At the entrance to artist Ed Marion’s upper-floor studio at Cherry Street Pier hangs a poster that reads, “We paint heads, and pineapples, and sunflowers, and people.” For visitors, that candid sentence comes to life immediately upon stepping into the room.

Neon-orange, turquoise, and purple pineapples pattern two of the walls, while vibrant, stand-alone sunflowers create a wallpaper of sorts that mirrors the fruit. In the center of it all stands Marion, dressed in a far less splashy black-T-shirt-and-jeans combo — his daily uniform — with a paintbrush in hand and an easel before him. Lately, he’s been using its wooden frame to hold not canvas, but cardboard, on which he’s painted faces from all across the city.

On a recent Thursday morning, Marion grabbed a cardboard pizza box from a stack of more than 20. Within seconds, he deconstructed it into a flat, square surface. It was a process that began every painting in his latest exhibition, “The Pizza Box Portrait Project,” on display through Sept. 29 in Cherry Street Pier’s gallery space.

“I paint right where the pie would sit,” said Marion, running his hand over the base of the box, rescued from a future life of grease. “When I’m done, if it’s bad weather outside, I fold everything back up to protect the portrait, like you would a pizza, and send it off with whoever was my subject.”

Marion launched the project last November with intentions to kick-start a portraiture practice and to give back to Philadelphians in gratitude for being offered a residency at the Cherry Street Pier. (Cherry Street Pier licenses 14 studio spaces to select artists who apply and meet certain criteria. The spaces are priced at intentionally affordable rates; Marion pays $400 a month for his studio.)

Across nine months, he invited nearly 60 people into his studio, at which point he’d try to capture their expressions in the confines of a pizza box. After each 75- to 90-minute session, subjects were gifted the final product to take home.

“I aspired to be a portrait painter but had mainly engaged only in self-portraits. I wanted to push beyond my comfort zone,” said Marion. “And more than anything, I wanted to just sit down with people and have a conversation. In a time where we’re tempted to pull out our phones every 15 seconds to see if the world has collapsed, it’s good to rediscover that the world is full of beautiful people.”

Pizza boxes became the canvas of choice because they were cheap, an “Instagrammable” square shape, and easy for recipients to transport, even in rainy conditions. He also enjoyed the irony of creating what could be considered a family heirloom on a platform that generally ends up in the trash.

“A couple of years ago, I lost both of my parents and a beloved aunt, and at some point I realized, everything disappears,” said Marion. “I was intrigued by the idea of making art on this fragile, everyday surface, and just observing what happens to it over time.”

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Marion orders boxes in bulk from a restaurant supply store. The outside, on which he stamps a signature “made with love in Philadelphia” logo, is white, and the inside is brown, which Marion covers, brushstroke by brushstroke, with colorful acrylics.

“I put a call to anybody and everybody [through Instagram], and these are the people who showed up,” said Marion of his subjects. “I painted my neighbors and friends, but also so many different strangers from all walks of life. Everyone holds something special inside of them, and this was a chance to see if I could capture that in my art.”

After years of working as a lawyer in New York, Marion, 58, decided to pursue art full-time in 2008, moving to Philadelphia five years later. (An affordable, bright and airy Northern Liberties studio space lured him from Brooklyn to the City of Brotherly Love.) Sketching had been his hobby since grade school, leading him to enroll in life drawing classes both in and after college. It wasn’t until much later in life, however, that Marion pursued painting — largely a result of being red-green color blind.

“As a young person, I thought people would make fun of me if I put down the wrong color. But I knew I drew really well, so as a 40-something-year old, I just went for it,” said Marion. “I love it — when I’m painting at my best, it’s a meditation. I lose track of time, I lose myself.”

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While Marion shies away from painting landscapes, he doesn’t consider color blindness to be a major obstacle. A basic knowledge of color composition always comes in handy, as do the labels on each tube of paint. The bigger challenge, Marion feels, is finding ways to extract emotion from a person and interpret it into art. He considers his portrait sessions resemblant of mini therapy sessions. He’ll ask subjects questions that intentionally give him both an insight into their life and a look at a range of facial expressions.

“He’s really good at engaging you, and so I was moving my hands a lot while I was talking,” said street artist Anthony Torcasio, 40, Marion’s 37th subject. “Somehow he was able to capture my energy and attitude in this static image, embodying the essence of both me and this snapshot in time.”

Marion’s 48th subject, Marina Marx, 32, considered her portrait to be among the best representations she’s ever seen of herself.

“When I walked in, I had just taken off my motorcycle helmet, and I had this Albert-Einstein-like hair. He told me not to touch it,” recalled Marx. “I’ve suffered from body dysmorphia, but when I saw the portrait, I immediately thought, ‘Wow, that is 100% me’. It made me feel very comfortable in my skin in ways I didn’t think art could do.”

The experience has shown Marion both the complexity and the joy of working with people, who are often in motion, even when asked to sit still, and have many stories to share. As a result, he plans to reorient his art business to focus more on portraits and less on pineapples and sunflowers. Marion also hopes to compile “The Pizza Portrait Project” series into a coffee-table book.

“I think that all people need to be seen and heard,” said Marion. “For the sitters, I hope that these portraits become a remnant of a time when someone saw something beautiful in them.”