Not many movies set in ancient Greece get shot in Montreal in the dead of winter. And yet that's exactly where and when Warner Bros. sent director Zack Snyder (Dawn of the Dead) to make 300, a somewhat true retelling of an epic battle from 480 BC, adapted from the graphic novel by Frank Miller (Sin City).

So, now that 300 has wrapped, it's up to post houses including Montreal's Meteor Studios to make all that studio footage of green screens and near-empty sets look like rocky mountains and sun-blasted Mediterranean city-states.

Meteor (Fantastic Four, Final Destination 3) is posting some 250 shots, using Maya, RenderMan and RealFlow, for the film's many liquids.

"The movie's pretty gory," says Jamie Price, Meteor's visual effects supervisor. "So there's going to be a fair amount of spraying blood."

The story recounts how a small band of Spartans - the Klingons of their time - held off an invasion by some two million Persians. It stars Gerard Butler (Beowulf & Grendel) as the Spartan king.

Like the equally violent Sin City, 300 is taking its cues from its book source, looking for CG-heavy scene-by-scene recreations similar to those that made Miller's collaboration with Robert Rodriquez such a sensation in 2005. But where Sin City was mainly black and white, 300 is soaked in color.

"We really increase the color contrast of the darks and lights very extensively," says Price. "So highlights get very blown out, and our blacks get very crushed. And we're de-saturating and tinting different sequences for different moods."

"It gives it - not a flat look, because it's very rich and bold - a more illustrative feel," adds Meteor GM Ghislain St-Pierre. "Everything looks realistic, but it has a kind of a gritty illustrative feel."

Some 70-odd Meteor artists are working on the footage, coordinating with the visual effects team of Grant Freckelton (Harry Potter and the Goblet of Fire) and Chris Watts (Corpse Bride, Harry Potter and the Prisoner of Azkaban) in L.A.

Most of the shots involve a pivotal nighttime battle between the Spartans and a phalanx of elite soldiers known as the Immortals. Meteor is also working on some daytime scenes set in Sparta itself, involving 3D extensions of the city.

But its big scene is the fight, which also requires a coastal road, a narrow mountain pass and the Aegean Sea. Meteor will deliver by the end of June.

Quebec FX house Hybride is also working on the project, but would not comment on the nature of its involvement.