We discuss the voting process depicted in the new papal thriller “Conclave” (in theaters now). Light spoilers ahead!

Twice in recent years, I hopped on a flight to Rome to cover one of the most mysterious, storied and secretive events in human history: the election of a new Pope.

That event is also known as a conclave, a term that lends its name to a 2016 Robert Harris book-turned-film thriller. “Conclave” takes place during a fictional meeting of red-robed cardinals who have flocked to the Eternal City to vote on who will lead the world’s approximately 1.4 billion Catholics.

Many are familiar with the final moments of a conclave, when white smoke rises from a chimney just outside the Sistine Chapel, sending the assembled faithful into a frenzy of jubilation, followed by the appearance of the newly elected Pope on the central balcony at Peter’s Church.

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But given that the Vatican doesn’t really do that do Hollywood, one wonders how the filmmakers were able to capture the nuanced details — from elaborate clothing to Latin vocal vows — on display in the film, which stars Ralph Fiennes, Stanley Tucci and John Lithgow as cardinals with odds and Isabella Rossellini as a nosy nun.

“We got a private tour of the Vatican, and they were quite welcoming, actually quite helpful,” says “Conclave” screenwriter Peter Straughan. “So it was a big research project, really. It’s a fascinating and theatrical world, so you want to get those details right. It’s a very lavish thing.”

Vatican officials seemed OK with the film’s shocking premise, Straughan adds, as well as its depiction of the political machinations of a conclave. “We didn’t want to be toothless in our approach to the Church, which has many faults, but we wanted to be respectful of the heart of the Catholic Church,” he says.

Straughan guides USA TODAY through the questions that arise when watching “Conclave.”

How much of “Conclave” was actually filmed in the Vatican?

No. “You can never film in the Vatican,” says Straughan. “We had to come up with alternatives.”

Most of these options actually existed in Rome, which is packed with marble-clad buildings from previous centuries that could double for many of the chambers, staircases, and corridors featured in “Conclave.” (One notable exception: The Sistine Chapel’s instantly recognizable interiors were recreated on a soundstage, and Michelangelo’s famous ceiling is a computer-generated replica of the real thing.)

Are the 235 Roman Catholic cardinals really being sequestered as juries until they elect a pope?

Yes. As shown in “Conclave”, when a Vatican official meets the assembled cardinals and says the words “extra omnes” (or “all out”), the cardinals are only allowed to interact with each other. “There should be no information coming in from the outside world, or going out, that could influence the election in any way,” says Straughan.

However, there are some officials who can act as emissaries when necessary, although the cardinals themselves cannot leave until a successful vote is taken, which means that a cardinal receives two-thirds of the vote and is elected pope. “While some people can go back and forth, I’m not sure they’re used as detectives like they are in our story,” says Straughan.

Do cardinals who gather for a conclave sleep on the premises?

The cardinals live at Casa Santa Marta, a fairly simple dormitory on the Vatican grounds. They are allowed to mix and mingle in nearby buildings and courtyards and eat together in a cafeteria staffed by nuns.

“Visually, you get this strange mix of absolute ancient beauty and enormous scale, contrasted with this almost business conference center feel,” says Straughan. “You get this big stage feel, with the Sistine Chapel and these men deciding who will represent the Catholics of the world, and then this almost modest backstage feel. Quite the contrast, which makes for a great environment.”

Is the voting process in a papal conclave as formal as shown in ‘Conclave’?

When cardinals gather to elect a pope, they vote as often as four times a day, especially in the first day or two, to determine which candidates are most likely to receive a majority vote. As seen in “Conclave”, the election process is not a raucous affair but solemn and filled with rituals. “Each time each cardinal votes, he must go up to the bowl where his written vote will be placed and recite an oath (in Latin),” Straughan says.

One by one, the cardinals place their folded ballots on top of a round plate and slide it into an oval urn while reciting an oath. As “Conclave” shows, these ballots are sewn together with a needle and thread and then burned with a chemical to send up either black smoke, signifying a deadlock, or white, signifying “habemus papam” — “we have a pope.”

This article was originally published on USA TODAY: Is “Conclave” a true story? We’re actually checking out the book turned movie