IN TARANTINO’S LATEST, A RADIANT HOLLYWOOD FABLE

Quentin Tarantino has, for a while now, been reminding us what’s so great about movies — or at least, what he thinks is so great about them.

He’s made an old-fashioned double-feature (“Death Proof,” of “Grindhouse”), resurrected the wide-screen format of 70mm Ultra Panavision (“The Hateful Eight”) and generally presided as the pre-eminent B-movie evangelist for a generation. The power and thrill of exploitation movies, he has earnestly espoused, can conquer all evils — or at least slavery (“Django Unchained”) and the Nazis (“Inglourious Basterds”).

But “Once Upon a Time ... in Hollywood,” set in 1969 Los