The most significant of all forms of physical conditions is proper lighting because bad light causes eye-strain and fatigue to workers. There are two sources of light like natural light and artificial light. Natural light is the best form of light from the point of view of health and efficiency of the worker. Natural light is termed as day light because it is available during the day time when there is sun. Windows should be large to avail more of natural light but care should be taken to prevent sunlight falling directly into surface.
Artificial lighting may be used as a supplement to natural light as natural light is not available always nor it can light all areas of the office at a time. Artificial light is considered to be best form of light because quantity, quality and intensity of light can be controlled easily. Artificial lighting is available from kerosine lamps and lanterns, wax candles, carbide lamps and electric bulbs.