Imogen Cooper's message Thursday night was a subtle one. In a Philadelphia Chamber Music Society recital largely of classics, the English pianist made no bold pronouncements. Haydn, Beethoven, Schubert, and a mesmerizing work by Thomas Adès were rendered in fine detail, but often expressively restrained.

Even in the Schubert encore at Cooper's Perelman Theater appearance, when many a recitalist will loosen up, it was about coloring between the lines.

But what colors. You come to Cooper for melody, and here she gave listeners not just a lot to consider, but also some beautiful emotion. She is a great believer in the power of the line — the feeling of pushing through a phrase to the end. A silken, rich sense of melody took listeners happily through the first moments of Beethoven's Piano Sonata in A Flat Major, Opus 110, and throughout the rest of the first movement. And then there is her rich middle-register sense of sound, so deeply satisfying.

Where other pianists (Pollini, Ashkenazy) draw attention to the contrasts that are so much a part of these composers and classical style in general, Cooper tends to make accommodations.

Glossy, legato lines were the hallmark of her approach to Haydn's Piano Sonata in C Major, Hob. XVI:50. And she had other ideas for color, like the charming music-box sound she brought to the section near the end of the first movement, or, in the big chords, the sound of grandness rather than brightness. The second movement came, if I'm not mistaken, with some extra ornamentation; these touches were completely in character and yet imaginative.

Schubert's Piano Sonata in C Minor, D. 958 is a bear of a piece. Parts of it seem more symphonic than pianistic. Rather than wowing with technique, Cooper uncovered the first movement's strange, disorienting chromatic section just before the recap by creating a coloristic haze. I know we don't know what key we're in anymore, she seemed to say. Just enjoy the sensation.

The Adès had some of that same feeling. Darknesse Visible, written in 1992, is a kind of mournful, spiritual deconstruction of a John Dowland tune from 1610. Here Cooper's repetition of single notes was so quick and deft they created the auditory illusion of the human voice.

A ghost of the chorale-like melody ends the piece — it is marked ppppp, a dynamic so quiet you nearly never encounter it — which Cooper used to glide, ever so slyly and without interruption, directly into the Beethoven. It startled in the best possible way.

Discount ticket alert: The Philadelphia Chamber Music Society will hold its annual $10 sale from 9 a.m. to 5 p.m. Dec. 5, with three additional hours, from 5 to 8 p.m., for online sales only. Twelve PCMS concerts throughout the season will be on sale for $10 per ticket for the one-day sale. pcmsconcerts.org, 215-569-8080.