The Oscar-winning ‘Gravity’ auteur details why he cast nonprofessionals (with one major exception) and became his own cinematographer, along with his obsessive attention to detail and a script so secret nobody was allowed to read it.

Alfonso Cuaron was nearly halfway through shooting Roma, the black-and-white Spanish-language film based on his Mexico City childhood, when he walked off the set. "I was in a really lousy mood," recalls the 56-year-old director. "I had been in a lousy mood for a while. And the scene was not working, so I said, 'Let me take a little walk.'"

He strolled down a tree-lined street in Mexico City's Roma neighborhood, a street his production designer had transformed to look exactly as it did when Cuaron was growing up in the 1970s. Parked along the sidewalk were replicas of old cars — in the exact colors he remembered from those days — while the extras on set were dressed just as his childhood neighbors used to be. Even the leaves scattered on the ground were copied from the deep recesses of Cuaron's memory. "I turned and said, 'Look at you, why are you in this foul mood? Just relax. How many people have the opportunity of re-creating their life?'"

Unlike most autobiographical projects, Roma doesn't center on a younger version of its creator. Although Cuaron does replicate a version of himself as a 9-year-old, the character doesn't see much screen time. Instead, the movie focuses on the two most influential women in Cuaron's youth: his mother (Cristina, renamed Sofia in the film) and the woman he still considers his second mother — his middle-class family's live-in nanny, Libo (Cleo in the film). The movie isn't so much a cinematic memoir as it is an ode to the sacrifices women make for family (both their own and those they take care of), and it already has become a top awards contender after debuting to raves in Venice, where it won the Golden Lion (it's slated to be released Dec. 14 on Netflix).

Cuaron had been thinking about making Roma for more than a decade; in fact, after his 2006 sci-fi drama Children of Men, he announced on Charlie Rose that Roma would be his next film. Of course, it wasn't — after a hiatus from the screen (he took some time off for personal reasons after going through a divorce), Cuaron returned with 2013's Gravity and became the first Mexican filmmaker to win a best director Oscar. After that, he was flooded with offers, but the pull to make Roma became overwhelming. "It started to be like this emotional need to do this film," he says.

His first step was research. He spent hours talking to Libo about her own experiences as his family's housekeeper. "I had endless conversations with her about every little detail about her routine, day by day, by almost, like, milliseconds," he says. "Like, 'When you got out of bed, how was it? Did you just lay down? Or did you spring up and go to work?'" They also spoke about the side of her life that Cuaron did not get to see, Libo's days off, away from his family. "It was very, very shocking to discover a whole new side of a human who is so close to me and part of my family," he says.

In early 2016, he wrote the screenplay in one pass over a couple of weeks. In the past, Cuaron had always shared his works-in-progress with a close cadre of creative collaborators, including his brother, filmmaker Carlos Cuaron, Shape of Water helmer Guillermo del Toro and Birdman's Alejandro G. Inarritu. Not this time. "I didn't want those notes to taint that stream of consciousness that I had," he says. "I was not going to allow my reason, my intellectual side, to interfere with the process of creation."

Even when he pitched the movie to Participant Media CEO David Linde — over vegetarian dim sum in London — Cuaron refused to show him any pages. Instead, he talked Linde through a detailed outline of the narrative. "Even though he grew up in Mexico City and I grew up in Eugene, Oregon, the sense of memory in a cinematic form came through from the very beginning," says Linde, who agreed to finance the film's $15 million budget.

Bringing Cuaron's memories to life — particularly in such a precise manner — required a long and intense preproduction process. During casting, for instance, Cuaron considered only actors who physically resembled the real people from his childhood. That meant hiring mostly nonprofessionals, with one major exception: 44-year-old Mexican actress Marina de Tavira, who has starred in several Spanish-language films, was invited to audition for the part of the mother. She was given no pages to study and wasn't told that she'd be auditioning for one of Mexico's top directors. She was simply instructed to show up without any makeup on.

"Everything was really magical, really mysterious," de Tavira says. Even after she got the role, she wasn't allowed to look at a script. Instead, Cuaron talked to her about the character and her background, never revealing that it was based on his own mother. But de Tavira caught on. "The way he was talking, I could see it was his mother," she says. "He didn't say, 'It's my mother,' but I knew."

To find the woman who would play the nanny, Cuaron and his team went village to village throughout Mexico, auditioning hundreds of women. "Part of the problem was that if they were from Mexico City, they were jaded by the city," he says. "They are more guarded than the optimists in the country." Yalitza Aparicio, a preschool teacher from a town in Oaxaca, brought her mother to her audition because she was concerned the meeting might be a trafficking scam. Cuaron took one look and knew he had found his Cleo. "I was very concerned because time was running out," he says. "But when she walked in, it was just a relief."

Cuaron didn’t have to look far to cast Cleo’s best friend and co-worker. He asked Aparicio who her real-life best friend was, so she introduced Cuaron to Nancy García García, whom he quickly cast. “I think that that helped Yalitza to say yes, you know? Because, ‘OK, I'm going to be with my friend in this crazy picture,’” he says.

