Every artistic endeavor considered beautiful or haunting or mind-altering or maybe just cool was most likely a grind. Someone had to give Michelangelo notes on the Sistine Chapel. The same goes for movie masterpieces. Producers do math, directors herd attractive human cattle, actors tediously memorize words. Movie trailers, the lauded first glimpse of something that culminates decades of eager fanboy angst, aren’t much different.

In 2005, two days after getting my undergraduate degree in film, I walked into Los Angeles’s Trailer Park, then housed in a little brick three-story building at Hollywood Boulevard and Ivar Avenue, a stone’s throw from where film legends press their palms into the concrete outside Grauman’s Chinese Theatre. (Trailer Park now stands directly across the street from the theater, a glowing motor lodge sign on top.) I had no experience and no ego—just a car. So I was tasked with driving freshly edited copies of shiny new trailers to marketing execs around L.A., an often dangerous, thankless job that technology has effectively eradicated.

Trailer Park was a buzzing hive of weird, funny, angry, often stoned people—most deeply talented—who banded together for about 20 hours a day to somehow perfectly encapsulate two-hour films into two minutes and 30 seconds (and then 60 seconds, 30, 15, whatever your wandering mind has time for). There were teams of editors and assistant editors, pacing producers and nebbish writers, graphics folks and sound engineers. And lowly runners. Sometimes Tom Cruise would ride up in a blacked-out Ford Excursion to pick at cheese plates and stand over an editor’s shoulder as she cut new versions of a Mission: Impossible III trailer. This is the grind.

No one was happier to see me than Jeff Gritton, then a towheaded 22-year-old runner who was getting the call to move upstairs and become an assistant editor. Now 35, you’ve almost certainly seen Gritton’s masterworks—he helped create the trailers for many of Pixar’s recent films, including stitching together an award-winning spot for Up and the theatrical trailer for last year’s Coco.

“Sometimes we’ll start on a trailer before they’ve even started filming,” Gritton says. “We just break down the script. Then we’ll get dailies—literally everything they’ve shot, hours and hours.” The dailies are covered in ghostly watermarks and stamped with the producer’s and house’s name for security’s sake, making them nearly unwatchable and of no real use to pirates. Theoretically.

Given the extraordinary and time-consuming process of CGI, sometimes green screens, motion capture dots on actor’s faces, maybe a cardboard cutout where a dragon will eventually go are still visible in these early cuts. “We’ll pick what we think are the best takes,” Gritton says. “The majority of the time it’s not what ends up in the film, which is why you see stuff in the trailer that you may not recognize later.” With animation, it’s even more convoluted. For months, Gritton often won’t have anything more to cut from than storyboards, or moving sketches known as animatics, and rough audio. (The Incredibles director Brad Bird famously temped the voice of Edna before giving himself the role.)

For larger projects, trailer editors have a window of time at the beginning, “four or five days,” to go through the footage, break down the film, write out the best dialogue, listen to music, and find a pace before they start cutting. “Ideally for version one, you’re going to have some time, a couple weeks, to work on it,” Gritton says. “But sometimes they call and we get two days.”

On the other end of that phone are people like Trenton Waterson. He worked as a Marvel creative executive during the second and third phases of the MCU, predominantly on Iron Man 3, before leaving to produce his own film projects. Marvel’s marketing team would call three or four trailer houses, sometimes with firm directives, and turn the trailer producers, editors, and copywriters loose on the footage.

“I remember the message of Iron Man 3 was: [intense trailer voice] ‘Does the suit make the man or does the man make the suit?’” Waterson laughs. Each house sent in two or three initial trailers, and then he and Marvel top men, president Kevin Feige and producer Stephen Broussard, would scrutinize the spots. “Five of the trailers really got it,” says Waterson. “Two or three were like, ‘Spectacle! Iron Man! Blazing laser lights! Soaring through the air!’ Great, but not our movie.” Sometimes one trailer house gets the green light, but more often the work is split between a couple of houses to get different perspectives and target different demographics. They’ll vie for the “finish” at the end (i.e., the final version that projects across the front of a theater). These houses are paid in the neighborhood of $50,000 to start on a trailer with one or two sets of revisions. If they’re chosen by the studio to finish a campaign, the final payout can reach up into the millions depending on the number of trailers, teasers, TV spots, and online campaigns that are ultimately created.

