You might think television sets can't get any bigger than they already are, yet last week, Philadelphia came close to installing one of the world's largest: a seven-story-high digital screen on the south facade of the Electric Factory building at Seventh and Callowhill Streets. Instead of broadcasting your favorite shows, this jumbo tube would have beamed advertisements across the city 24 hours a day.

In the end, the city councilman promoting the building-sized screen, Mark Squilla, thought better of the idea and pulled a bill to override Mayor Nutter's veto of the project. Big Brother would not be staring down at Philadelphia, after all. Crisis averted.

Not quite.

As digital screens become cheaper and more sophisticated, everyone wants to hang a version on their building. Most would probably use the technology to convey basic information, like special events, rather than broadcast paid advertisements. It's also unlikely many building owners would aspire to the proportions of the digital wrap proposed by the Electric Factory's owner, Myron Berman.

Even so, the coming deluge of small digital signs could cumulatively have just as dramatic an impact on our experience in the city as that single monster screen. It's not a Blade Runner world yet - overrun by wall-to-wall electronic images - but the future promises to be a lot more visually cluttered than the analog present.

Digital signs are far more distracting and harder to ignore than static ones, says Jerry Wachtel, a California psychologist who studies the effects of digital imagery. Unlike the devices we carry in our pockets, the screens we see as we stroll past buildings and billboards don't give us the option to "skip this ad." As Wachtel says, "you can't escape them."

Like many American cities, Philadelphia is already behind in controlling the onslaught. There are at least 15 digital billboards beaming advertisements along the city's highways, including one on North Fifth Street visible from Independence Hall. Council has given Market Street's Gallery mall permission to drape its blank walls in electronic advertising to mimic New York's Times Square. City legislators granted the same favor to newsstand owners, who are losing sales with the decline of print media.

That's only the beginning. The Franklin Institute and the Convention Center are looking at installing digital panels to broadcast information about their activities. The Kimmel Center has been operating a digital message board for months on its Spruce Street cube. Digital signage will soon be as common as address numbers on our buildings.

Yet Philadelphia, like many other cities, can barely keep up with regulations. Because signage is a specialized topic, the commission charged with rewriting the city's zoning code decided to outsource that portion of the rule book. The Nutter administration convened a "sign controls working group" to determine the rules.

After years of work, they've made headway on crucial issues such as fixing brightness levels and limiting the frequency of image changes. Those two measures are key to keeping digital signs from becoming too intrusive.

But the group continues to chew over important philosophical issues: Should billboard owners have to get a variance to convert their static signs to digital? If store owners start installing electronic nameplates to identify their businesses, how do you keep them from slipping paid ads onto their screens? And what about design? How does the city begin to control that?

Regulating digital signs in Philadelphia is complicated by visions of dollar signs. Billboard companies are big campaign contributors, especially to City Council, which must ultimately pass a bill spelling out the new rules. Councilman William Greenlee says members are now trying to find "a happy middle ground between various interests" - that is, the public interest and the interests of outdoor advertising companies.

As the battle of the Electric Factory digital wrap illustrated, the city is also easily seduced by the prospect of earning revenue from signs. Squilla was able to win wide support on Council for his bill because Berman agreed to contribute a large sum to the neighborhood school on top of the usual billboard tax. "I thought it was a neat way to get some extra funding for schools," Squilla told me.

But are we really ready to deface the public realm for anyone who offers to pay?

Certainly, it's unrealistic to imagine that digital signs can be kept out of our city completely. Philadelphia also has a proud history of using electronic signs well; the PSFS sign has always been a comforting beacon. Unfortunately, the new sign rules don't begin to grapple with the larger philosophical concerns.

Take the digital sign the Franklin Institute wants to install on a post in front of its building on 20th Street to replace a static sign that promotes its special exhibitions. The digital version would have two sides, including one facing the Parkway.

Technically, all billboards are banned in Philadelphia's residential neighborhoods. But in a city where residential, commercial, and industrial districts are jammed together, digital billboards can be seen far and wide across the city's low skyline.

A recent permit allowing a billboard at 11th and Vine Streets to be converted to digital means Peter Kendzierski, a painter, will have a giant television broadcasting into his living room night and day. He's fighting the permit in court. Washington Square residents, meanwhile, are increasingly concerned about the flashing images coming to the Gallery and the Market Street sign district.

Digital signs are the future, and the future, it seems, is already here.

Contact Inga Saffron at 215-854-2213,, or follow on Twitter @ingasaffron.