For Beethoven's "Fidelio," now playing in the Kennedy Center Opera House, the scale is monumental and the de'cor comes largely in shades of black and white.

This color emphasis applies not only to John Gunter's massive dark gray sets, depicting various parts of a Spanish fortress-prison, but to the opera's manic-depressive emotional range and its starkly polarized heroine and villain: Leonora, a woman of matchlessly pure wifely devotion, against Pizarro, a man of monstrously cold-blooded political vindictiveness.

"Fidelio" comes close to matching Menotti's "The Consul" (so far, still the highlight of the current season) in the intensity of emotion it generates. The music is better than Menotti's, but the production does not quite equal "The Consul" in variety of color, richness of imagination and theatrical effectiveness for a modern audience.

This is an old-fashioned melodrama from beginning to end: the story of a man kidnaped and hidden in a dungeon by a political enemy, tracked down and saved by his faithful wife, who disguises herself as a man to facilitate her search. Like that of most of the traditional operatic repertoire, "Fidelio's" survival is a tribute to the preservative powers of great music. As a spoken drama, it would not last a week with general modern audiences. But as presented by the Washington Opera, with Gerard Schwarz conducting a generally good cast, it is an intense, sophisticated and satisfying theatrical experience.

The credit must be distributed widely among the participants -- above all to Schwarz for the pacing of the drama, the balancing of the voices and the subtly effective use of the orchestra throughout. One of the company's finest technicians, lighting designer Joan Sullivan, stands out particularly in this work, where the interplay of light and shadow has great thematic value.

Michael Hampe's stage direction is often static, but that frequently fits the mood of the opera. And there are times -- for example, in the tense silence before the Act 1 quartet "Mir ist so wunderbar" -- when his artful direction makes the expectant silence crackle with suppressed energy. Gunter's sets (small variations on a single set) make a statement that would be eloquent even without words and music.

Among the singers, James McCracken, in the role of Florestan, is the second to the last to make his appearance, and his music fills a relatively small part of the opera's total running time. But even in chains, crouching in a corner of the darkened stage, he dominates the action for much of Act 2, beginning with his electrifying shout of "Gott!" -- the first word heard after the second-act curtain goes up.

His aria "In des Lebens Fru hlingstagen" becomes the emotional highlight of the second act, and possibly of the entire work, though there are two other transcendent moments: the chorus of prisoners let out into the sunlight briefly in Act 1 (beautifully sung on opening night Saturday) and the dramatic confrontation between Leonora (soprano Laila Andersson-Palme) and the murderous Don Pizarro (Roger Roloff) in Act 2.

Roloff is a splendid villain -- deep and rich of voice, arrogant in his bearing and merciless in his treatment of enemies and social or political inferiors. Andersson-Palme had a few minor problems on opening night but was an appealing and generally effective Leonora/Fidelio. One problem that should be ironed out for future performances is the awkward, time-consuming way she draws her gun in the climactic confrontation with Pizaro. This should be a sudden, smooth gesture, coming as a shock.

Among the secondary roles, William Wildermann stood out with a vocally impressive and dramatically convincing portrayal of the jailer Rocco, a good man in a harrowing situation. Marcus Haddock, who has performed well this season in "Romeo and Juliet" and "L'Italiana in Algeri," continued his good work in the role of Jaquino. Faith Esham caught the character and mannerisms of Rocco's daughter Marzelline with fine precision and an attractive personality. Her voice was sometimes outbalanced in ensemble numbers, particularly in Act 1 and when she was singing below mezzo-forte, but this sounded like an opening-night problem of adjustment.

The same may be true of the occasional inaudibility of Andersson-Palme's high notes. She has what sounds like a potentially great voice, but it came across with uneven impact on opening night. Schwarz used the orchestra superbly to support, never to cover, the voices, but the acoustics of the Opera House sounded slightly problematic. It is not a serious difficulty, but there was sometimes a significant difference between the impact of the men's and women's solo voices.

This would probably not have been noticeable in the Eisenhower Theater and certainly not in the Terrace Theater, but "Fidelio" is a grand opera production that would not fit comfortably in the smaller houses. And the Washington Opera's handling of its challenges showed the company's readiness (perhaps in everything except budget) to tackle some of the more demanding grand opera repertoire.

Among the many overtures Beethoven composed for this opera, the most popular -- "Leonore" No. 3 -- was used here. It was played at the beginning, not in the middle of Act 2 where a deplorable custom sometimes inserts it, and it was well interpreted, though the orchestra could have used a bit more muscle at the major climaxes.

Beyond the music and the acting, the use of light and color in this production deserves mention. For the final scene, the prison walls are symbolically split apart and a massive stretch of blue sky spreads itself across the stage, which is crowded for the first time with ordinary people, outsiders in the dark, confined world of the prison. At their head is Prime Minister Don Fernando, the opera's deus ex machina, brought in to set things right as quickly as possible.

His costume uses the bright colors available to a gentleman at the beginning of the 19th century, and the crowd of townsmen and women in their everyday garb contrasts sharply with the prisoners in their rags and chains, and with the soldiers in their black-and-white uniforms. It is the return of sanity and normality to the oppressive, black-and-white world of isolation and confinement, which may symbolize Beethoven's private hell, cut off from the everyday world by his deafness, his special brand of idealism and his lack of patience. This final scene has a few longueurs, but they may be necessary to balance the prolonged tension of earlier scenes.