Is the black-and-white cinematography the reason I found this ambitious Amazonian adventure to be less than vivid, despite its hallucinatory setting? Whatever the reason, for a movie about white explorers pursuing a rare plant amidst the region’s indigenous peoples, where they encounter strange shamans and head-tripping substances, Embrace of the Serpent felt oddly safe. We’re always aware that director Ciro Guerra is filming a movie, rather than flirting with the sort of madness that defines something like Werner Herzog’s Aguirre, the Wrath of God. Still, there is much to admire about the film’s structure, as we switch back and forth from an ethnographer in the early 20th century to a botanist exploring the same territory some 40 years later. Both scientists happen to be led by the same man, a lone survivor of his people who embodies the film’s lament over lost culture (and is memorably played, at various ages, by Nilbio Torres and Antonio Bolivar).