Canadian director Sarah Polley (pictured) opened up about the “agony” and difficulty of telling her family history, in a post-screening Q&A following the Toronto premiere of her feature doc debut Stories We Tell.

After enjoying its world premiere in Venice and previewing at Telluride, Polley’s NFB-backed documentary played to a crowded house at Toronto’s Bloor Hot Docs Cinema Friday night (Sept. 7) as part of the Toronto International Film Festival (TIFF).

The screening was preceded by an impromptu musical performance from Toronto ensemble Choir Choir Choir, who performed The Beatles’ In My Life, and was attended by a number of Polley family members, as well as by esteemed Canadian author Margaret Atwood.

(Stories We Tell opens with a quote from Atwood’s book Alias Grace, which Polley is currently adapting for the big screen.)

Talking to the audience in a Q&A after the screening, Polley (who previously declared she will not be doing one-on-one interviews to promote the doc) talked of the difficulties she faced in editing together a film that was so personal, and probed so deeply into family affairs.

“It was really hard,” she said. “I don’t think it was about the film, I just knew I wanted to get the hell out of the editing room every day. I spent a lot of time on my BlackBerry when I was there.

“Every second of this, pretty much, was agony. You start to realize why most people spend most of their lives avoiding talking about their families and their childhood.”

She also addressed the decision to omit almost any mention of her own acting and directing career and successes from the documentary, as well as a lot of the footage that was available of her mother acting.

“It sort of felt like it would take away from the story a little bit,” she explained. “We did actually have a lot of footage of my mum acting, but the film was [already] so long.”

The documentary loosely explores the life of Polley’s late mother, actor Diane Polley, and her father, Michael Polley, as told by a number of family members and friends. It mixes talking head interviews with archival footage and other techniques to paint a rich and interesting consideration of the choices families make when conveying historical narratives. And it features plenty of twists.

So far, the film – which opens in Canada next month via Mongrel Media – has been winning rave reviews.

Before the Friday night premiere started, Polley appeared visibly nervous and moved by the occasion, coming close to tears as she dedicated the screening to her mother, who she described as being “a force of nature, the life of the party… and the best mother a girl could have,” adding: “I’m so grateful I had her for 11 sweet years.”

The director also paid tribute to the NFB and her collaborators on the doc. “The film was a collaborative effort – every film is a collaborative effort, but this one more than most,” she said.

She thanked editor Mike Munn, who “deserves so much more than an editor credit”; director of cinematography Iris Ng, who “helped create the concept for the film”; initial producer Sonia Hosko, “who helped produce the first interview”;  and producer Anita Lee, without who the film “never would have been made.”

Stories We Tell is Polley’s first feature-length documentary, following her acclaimed fiction films Away from Her, which won a Genie Award and an Oscar nomination for Best Adapted Screenplay; and Take This Waltz, which played to considerable praise at TIFF last year.