'Skin'

★★ 1/2 OUT OF FOUR STARS

Rating: PG-13; some violence and sexuality. Where: Edina.

An improbable true story of bloodlines and color lines, "Skin" dramatizes the life of Sandra Laing. Although she was born to white Afrikaner parents in apartheid-era South Africa, a genetic quirk gave her dark skin and curly hair. When her appearance at a whites-only school created an uproar, she was reclassified as "colored" under apartheid laws. Her eventual decision of which racial identity to choose redirected her into a life of hardship among oppressed blacks and estrangement from her family.

A provocative personal history is no guarantee of a compelling biography, however. "Skin" is heartfelt but clumsy. It feels hurried, looks cheap, and works overtime to simplify a complex, flawed character into a noble, tragic heroine. "Skin" never probes as deeply as it should; it never reaches the heart of a family that struggles against its own flesh and blood.

Sophie Okonedo (Oscar-nominated for her work in "Hotel Rwanda") plays Sandra as a teen and an older woman. She is jarringly miscast as a schoolgirl, but brings hushed dignity to the part. She can cast a glance that whispers of distress -- useful, because Sandra's life was unspeakably hard.

'Crude'

★★★ OUT OF FOUR STARS

Rating: PG; in English and Spanish, subtitled. Where: Lagoon.

In this documentary, the anger onscreen spreads as inexorably as toxic sludge. It follows a lawsuit filed by 30,000 Amazon tribespeople against petro-giant Chevron for contaminating an area the size of Rhode Island. It's a classic David vs. Goliath face-off and at first "Crude'' looks like one more environmental agit-doc intended to outrage and inspire. Director Joe Berlinger is no doctrinaire hack, though. His previous movies -- including "Metallica: Some Kind of Monster'' -- coolly stare down their subjects until other stories start to emerge, and so it is here.

The rousing primary narrative involves Pablo Fajardo, a likable former laborer turned activist attorney, but that story line gets upstaged by the media circus the plaintiffs mount to win over American hearts, minds and tax-free contributions. In the end, Ecuadorean judges present Chevron with a $27 billion cleanup bill it will refuse to pay, Fajardo gets a CNN Hero Award and villagers continue to sicken, whether we're paying attention or not.

TY BURR, BOSTON GLOBE