It turns out that it takes a lot longer to talk about the pros and cons of a new sign than Philadelphia’s Zoning Board of Adjustment imagined.

The board allotted two hours for today’s hearing on whether Unisys Corp. can put a big sign on the building it plans to make its new world headquarters: Two Liberty Place in Center City.

That wasn’t even enough for Unisys to finish pleading the merits of its side of the case. It contends that the red logo, glowing in 11-foot-high letters from the 38th and 39th floor, are crucial to its branding efforts and will help the city’s image as well.

The zoning board said it would reschedule a second half of the hearing sometime in September. Opponents, who include residents of the building, will have their say then about the artistic merits of the sign.

The proposed LED signs - facing east and west - have drawn heavy opposition from residential and corporate tenants in the building, as well as others who argue that the signs will ruin the aesthetics of the blue-glass tower and mar the city's skyline.

Unisys plans to move its 225-employee headquarters from Blue Bell to the building, and as part of the deal, wants the 912-square foot signs to raise the visibility of its brand.

Unisys says it will rethink its move if it doesn't get approval for the signs. "If we don't get the right to put up our logo display, we would need to reevaluate our business case and decision," Brian Daly, director of media relations for Unisys, said before the hearing began.

The hearing before the Philadelphia Zoning Board of Adjustments is scheduled for noon at 1515 Arch St. on the 18th floor.

To get the signs, Unisys needs a zoning variance. It also needs to appear before the city Department of Licenses and Inspections and faces a federal lawsuit filed by opponents.

The Unisys logo, which would be located on the 38th and 39th floors, would not be alone on the skyline.

PECO has its famous crawling message board. Aramark has a prominent Center City sign.

The former PSFS building stands out at night with the still-present "PSFS" letters glowing in red atop the architectural landmark.

Critics, however, are concerned that allowing Unisys to have its signs may open the floodgates for other corporate logos to dominate and change the character of Center City.