Although neon lights and signs are seen glowing in a wide variety of colors, the actual color emitted by pure neon gas when electrified is a bright orange-red color. The additional colors created by what became known as "neon" lighting are the result of other gases or chemicals that are used to produce the various desired hues. Carbon dioxide, for example, will emit the color white when electrified, and helium will emit the color yellow.
Neon is one of the elements categorized as a noble gas. The element was not discovered until 1898 because of its appearance in the atmosphere being limited only to trace amounts. Neon was first isolated along with two other noble gases, krypton and xenon, by the fractional distillation of air in which a two-step process of condensation and evaporation was used.
The brightly glowing neon lights that are used in commercial signage are made from electrified sealed glass tubes containing a rarefied gas such as neon or one of a number of other gases that emit brightly-colored photons when ionized. The term "neon" used to describe the popular lighting fixtures is a result of the use of neon as the first emitter. An electrical potential of several thousand volts is applied to the electrodes at either end of the glass tube containing the gas. The gas then becomes ionized and emits the characteristic bright light, the color of which depends upon the gas used.