SNOHOMISH — With the industrial buildings and alleyway walls that typically serve as their canvases nowhere in sight, a group of urban artists recently gathered in a field near Snohomish to create their art.

The scent of aerosol paint floated through the air last week as about a dozen people gathered around a 105-foot long, 10-foot tall canvas, some on ladders to reach the top. One painted a bus, another a portrait of what appeared to be a Roman philosopher.

Dozens of lawn chairs were set up for the crowd to watch them work last week.

The artists came from different parts of the country, mostly California. John Carswell invites them each Fourth of July to his home, southwest of Lord Hill Park.

Carswell runs a few local business and owns a large collection of street art. He began buying pieces more than a decade ago. The group usually paints a few pieces that Carswell buys for his collection.

Many of those who visit have never left their hometowns, said one of the group’s leaders, an artist who goes by the name Skill. The trip is a way for them to get out of their neighborhoods and to preserve their culture, he said.

Carswell grew up in Santa Barbara, California, where he had a life unlike some of his friends.

“I was from a doctor’s family, so my world and theirs was pretty different,” he said.

Carswell was intrigued by the older teenagers’ tattoos and graffiti. As he got older he became more invested.

“It really bothered me that so much of this stuff is just beautiful artwork, and these guys spend hours doing it,” he said. “Then one day, it’s just whitewashed off of there, or it’s tagged over. I just started thinking it has to be preserved.”

Carswell got to know other collectors. In time he was introduced to well-known street artists, including Skill.

Skill helped establish the group, called Under the Influence, in the mid-1980s. It’s still going today. One of their main goals is to preserve art and performance pieces, such as music and dance.

Worldwide, there are roughly 200 members. About 40 traveled to Carswell’s property last week. He’s working on a documentary about the crew.

The trip is a way for members to get out of their usual routines, especially for those who may have gang ties or addictions to drugs and alcohol. It’s helped keep some young people from getting involved with those temptations, Skill said.

“This trip is key for them, because they are able to come out of the inner city and for the first time see a lot of trees, parks and horses, things they are not always exposed to,” he said. “Right now, their eyes are wide with inspiration.”

Carswell doesn’t believe anything like the mural has been done before. He’d like to see it in a museum someday.

The group started to paint on the blank canvas around 11 a.m. Six hours later, it was covered in bright orange and yellow hues — a backdrop for the silhouette of a city skyline with the Space Needle.

Over top was a recreation of an alley with graffiti tags and other intricate paintings.

Hundreds of party-goers mingled with people they may have never expected to meet. Barbecue was piled high on paper plates. And fireworks were planned once the sun went down.

Stephanie Davey: 425-339-3192; sdavey@heraldnet.com; Twitter:@stephrdavey.