Thanks to a reader for sending this link to the work of Caravaggio, who is inspiring Gibson and his cinematographer:

Gibson says it is crucial that the story look realistic, not, as he puts it, "like a cheesy Hollywood epic." He chose cinematographer Caleb Deschanel, who worked with him on "The Patriot." Deschanel took as his inspiration the dramatically lit works of the Italian Baroque painter Caravaggio.