Major changes — both personal and professional — impacted the filmmaker's experience on his new movie, but he remains undeterred.

It’s safe to say “Phantom Thread” was one of the most difficult production experiences of Paul Thomas Anderson’s career. He started shooting his ‘50s period drama on the day of the presidential inauguration; during the shoot, leading man Daniel Day-Lewis decided to retire; and on the last day, Anderson learned that his longtime friend and mentor Jonathan Demme had died.

“The world was a very, very different place than it was when we started writing this story,” Anderson said, in a conversation from his room at the Crosby Hotel in New York. Recalling the start of the production, his voice became so soft it sounded as though it could break at any moment. “It didn’t make it easy to look at your country on fire, and you’re telling the story of a self-consumed egomaniac,” he said. “But that was the situation we were in.”

Yet the intimate saga of Reynolds Woodcock (Daniel Day-Lewis), Anderson’s prickly British dressmaker, didn’t transform into an avatar of modern-day concerns. Instead, as the fussy loner finds his match in insuppressible new muse Alma (Vicky Krieps), the movie becomes an unexpected paean to surviving the travails of creativity through companionship, as she forces her way into Reynolds’ insular world. Anderson, who spends years tinkering with uncompromised movie ideas, has certainly faced a similar challenge in his own trajectory.

Having fathered four children with wife Maya Rudolph over last 12 years, his personal and professional allegiances have grown more complicated. “I think you make a choice of a certain life, to share that with somebody, and to start a family, or not to do that,” he said. “That’s pretty fucking black-and-white right there.”

No prior Anderson protagonist invites as much scrutiny into the filmmaker’s own life. He’s unlikely to find much in common with the frumpy stoner detective of “Inherent Vice,” the quasi-Scientologists of “The Master,” the oil barons in “There Will Be Blood” or the porn stars of “Boogie Nights.” For the first time, Anderson seems to have channeled some of his own sensitivities into a singular character, one whose commitment to his artistry runs counter to his relationship with the world. “I’ve thought about this a lot because it keeps coming up,” he said. “Sewing by its very nature requires a kind of patience and focus that I don’t have, but I have it for sure in other ways.”

If anything, Reynolds may represent Anderson’s creative ideal. “If you came and saw what my desk looks like, you’d be like, right, he’s not Reynolds Woodcock,” he said, and chuckled. “I mean, I am not meticulous at all. I’m really impatient.” Anderson may be dodgy about the parallels, but he unearthed more of himself than even he may realize. Despite Reynolds’ precision with a needle, the man frequently loses his patience with anyone he deems a distraction, including Alma and Cyril, his icy business partner and sister (Lesley Manville). It’s not a stretch to see echoes of Anderson’s disinterest in promoting his work, much less digging into its thematic concerns.

As Alma gets into the habit of bugging Reynolds while he’s in the midst of his designs, or tossing out the last word of every snippy argument, “Phantom Thread” goes through that miraculous transformation of genres as only a PTA movie can: It shifts from brooding drama to comedy. Given the precision of the storyteller behind the camera, this happened by design.

“One of the funniest things you can have is somebody who takes themselves seriously, whether it’s Ron Burgundy or Reynolds Woodcock,” he said, drawing an unexpected parallel with Will Ferrell’s “Anchorman” character. “That lends itself to humor. Those are the funniest bits. Seeing somebody so serious and so self-consumed, which is kind of inevitable in the business of fashion. It’s kind of like a prerequisite at times.”

Nevertheless, that’s exactly how Anderson often comes across. He tend to address his process in only the vaguest terms — showing how he maintains a unique alchemy to his approach, and how little he enjoys talking about it. His movies frequently feel like living creatures that come alive the longer you watch them, developing in ways you would never expect.

Good luck getting him to demystify that. He declined to go into specifics about scenes left on the cutting room floor. (“The magic is trying to preserve what’s there,” he said, though that hasn’t stopped his actors from singling out some excised scenes).

He described his writing process as “a really funny combination of way too much overthinking about backstories, and then way under-developed, never spoken about, just pure instinct, just see something and come up with an idea.” In other words: “It’s such a mess about how we get to things sometimes… Some come really easily and quickly, they just happen as instinctual ideas. Others are belabored, eaten up, and way overworked. It’s just part of the process.”

He gets especially dodgy when asked about Daniel Day-Lewis’ retirement plans, a subject that cast a long shadow on the movie’s release. Day-Lewis’ fleeting rationale for this outcome hints at Anderson’s own current mindset. The renowned Method Actor has described his decision as related to being “overwhelmed by a sense of sadness,” and even went so far as to say that the emotional downturn impacted Anderson as well. The pair forged a deep bond on the set of “There Will Be Blood,” sharing an evident commitment to burrowing inside their work at all costs, and now both seemed to be paying a price.

Anderson sounded at once in denial about Day-Lewis’ decision, and devastated that “Phantom Thread” could have something to do with it. “He’s always talked about it,” Anderson said. “It’s not even new, you know?” Of course, when Day-Lewis released a statement announcing his plans over the summer, it brought a new degree of finality to the decision. “I’m burying my head in the sand with the whole thing, honestly,” Anderson said. “I have to take it seriously because he’s serious and that’s what’s going on, but I’m trying not to say the possibility that we might not be able to work together again.”

He declined to elaborate on his discussions with the actor. “I’m not about to create even more mystery about it,” he said. “I think he’s been pretty clear about it and I’m not in the position of betraying someone’s trust, even if they had shared something with me.”

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