Last season, Janice Hall substituted twice as Rosina in the Washington Opera's well-groomed production of "The Barber of Seville." This season, the role is completely hers, not only in terms of singing assignments between now and Jan. 16, but even more in the musical ease and dramatic impact of her performance. Here is a Rosina who completely justifies all of the incredibly (and hilariously) complicated machinations of the plot: the raucous street musicians in the opening serenade, the secret messages and disguises, the faked drunk scene, the platoon of colorfully costumed soldiers who march in to stop a duel (sword versus walking stick), the singing lesson with its whispered counterpoint of love and conspiracy, the bribery, the abduction plot, the trumped-up panic about a possible scarlet fever epidemic. All of this and much more would be little enough effort to win the hand of a woman as beautiful, spirited and clever as Hall's Rosina, even if she did not have such an exquisite voice.

Two exquisite voices, in fact: a rich mezzo and an agile coloratura, different in texture but almost seamlessly joined together. In either voice, she sings with intelligence, beautifully clear diction, a lavish variety of dramatic emphases and finesse of characterization. All of this works particularly well in the intimacy of the Terrace Theater, where the arching of an eyebrow or the subtlest shading of a syllable can have their full impact.

It would be too much to say that the whole production belongs to Hall as fully as the role of Rosina, but she is the major new element in this year's presentation of last year's notable box-office success. Hall shares her honors with a generally strong cast, mostly brought back to repeat last year's fine performances: J. Patrick Raftery as Figaro, William Dansby (fresh from his triumph in "The Rake's Progress") as Basilio, Joseph McKee as Bartolo and Tony Torchia and Art Treichel in smaller roles.

Two newcomers, Alan Kays as Almaviva and Judith Borden as Berta, seemed to have small vocal problems on opening night. The first tenor aria, "Ecco ridente in cielo," is a serious technical challenge to any singer -- perhaps even more in Rossini's original version which is used in this production. On Saturday night, Kays sounded not quite warmed up, and the impression was confirmed by his improvement later in the evening. In Borden's case, edgy sounds in "Il vecchiotto cerca moglie" were probably a matter of deliberate choice: comic effect rather than tonal beauty. And the choice may have been the right one, since she was very funny -- as was Kays when he got into the comic business of Act II.

The finest moments of the evening came in that act, which offers one dazzling invention after another, from the opening "Una voce poco fa" through "La calunnia" (done by Dansby with tempestuous brilliance), the letter duet of Figaro and Rosina, the drunk scene and the military intervention. There was a special quality in those moments when Hall and Raftery shared the stage, a comic grace and spontaneity, a dramatic finesse added to pure vocal ability that was a joy to behold and seemed equally a joy to the performers. Raftery (a singer clearly destined for stardom), threw himself into the role with a wholehearted enthusiasm that seemed on the verge of drawing blood when he shaved Bartolo and that nearly toppled him to the floor once when he sat down on a stool with slightly too much e'lan. But he stayed in his role without missing a beat even while struggling to recapture his balance, and he integrated the accident into the performance. This impromptu episode was very much in the tongue-in-cheek, commedia dell'arte spirit which permeates Lou Galterio's stage direction. It harmonizes with the anonymous hand that pops out from the wings to take Figaro's guitar when he is through playing with it and the actors' constant playing off the flimsiness of the scenery (all backdrops, really, which could be a drawback in a more pretentious kind of production.)

In the pit, John Mauceri maintained the high standard he has set in other productions, even with the Terrace's acoustics, which cruelly highlight the smallest orchestral blemish.

This "Barber," coming back for its second season, offers a special kind of perspective on what has been happening recently to the Washington Opera. Last year, it was (at least for those who do not have a special affection for "L'Amore dei Tre Re") probably the highlight of the season. This year, it is still as good as ever and perhaps even better, but after "La Bohe me," "The Magic Flute," "Monsieur Choufleuri" and "The Rake's Progress," it no longer seems extraordinary. The exceptional standard set by this production is becoming the rule for the Washington Opera.