Quentin Tarantino defended his decision to make slavery the backdrop to his new revenge-western Django Unchained, saying that he found the research he did on the subject "incredibly shocking" and that, violent as his film may be, the reality was "far worse".

Tarantino was speaking to an audience of Bafta members and critics after the first UK screening of Django Unchained on Thursday night, which sees former slave Django Freeman (played by Jamie Foxx) team up with a German bounty hunter (Christoph Waltz) to find and rescue his enslaved wife.

"We all intellectually 'know' the brutality and inhumanity of slavery," Tarantino said, "but after you do the research it's no longer intellectual any more, no longer just historical record – you feel it in your bones. It makes you angry, and want to do something … I'm here to tell you, that however bad things get in the movie, a lot worse shit actually happened."

"When slave narratives are done on film, they tend to be historical with a capital H, with an arms-length quality to them. I wanted to break that history-under-glass aspect, I wanted to throw a rock through that glass and shatter it for all times, and take you into it."

Watch the international trailer for Django Unchained. The Weinstein Company

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Tarantino said he was particularly concerned to target what he called the southern aristocracy – the plantation-owing families represented in the film by Leonardo DiCaprio's character Calvin Candie – calling them "an absurd, grotesque parody of European aristocracy". "I did a lot of research particularly in how the business of slavery worked, and what exactly was the social breakdown inside a plantation: the white families that owned the houses, the black servants who worked inside the house, the black servants that were in the fields, and the white overseers and workers that were hired to work there."

Describing his film as "a big-budget, big-screen, quasi-epic … spaghetti western", Tarantino also mentioned he would be keen to make more films in the same vein: "I'd like to do a couple more, dealing with the same issue: but different story, different characters." He also let slip the film was rooted in his long-term critical interest in the Italian-produced variant on the western genre: he said the story "came to him" while he was working on a book chapter about film director Sergio Corbucci, director of the 1966 film Django that inspired the film's title. (Franco Nero, the star of Django, makes a cameo appearance in Tarantino's film.)

But some things don't change. When asked if he had considered using digital effects to replace the copious bloodletting customary on spaghetti westerns, Tarantino shot back: "Not at all; no fucking way. What's the point of that?"