Reflector Fixtures
A new concept for achieving large fixture surface areas in task lighting is using reflector fixtures. Reflector fixtures not only provide large surface areas, they also provide great flexibility. They can easily be aimed and they are less constrained in mounting location than light fixtures. Thus, reflector fixtures can adapt to changing conditions, which are an essential feature of efficient lighting.
Shaped specular reflectors, such as the photoflood fixtures discussed below, can provide good control of the light distribution pattern when used with incandescent lamps, compact fluorescent lamps, and HID lamps. In fact, reflector fixtures can limit the illuminated area so sharply that it may be desirable to broaden and soften the edges of their distribution patterns. For example, some photoflood fixtures allow you to modify the breadth of the pattern by adjusting the depth of the lamp within the fixture.
Diffuse reflector fixtures that use conventional fluorescent lamps, also discussed below, can provide good task lighting for larger task areas.
A problem with reflector fixtures is that they leave the bright lamp visible from the side, causing glare in adjacent areas. Even conventional fluorescent lamps may be too bright for some applications. A solution to this problem is to install a light shield around the lamp, as described below.
Reflectors generally absorb less light than diffusers. The reflectivity of most eligible reflector types is 85% to 90% when clean, whether the reflector is diffuse (e.g., white enamel) or specular (e.g., spun aluminum). As with diffusing fixtures, the total light loss is increased by multiple reflections and light trapping in the fixture