Neon - Just what is it anyway?
Good question you have there. Neon was originally discovered in 1898 by the British chemists Sir William Ramsay and Morris W. Travers. It was immediately recognized as a new element by its unique glow when electrically stimulated. The French were the first to actually make a neon advertizing sign illuminate.
Neon itself is an inert gas of Group 0 (noble gases) of the periodic table. Colourless, odourless, tasteless, and lighter than air, neon gas occurs in minute quantities in the Earth's atmosphere and trapped within the rocks of the Earth's crust. Though neon is about 3-1/2 times as plentiful as helium in the atmosphere, dry air contains only 0.0018 percent neon by volume. Neon liquefies at -246.048° C (-411° F) and freezes at a temperature only 21/2° lower.
The gas is produced industrially by the fractional distillation of liquid air; the most volatile fraction is composed of a mixture of helium, neon, and nitrogen. Nitrogen is removed by condensation under increased pressure and reduced temperature, followed by adsorption on highly cooled charcoal. Neon is separated from helium by selective adsorption on activated charcoal at low temperatures. Processing 88,000 pounds of liquid air will produce one pound of neon. No stable chemical compounds of neon have been observed. Molecules of the element consist of single atoms.
By itself, neon does nothing much. However, when neon is placed in a pure state under low pressure, it will emit a bright orange-red light if a high voltage electrical current is passed through it. The term "neon" is generally referred to for all "neon signs". Alas, this is inaccurate!
Technically, the correct terminology is "cold cathode lighting". Illuminated neon tubes are always cool to the touch. Incandescent lamps emit a lot of heat when lit. If you've ever touched a lit 60 watt bulb, you can verify that. When you see a "neon sign" as such, it may or may not contain any neon.
What??? O.K. I'll explain further....
A clear tube on a neon sign that lights up in that famous reddish-orange is neon. That is why the clear glass tubing is used, to provide the best medium for letting the neon gas emit its' glow brightly. What other kind of encasement can provide no brightness loss and tolerate high voltage electric current?
A colored "neon" tube on the other hand usually contains no neon. Most of the time the tube would contain Argon gas and a trace of Mercury. Argon gas, like neon (and several other gases), will emit a glow when high electric voltage is applied. Argon glows in a pale blue. Colored "neon tubes" come in two ways. Most colored tubes have a powder fluorescent coating on the inside to enhance the illuminated appearance. Some colored tubes have color in the glass itself with no inside coating. Colored glass tubes are harder to bend and shape than their clear tube counterparts. That is why the more color a neon sign has, the more expensive it is!
Yes, a colored tube can be charged with neon. Some special colors are created that way. "Regal Pink" is one such special color. Sometimes a red colored tube will be charged with neon for a deeper rich red color. White tubes charged with neon glow in a peachy color. The combinations go on and on...
As far as the history of neon signs themselves, the first neon sign arrived in the United states in the 1920's. That first sign was installed at a Packard dealership in California. It absolutely amazed everyone who saw the sign. At first only rich people or large companies could afford the new advertising medium.
Still, more and more signs appeared on America's horizon. The rest as they say, is history. The city of Las Vegas, Nevada and U.S. Route 66 being key places where neon signs became commonplace. Prices for signs came down as more neon shops opened competing for business. Neon peaked in the 1950's and early 1060's. As the economy changed with technology, back-lit signs overtook neon.
The new back-lit signs were cheaper to make and basically were low maintenance. Neon signs today are for the most part not as elaborate as their predicessors. Especially the blinking mechanisms since many cities forbid them as too distracting and a cause of accidents. The most common use today of cold-cathode lighting is in "neon channel letters". Stores and Companies spell out their name and /or logo on the exterior of their stores, offices and buildings. Mall stores too extensively use channel letters for signage.