Director Ryoo Seung-wan on the on-set approach of Park Jeong-min and Zo In-sung in 'Humint'

Vladivostok, where secrets and truths sink into an icy sea, is the setting for the film “Humint.” Against that harsh backdrop, director Ryoo Seung-wan captures characters colliding at close range. Alongside Ryoo’s trademark action and tension, the film’s pull is also the actors’ screen presence. Off camera, however, the mood was lighter, with confessions like “I worried it would feel cringey” and sheepish explanations such as “I just walked.”

Park Jeong-min plays Park Geon, a section chief in North Korea’s Ministry of State Security, portrayed as a man of cold judgment and quick movement. Park said he trained by going back and forth between the gym and running routes to narrow the distance between himself and the character.

“When the director gave me the script, he said Park Geon is a masculine character with a lot of action, so I needed to prepare,” Park said. “I trained at the gym. I thought he should be someone with a clear purpose, a wild kind of person. Usually, once filming gets going, you start to get self-absorbed — you think no one else can play the role, so you fuse the character with yourself. But with ‘Humint,’ I was scared. Until I saw the finished film, I worried the distance between Park Geon and Park Jeong-min was so big it would make me cringe. Thankfully, after watching it, it didn’t feel that way. I was relieved it wasn’t awkward.”

Park said the references Ryoo provided while shaping Park Geon’s sharp image sometimes added welcome pressure.

“There were so many films,” Park said. “Director Ryoo would put movies on a USB drive or lend me DVDs. There was ‘Tinker Tailor Soldier Spy’ and Hong Kong films, too. Watching them actually made me more confused. I’m not Chow Yun-fat. Ha.”

As Park worked to project a tougher look, crew members also focused on presenting what he called “the coolest Park Geon.” Park said the lighting director studied his face from every angle, down to the height of a single strand of hair, to find the most effective visual design.

“Before we started shooting, the lighting director told me to come to the production company office,” Park said. “They filmed my face 360 degrees and tried countless designs — hair up, hair down — to find a masculine look that fit me. The lighting director was under pressure, too. Ha. I had to look good.”

Park said he also kept up daily routines to maintain his appearance on camera.

“I mostly ran,” he said. “These days people call it ‘trimming the margins.’ Ha. Even after losing weight, I ran every morning to reduce puffiness before filming. It made a big difference.”

Ryoo said Park’s preparation stood out to the entire set.

“Jeong-min came in after losing a huge amount of weight,” Ryoo said. “I was surprised, and the staff were, too. He looked like a different person. As always, Park Jeong-min is known for thorough preparation and for immersing himself in his role. There are many actors with sculpted faces, but I think the actors we’re drawn to are the ones whose attitude shows on screen. Sometimes you can feel a person’s mind even in a shot of their back. In the end, what’s captured is the actor’s condition. A director can’t manufacture an actor’s charm. You can find an optimal angle and set the lights, but you can’t sustain it for two hours with that alone.”

If Park reshaped himself with careful discipline, Zo In-sung, who plays a National Intelligence Service agent known as Manager Jo, began from a different place. Ryoo said he wrote the role with Zo in mind from the start, and described a strong overlap between the character and the actor.

“The character’s name is ‘Manager Jo’ because I was thinking of Zo In-sung when I wrote the script,” Ryoo said. “Viewers will be curious about him, but you can think of Manager Jo as Zo In-sung. Ha. He lives alone, he only works, and when his own work (acting) doesn’t go well, he suffers. The sync rate is very high.”

A walking scene that some viewers have described as a “runway” moment also drew differing, playful takes from actor and director.

“I just walked,” Zo said. “They told me to walk in, so I walked in. Ha. There wasn’t any special direction. I thought it was important to carry over the emotion from the previous scene. I didn’t intend to walk in a cool way.”

Ryoo said the scene was not designed to look like a runway, but that it stayed with audiences.

“We didn’t deliberately make it like runway walking,” he said. “Zo In-sung is harder to shoot in short takes. There are long walking scenes early on for Park Geon, too — he walks a long way, even to a North Korean restaurant. But no matter how long Park Geon’s scene is, what stays with viewers is Manager Jo’s walk. Ha. I wanted to tell the story of someone who ultimately has to walk alone, someone who ends up alone at some point. In-sung actually stripped away model-like walking and kept it plain. He’s someone from a different world.”

Ryoo’s view that an actor’s appeal is not created by a director but captured in the performer’s on-set “condition” runs through “Humint.” The film, he said, was filled by the actors’ hard-won self-proof — Park and Zo aiming for a strong image without losing humility, and bringing energy that contrasted with Vladivostok’s cold landscape.