In her droll and vibrant adaptation of "Vanity Fair" — starring Reese Witherspoon as governess Becky Sharp, the wench who waltzes her way into English society — Nair frames the adventuress as an opportunist who did to London what England was doing to India. To that end, Nair ornaments her lush film and its luscious characters with plunder of the Raj.

"Thackeray understood that it was the rape of the colonies that enriched and sustained the middle classes at home," Nair, 46, reflects by phone from Manhattan. "That was his milieu, his circus, his carnival."

And Nair makes it her own. With "Vanity Fair," which opens today, she celebrates a familiar rite of passage for female directors, the literary adaptation. Nair paints it in sunburned shades of chile-red and plum and pomegranate. And she shades it with the nuanced touches that Agnieszka Holland brought to her superb translation of Henry James' "Washington Square" and Jane Campion to hers of James' "Portrait of a Lady."

"Becky's so modern, isn't she?" observes Nair, who was born middle class in a small town near Delhi, educated at Harvard, and has homes on three continents with her Ugandan-born husband, Columbia University government professor Mahmood Mamdani, and their son, Zohran.

This is hardly the globe-hopping filmmaker's first movie about an outsider making her way in an unfamiliar society.

Nair was naturally drawn to Thackeray's sprawling novel, which directly influenced "Gone With the Wind" and "The Bonfire of the Vanities," because she is at heart a social cartographer. As Nair deftly demonstrated in "Mississippi Masala" (1992) and "Monsoon Wedding" (2002), it's fun to map the trade routes of arrivistes, and even more fun to enjoy the spectacle of their accumulated spoils.

Nair is perhaps overqualified to take on Thackeray because, as she jokes, "it was the Indians who taught the English about class and hierarchy and arranged marriage," exclusive parties that uninvited guest Becky crashes.

For Nair, the novel "Vanity Fair" is uniquely cinematic, because the characters "simultaneously observe as well as participate in life, enabling us to see society's paradox as well as its hypocrisy."

Becky is a seductive pragmatist, the Jessica Rabbit of literary fiction. She's not bad ... just drawn that way. She seduces the rich and gives to the deserving poor — herself — caring not one whit about what others think. "I've never believed in moral black and white," Nair says. "I've always believed in gray."

Admirers of Nair's emotional use of color would add that she also believes in red, in the scarlet of passion and fallen women, in the crimson of blood and vital organs, in the vermilion of lip rouge and Oriental rugs. The dramatic high point of the movie comes on the eve of Waterloo as Becky, in a red undergarment and ripely with child, bids her husband a last goodbye before he leaves for battle.

"I loved the themes of that moment — the miracle of birth, the threat of death, the glory of the belly," Nair says of what she dubs "my pregnant love scene." And yes, Witherspoon was 7› months pregnant with her second child (by actor Ryan Phillippe), Deacon.

Like Holland's "Washington Square" and Campion's "Portrait of a Lady," Nair's "Vanity Fair" is perhaps more sympathetic to its heroine than was her creator. Nair begs to differ with that interpretation, maintaining, "I always thought that Thackeray was with Becky all the way," although he thought "she was an acquired taste, like hot pepper."