Given how trailers have exploded in popularity due to streaming and YouTube, Waterson also notes how studios have rejiggered their shooting schedules to front-load them with “trailer moments.” “For the first two weeks of Avengers, we purposefully shot a crazy amount of stuff because they were already thinking about Comic-Con the next year,” Waterson says. “They’re like, ‘It’s nine months for visual effects. We gotta get this in the can!’”

Other studios have no idea what they want. “Sometimes it seems like the houses are looked to to provide the basis of a strategy,” says Travis Weir, once a copywriter at Trailer Park who now cuts behind-the-scenes footage for the likes of Sony and Paramount. “Sure, that’s a big part of what we were paid for, but sometimes it’s a little surprising. It’s like, ‘Well, you guys are the ones making the fucking thing. Don’t you kind of have an idea?’”

While everyone generally agrees it can be easier to craft trailers for good movies, Bill Neil, an editor at Buddha Jones, suggests that since he’s looking at elements rather than a completed work, it’s difficult to judge the ultimate merits of a film. “We try to discover the best stuff about each movie,” says Neil. “What’s exciting about the movie, what’s the best possible version of it, because it’s not fully formed yet. We get inspired by that idea, and that’s what we work off. When the movie comes out and it’s not so great, well, we gave it our best shot.”

As producers and editors are toiling, copywriters are hiding in their offices, taking dozens of stabs at six-word taglines and crafting splashy narration for trailers and TV. “It’s abstract art,” says Weir. “Sometimes, I would just write the most offensive, absurd, and completely tonally off thing and just bury it in there just to see if anyone was reading. More often than not, that would end up being a contender.”

More focused experimentation is happening in the bays, where editors like Neil and Gritton are designing new methods to make their trailers stand out among the eight to 10 you may see ahead of most big-budget Friday releases.

“With a lot of narrative film editing, you tend to want the editorial to be invisible,” says Neil. “With trailers, it’s much more style-driven. You can be much more showy—you want to be showy.” For Neil, the heart of the trailer is music and sound design. Think the Inception “bwooong.” Multiple people told me that it was Neil’s work for the 2003 Texas Chainsaw Massacre remake that redefined how horror trailers are cut. With the simple winding whir of camera, he raised the bar.

“The frame was shuddering and the footage was sizzling and the sounds were right up at the front of the mix, not buried in dialogue,” says Weir, who joined Trailer Park with hopes of working with Neil. “His influence to me was audacious. He was calling attention to his cuts, but not in a way that was unwarranted. The trailer kind of sits apart from the movie, but in some subliminal way, it was about telling the audience, ‘Don’t worry, it’s not the Texas Chainsaw you’ve seen.’”

Neil, who’s been cutting for more than 20 years, has since worked on trailers for “just about every horror film remake” since, including Dawn of the Dead. He also cut some of the most memorable trailers since 2000, including The Prestige, The Wolf of Wall Street, Flight, and Mother!, the last of which he called a “jaw-droppingly difficult movie to try to sell.” His trailer for the culmination of M. Night Shyamalan’s Unbreakable trilogy, Glass, debuted last weekend.

A newer trend is the use of slow, powerful covers of famous songs. Think The Social Network and “Creep,” Fifty Shades of Grey and “Crazy in Love,” and most recently Ocean’s 8 and “These Boots Are Made for Walkin’.” For Coco, Gritton and the studio had tried dozens of songs, but nothing really worked. So he had one of his friends strum a cover of “Bitter Sweet Symphony” on a Mexican guitar and got the nod.

Once an editor and producer have locked in their initial versions, studio notes are addressed—sometimes for months in the lead-up to a trailer’s release. Then the timeline accelerates. “Most trailers are getting up past 30 versions,” says Gritton. “It’s definitely not unheard of for some to make it to 100 versions.”

