Image copyright Getty Images Image caption Schoonmaker and Scorsese edit his films together but she says "we don't fight"

Martin Scorsese's long-time collaborator Thelma Schoonmaker has said it would have been impossible to make The Irishman without Netflix.

"Nobody would fund this movie," the esteemed film editor tells BBC News. "Scorsese and Robert De Niro struggled for seven years to get funding."

"The studios are a little afraid of this kind of thing, but it's been such a big success - maybe they're learning a little bit from this," she says.

Schoonmaker, who got her eighth Oscar nomination for the film, says Scorsese's insistence on using de-ageing technology on the actors was "one of the problems" because it was prohibitively expensive.

"Finally Scorsese's general manager said 'Netflix will give you the money and they will leave you alone' - and they did," she says.

"I can't tell you what a blessing that was. We're sorry about the [short] theatrical release but nobody else would make this movie. The film wouldn't have been made without Netflix."

As well as providing the money for the mob drama, which according to Forbes cost about $160m (£122m), Netflix also stepped back from interfering with the film itself, according to Schoonmaker.

There were no objections to the long running time of three hours 29 minutes "because when they saw it they were riveted", she adds.

Variety's Owen Gleiberman said of The Irishman's length: "One might even ask: Why, in the age of skittery attention spans, did Scorsese choose to make a three-and-a-half-hour magnum opus for Netflix? But the answer, it turns out, is rather up-to-the-minute. That running time is a mere blip in the world of binge-watching; if The Irishman weren't a movie at all but, in fact, a show (a limited series, say), we'd be talking all of three episodes."

Image copyright Netflix Image caption Robert De Niro (Frank Sheeran), with Joe Pesci, who plays the role of the "quiet-don" Russell Bufalino

Schoonmaker, 80, has edited 23 of Scorsese's films over her 50-year career. She's won Oscars for Raging Bull (1980), The Aviator (2004) and The Departed (2006) and is up for a Bafta at this year's awards.

The nominations feel "absolutely wonderful", but she admits: "I wish Marty was getting those nominations instead of me.

"We don't make movies for awards," she continues. "We have the most wonderful reward, which is the reaction of our friends and the audience, that's what means the most to us."

Image copyright Netflix Image caption Oscar-winning Al Pacino had never worked with Scorsese before this film

She says it's "a little embarrassing that I've had so many" awards and nominations but adds modestly: "It's because Scorsese's such a great editor himself, and he taught me everything I know, I never knew anything when I first met him."

They met in 1963 on a six-week film course in New York, not long after she had finished studying at Cornell University.

"And what luck that was, you know? I maybe never even would have become a filmmaker if I hadn't met him," she says.

She goes on to recount how Scorsese introduced her "to my husband, the British director, Michael Powell", whose films include The Red Shoes and Black Narcissus.

"So I work for a genius and I was married to one, and I work with a lot of geniuses like Robert De Niro and Joe Pesci and Al Pacino. I mean, how much more could you want out of life?"

She clearly adores her work, but says the role of film editor is a "mysterious one", and not many people outside the industry know what she actually does.

Media playback is unsupported on your device Media caption Oscars 2020: Who's been nominated?

"You would have to sit in the room with me to find out. I make 100 decisions a day with Marty - basically what we do is we get raw footage from the set [and] our job is to figure out how all the shots will work best. Is the scene flowing, is it too long, too short, are we building up one character too much instead of another? It's hard to explain beyond that.

"It's just the most wonderfully creative job. It's as if you're sculpting a raw clump of clay. You're gradually forming it into a shape."

One of the secrets of their long-standing partnership is that they get on so well.

"It's never an argument with us, I'll just present him with options," she says. "A lot of editors and directors do fight over movies. It's an ego battle, and that's terrible for the movie. But fortunately - he trained me after all - I know what he likes and he doesn't."

It turns out that Scorsese "hates it when an actor uses eyebrows to emphasise something. He does not allow eyebrow movement", so Schoonmaker steers clear of them.

Image copyright Netflix Image caption Ray Romano (Bill Bufalino ), Al Pacino (Jimmy Hoffa) and Robert De Niro (Frank Sheeran) after being "youthified" in the film

Asked if she's ever tried to overrule him, she laughs.

"I just wait until he's ready. I think an editor's job is to give the director the film the way they've designed it. And then if you feel you have some alternate ways to go, show that to them, but I never show Scorsese anything other than what he originally planned."

Image copyright Netflix Image caption Joe Pesci and Robert De Niro look youthful in this scene as well

She also thinks "being a woman helps in the sense of sensing some vulnerabilities and things that maybe he didn't see on the set, you know, because he's got a small monitor - I can pull out maybe a piece of acting he didn't notice".

She wonders if women have been more successful at breaking into editing than, say, directing, "because women are better maybe at collaborating with directors".

The film editing Oscar has been won 15 times by a woman for films including 1975's Jaws (Verna Fields) and 1977's Star Wars (Marcia Lucas). The directing Oscar has been won just once, by Kathryn Bigelow for The Hurt Locker in 2009.

Schoonmaker thinks this year's film nominations have been "disappointing" for female directors, noting that Scorsese has championed British director Joanna Hogg by executive producing her films, and that he "feels strongly" about supporting female directors.

On the lack of diversity in the acting nominations, she says: "I haven't seen enough films to really say. I work so hard that I rarely see them. I don't know what the options were this year, so I don't know if I can really comment on that."

Image copyright Getty Images Image caption Schoonmaker has also worked with Leonardo DiCaprio on Scorsese's films

As for working with the de-ageing process making The Irishman's stars look 20-30 years younger, it had been done before, but Scorsese wanted to try something new.

Schoonmaker admits she was initially unsure about it.

"Well, I was worried. I had no idea if this was going to work because it's a new process, much better than the process everyone's been using up to this point where the actors have to wear a helmet and have dots all over their face, two small cameras at their chin.

"Scorsese just said 'my actors are not going to be able to work like that'."

So they used Oscar-nominated visual effects supervisor Pablo Helman from Industrial Light and Magic, who created a system using two infrared 3D cameras on either side of the camera lens to capture the movement of the actors.

She and Scorsese then fully edited the film before it was sent off to be "youthified".

After that, they requested a few tweaks.

"When we got the first de-ageing shots we had to collaborate with ILM a lot to say 'I think you went a little too far there, maybe we've lost a little of De Niro's subtlety here, maybe you have to put in that little wrinkle that was to the right of his nose'. Where is the acting, you know? It's not just the eyes. So it was a joyful challenge, it wasn't a problem."

Image copyright Getty Images

With the awards season concluding next month, Schoonmaker is sanguine about whether they will win.

"So many of our films were never acknowledged by the Oscars - Raging Bull never got a best director or best film, Goodfellas did not, and so on.

"In time, what's so great about Scorsese's movies, is they may not win the awards, but they become classic. People love them. They look at them over and over.

"So that's what's really important. Does the film last? These do, and I'm so proud to have worked on films people still love and watch all the time. Whereas some of the things that won instead of us, nobody's watching them. So that's much better, to be lasting."