Abstract :
Developments in light sources since and before World War II have been extensive, and the effect of light on the total field of view of human vision is being considered more and more in artificial illumination. Incandescent light sources, which include arc and filament lamps, and vapor discharge sources, which include metallic vapor discharge and hot- and cold-cathode fluorescent lamps, have many different characteristics which make them suitable for various applications, but no one type of lamp is suited for all purposes.
