Light-emitting diodes (LEDs) appear to be everywhere these days. They are used in internal and external automotive lighting applications, traffic lights and some information display systems. But these LEDs are really quasimonochromatic light sources and not white light sources. Furthermore, they are primarily used for direct rather than indirect lighting applications. Recent advances in the technology have raised managers' and illumination engineers' consciousness about white LEDs' potential integration into indirect illumination systems requiring daylike lighting conditions. But some fundamental questions remain about whether these LEDs are ready for general deployment, especially when evaluated against halogen and metal halide technologies. Halogen and metal halide sources are continually being made brighter, more reliable and lower in cost…