Straight Fluorescent and Compact Fluorescent Lamp Tubes

An electric current flows between the electrodes creating a low intensity arc which excites the mercury vapour and produces mostly non visible (UV) radiation which in turn excites the phosphors which then emit visible light. Fluorescent have higher efficacy than incandescent lamps, producing 3 to 5 times as much light for a given input power and thus producing much less heat.

The quality of the light a fluorescent lamps produce depends largely on the blend of chemical ingredients used in making the phosphors; there are dozens of different phosphor blends available. The most common and least expensive are "cool white" and "warm white." These provide a light with relatively poor color-rendering capabilities, making colors appear washed out, lacking luster and richness.