The process of adaptation is always different depending on what source material you’re working with, but my co-writer Thomas Bidegain and I always start by having several weeks’ worth of conversations.

During this time, we exchange all sorts of references including films, pictures, and music. We already know the story, but the big question remains: What will the film be like—its form, drive, tone, and rhythm?

Before writing our first draft, I read the source material at least twice. The first read is to get a general feeling for the story, and the second is to take meticulous notes in the margins and to fold every other page corner. Because Patrick deWitt’s The Sisters Brothers is such a rich novel, we constantly referred back to the book during the entire adaptation process, and even during production.

Cinema is a collective effort, and we all look for gold in the same river. I’m faithful to my key collaborators: Juliette Welfling for editing, Alexandre Desplat for music, Michel Barthélémy for production design, and Tom for the writing process. Over the years, we’ve developed our own language and vocabulary.

The writing process is so long, my God! For that reason, Tom and I have seen each other, or at least been in some form of contact, on a daily basis for the past 15 years. We spend a lot of time in the same room when we write, and the rest of the time we talk over the phone.

During production, Tom and I watch the dailies and write notes while we talk. Often, we’ll rewrite scenes based on the results of what we’ve already shot. Ken Loach works in a similar way with Paul Laverty; we call it the “inclined plan theory.” The ball has to keep rolling. The script, just like the rest of the film, has to be evolving all the time. I consider the screenwriter’s involvement during production to be essential, as it’s not uncommon to develop some characters even at a very late stage.

Jacques Audiard makes his American moviemaking debut with the Oregon-set The Sisters Brothers. Image courtesy of Anapurna Pictures

Usually we hand over three drafts, all of which employ different forms of storytelling. Between these drafts is where our research and development happens. It took us some time, for example, to understand  that the characters of John Morris (Jake Gyllenhaal) and Hermann Kermit Warm (Riz Ahmed) needed further development to add tension to the film.

We ended up writing many more drafts than three, and because Patrick’s book is so rich in episodes, the scenes that we wrote would appear, disappear, or get moved around. At one point, Tom and I came to realize that The Sisters Brothers is more fairy tale than western, and this formal framework helped us be more selective with moments from the novel.

There’s no rule for when or when not to consult with the author of your source material, but language is always a key element. My English is bad, so we wrote in French and had the French draft translated later. Patrick went over some of our dialogue, too, adjusting the phrases the way you would with musical notation.

Patrick’s novel has a peculiar, darkly funny tone, and the titular brothers serve that tone as a comedic duo. But the novel is also written in the first person, and combining that singular point of view with the comedic rapport of a duo wasn’t easy. You have to lean on your actors to strike that balance. Of course, John C. Reilly immediately picked up on the humor, as did Joaquin Phoenix.

I don’t tell my actors what to read. I loved that they all came with their own ideas for their characters. Once you’ve given that much, it simply becomes a matter of what you tell the actors to keep, and which button you need to keep pushing, or stop pushing.

What makes a screenwriting partnership last? Tom is a good cook and a cinephile. Those are the secrets to our ongoing success. What makes an adaptation work? Adapt your source material, then adapt your adaptation. Then keep writing. MM

—As told to Daniel Joyaux

The Sisters Brothers opened in theaters September 21, 2018, courtesy of Annapurna Pictures. All images courtesy of Annapurna Pictures. Featured image: Prolific French auteur Jacques Audiard (R) directs co-stars Joaquin Phoeniz (L) and John C. Reilly (C) on the set of The Sisters Brothers. This article appears in MovieMaker‘s 2019 Complete Guide to Making Movies, on stands November 6, 2018.