CARRBORO - If you head west on Main Street through the Greensboro Street intersection, you can't help but notice that what was formerly a drab and featureless alley between the Clean Machine and Scavenger Antiques now pops with color and imagery.

A new mural stretches the entire length of the alley on the wall of the Clean Machine. At the far left, closest to the sidewalk and Main Street, is the large head of a woman in profile, blowing what appears to be a breath of air that changes into stream of water, which swirls and swoops the length of the alley, past a few small figures and other images, before it disappears at the far right.

"I had a version of it that was a female figure blowing flower petals on a gust of wind, but the idea changed as I got to the site," said the artist, Casey Robertson. "It was lot longer than I thought it would be, so I had to work in some new ideas."

That's what Robertson, who works as a freelance designer and illustrator ( www.snakehawk.blogspot.com), likes to do with his artwork.

"I hope to introduce some ideas that aren't too shocking - I like to present things that people are comfortable with - but that also open your eyes to new ideas and images."

The mural came about through a collaboration between Robertson and Nathan Mills, the property manager of the Clean Machine building.

Mills recently launched a new Web site, www.daytripp.com, that is designed as an online guide to businesses in Chapel Hill and eventually Carrboro. He knew Robertson and was familiar with his artwork, and when he looked at the blank wall at the Clean Machine he saw an opportunity to do several positive things at once.

"I have a deep appreciation for Casey and his art, and I knew he was looking to drum up some work," Mills said. "I also thought we could do some good by brightening up that alley, which was pretty drab, and putting something beautiful in there. And it's also a way to sort of create a point of interest for my project; we're not in Carrboro yet, but we will be this fall, so the mural is sort of a pre-emptive move in preparation for that. Businesses work best when they find a way to serve multiple interests."

Robertson drew up a sketch, ran it by the Carrboro Appearance Commission for approval, selected colors and made his initial sketch on the alley wall. While many muralists work from a grid - which makes it easier to transfer a small image onto a huge surface - Robertson free-handed the design based on his sketches.

"I really enjoy the impact of painting big," he said."Translating small to big takes practice, and I just ran with it. I had a blast."

The folks who run the Clean Machine have heard a lot of feedback, said manager Tamara Sanders.

"People love it," she said. "It sort of fits in with what we do - not our cycling mission but open creativity. I think it's great."

So does Mills.

"I'm blown away," he said. "I was expecting something smaller in scale. Casey didn't make a lot of money on this - he did it mainly because he loves it - but he did such a great job. It's fun, light-hearted, colorful. Carrboro is all about being unique and interesting. Casey's work fits right in."

Robertson's mural has a contemporary street art or comic book look, as opposed to the familiar murals done by Michael Brown throughout downtown Chapel Hill. Robertson said he's a big fan of Brown's, but he has his own approach.

"He's a great artist, and I have a lot of respect for his work," Robertson said. "I do things a little differently. I have my own ideas to express. That's the beautiful thing about art - everybody has something different to say."