Fluorescent lights are an advanced version of low-pressure mercury lamps. It passes an electric arc between cathodes, vaporizing small amounts of mercury. A phosphor coating on the inside of the glass then absorbs this energy and converts it to visible light. Special blends of phosphor can increase the base CRI of about 60 to as high as 85 and are available in almost any color (Kelvin temperature). Large surface areas make them less directional than other light sources. This natural diffusion makes them ideal for many applications; however in areas that require directional control (spots lights, down lights etc.,) reflectors may be necessary.
Linear tube fluorescent
Linear tube fluorescent lights provide up to 100 lumens per watt with a rated life of 24,000 hrs and have become the standard for most general lighting needs. Fluorescent tube lights require a ballast to start.
Compact Fluorescent (CFLs) lights use a much smaller diameter glass that starts and ends in its own ballast and screws into a standard medium base socket. CFLs are now available in many shapes and sizes and are a tremendous option for almost every application. Care must be taken to select the proper CFL. What works best in one application may not be the best choice for another application. As of yet the efforts to develop a truly universal, one size fits all product have not been very successful. However excellent products are available for the following applications ceiling fixtures, shaded lamps, ceiling cans, wall sconces, touchier lamps, small flood lights, vanity strips and fixtures and many other decorative and low light level applications.