It took just one song, and a simple ditty at that, Thomas Morley's "It Was a Lover and His Lass," for Dame Janet Baker to make a lasting favorable impression on a Kennedy Center Concert Hall audience last night. Slipping ever so gracefully from an elegant forte passage into a piano mid-register, her lustrous mezzo-soprano lost none of its brilliance while retaining the perfect tonal clarity generally expected from one with such remarkable breath control.

Baker has been a favorite in this country since her American debut nearly 20 years ago. She can make the transition from recitalist to opera artist with uncommon ease. In either setting, she brings an expressively dark-hued voice and a regal bearing.

Last night, Baker did little to alter her reputation. The inclusion of English, German and French songs may have been predictable. But her approach to the familiar material showed variety, indicating that she has rethought at least some of her previous interpretations.

A quintet of popular Schubert lieder came across solidly, if not spectacularly. "An die Musik" and "Am Grabe Anselmos" had a minimal amount of dramatic tension. Baker's rendition of "Der Tod und das Ma dchen" was a surprise. Instead of conveying the maiden's confrontation with Death in a mood of suppressed hysteria, she chose a more neutral tone, one of quiet resignation for the heroine.

Four songs by Faure' received uneven treatment. Baker brought a suitably light timbre to "Les Roches d'Ispahan." Repeating the process in "Clair de lune" did not work. This piece requires a brighter, sweeter voice than Baker possesses to bring out the details in Faure''s music and Verlaine's text. Airiness without color made for a dull performance, the only real disappointment all evening.

Baker's readings of selected English songs were as eminently satisfying as her Faure' was irregular. "Let Us Garlands Bring," Op. 18, by Gerald Finzi was a mixture of haunting beauty and pastoral charm. Themes of death lurk around every corner in this mini cycle, which she capped off in upbeat fashion with "It Was a Lover and His Lass."

Pianist Martin Isepp, coincidentally the son of Baker's voice teacher, Helene Isepp, was not so much an accompanist as a coauthor. His playing was sensitive to the needs of each work on the bill. In handling Faure''s "Clair de lune," he brought a rhythmic fervor -- consistent in its instability -- that pushed along the vocal line.