Writing this interview with Hollywood movie editor Tatiana S. Riegel was hard.

I spent nearly an hour on the phone with Riegel, who began her editing career on films like "JFK" and "Pulp Fiction" before working on the pilot episode of "Game of Thrones" and movies such as "The Men Who Stare at Goats". We discussed the editing process and her latest film, "I, Tonya" -- and our talk was so fascinating, I didn't want to cut anything out of the transcript.

Sadly, this article would have ended up five times too long. So I had to apply some of the things I'd learned from Riegel about editing: moving things around to get the most impact and, if necessary, losing bits I loved.

"It's so hard," Riegel told me. "Writers, directors, even editors fall in love with scenes and moments that are terrific in and of themselves but overall are not helping the story." So a clear-sighted ruthlessness is required to trim those moments away. "Sometimes," Riegel explains, using an old adage, "you have to kill your babies."

Tatiana Riegel

"I, Tonya", starring Margot Robbie as controversial Olympic skater Tonya Harding, is now playing in the US. It's coming to the UK in February and to Australia in March.

Q: You've collaborated many times with "I, Tonya" director Craig Gillespie. Do you still have to maintain a certain distance to keep that clear-sighted perspective on the overall movie?

Riegel: I try to, yes. I like to think of the editor of a film as the only audience member. Everybody else is shooting in Atlanta, and I'm sitting in Los Angeles watching it on a monitor in the form that an audience member would.

Even when I am on location, I try to go to the set as little as possible because I don't want to be influenced. There are lots of times where on the set people think, "That's hysterical; we've gotta use that; that's gotta be in the movie." Then they actually look at the daily, and it's not that funny in the daily.

What about balancing the overall tone of the film?

Riegel: ["I Tonya"] is a tricky one because it's got a mixture of some pretty serious and brutal stuff, like domestic violence, but also a very, very emotional story, and then also mixed with comedy in sections. Five degrees either direction could be a disaster.

How can editing change the tone or emotion?

Riegel: You can make adjustments in performances to make a scene funnier or more serious, make a character more sympathetic, harsher or scarier.

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For example, through the timing of the actual edits, through sound design and music, you can come up with a whole symphony of things that create tension and suspense. An example in this film is where Tonya Harding is about to go out and skate at the Olympics at Lillehammer [Norway] and her shoelace is broken. She's very nervous; everything has led up to this point; the world is coming close to crumbling down. The clock is ticking and you hear the stadium outside: Everybody's stomping their feet, waiting, waiting, waiting. There's a lot of tension in that particular moment that was created and manipulated along the editorial process with not just the picture, but the sound and a number of elements.

That's one of the really fun things about editing in general, frankly: the manipulation that we get to accomplish.

What kind of problems come up during editing?

Riegel: Sometimes something that is completely clear in the script is absolutely not clear in this movie, oddly. Other things that are fine in the script are all of a sudden redundant in the movie -- you don't need a particular actor saying a line of dialogue, because we're seeing exactly what happens, so we can just show it rather than have them say it. And there are many scenes where in the film version you come into the scene much later than you do in the script, or leave the scene much earlier.

What's the workflow of the editing process?

Riegel: Literally, we put index cards with the names of every scene on a table, and like a jigsaw puzzle, just move stuff around visually. "This scene makes more sense up here when this character is doing this or that. That scene makes more sense back there. If we put these scenes back-to-back, it has much more impact than if they're separated by a few other scenes."

With all these adjustments, how much can a movie end up deviating from the original script?

Riegel: Tremendously, depending on the film. I've worked on many films where we've completely changed the structure. It works marvelously in the script and then all of a sudden, when they're actually in that visual medium, they no longer work the same way.

"I, Tonya" early on had a different ending. In the script, it had several more scenes after where we actually ended the movie. The scenes were fantastic, but overall, when we watched the movie, it was much more powerful to end it where we did.

When does the editor come into the filmmaking process?

Riegel: We start when they start shooting, and sometimes even before. On large visual effects films, they will often do what they call previz, or previsualization, which are animated sequences that an editor and the visual effects company create before the film is even shot. I come into some movies a good four to six weeks before they start shooting to go through these previz sequences and edit them and talk about them with the director, the director of photography and the visual effects team.

But on a regular movie I start usually a few days before shooting to get everything set up. What they shoot on Monday I start cutting on Tuesday, and try to turn stuff over to the director as quickly as possible so that they can get an idea of what they've got, the coverage, the performances, the tone, so they can begin to make adjustments.

In terms of the technology available, are we at the point where you can edit the movie on a laptop?

Riegel: There's some editors that cut right on the set. With certain action sequences that's necessary -- on this film they had a video playback guy [on set] for the skating sequences, to cut something together very roughly just to make sure they have all the pieces.

I like looking at things on a slightly larger monitor. It's really nice just to have the proper environment and stay focused.

With multiple takes and multiple edits, how important is organization of this mass of material?

Riegel: A lot of that is just, for me, memory. I watch all of the dailies when they first come in, which is not only fun but it's an important stage of the game. I take very extensive notes and I watch every single take, not just the director's preferred takes, because I use bits and pieces from all of the takes. It happens all the time where you use the audio from one with a picture of another, where I like an inflection of a line reading a little bit better.

How does your work as the visual editor feed into the work of the sound editor?

Riegel: Ideally we lock the edit and hand it to the sound people so they have a finished product to work on. That almost never happens. Because of schedules and stuff, we're always cutting until the last minute.

But once we do hand it over, we do what's called a "spotting session" with the sound designer. We go through and talk as we're watching about what we want from a scene. It's things like, we want this particular type of sound effect, or it can be a much more emotional thing, like sometimes quiet is really impactful. There's a scene in the film where we cut from a very loud scene to a very, very quiet scene where [Tonya] is just sitting in her dress and all you hear is her breathing and the air conditioner -- and it's very, very impactful.

That's the other reason I try to stay away -- I have a lot of work to do. I can't go hang out on the set, as good as the snacks may be. I have to get my work done!

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