Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Christmas lighting technology has been subject to considerable development and variation since the replacement of candles by electric lights. Incandescent lights, the type most commonly used in Christmas lights, produce a broad-spectrum white light, and are colored by coating the glass envelope with a transparent or translucent paint which acts as a color filter. Some early Japanese-made lamps, however, used colored glass. Though less expensive, the painted lamps suffer from fading or flaking of the paint when exposed to weather. Older bulbs were also coated on the insides of the bulbs to prevent this effect, but were more costly to manufacture. Light-emitting diode (LED) Christmas lights are quickly gaining popularity in many places due to their low energy usage (about one tenth the energy used by incandescent bulbs), very long lifetimes, and associated low maintenance. Colored LEDs are also far more efficient at producing light than their colored incandescent counterparts.