They're as ubiquitous as mushrooms after a summer rain and seemingly nearly as ancient: all those political signs popping up along area roadsides and seemingly any open green space.

Unnoticed by most non-politicians, though, the humble yard sign has undergone major changes, thanks to the digital revolution and high-tech printing.

Once upon a time – say, as recently as 15 years ago – aspiring office holders would phone a local print shop or ad agency to churn out signs. Each party had its preference, said Jan Brewington, a New Hanover County native and longtime Democratic activist. Democrats, for example, tended to steer their business to local advertising executive Nat Bost.

"It's not like that any more," Brewington said, with a hint of a sigh. "Now, people are getting it done online."

Some Wilmington businesses are still printing signs for local candidates. David Hervey of Fastsigns said his firm has handled orders for about a dozen campaigns this season.

"Some candidates are staying loyal to local businesses," said Sabrina Davis, president of Port City Signs. More and more often, however, Davis said, candidates are turning to out-of-state companies that can take orders online, offering economies of scale and prices that locals find hard to match.

"Once you file to run, you'll get a hundred of these offers in the mail," said Carolyn Justice of Hampstead, vice chairman of the North Carolina Republican Party. "It's like when you get a ticket, and all of a sudden you get letters from half the lawyers in town."

Justice, a five-term member of the state House from Pender and northern New Hanover counties before retiring in 2012, always used Hampstead Printing and Signs for her signs.

On the other hand, Rob Zapple, a candidate for New Hanover County Commissioner, said he's ordered through Heritage Advertising of Huntsville, Ala., for his last two races.

Former New Hanover County Democratic Chairwoman Louise McColl said she normally works with Gill Studios of Shawnee Mission, Kan., an 80-year-old company that's become one of the nation's largest political printers. Founder Forrest Gill is credited with inventing the self-sticking bumper sticker shortly after World War II.

Not only that, added Carl Gerlach, Gill's vice president of marketing, while in his 90s Gill created the modern two-sided sign, the kind that folds over its frame.

This points to the evolution the humble yard sign has taken. The old wooden stake is largely gone now, replaced by a wire frame. Cardboard is coated in polyurethane to stand up better to bad weather, Gerlach said.

It costs a bit more, but signs can be printed on corrugated plastic, with the wire frame fitting through the corrugated holes.

Prices vary, depending on the size of the sign, the size of the order, the number of colors in the printing and a number of other factors, Gerlach said. Campaigns can design a sign themselves or pay the company to do it. Even so, if a candidate is willing to order 1,000 signs or more, he or she can pay as little as $1.50 per sign, or perhaps $2.75 to $3 apiece for two-sided, two-color signs.

Putting a campaign sign together is something of an art, Gerlach said.

"You can't put too much on one, or people won't be able to read it as they drive by at 35 miles per hour," he said.

Generally, a candidate's name and the office they seek will be enough, perhaps with a catchy logo. Campaigns like to "brand" themselves, Gerlach said, which is why they often do their own design in-house or through an ad agency.

A candidate's party affiliation is usually optional, except in areas where one party or another holds a clear lead in voter registration. Red-state candidates might be more likely to identify themselves as "conservative."

Otherwise, Gerlach said, it's hard to tell a candidate's politics simply from a sign. Democrats and Republicans, liberals or conservatives, don't generally choose specific colors.

"The most common sign colors are still red, white and blue," Gerlach said. "Or red and white, or blue and white or some other variation."

How many signs are enough? When Justice was running, she estimated she always ordered more than 1,000 signs. A lot of people don't realize that Pender is North Carolina's fifth-largest county in area, so she had a lot of rural roads to cover.

"If you're in a small county, I guess it's somewhat different," Justice said. "But I'll tell you this: No matter how many signs I ordered, I always ended up ordering more."