The concept behind neon signs was first conceived in 1675, when the French astronomer Jean Picard observed a faint glow in a mercury barometer tube. When the tube was shaken a glow called barometric light occurred, but the cause of the light (static electricity) was not then understood.

Even though barometric light was not yet understood, it was investigated. When the principles of electricity were discovered, scientists moved forward towards the invention of various forms of lighting. By 1855, there was the geissler tube named after Heinrich Geissler, a German glassblower. Gas in the tube was placed under low pressure and electrical voltage was applied, the result was that the gas glowed. After electrical generators were invented, many people experimented with applying electric power to tubes of gas. Several electric discharge lamps or vapor lamps were invented from 1900 onwards in Europe and the United States. Simply defined the electric discharge lamp is a lighting device consisting of a transparent container within which a gas is energized by an applied voltage, and thereby made to glow.

Before there were neon signs in America, there were commercial sign tubes that used a carbon dioxide fill. The carbon dioxide signs were made by a man called Moore. Neon gas was discovered by William Ramsey and M. W. Travers in 1898 in London. Neon is a rare gaseous element present in the atmosphere to the extent of 1 part in 65,000 of air. It is obtained by liquefaction of air and separated from the other gases by fractional distillation.

The French engineer, chemist, and inventor Georges Claude was the first to apply an electrical discharge to a sealed tube of neon gas to create a lamp. The word neon comes from the Greek "neos," meaning "the new gas." On December 11, 1910, Georges Claude produced the first neon light in France, which he displayed at the Grand Palais in Paris. His invention was patented in 1915, and in 1923 Georges Claude and his French company Claude Neon, introduced neon gas signs to the United States, by selling two to a Packard car dealership in Los Angeles. Earle C. Anthony purchased the two signs reading "Packard" for $24,000. Neon lighting quickly became a popular fixture in outdoor advertising. Visible even in daylight, people would stop and stare at the first neon signs dubbed "liquid fire." Nothing catches the eye like neon, and it has been the most effective medium for signs all over the world ever since.

Toward the end of the 1950's, as many of the old neon sign craftsmen were retiring, the neon industry could not keep up with demand, and other forms of signage became popular using new plastics, and fluorescent bulbs. While the initial cost of these newer types of electrical signs was cheap, fluorescent bulb life is very short which greatly increases maintenance costs over the life of a sign. Because neon tubes last for many years, are so much brighter, create more eye appeal, and can be bent to any shape, the demand stayed high. To fill this demand, new craftspeople were trained and neon rose again to become the most effective medium for electric signs.

Today the manufacturing process remains basically the same. Each tube is hand made, heated to a pliable state by fire with a gas torch, bent to shape, blown out, and then laid on a heatproof pattern for final adjustments before it cools and becomes hard again. The mechanical equipment required purifying and process the tube into a vacuum tube has improved greatly, thus improving the quality and life of modern neon signs.

Since neon was first used in signs, it has captured the imagination of everyone who sees it. Neon grabs your attention and holds on until the message has been effectively delivered. Neon is commonly used as a great accent to other type of signs; for instance, it is often used to illuminate the interiors of channel letters and other closed-face signage.

How does a Neon Sign work?

Hollow glass tubes used to make neon lamps come in 4, 5 and 8-ft lengths. To shape the tubes, the glass is heated by lit gas and forced air. Several compositions of glass are used depending on the country and supplier. What is called 'Soft' glass has compositions including lead glass, soda-lime glass, and barium glass. "Hard" glass in the borosilicate family is also used. Depending on the glass composition, the working range of glass is from 1600' F to over 2200'F. The temperature of the air-gas flame depending on the fuel and ratio, is approximately 3000'F using propane gas.

The tubes are scored (partial cut) while cold with a file and then snapped apart while hot. Then the artisan creates the angle and curve combinations. When the tubing is finished, the tube most is processed. This process varies depending on country; the procedure is called "bombarding" in North America. The tube is partial evacuated of air.

Next, it is short circuited with high voltage current until the tube reaches a temperature of 550 F. Then the tube is evacuated again until it reaches a vacuum of 10-3 torr. Argon or neon is back filled to a specific pressure depending on the diameter of the tube and sealed off. In the case of an argon-filled tube, additional steps are taken for the injection of mercury; typically, 10-40ul depending on tube length and climate it is to operate in.

Red is the color neon gas produces, neon gas glows with its characteristic red light even at atmospheric pressure. There are now more than 150 colors possible; almost every color other than red is produced using argon, mercury and phosphor. Neon tubes actually refer to all positive-column discharge lamps, regardless of the gas filling. The colors in order of discovery were blue (Mercury), white (Co2), gold (Helium), red (Neon), and then different colors from phosphor-coated tubes. The mercury spectrum is rich in ultraviolet light which in turn excites a phosphor coating on the inside of the tube to glow. Phosphors are available in most any pastel colors.

Neon lights operate on relatively high voltage, but very low amperage (high pressure, but very low volume). Imagine a garden hose with only a trickle of water. Put your thumb over the end, and it comes out with more force, but you use much less water. Just like water pressure, a transformer is needed to increase the electrical pressure from your wall outlet, to the required current to make the gas inside the tube "glow". Even though neon operates at a higher voltage, the transformer (included with your sign) does all the work, thus keeping your electrical cost low.

Common Coloring Methods

Insert Inert Gas	As mentioned above, people use neon and argon/mercury. Neon gives off a reddish-orange color, while argon/mercury is a light blue.
Fluorescent Powders	Many neon tubes are coated on the inside with fluorescent powders that filter out different colors from the light spectrum. In combination with the different gasses, an even greater number of colors are achieved. For instance, a green tube, filled with argon/mercury (blue gas) will light up green. Fill the same tube with neon (red gas) and it lights up orange. Likewise a blue tube, filled with blue gas will light up blue, and the same blue tube filled with red gas will light up pink.
Colored Glass	The use of colored glass is an old world method, which achieves the most vivid colors (reddest reds, deepest blues, etc.), but they are not as bright as other neon. They are also more costly, so are not used as widely for signs as they once were. However, for neon artwork, they are unparalleled in beauty.

Want to know more about Neon Signs? Please contact the Sign Shops listed in Allprintings.com.