The architecture of light: architectural lighting design concepts and techniques. A textbook of procedures and practices for the architect, interior designer and lighting designer pdfdrive com

Efficient and versatile, fluorescent lamps create diffuse light that can have many different color temperatures and different color-rendering
Figure 8.4 Common shapes of halogen incandescent lamps.
capabilities.
Fluorescent technology has come a long way since the days of flickering, humming, blue light. The most significant aspect of fluorescent lamp technology is the vast range of color temperatures and color rendering capabilities.
Consequently, care must be
taken in specifying them. If a designer does not specify the particular color temperature and desired color-rendering index of a fluorescent source, the product delivered can be
very surprising and less than desirable.
Fluorescent lamps work through a very novel management of technology based on phosphorescence. Figure 8.5 shows the components that are at work in all fluorescent lamps. Long, linear fluorescent lamps and twisty, compact fluorescent lamps are all basically hollow glass tubes filled with vaporized metal. When this “cloud” of metal vapor is excited by a bombardment of free electrons, it gives off a limited spectrum of mostly ultra-violet radiation. The magic of the technology is the white powdery coating of mineral phosphors that line the inside of the glass tube. These phosphors glow by translating the limited- spectrum, ultra-violet radiation into a much broader spectrum of visible light.
The quality and make-up of the phosphor coating is what determines the color-
rendering properties and color temperature of the lamp. This phosphor coating can be engineered to deliver light that exhibits any version of cool or warm: bluish, violet, pinkish, orange-ish, yellowish, etc. Using electricity to excite the metal vapor and the translation made by the phosphor coating are efficient processes that create very little heat.
Fluorescent lamps also require a device called a ballast that starts the
lamp and stabilizes the electricity delivered to the lamp. These electronic or magnetic devices range in size and must be located in or near the fluorescent luminaire.