 1-14).

PLANE REFLECTORS. When you want to provide fill-in light for shadow areas, it is often desirable to substitute a plane reflector (sometimes called a reflector board) to redirect the light from a direct light source (fig. 1-15). The plane reflector is placed so it receives light from the primary light source and reflects the light into the shadows. The efficiency of such a reflector depends on its surface and tone, as well as size and distance from the subject being photographed. The subject area covered by a plane reflector depends on the size of the reflector. When the surface of the reflector is matte or textured, it reflects diffused light and some of the reflected light is dispersed over a wide angle.