Classic comedy repopens N.Y's Vivian Beaumont; The Philadelphia Story Comedy by Philip Barry. Directed by Ellis Rabb. Starring Blythe Danner, Edward Hermann, Frank Converse.

After being gloomily dark since mid-1977, the Vivian Beaumont Theater at Lincoln Center has come brilliantly alight and alive with this 40-year-old social comedy by one of the American masters of the genre.

From the lush prefatory measures of Claibe Richardson's incidental string music to the nuptial curtain calls at the end of the evening, the revival of this romantic hit under Ellis Rabb's silken direction never strikes a false note or makes a false step. Barry's sparkling stage piece about the humanizing of a Main Line Philadelphia Filly is a comedy of manners from the days when there were manners to write comedy about.

For those who don't recall the play or the film (kept happily current on late-night TV), "The Philadelphia Story" concerns the socially prominent Lord family. Divorcee Tracy Lord (Blythe Danner) is about to marry self-made coal-mining tycoon George Kittredge (Richard Council). Who should appear on the opulent scene but Mike Connor (Edward Hermann) and Liz Imbrie (Mary Louise Wilson), a writer-photographer team from ferreting Destiny magazine. Who also should appear but Dexter Haven (Frank Converse), Tracy's former husband, and her father (Douglass Watson), a penitent playboy whose scandalous affair funds more forgiveness in Mrs. Lord (Meg Mundy) than in the rigidly uncompassionate Tracy.

With subtle craftsmanship and cleverly astute rationale, Barry dramatizes the humanizing effects on Tracy of her encounters with Dexter, with the father she scorns, and particularly with Mike, and the anti-establishment magazine writer with the touch of a poet. Mike's prejudices evaporate as he discovers the charm , intelligence, and impulsive generosity of the patrician bride-to-be. The consequences of their near romance and nonfatal escapade propel "The Philadelphia Story" to the comic romantic denoument for which Barry was aiming and win for Tracy the wisdom of an understanding heart.

The production at the Vivian Beaumont revels in its own high style and distinctive flavor. Blessed with a comic sense as delectable as it is fastidious, Miss Danner also projects the prejudice against weakness and Iron Maiden censoriousness that make Tracy so formidable an heiress. She is admirably matched by Mr. Hermann as a romantic who sees himself as a Jeffersonian democrat and mr. Converse as the glamarous scion and sailboat skipper who has never stopped loving Tracy.

Director Rabb uses the enormous Beaumont stage with extravagant imagination. What's more, he makes the actors seem at home in it. "The Philadelphia Story" reopens the Beaumont with grand and glorious panache.