“You have to be able to see that your work is shit so you can challenge yourself for the next one,” director Robert Eggers asserts. “If you feel like you’ve succeeded you can’t grow.”

If he wants to grow, Eggers is going to have to work very hard not to read any reviews of his new film The Lighthouse, because the consensus is that the film is a raging success by every measure. A mysterious black and white arthouse horror set in the brutal isolation of an 1890s lighthouse, the film is essentially a two-hander between lighthouse keepers Willem Dafoe and Robert Pattinson. Their relationship quickly deteriorates due to suspicion, power plays, paranoia, and possibly a supernatural assault. Is this psychology, toxic masculinity, or an ancient force?

Maybe it’s just Eggers. Growing up in New England, surrounded by stories of witches and Salem, the 36-year-old director was always fascinated by the way religion and folklore intersect and shape our understanding of the world. “Growing up in New England in a house in the woods where there are 18th century family plots, you have a sense of that New England folklore,” he notes. “So witches and other beings like vampires and werewolves always fascinated me. For kids, there was a sense of folklore that we created in all the old houses. There was an old New England house with a woman who was a hoarder, and as kids we thought of her as a witch, because we knew what that was.”

It’s no surprise, then, that his debut feature was The Witch, a beautifully realised and tense period horror tackling folklore, religion and patriarchal control in Puritan New England. The Witch was met with adjectives like “unconventional” and “enigmatic” – though compared to The Lighthouse, it feels utterly accessible. Is Eggers pleased that audiences find his work ambiguous, or is there ever a desire to sit people down and say, ‘No, you don’t understand just how smart I’m being here, let me explain it to you’?

“I hope that even at my most inebriated that’s not something I would say to somebody!” he laughs. “No, that’s not my mode. I don’t think there’s much to interpret in The Witch and to me, the movie is quite clear. But I’m genuinely happy that people can find different interpretations within it. Meanwhile, The Lighthouse is meant to obscure, as the plot is incredibly thin and it is supposed to be unexplained. That’s a different kind of storytelling.”

Ambiguity can be tricky to direct and act, and Robert Pattinson told Eggers early on, “I don’t want to make a movie about a magical lighthouse. I want to make a movie about a fucking crazy person.” How did the director balance the film’s ambiguity with his own certainty of vision, and his actors’ potentially different interpretations?

“Rob and Willem both have their techniques, and they know what works for them,” says Eggers. “But they also have done a lot of work with auteurs, and thankfully work with wannabe auteurs like myself. They know that for the film to have any chance of succeeding, they have to submit to my technique. Then it’s up to me to bend as much as possible under the umbrella of my vision to work for them. Willem doesn’t care about backstory and intention and that stuff, he kind of just says what’s on the page. But Rob wants to know backstory, intention, all these different things. I provided him with a lot of research so he could make his own choices, and then he trusted his gut.”

Pattinson and Dafoe give incredibly committed performances, and Pattinson has been (largely cheerfully) open about the shoot’s gruelling intensity. They weren’t the only ones who found the shoot rough. “Every day was really hard,” admits Eggers. “Any time we thought, ‘Oh today will be an easy day’, it turned out to be incredibly difficult! We were tying the schedule in knots, and we were at the mercy of the weather, because we needed bad weather. So the good weather was putting us behind schedule. But also, when it’s zero degrees and there’s gale force winds, you can’t move quickly. And then in studio, things like the lighting and choreography were very tough. Willem would say that the most trying scene was – spoiler alert – where he’s lying in the mud delivering a speech, while dirt is being thrown in his mouth. Which is fair enough!”

Eggers shot the film in 35mm black and white, and uses a square aspect ratio to evoke the feeling of an early sound film. But he also plays with light, shadow and shooting angles to create an extraordinarily atmospheric cinematic language, which feels theatrical yet immersive, ambitious yet claustrophobic. It feels uncompromising in its vision and execution, which is another description that was applied to The Witch. But for Eggers, were compromises made?

“The Witch had a lot more compromises than The Lighthouse,” he reflects. “Because it was my first feature, I had less power, less experience, less skill, less money. I’m proud of The Witch because I know the obstacles we faced, but I’m disappointed in it in ways I’m not disappointed in The Lighthouse – even though I’m very glad I don’t have to watch The Lighthouse again! But this time, our collaborators were all very supportive of everything we wanted to do.

“There was one compromise that upset me… Okay.” Eggers pauses, as if preparing for a rant, or readying me to think him an obsessive oddball – both of which do indeed occur, albeit in endearing fashion. “The boots that Rob and Willem wear, they had to be made for the film, because those type of wellies from the time period don’t exist anymore. But they were so expensive that their other footwear had to be readymade and not custom-made for us. And while Rob’s work boots and Willem’s dress boots are period correct, I’m very frustrated that those are shoes that have been in other movies, because they’re easy to get. I wanted something more specific than something more generic – correct, but generic. That’s an example of the type of compromises I made on this movie.”

Eggers is currently bringing his uncompromising vision to Belfast, where he’s due to start filming the Viking saga The Northman, rumoured to be starring Anya Taylor-Joy, Nicole Kidman, Willem Dafoe, and brothers Alexander and Bill Skarsgård – though true to form, the director is being slightly superstitious about the whole thing.
“We’re prepping, and if anyone wants to see that movie, think happy thoughts!” he says. “I’ve seen things fall apart but things are looking good. As my Icelandic co-writer Sjón would say, in their version of ‘touch wood’, ‘7-9-13 knock knock knock.’”

Whatever happens, the footwear on his next film is going to be amazing.

The Lighthouse is in cinemas from January 31.