Neon alters language, its gaseous glow elevating dull verbs (EAT), bland nouns (HOTEL), and vapid antonyms (VACANCY/NO VACANCY). In red and blue neon, even a flat announcement like OPEN acquires a cold yet undeniable fire.

But neon’s cool heat alone did not make the OPEN sign the visual loudspeaker of American small business. First, neon had to evolve from handicraft to commodity, from carefully considered decision to impulse purchase, from custom manufacture to mass production. Only then could OPEN join the pay phone and public toilet as invisible icons that don’t appear until you look for them.

The sign’s ubiquity was a long time coming. Until a decade ago, a simple neon OPEN sign retailed for as much as $400. That’s not cheap, but it’s far less expensive than the first neon sign sold in the United States, which blinked on in 1923 when a Los Angeles car dealer had a “Packard” sign made for $1,200 (by comparison, the cheapest new Packard on the lot sold for $3,600).

Invented by a Frenchman, the neon sign quickly became an Americanism. “Neon in America meant progress, vitality, urban excitement. It symbolized American energy,” writes Rudi Stern in his 1988 book, The New Let There Be Neon. A neon sign in the window also advertised the fact that a merchant was flush enough to have spent some coin. But even after the neon patents expired in the ‘30s and the form boomed, signs stayed expensive. And thanks to their fragility and artisan nature, they also remained locally produced. In the medium’s heyday, the 1940s, the United States boasted more than 2,000 neon shops. Today, there are a mere several hundred.

What changed the neon-sign business was the beer business. In the course of a few postwar decades, outfits like Fallon Luminous Products and Everbrite learned how to manufacture durable, transportable neon signs for Coors, Miller, and the various Anheuser-Busch brands. Protective plastic housings, sturdier mounts, lighter transformers, and shock-resistant shipping boxes gave the signs greater mobility. Mass production cut costs.

But aside from beer logos and a few other popular corporate insignias, neon was a tough mass-market sell, despite competitors’ efforts to break new markets. It wasn’t until the mid-1980s that Fallon and Everbrite devised blue and red OPEN signs (it’s a matter of dispute who made the first one), but the way they sold them–door-to-door, mostly–kept prices high. A generic OPEN cost about what a local shop would charge for one made to order, and the market responded accordingly. In a good year, Everbrite sold only about 500 signs.

Today Everbrite moves 15,000 OPENs a year, and Fallon is just as busy. The market blossomed in the late 1980s, with the rise of wholesale buyer’s clubs like Costco and SAM’S Club. “Their customers were mainly small businesses,” says Tim Fallon. “We showed a classic size sign to SAM’S. They tested it, and it hit.” Everbrite President Jeff Jacobs pitched Costco, which also saw OPEN signs fly out of the aisles. Now SAM’S Club sells Fallon’s signs for about $115; at Costco, Everbrite’s sell for $119.99.

Experienced production-line workers fashion an OPEN in about 10 minutes. Despite their name, many signs contain gases other than neon. A few puffs of argon fill the blue border of an OPEN; neon itself powers the red portion of the message. In the new generation of OPEN signs, the red is redder and the blue bluer because the glass tubing is coated with colored ink. If reheated, as they would have to be in the course of repair, the inks melt into brown goop, making the signs such a pain to fix that it’s easier to buy another than to take a broken model into the shop.

The classic OPEN sign is a 35-inch by 15-inch rectangle, with a dozen feet of 12-millimeter tube in the word OPEN and another 8 feet in the border. One reason the sign has achieved world domination is because the letters’ height-to-width ratio approximates the Golden Section–1-to-1.618–so beloved of artists, architects, and the ordinary human eye. Another is that the size fits most transoms, windows, and walls. Still another: The shipping box stacks easily on a standard pallet.

Mavens can discern between makers at a glance. Fallon sets its OPEN in a molded plastic case, while Everbrite’s mounts on a metal armature. Everbrite markets the classic rectangle only, while Fallon offers a vertical OPEN, as well as an Art Deco bullet shape.

The OPEN sign’s popularity tracks that of the strip mall. Immigrant shopkeepers and boomer entrepreneurs needed to let passers-by know they were ready for business. Fifty years ago they’d have scrawled OPEN on a shirt cardboard and perched it to catch the eye of a passing pedestrian. But who window shops anymore, except at 35 mph, through a window set in the frame of a vehicle?

The lingua franca of commercial America has done what Esperanto could not: achieve universality. In Vienna, a few neon signs do growl GEOFFNET. But more often the word is OPEN–evidence, says one neon connoisseur there, of continental affection for Americana, along with a changing European culture. “In Austria, there used to be customs about when businesses could operate,” says Dusty Sprengnagel, who owns a shop called Neon Line and whose book on neon will reach store shelves later this year. “Most shops closed at 6 p.m. weekdays and on Saturday were not open or were open only until noon. We all knew the rules, so no one needed an OPEN sign. But things have changed. Shops may be open later, they may be open all of Saturday. The OPEN sign is not pretty, but it provides the information you need.”

With OPEN going platinum, why not a neon CLOSED sign? Everbrite tried one, but it tanked. An OPEN sign is a binary beast, it seemed–if a store owner turned it off, the message was implicit. You couldn’t say the same of a CLOSED sign–if it was off, would that mean proprietors lurking in the back waiting to make a sale?

An unlit OPEN has a fearsome power of its own. “We get calls from people whose signs aren’t working. They’re desperate,” Everbrite’s Jacobs says. “A guy told me, ‘I run a video store. I broke my sign washing my window. I’ve got to have another one right away, because my competitor on the next block has a neon OPEN sign. People can see that he’s open, but with my sign broken they think I’m closed.’ “