Though the experience of making such a film, shot in 35 days outside of New Orleans, might be expected to be weighed with the heaviness of its subject, the cast says the process was too focused, too fast-moving for such a mindset. Says McQueen: "If you start thinking about it in such a way, it will paralyze you."
Michael Fassbender, who starred in both of McQueen's previous films, plays Edwin Epps, the far harsher of two plantation owners. (The other, more benevolent plantation owner is played by Benedict Cumberbatch). He's described with understatement as "a man of hard countenance."
Fassbender sought to find the humanity in Epps, who's torn by his love for his most prized cotton-picker (Lupita Nyong'o, in a shattering performance).
"You are going to places that are uneasy, but it's my job," says Fassbender. "Of course the emotional elements follow, and they do have an effect and there's a residue going home with them. But concentrating on the work sort of protects yourself from that."
The film, made with a budget reportedly of $22 million, was produced by Brad Pitt's production company Plan B, and the actor appears in a small but pivotal role, warning Epps of a coming "day of reckoning." Speaking to reporters at Toronto, he expressed his deep pride in having been a part of "12 Years a Slave."
"If I never get to participate in a film again ..." he said, trailing off. "This is it for me."
Follow AP Entertainment Writer Jake Coyle on Twitter at: http://twitter.com/jake_coyle
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.