Ten years ago, a dedicated group of runners, all misfit 20-somethings with other career aims, raced DVDs and tapes of each version to Fox, Sony, Disney, and more. In the film vault, runners hung out and “borrowed” copies of Borat for a weekend six months before the movie’s release. According to former runner Dave Horwitz, now a staff writer for Rick and Morty, they complained of Entourage-level villainy from executives and “embellished immensely on mileage sheets” when gas was pushing $5 a gallon. Today, dedicated fiber-optic lines between the studios and the trailer houses instead run a live playback feed in real time. Yet the business is again shifting eagerly to secure streaming services. But the gist is the same: Editors make the changes. They post a cut. Notes come in. The cycle repeats.

The editor will stay all night if they have to, to get it just right, only to have the producer come in and tell them the music hits too late. There’s even a graveyard shift to deal with emergency requests that may come in from the studios after 9 p.m. if, god forbid, someone actually leaves on time.

“I jump on a lot of things. Sometimes it’s as simple as cutting in graphics and voice-over. Other times it’s major notes,” says Natalie Chetkovich, who’s been Trailer Park’s mainstay at night for 15 years. “I have to be a jack of all trades. They’ll throw me on action, and then I’ll be on romantic comedies, and then I’ll be on political dramas.”

Chetkovich remembers fielding a call from producer Jerry Bruckheimer near midnight in 2008 when Confessions of a Shopaholic—a film about a shopping addict drowning in credit card debt—needed to be repackaged overnight in light of the financial crisis.

”For a long time it was a bit of hidden secret,” she says. “The clients didn’t know we had someone working at night. It’s like, ‘We magically had it done in the morning, how did that happen?’”

“All of this up to now has been the ideal—a nominal march of progress to the finished product. It is rarely that,” says Weir. “Deals expire. Reshoots happen. Movies get shelved. The director finally gets to a place with decent Wi-Fi and watches Version 25, only to flag half the shots for spoilers. He hates the music or claims the movie it sells is not the movie they made. Patience wears thin or someone gets too salty on a call and it’s already too late to apologize.”

Few directors have final cut of a trailer, but most get some say depending on their status. “[Someone like] Shane Black probably just gets shown the trailer,” says Waterson. “I’m not there anymore but I’m more than positive the Russo brothers were heavily involved in [the trailer for Avengers: Infinity War] just because they had that much leverage.” Gritton remembers Christopher Nolan sending only about 40 minutes of footage total, not the typical hundred of hours, to cut the entire Dark Knight Rises campaign.

Assuming the finish is finally won, that watermarked mess is replaced at finishing houses with clean footage and mostly completed VFX and CGI shots. Rough animation is swapped for the real thing and recorded performances are added. Sometimes jokes no longer line up. “You’ll start getting closer and closer and then you’ll get the list from the studio’s animation team that details which shots won’t get done in time,” Gritton says. “So now you have to find something new.”

The final step is the sound mix, where often the film’s director, studio executives, trailer editors, producers, and anyone else responsible shows up. “‘Raise this line, lower this sound effect. Do this. Do that.’ Those mixes take hours and hours and hours,” says Gritton. And even then, he’s seen months of work die at the deadline.

Once the trailer is completed, it’s finally sent to theaters and uploaded to YouTube, at which point some Twitter egg named Cornholio6374438 will call it trash and complain about spoilers.

For that, most trailer editors will politely instruct you to pound sand. “There are companies that test-market trailers with hundreds of people from different demographics all around the country,” says Neil. “When they’re asked what they’d like to see, a lot of times the answer is ‘more.’ More information, more story, more scares. To make it more broadly appealing, to get butts in seats, you might have to show a little bit more. People want to know what they’re buying. They don’t want to just go in blindly. If you’re sold on the movie already, you don’t need to watch the trailer.”

Advice not taken. Thanks.

Matthew Kitchen is an editor for The Wall Street Journal’s weekend feature section Off Duty and a stan for The Prestige trailer.