Nick Frank likes to summarize his approach to photography with one phrase: "Reduce to the max."

Get to the point. Remove all distractions. It's a framework that lends itself well to Frank's series on subway stations in Munich, Germany, where he lives.

"Pictures are often overloaded with information so what I'm doing is trying to flatten the image until you see the essence of the main subject," he says.

The Munich subway, or U-Bahn, began running in 1971 right before the 1972 Olympics and is known for the bright color schemes and artistic designs that line many of the subway's 100 stations. In a 1997 book by Christoph Hackelsberger, a member of the city's subway planning council is quoted as saying that transit stations should "radiate a positive mood" and purposefully "help make a passenger's wait more pleasant."

Many of the stations are designed by well-known German architects and the subways themselves are used by hundreds of millions of people each year.

To avoid the crowds and get the kind of clean, empty shots that make up the series, Frank says he has to show up between 5:30 and 6 a.m. on a Sunday morning because that's the only time the subways aren't packed. Even then, he says he only has about an hour before things get busy.

Frank is also not shy about using Photoshop to clean things up even further. The gist of the photo is still present, but he's not afraid to remove trash from the floors or cut a stray person from the background, all with the end goal of trying to create the kind of singular focus that makes his photos pop.

"My photos are not about reality," he says. "It's about what I'm seeing."

He says he was originally drawn to subways not only because many of them are architecturally interesting but also because they tend to be places of creativity. Like many people who ride the trains to work, Frank says he does some of his best thinking on his morning and afternoon commute.

"You usually use the time in the subway to reflect on your day," he says. "It's not about talking to other people, it's all about yourself. Most of my advertising ideas are developed in the subway."

He hopes his photos, with their sharp lines, symmetry and clear focus, help people call up a similar visceral experience to the one they have while on the trains.

"I want to transport you back," he says.

Frank is currently running an Indiegogo campaing to fund more subway shoots around the globe so please visit his site for more information