PHILADELPHIA — It’s a low form of art.

Street level, in fact.

And yet, from these, the flat rounds of cast iron that dot city streets and sidewalks, that help cars roll smoothly and seal entrances to underground tunnels, Russell Muits has extracted industrial beauty.

For him, manhole covers do more than intrigue. They beckon.

The 38-year-old South Jersey graphic designer has embarked on a coast-to-coast odyssey, traveling from Camden, N.J., to Philadelphia to Seattle and back, searching out unusual manhole covers and, through the hands-on application of ink and canvas, transforming them into hypnotic prints.

Of course, his quest has simultaneously introduced him to wary passersby and doubtful cops, who wonder what the heck he’s doing, rolling paint on public property. But even they tend to soften, drawn into conversations about time, place, history and art.

“I didn’t expect to love it so much,” Muits said.

Manhole covers, he said, aren’t simple, circular chunks of metal that are just a way to keep pedestrians from disappearing into subterranean caverns. They open windows onto the quirks and notions of their home cities, and the best offer single-image, in-ground art shows:

A Buddhist-mandala-like-image graces covers in Louisville, Ky. In Chicago, a city of rivers, some covers show a small fish. Pittsburgh has lightning bolts; Speedway, Ind., a checkered flag.

The covers in Salem, Mass., don’t feature a broomstick. Instead they show a tall sailing ship, the symbol of the city’s early American success.

Muits has hit all those towns, on what he calls “print missions,” accompanied by his fiance and coconspirator, Yolanda Magpantay.

“Some people probably think it’s a little ‘out there,’” she said. “Everyone sees art in their own way. We see it in the streets.”

Pop-up art shows

Far below the soaring, elevated highway of I-95, Muits has hung a dozen canvases between two pylons, the graffiti of FDR Skate Park providing a gritty backdrop.

Occasionally he sets out groups of canvases to gauge the play of color, shape and light. At the park on Thursday he got an idea: pop-up art shows to be held whenever he lands in a new town and pulls a few prints. A show could last a day.

Muits grew up in Franklinville, Gloucester County, the son of a history-teacher father and stay-at-home mother. A week before high school graduation, he was set to attend Stockton University, but a last-minute presentation by Hussian College School of Art changed his destination.

Today, his Subaru Forester has been converted into a mobile studio, complete with drying rack. So far he’s created about 80 life-size prints in about 30 cities. His goal is to make at least one print in every state.

Is it art? Is it illustration? Is it a kind of found-object craftsmanship? Does it matter?

“This kind of hearkens back to a rubbing,” said Heather Ujiie, who teaches fine arts, textiles and fashion design at the Moore College of Art & Design. “He’s taking something that’s neglected, or discarded, like a manhole cover — where the waste runs, underneath us - and taking note that it’s a beautiful object, and honoring it.”

Date to ancient Rome

Manhole covers date at least to ancient Rome, where they were made of stone. Beginning in the 19th century, covers began to be cast of iron — strong, cheap, and too heavy to steal.

Today they’ve gained a certain popularity. Instagram and Pinterest sites extol their beauty — literally, cover art — and there’s at least one book on the topic, Drainspotting by artist and film director Remo Camerota, about Japanese manhole covers.

Muits’ obsession began in 2007, when he worked as an art director in Seattle. The city had commissioned artists to design manhole covers that represented facets of Seattle — fish, flowers, whales, water.

One cover depicting a map of city streets was outside Muits’ office. He admired it for weeks before one day, as he and a friend gazed anew, Muits had an epiphany:

“We should make a print of this.”

They picked up rollers, paint and paper at an art store. That was the first print.

Sometimes he’ll hit a city cold, carrying only a hunch. Other times, he’ll notice an Internet photo of a striking cover, then call people at city departments to try to learn its exact location.

Every canvas is different, but the process is always the same.

First, Muits gets down on hands and knees, scrubbing the metal like he intends to eat off of it. When the cover drys, he rolls paint across the surface. Often this is when the police show up. After he explains the project, Muits said, they usually calm down. A Boston police officer actually directed traffic so he could work.

Then Muits places the canvas on the manhole and presses down with his hands — the uneven pressure creating contrasts in the print. He lifts the canvas, clamps it to a sheet of plywood, and puts it in his car to dry.

Then he goes back and cleans off the paint that’s stuck to the manhole cover.

Today, having traded the rigid hours of a company job for the flexibility of self-employment, his search has expanded. Next week he’s heading south. Sometime after that, he’ll go west.

He’d like to do a show. And maybe a book. Maybe an online shop where people could buy T-shirts, photos or prints. He eventually wants to take a print from every state and create a giant, manhole-cover map of the United States.

After that, who knows?

“I’ve probably said, ‘This is my last canvas,’ five to 10 times,” Muits said. “I think there’s always going to be the next one.”