A song, if you’ll permit Chris Porterfield the analogy, is like a dark room.

The singer-songwriter behind Field Report, which is opening for Aimee Mann at the Rialto Theatre on Friday, says he writes songs with details that emerge bit by bit, letting the whole take its shape slowly.

“A song, the first time you hear it, there’s so much info to take it. There’s the music, the words, the way things were recorded. It’s almost as if you were put blind into a big room and as your eyes adjust to the darkness, you start to pick up the little details,” he says.

Even in some of his most character-driven songs, Porterfield writes with an exceptional sense of place, working listeners into his world with small sketches that evoke so much more.

“I think anywhere you are, if you’re sensitive to it, you can have some kind of moment of awareness or some kind of sacred experience, anywhere you are. Trying to get into places in the songs is just an attempt to mostly let the listener figure out where they are. The little details help them triangulate the stories,” he says.

Those stories, those songs, came slowly for Porterfield, who thought he was done with music for good when his old band broke up. That group — DeYarmond Edison — spawned both Bon Iver and Megafaun, similarly folk oriented acts that have seen good measures of success. But those bands had little to do with what Field Report would become.

“I honestly thought that I was going to be done with all this. I sold all my gear and I stopped playing. I moved to Milwaukee and I got married, bought a house, had a job; I was grown up. And these songs just started coming, without any real intention to start writing,” he says. “I’d never done that before, I’d just always been a side player. It was a welcome surprise. I found it exciting. It felt so good to start doing that, I just started spending more of my time and energy into getting better. It’s been a continuing revelation.”

One of the standout songs on Field Report — released last month on Partisan Records — is “Taking Alcatraz.” It follows a nameless character through an arc of decision and regret, yet never spelling out too much of the specifics, just that it’s about the Native American occupation of Alcatraz that began in 1969. In doing so, Porterfield simultaneously ties into a very personal and universal sort of emotional pull while provoking curiosity about the real world story that inspired the song.

“I like songs that bring something new to light, even if its just a place or a character. If you’re unfamiliar with a detail in a song — anybody’s song — and you have to do a little work to figure out what the narrator is talking about, I think it enriches the whole listening experience,” Porterfield says. “I like to put in some of that information for people to dig into if they want. I was fascinated with that whole situation, the group of Native Americans that took over Alcatraz. There wasn’t anything there, they just wanted to make a statement. The narrator was invited but chose not to take part and watching it from a distance and feeling guilt for not really being there.”

It’s that complicated emotional portrait of a personal conflict that’s rendered so well.

“In order to have any license to put a character into a situation, you have to be able to reference your own experience too to make that authentic. What I’ve experienced and a lot of people have, is being forced to reckon with decisions they’ve made,” he says.

Porterfield, who went to college to study journalism before finding a job in student affairs at Marquette University, says he enjoys the freedom of creating a new world in his songs.

“There are a lot of people speaking on this record that are not necessarily me. The ‘Alcatraz’ narrator, the woman in ‘Fergus Falls.’ I probably have a lot in common with these characters generally, but not as far as the specific stories,” he says. “The nice thing about songs is that it’s not like you’re writing an essay or some kind of newspaper piece. You can pay fast and loose with facts and characters. It’s about creating an emotional experience.”

The songs, though, were just the first part of the journey for Field Report.

“I’d been collecting these songs for a few years and also had been trying to piece this band together,” he says. “It was probably about this time last year that things really started to gel and that’s when we added our pedal steel guitar player. Finally the sounds were starting to line up with what I’d been hearing in my head all along. We decided it was time to take these songs to the studio and thinking about how to make that happen logistically.”

Bon Iver’s Justin Vernon offered up his April Base studio and Field Report recorded the album in six days last December, tracking nearly everything live. Then it came to finding a label and hitting the road for an intense year of traveling and performing.

“I wanted to have this thing be a real snapshot of a band in a moment in time,” Porterfield says. “The energy has been gathering around this whole thing and we’ve had some pretty cool opportunities to be on the road with some awesome people. We’re still pretty new at being a touring entity, just following the energy at this point.”

Opening for Mann in particular is a joy for Porterfield.

“It’s unbelievable. She has been a hero of mine for a very long time, before I ever started writing songs. Her lyrics are some of the best ever. I’d put her up against everyone. Her choices on the stage and in the studio are impeccable. What a thrill for us to be able to play with her.”