In the age of the big-budget studio franchise, a key for writer-directors is surprisingly simple: Be realistic.

“We tried to write something in the script that we could make,” says Derek Cianfrance, the multi-hyphenate behind The Weinstein Co.’s “Blue Valentine.” “You have to balance stubbornness with your belief, and you have to know what’s real, what’s delusion.”

Cianfrance isn’t alone in his pragmatism. In a time of slashed slates and reduced budgets, the independent world has had to scramble for financing and support more than ever. Keeping financial realities in mind during the writing phase can be the first big step towards completing a film.

“Generate your own material. That’s where you can be overruled or outvoted by no one,” says “The Town” writer-director Ben Affleck. “I think all you can do is try to find something you believe in and figure out how to get it made … If people are interested in it, it will give you that entree.”

While financing for arthouse fare might be tough to come by, all the penny-pinching has an upside for writers with a strong creative vision.

“It’s making people more defiant in knowing that risk is all they’ve got,” says “Winter’s Bone” hyphenate Debra Granik. “All they’ve got is to remember Dennis Hopper making all of his films. Remember John Cassavetes in his basement making all of his films. … It’s what made films in different decades interesting.”

Granik, a fan of Cassavetes and some of the edgier movies of the 1970s, instantly fell in love with Daniel Woodrell’s novel about a girl from the Ozarks struggling to keep her family together after her father’s disappearance. She wanted to make the film true to the book and true to the place (casting many Missouri locals) while creating a project investors could believe in.

“I live in the world that tells me that certain subject matters, by definition, cannot be seen as commercial,” she says, explaining that finding financing for the project was nearly impossible. “We tried absurd ideas. We tried conventional ideas. We tried playing with the system. We tried a lot of different things.”

And Granik, whose previous writing-directing credits include “Down to the Bone” and “Snake Feed,” says that it’s not always her content that’s prohibitive.

“The films I want to make usually can’t contain a known financeable star,” she says, noting that it’s not just because the Brad Pitts and Sandra Bullocks have high price tags. It’s also because Granik worries that a known face might pull an audience out of the story, making her favor an unknown actor. In some cases, that means refusing money.

“The biggest risk that I want to figure out with any financier is, can they take the risk to introduce new actors?” she says. “I can’t look anyone in the eye and say, ‘Yeah, the five people you just told me that are worthy are my five choices.’ It won’t be the kind of film I know how to make well.”

At one point, financing for “Winter’s Bone” looked good — a company had committed a larger budget than Granik was used to, and they were almost ready to shoot. Then they got cold feet and pulled out. Eventually Granik and her team secured the necessary, but not cushy, $2 million.

But creativity, say these writer-directors, thrives at lower numbers.

“I think it’s difficult to walk that (creative) line at $100 million,” says Cianfrance. “At $100 million, there need to be more guarantees.”

Affleck agrees that “freedom is inversely proportional to the amount of money you spend.” The writer-director-thesp, who also co-wrote 1997’s much-lauded “Good Will Hunting” with Matt Damon, says they “wrote that script because we saw ‘Reservoir Dogs’ and ‘Clerks’ and ‘Slacker’ and movies where you could make them for a million dollars, and it seemed like a reasonable amount to raise. I don’t think that’s a bad model.”

“The Town,” which sources say cost $36 million, stayed pretty true to Affleck’s vision. It also stayed within the under-$40 million range of most non-franchise studio fare.

“The less money your film costs, the less amount of people you have to please,” echoes Granik, who feels comfortable working at the lower numbers.

Sofia Coppola, too, keeps costs down to retain creative control.

“It always seems like you can get yourself into a heartbreaking situation if you were making a movie that you didn’t have creative control over and had to listen to executive’s notes and not follow your heart,” says the “Somewhere” scribe and helmer.

Sometimes those creative risks pay off. “Winter’s Bone” has already cumed triple its budget and is likely to get a second wind off its early kudos. Other times, they can harm the film’s commercial potential even after it’s finally been made. In “Blue Valentine,” a much-publicized sex scene between Ryan Gosling and Michelle Williams got the film slapped with an NC-17 rating, a label which TWC and the filmmakers are currently fighting.

But would that scene have even made it into the picture had a major produced it?

“It’s a non-issue because a studio would never make this film in the first place,” says Cianfrance. “And we tried every studio to make this film.”

Ask Granik, Cianfrance, Affleck and Coppola, and they’ll tell you that that perseverance is necessary from step one. And even a critical or box office hit right behind you doesn’t guarantee an easy jump to the next project.

“What I would like to come out of ‘Winter’s Bone’ would be that Roadside would just have this increased courage and that other companies would kind of see a little light right now,” says Granik. “Each year, there could be one or two American films that someone wouldn’t be afraid to touch.”

Until then, however, persistence, a realistic vision and a white-knuckled grip on creative control might be the best recipe for any writer-director.

Granik’s mantra puts it bluntly:

“By hook or by crook, we will get this made.”

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