There’s controversy over whether Chris Rock lifted the idea for a documentary about African-American hair from somebody without paying for it (filmmaker Regina Kimbell has filed suit against him, saying that his picture copies hers, a movie called “My Nappy Roots” that she claims to have shown him). But with all due respect to Ms. Kimbell, whose film I’ve not seen, whoever was responsible, it provides a surprisingly fascinating subject that in the case of “Good Hair” yields lots of laughs.

Rock, whose delivery improves at it goes along although it never quite loses the sing-song quality characteristic of his work, starts from the question why African-American women (and some men) go to such lengths to straighten their hair despite the fact that the use of “relaxers,” as they’re called, is not only painful but hazardous. That takes him into questions of societal expectations and standards of “beauty,” as well as the issue of how few of the companies making products directed toward blacks are actually black-owned. (Al Sharpton, predictably, has some strong words about that.)

An ancillary topic is weaving—braiding extensions into hair—which takes Rock on a journey to India, where much of the real human hair used is collected from temples where Hindus are shaved as an act of sacrifice to the gods. Rock visits operations were the hair is collected and prepared for transit, as well as American shops and salons where it’s sold. He also visits—with amusing results—beauty parlors and barbershops where African-Americans talk quite candidly about how women’s obsession with “good hair” affects their relationships.

The picture begins, returns periodically and closes with a visit to the Bronner Brothers International Hair Show, where a small group of stylists compete putting on elaborate hair-cutting exhibitions to be chosen as the best of the best. It’s certainly one of the most absurd competitions one is ever likely to see—part of a big convention for hair-styling products—and offers plenty of chuckles, though most will be over the crassness and stupidity of it all. You have to give Rock credit for keeping a mostly straight face throughout it.

Technically the picture is hardly a model of style, but the homespun visuals somehow seem right.

Rock’s treatment of the hair biz may not be a great documentary, but like the title says, it’s pretty good.