While Cuaron continued filling out his cast — including Veronica Garcia as the grandmother who lives with the family and Fernando Grediaga as the father who abandons his wife and children, just as Cuaron's own father had — production designer Eugenio Caballero began mapping out the sets and locations. It wasn't easy since he wasn't allowed to see a script, either. Instead, he had to rely on verbal descriptions. "I was surprised by how detailed [Cuaron's] memories were — down to the toys that he and his sister played with," says Caballero. "He had been gathering memories from the rest of his family, so it was a beautiful package to start with."

It took time to settle on a house to stand in for Cuaron's childhood home, but they ended up finding a near-enough facsimile in Mexico City that was scheduled to be demolished, which allowed Caballero to rip apart the interior, adding movable walls. Much of the set decoration was made up of furniture reclaimed from Cuaron's family, and Caballero went so far as to put in hand-made tiles exactly like the ones the director remembered from his home. "You needed to create a floor that sounds like a floor and feels like a floor and smells like a floor," says the set designer. "It helps the actors."

Even the briefest scene, in which Cleo is seen on the rooftop hanging the laundry, required Cabellero to scout more than 120 rooftops to find the one that most closely resembled Cuaron’s own. “It's a very Mexican thing, the people that worked in the houses — the housekeepers — would have a world up there that was rarely seen by the people that lived in the house,” he says. “It was their domain, in a certain way.”

The costumes had to also be constantly readjusted to meet Cuaron’s expectations, and because the film was in black and white, often garments had to be dyed a hue lighter or darker to get the contrast that Cuaron wanted onscreen. At one point, Sofia wears a blouse with a floral print that costume designer Anna Terrazas describes as “perfect” — except for the one little corner of it that Cuaron thought was a bit too white. “I was like, ‘You know I cannot dye the whole thing because if I dye it then the flowers are going to change,’” she says. “And he was like, ‘Well, I don't care what you do. Maybe just paint it by hand.’” So she did.

One thing Cuaron didn't have control over, however, was the availability of his longtime cinematographer Emmanuel Lubezki. Cuaron and Lubezki, known as "Chivo," had collaborated closely through the months of preproduction, but when Roma's start date got pushed for more prep time, Chivo ran into scheduling problems. "He started telling me he didn't think it was going to work, and I didn't want to hear him," says Cuaron. When it became clear that Chivo wouldn't be available, Cuaron met with other DPs. "But this was a film I was doing back in Mexico in my mother tongue. I didn't want the work on the set to be in English. That's when Chivo told me, 'Come on, stop fooling around. You have to do it.'"

So Cuaron, who already edits his own films, became his own cinematographer. Although he studied cinematography in film school and had DPed some television, Cuaron sent Chivo his dailies at first. "Finally he said, 'Man, you're doing great. Stop bothering me,'" says Cuaron.

Even during the 108-day shoot (which began in November 2016), nobody was allowed to see Cuaron's script. He'd meet with each actor at the start of the day and walk them through what his or her character would be doing, sometimes giving a few specific lines but not much else. The actors seldom knew what the other players in their scenes were going to do. "I wanted everybody, actors and crew, to learn the circumstance of the characters day by day, the same way that you learn in life."

When Cuaron finished shooting, he put together a 10-minute reel to show distributors. Even for an Oscar-winning director, selling a black-and-white Spanish-language family drama set in the '70s was no easy task. Netflix was one of a handful of buyers that expressed interest, offering around $20 million for the rights in late 2017. Linde and Cuaron, who used Dolby Atmos for the film's rich sound design, debated for weeks before committing to the streaming giant because of the filmmaker's hope that "as many people as possible see it on the big screen and with the proper sound." But what became more important, says Cuaron, is that as many people as possible see it. So they went with Netflix and its 137.1 million subscribers around the world. "It was a combination of wanting the film to be seen in theaters but also to be seen by millions," explains Linde.

And after reports that Cuaron has continued to emphasize his desire for as many people to see it in theaters as possible, Netflix announced on Oct. 31 that, in a major course correction, it would release Roma in theaters, starting with several cinemas in Los Angeles, New York City and Mexico on Nov. 21, more than three weeks before its official Netflix debut in mid-December. It will add additional limited engagements on Nov. 29 and Dec. 7 in more top markets such as London, and it's expected to play in 20 countries once it rolls out globally Dec. 14 on Netflix.

Early screenings have been more emotional than Cuaron anticipated. "It was strange, people coming up and hugging you, crying," he says. "But they're crying about their own memories." For him, though, it was on that grouchy day in Mexico City when he walked off set that he realized how much his own emotions were tied up in the film. He'd been so focused on the engineering challenge of re-creating his childhood — of getting every element correct — that he'd lost sight of why he was making the movie in the first place. "That was my awakening to what was going on inside me because before that, it was an obsession about the details," he says.

On that particular day, Cuaron was shooting the sequence in which the father walks out on his family. He'd been talking to the actor about how to approach the moment. "I said, 'When [your family] talks to you, you feel suffocated,'" recalls Cuaron. " 'But when you get into the car, you start breathing. You drive away, and man, you're breathing for the first time.' And that's when I realized that I was directing the scene in which my father is leaving. I have always seen that moment with judgment. I have always judged my father for leaving. I have never stopped to think what he was feeling."

A version of this story first appeared in the Oct. 31 issue of The Hollywood Reporter magazine. To receive the magazine, click here to subscribe.