Industry vets Lynn Harris and Matti Leshem pooled their wits on Sony's smart summer hit starring Blake Lively.

Fall is the season for Oscar movies; cheap summer thrillers are long forgotten. However, it’s a good time to honor the sleeper success that is “The Shallows.” Today is the film’s DVD release, the final platform for a little $17 million movie that stars Blake Lively, a shark, and a coral reef, and grossed $116 million worldwide.

There’s a sophisticated intelligence behind this movie, manipulating suspense with unexpected twists. This does not happen very often. So what did the producers and the studio do right?

1. Target women.

In fall 2014, veteran production executive Lynn Harris (“Man of Steel,” “Gravity”) founded indie production company Weimaraner Republic Pictures with her fellow dog-loving husband, Matti Leshem. Their goal: produce high-concept movies on modest budgets, aimed at the under-served women’s audience. Leshem brought Anthony Jawinski’s script for “The Shallows” to Harris.

“It was a true thriller and had that surfing and escape thing, that’s so good for the summer,” he said.

Added Harris: “And it had, for us, the thing we’ve been talking about since starting the company, which is focusing on strong female characters.”

The movie pits a smart medical student surfing on a remote Mexican beach against a lethal shark that won’t leave her alone. She’s stranded on a rock with a bleeding wound, accompanied by a seagull (think Wilson the soccer ball in “Castaway”), and must figure out how to outwit the shark and get back to the beach.

That script (then called “In The Deep”) became the subject of a lively bidding war, and the producers sold it to Harris’ old New Line colleague Michael De Luca at Sony in October 2014. When Tom Rothman came in as studio chief, he quickly greenlit the movie to star Blake Lively (“The Age of Adaline”), and changed the title to “The Shallows.” They were shooting by October 2015, for a June 2016 release.

2. Aim at the middle.

“It’s focusing on filling the hole that nobody else is trying to fill,” said Leshem. “It’s a pretty simple strategy. We’re living in an environment where people are taking huge risks on ridiculous sums of money that we’ve watched not pay off, time and time again, so when you come up with a movie that’s fresh, and people made an effort to make it and, all of a sudden, it does pretty well, you wonder if the middle is really going out of this business or not. Should the studios really be focused on making more of those $30 million titles? Yes. But they’re not.”

Harris is convinced “that the world is not just about franchises, and that, if you develop quality material and put it together, it can get made. Some of the stuff will be at studios; some of it will be homegrown. We’re working with writers, getting good scripts, trying to put packages together before finding either a studio home for them or a financier.”

They have no agent to commission them. They aren’t affiliated with a studio, so they are free to work where the enthusiasm is highest. “You’re not getting handed anything,” said Leshem. “You’ve got to earn; you’ve got to eat what you kill.”

“There’s a business model that does seem to be in the midst of breaking right now, ” said Harris. “We’re seeking audiences looking for quality, wherever it comes, and entertainment, wherever it comes, rather than being force-fed.”

3. Cast against type.

Going in, they figured the core audience for the movie was teenage girls and Blake Lively fans. She tests well with women 25-35 and boasts over 11 million fans on Instagram.

While she’s gorgeous and athletic, the filmmakers needed her to be a strong actress. “She works her ass off,” said Leshem. “She was our first choice. For me, it all goes back to my daughter, who loved ‘Gossip Girl.’ Blake Lively is smart and intuitive and understands her brand and what she can do and can’t, and is willing to go for it when she’s acting — really go for it.”

“A big part of our process is finding a full-formed human,” said Harris.

And Sony marketing was willing to chase Lively’s fans into the digital space. “We knew that’s where they were: online,” said Harris. “So the idea was to convert those young women and Blake fans to say, ‘I have to go to the movie theater to see this movie.’ So we fed out small pieces of the film that would look cool on your screen. Intuitively you go, ‘That would be cool to see on the big screen.’ When the shark jumps out to eat the surfer, even though you’re giving up a moment in the film, people are watching that on their phones, and you want to see that in a theater. That was our goal.”

