How Director Lee Sang-min and Actor Kim Hye-yoon Built the Fear in 'Salmokji'

A film is made through many points of view. Even in the same place at the same time, a director and actors may experience the moment differently. “Choi Song-hee’s B-Cut” looks beyond the “A-cut” on screen to the vivid record of what happened on set. By weaving interviews with directors and actors, it reconstructs the “B-cut” moments that were often more intense than the finished frame. <Editor’s note>
 
NOTE: This story contains spoilers for the film.

The horror film “Salmokji” begins when an unidentified figure appears in a reservoir road-view image. A team returns to the site to film again and encounters something in the dark, deep water. Rather than leaning on a simple ghost story or shock tactics, the film builds dread by stacking small, unexplained signs and the sense that people at the water’s edge are slowly being overtaken. On set, director Lee Sang-min and actor Kim Hye-yoon discussed in detail how to shape that fear.

Lee and Kim share a love of the horror genre, but approached the material from different angles. Lee focused first on sound, devices and the texture of the location, while Kim built the emotions of a character who tries to hold on but ultimately begins to crack. Their perspectives, they said, helped make the film’s fear more layered.

“Kim Hye-yoon is sincere and exemplary by nature,” Lee said. “Since this is my first film at this scale, she was a huge support. She gave a lot of good ideas, and I was grateful that she helped organize difficult ensemble scenes. Her expressiveness is excellent, too. She seemed to know exactly what the right level was. I think we worked together really well.”

Kim said Lee came to set with clear images in mind but left room for actors to explore. “On set, the director had a firm picture of the script in his head, but when it came to acting, he opened things up so we could freely offer ideas and try things,” she said. “He’s the type who likes building scenes through lots of conversation.”

Their shared genre interest also carried into discussions about equipment and staging. Lee said he regularly watches horror content on YouTube and wanted to bring elements he found frightening into the film, including a “ghost box,” a device often used in paranormal videos.

“I really like horror YouTube,” Lee said. “Watching YouTubers use things like a ghost box, I thought, ‘Someday I have to use that in my movie.’ Usually you just hear static, but if, at a certain spot, words start pouring out, that would be terrifying. Those were elements that scared me even on YouTube, so I tried to blend them into the film.”

Kim said she was familiar with the device as well. “Since I really like horror, I knew about that equipment,” she said. “The director also knew the ghost box well, so we talked about the gear and discussed how to use it. Ha.”
Kim plays Su-in, a central figure in the team heading to Salmokji. The character must project leadership, but carries an emotional fault line that could collapse first. Kim said she built Su-in around two key ideas: fear of water and guilt.

“When the director and I were creating Su-in, we used fear of water — trauma — and guilt as keywords,” Kim said. “She’s under a lot of stress from that, so I thought it would be good if she looked exhausted in every way. I designed her to seem worn down and tired, and even when she’s with others, to look like she’s lost in different thoughts.”

Lee said he began by researching road-view filming and assigning roles needed for the job, such as a road-view controller and a command post. He then built Su-in’s backstory around the film’s water spirit, which he said must “pull” someone into the water through the character’s narrative. He also wanted each team member to have a different private goal, with Su-in serving as the group’s anchor.

“I thought we needed a leader-type character who holds the center,” Lee said. “She needs rational judgment, but why is she obsessed with Salmokji? That’s why I gave Su-in the keyword ‘guilt.’”

Su-in’s past is not fully explained in the film; viewers are left to infer it from dialogue and mood. Kim said that choice helped keep attention on the fear created by the setting itself.

“I wanted audiences to focus only on what happens in the film’s ‘space,’” Kim said. “I wanted to unpack the backstory, but no matter how I thought about it, it felt like the flow would drift in another direction. So I think we ended up conveying it only through nuance. Su-in has an experience where she almost died in the water, and because of that trauma she’s afraid of water. She’s assigned to Salmokji for road-view filming, and even though she doesn’t want to go, she goes anyway. We tried to capture the fear of the space itself and the discomfort of the water.”

Kim added that Lee explained Su-in’s backstory when she first received the script, even though it would not be shown directly on screen. “I tried to compress those emotions and show them to the audience,” she said.
One scene Kim said she remembers most strongly involves skipping stones. The moment, with Kyung-jun and Sung-bin tossing stones as if killing time, briefly slows the pace before the film turns the familiar rhythm into sudden fear.

“As a horror fan, my favorite scene in this movie is the skipping-stones scene,” Kim said. “It was also the moment that startled me the most in the theater. During filming, I couldn’t see what was coming from the other side because it was CG, but on the big screen it really surprised me — and it was truly scary.”

Lee said sound was his top priority in shaping that sequence. “When should it become quiet? The best moment in a horror movie is when everyone holds their breath,” he said. “I wanted to bring out the silence. I wanted the sound of the stone flying in, the impact, and the splash to feel sharp. I talked a lot with the sound engineer about how strong the lapping should feel. When you don’t know it’s water, we cut the sound down, and once the camera tells you it’s underwater, we made it feel bigger.”

In the end, the film’s fear was built through more than one method. Lee tightened tension through the arrangement of space, sound and devices, while Kim carried Su-in’s inner collapse, shaped by trauma and guilt. Their different approaches to the same reservoir, they said, meet in the finished film’s chilling tone.