Tonight's presentation of "A Star Is Born" at the Warner in a lovingly reconstructed near-approximation of its original 1954 version, which ran 181 minutes before being shorn of a "lost" 27 minutes several weeks into the engagement, is a special moviegoing event of clear cut philanthropic value.

Proceeds from this benefit showing, scheduled to begin at 8, are earmarked for film preservation programs associated with the Academy Foundation, an educational and cultural branch of the Academy of Motion Picture Arts and Sciences, and the American Film Institute.

Called a "Decade of Preservation," the effort is designed to rally and sustain financial support for needed programs of film rescue and restoration.

The Warner showing is the second of a six-city benefit tour arranged by the Motion Picture Academy with the permission of Warner Bros., the film's distributor. The first performance was Thursday at Radio City Music Hall, packed with a clamorous throng obviously predisposed to whoop it up with adoring, indiscriminate appreciation whenever the late Judy Garland did anything.

This phenomenon is unlikely to be imitated with comparable atmospheric impact anywhere else on the tour, and maybe it's just as well. The cultish tumult heard in Manhattan tends to exaggerate rather than obscure the obvious limitations of Garland's one-dimensional role as a suffering show-biz spouse and her rather painfully variable performance, which ranges from the thrilling during certain moments of vocalizing to the embarrassing during other moments of anxiety-ridden blubbering.

Garland may indeed turn you inside out emotionally while singing two Harold Arlen-Ira Gershwin numbers that are staged with extraordinarily moving directness and simplicity, "The Man That Got Away" and "You Brought a New World to Me." A similar excitement can be found in the introductory part of the lamentably overblown production number "Born in a Trunk."

Ironically, the overreaction at the Music Hall served to enhance one's appreciation for the most formidable dramatic aspect of this strangely haunted, discordant movie--James Mason's superb performance as Norman Maine, the alcoholic star whose career hits the skids soon after he discovers and promotes the career of Garland's character, an unknown jazz band vocalist named Esther Blodgett. Mason himself makes an overreaction to Garland superfluous, because he projects such delight in her presence and talent. The Garland cult is in thrall to a ghost, but Mason's Norman is fascinated with a living woman.

I don't think Mason has ever utilized that beautiful, insinuating, breathy voice with greater expressive skill. He also does remarkably subtle, stunning things with his hands and body.

Watch him particularly during "You Brought a New World," set in a motel room the night after Norman and Esther have married. Mason is turned away from the camera as Garland sings; without upstaging her, he nevertheless imposes a deeply stirring presence. In addition, note the imaginative originality and eloquence of his reactions to suffering a public beating and humiliation during that famous painful encounter at Hollywood Park with Jack Carson as his resentful, vindictive ex-press agent.

The leading roles have always been curiously out of balance in the three movie versions of "A Star Is Born." Watching the 1937 version now, it's difficult to credit Janet Gaynor's star quality, which was understood at the time but appears in desperate need of documentation two generations later.

The 1954 version is also out of whack, though not because Garland's star quality is hazy. It's a shame that she must play such a trembly emotional simpleton when Mason--and for that matter the principal supporting actors, Carson and Charles Bickford and Tommy Noonan--plays a multidimensional role in a psychologically aware, modern style.

Mason is scheduled to appear tonight, along with Academy president Fay Kanin and film historian and archivist Ron Haver, who discovered the missing material in the Warner Bros. vaults during an eight-month search encouraged by Kanin and authorized by Warner Bros. president Robert Daly.

Shot in CinemaScope and Technicolor, "A Star is Born" originally appeared in 150 roadshow engagements augmented by four-track stereo. After several weeks of decent but evidently disappointing business, Warner Bros. acquiesced to exhibitor pleas and cut the film by 27 minutes. The director, George Cukor, was out of the country at the time and unable to supervise the process, which fell to unidentified studio authorities.

Later, Cukor reflected that he and screenwriter Moss Hart could have "sweated out" a comparable stretch of footage with far less distortion to the exposition. He also resented the insertion of the "Born in a Trunk" number, which was directed by the hapless choreographer, Richard Barstow, and added a hulking 18 minutes to the running time.

The Warner Bros. film exchanges were ordered to make the cuts and return the surplus footage to the home office. Similar instructions went to Technicolor, which had custody of the negative. Haver succeeded in locating a complete stereo soundtrack and about 20 minutes of corresponding footage, including two complete musical interludes, "Here's What I'm Here For" and "Lose That Long Face," discovered in the stock footage vaults, where some editor had also preserved alternate takes of musical numbers. The former is probably the single most gratifying restoration, for it retrieves not only the song but also a charming sequence. The latter is further conclusive evidence that the movie could have used a superior choreographer.

A remaining seven minutes of expository material, mostly concerned with a period in which Norman and Esther have briefly lost contact, are suggested by the use of production stills to illustrate the surviving dialogue track. Obviously, this stretch lends itself to easier cutting than extended passages. With perhaps a five-minute trim here, 10 minutes out of the lumbering mid-section of "Born in the Trunk," and the stray minute here and there, Cukor could no doubt have reached 154 minutes with a minimum of damage.

Instead of reviving Garland's movie career, "A Star Is Born" proved a premature Waterloo. Though still in her early thirties when the film was made, she looks disconcertingly plump and dowdy and roughly 10 to 15 years older than Esther probably should. She never made another major musical and always ended up in sadsack parts. Perhaps she should have returned in a musical rouser.

"Star" is an unusually somber example, basically a tearjerker with song interludes. It's also structurally misshapen: the first act is all drawn-out exposition, the second all downhill resolution.

Nevertheless, it's gratifying to see it return in a more or less complete edition. While never a great movie, it's one of those legendary, haunting failures with undeniably great things in it.