READ MORE: How ‘Gravity’ Inspired This Summer’s Crazy Shark Movie

4. Pick the right director.

Getting the studio to go with Jaume Collet-Serra (“Non-Stop”) took some persuading. The genre director-for-hire was respected, but not exactly a hot property. Leshem took Collet-Serra in to meet De Luca, who asked him, “Why do you want to make this picture?” Serra replied, “Because I don’t know how to make it. I cannot figure it out.”

“Nobody realizes what a good filmmaker he is,” said Harris. “At a studio, he’s a guy who will deliver a beautifully done movie. I loved the way he talked about filmmaking and manipulating an audience’s perspective, because the only thing he cares about at all is the audience’s experience. We had him and we lost him, and we had him and we lost him, and we didn’t really want to make this movie without him. He’s the only director who, on a film like this, will have a conversation about Tarkovsky’s ‘The Sacrifice’ as a reference to a scene that Blake Lively is in.”

5. Be willing to break the rules.

The location of the isolated, pristine beach was the producers’ second-biggest hurdle. The director had no idea where to shoot. Most of the beaches they scouted in Queensland, Australia (where there was warm water during the winter shooting period, as well as a rebate) were next to a city or town or theme park. But Collet-Serra wanted to find a place that no one had seen before, because he wanted the ticketgoer to have an experience that they haven’t had before.

They also needed their surfer heroine “to always see the entire beach from where she was,” Leshem said. “And the audience always had to feel like the entire beach was around her. Then there were particular conditions and surf. All were beautiful, but none had that quality, and we were getting very worried and frustrated.”

The location scout suggested a spectacular but remote island two hours away from Sydney, which had never been used on film. “This island has 350 inhabitants, okay?” said Leshem. “It’s a crazy place, and they’re all Luddites. They voted not to have cell service on the island. We’re walking around, finding different beaches, and we said, ‘We saw this beach from a plane, can we go there?’ We go onto the beach, look at each other, and go, ‘We’re going to shoot there?’ It was like that. Of course, we didn’t take into account that this is going to be really tough.”

They accessed the beach via nine vessels, including a 150-foot boat, bringing two trailers, a camera truck, and an open-sided production tent with folding tables and chairs. The site was a protected marine park, so the filmmakers had to check with marine biologists to make sure they didn’t harm a single fish. There were no cars. They rode bikes. No fax machines.

In the water, the production team fabricated the rock on massive pylons in concrete blocks, all in 20 feet of water. That’s where Lively perched to escape a circling shark that has taken a bite into her leg.

Finally, they kept the movie on that beach. No cutaways to loved ones back home. “You have to,” said Harris. “It’s experiential. The whole idea of the movie is that it’s her experience.”

During editing, Harris wanted to slow down, “so that you could get a glimpse at that vista, what the landscape was, so you can get a sense that there’s production value that you’ll want to see on the big screen. The biggest thing is that you want to be in the room with people, for a thriller, because when you watch people watch the movie, it’s so fun.”

“There aren’t that many films that you have to go see in a movie theater,” added Leshem. “But most are big tentpoles where it seems obvious why you’d want to see it in a theater. In a film like this, you have to give a reason to go. That’s really what we tried to do.”

6. Use VFX wisely. And when in doubt, use the real thing.

“There are basically no shots in there that aren’t a visual-effects shot,” said Leshem. However, even though there were 1,100 visual effects shots, cinematographer Flavio Martinez Labiano incorporated real-world elements in every scene.

With the seagull, they planned to use a puppet and CGI. But Leshem was obsessed with getting a real bird, even though they are tough to train. They hired American animal trainer Katie Brock, who found three seagulls that were house-trained after an injury.

Finally, Lively insisted on an element of Method acting with the seagull. “There are a lot of magical moments that happened because of the seagull really working with Blake,” said Leshem. “She was great with it. She didn’t want to get to know the seagull until she got to the rock, so when it’s biting her, it’s really biting her.”

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