One of the most ambitious murals in Philadelphia is coming to completion this week.

Two city blocks of Germantown Avenue, at Lehigh Avenue, have become an abstract color field of giant painted stripes and solids.

Unlike thousands of other murals already painted on Philadelphia walls, this features no portraits or landscapes, contains no symbols expressing the character of the community. It doesn't tell a story. It is designed to boost the local economy.

"This is social practice," said Jane Golden, director of Philadelphia's Mural Arts Program. "The merging of art and development is coming to life."

With a $300,000 budget of public and private funds, Golden invited the Dutch artists known as Haas and Hahn (Jeroen Koolhaas and Dre Urhahn) to live in an apartment above Germantown Avenue and Huntingdon Street for a year, to design and execute a mural that would splash across all the building facades for a solid block, spilling over into the surrounding blocks.

The block of buildings -- street-level storefronts with apartments above -- is a broken smile of inhabited, vacant, abandoned, and crumbling. The facades were plagued with flaking paint, rotting cornices, and rampant graffiti. The artists needed to tie them all together with a bold graphic design.

"Every building has it's challenges," said Urhahn. "You end up standing in front of it, and looking at it, and realizing it's probably the first time anybody has ever looked at that building for a long time, and cared."

'Dutch masters' with international reputation

Haas and Hahn earned an international reputation for their mural work in the favelas in Rio de Janeiro, where poor, makeshift housing is a haphazard construction of randomly stacked rooms and extensions. The artists pulled them together with bright colors and bold geometric shapes.

"The favela is a growing neighborhood. The hope is reflected in the architecture. People are always building building building," said Urhahn, standing in front of a building on Germantown Avenue with plywood for windows. "Here the architecture is basically in decline. Houses are falling down through neglect."

Some of the building facades were improved, but only enough so they could receive a coat of paint. Nobody involved with the project -- neither the artists, the Mural Arts Program, nor the merchants who participated -- expected color to fix what's wrong with the Germantown Avenue commercial corridor.

The mural is not meant to be the change, but to spark it.

For starters, the artists hired locally. The huge task of painting dozens of buildings required a crew of painters. About 25 people, most from the very neighborhood they were painting, were trained, put to work, and paid.

The entire project is a hybrid of graphic art, civic engagement, and market branding. The head-turning weave of reds, greens, browns, yellows, and pale blues is an oasis of color in a sea of red-brick, North Philly rowhouses.

The oasis does not impress everyone. Some shop owners find the blend weirdly mismatched.

"The different colors, it's kind of funny looking," said Gloria Howard, owner of the Hair Essentials salon. "But it's puts a better touch on the Avenue."

It may look chaotic, but the colors are clean and coherent. The buildings are unified by a common streak of yellow or an echoing pattern.

The street also appears clean because it's actually clean. The city of Philadelphia has started sending out crews daily to clean the sidewalks.

Mobilizing merchants

This is the first Mural Arts project in which the city's Department of Commerce is closely involved. The department had been trying to get the merchants in this corridor to establish an association, but many shop owners did not have enough time, energy, or optimism to get behind collective improvement. Revitalization efforts came and went. There was not a lot of hope left.

"Before we had meetings where -- there are about 80 stores on this block, and five people would show up," said Tim Smith, owner of Timco, a clothing store. "In the past there was meeting after meeting and nothing was getting done. So people start falling off. Now they see colorful things happening, people are starting to look more into it."

If they can get behind a collective mural, the thinking goes, merchants can get behind an association. With a viable, collective representation in the corridor, the city's department of commerce can more readily work on improving business prospects along the Avenue. The Haas and Hahn mural means there's a there there.

"When these commercial corridors look more interesting, people -- if nothing else out of curiosity -- show up," said Philadelphia's deputy mayor for commerce, Alan Greenberger. "Merchants want to respond up to the level that the painting now gives to the corridor. They start thinking about improving merchandising. People start to notice."

The mural has already turned the heads of shop owners farther up the Avenue, who have asked the artists to continue the blocky colors across their own facades. Haas and Hahn say they will, if there is funding. Otherwise, the crew of painters they have trained are available for hire.

They are the newest business on Germantown Avenue.