The real Russian spy story that inspired The Americans, FX’s acclaimed drama about Russian sleeper agents living, working, and raising a family in the US, didn’t actually take place during the Cold War. That saga unfolded decades later. But in 2013, when Joe Weisberg created the show, he thought American audiences no longer considered relations with Russia to be tense, so he set it at the time when US-Russia tension was at its peak, in the early 1980s.

It’s a good thing he did, because beyond ratcheting up the intensely suspenseful plot lines, the time-capsule effect makes for some of the most unexpectedly fun production design and costuming on TV. There are high-waisted mom jeans, loads of turtlenecks, tan suits, Flashdance-style gym wear, and wigs of countless frosted varieties. The clothes aren’t about caricature, though. They’re about recreating the era down to the last pleated detail.

The wardrobes on The Americans are the result of exhaustive research by the show’s costume designer, Katie Irish, and her team, who obsessively dig through any documentation they can find from that period—the current season is set in 1984—to create the looks for the cast. ”I look through everything from magazines like Vogue, Cosmo, or GQ, Better Homes and Gardens sometimes,” Irish says. “I look at Sears catalogs. I look at J.C. Penney. I look at old school yearbooks. I look at movies and music videos that came out at that point. Anything where there might be photos of people in real life or the aspirations that people wanted to achieve.”

Irish and her team also put together research boards that help them nail down a character’s look. Renee, one of this season’s new additions, played by Laurie Holden, is introduced at the gym, and her board is appropriately covered in brightly colored spandex and leg warmers. Tuan, another new character, played by Ivan Mok, mimics the now endearingly quaint model of cool American teenage guys in 1984.

Katie Irish/The Americans 1984, the age of aerobics.

Patrick Harbron/FX Laurie Holden as Renee, in a very 1980s leotard and socks.

Authenticity is crucial. Irish is always telling the cast to pull their high-waisted pants up even higher, because that’s how people wore them before the era of low waists.

Patrick Harbron/FX The Cold War look.

The point is to use clothes to embody the characters and bring them to life in a way that lets audiences believe in and feel invested in them. The show’s leads, Elizabeth and Philip Jennings, played by Keri Russell and Matthew Rhys, are characters who live their lives in costume, in a sense. They dress like the upper-middle-class travel agents that they have embodied for years, but there are subtle hints at their internal selves, as ideologically driven Russian spies. “They’re Russian at the core,” Irish explains, “and they don’t want anything that is overtly capitalist.” You won’t see much logo branding on their clothes.

The process of finding garments that look the part can be arduous. Irish has two full-time shoppers who work 10 hours a day, five days a week searching shops in New York for the right items. They also rent pieces, and frequently have garments custom-made. (Luckily, the surging popularity of retro sneakers means at least those are easy to come by.)

Katie Irish/The Americans The research board for the character of Tuan, played by Ivan Mok.

The source material can be amusing in a “How did we ever dress like that?” way, something Irish and her team occasionally have to tone down for the clothes on screen. The show will not soon start to look like a spy remake of 1980s soap opera Dynasty, in all its shoulder-padded glory. “There are some things that, viewed with a modern eye, would be too jarring or too comedic for anybody to wear and be taken seriously with the plot lines that are happening on our show,” she says.

One place where the show doesn’t seem to hold back are the disguises the Jennings often wear. Their endless supply of wigs and fake facial hair have become one of the show’s signatures. The production holds a hair-and-makeup disguise meeting so everyone, including Irish, can nail down the details of each look, again with authenticity in mind.

Patty, one of the disguises Elizabeth adopts in season four, was a favorite for Irish because she was much more over-the-top in her glamorous and “very current” 1980s fashion choices.

In the latest season, the Jennings are masquerading as another family, the Eckerts. For their covers, Elizabeth plays a stewardess, and Philip a pilot. “That means that his mustache can only be so long, his hair can only be so long,” Irish says. “Your oxygen mask has to be able to fit over comfortably without being blocked by any hair.”

Authenticity is in the details.