Aimard, Orchestra of the Age of Enlightenment, Rattle, Royal Festival Hall

The repertoire of the OAE is creeping away from the 18th century and into the 20th with such unashamed eagerness, it wouldn't be at all surprising to see them throwing up an urtext edition of "Hit Me Baby One More Time" in a few seasons. Last night, we got 20th-century French impressionism, including a work that was premiered in 1933. Some might call this expansion into the las

Though it doesn't immediately tally on paper, the match-up made complete sense. Few other periods of music can benefit more from the qualities that a period ensemble like the OAE can offer than the French school of Debussy, Fauré and Ravel. And there are few people better at dealing with the musical space and colour of this period than Rattle. No one interested in the possibilities of sound, then, would have been left disappointed with last night's concert. The only problem was the OAE's unfamiliarity with the music, which meant that local interest usually trumped cumulative impact.

Pierre-Laurent Aimard deployed the various colours of his period instrument as a watercolorist might

Still, vivid music frequently became fantastical. We rolled around inside a barrel at the start of the Ravel Piano Concerto for the left hand, the croaking double basses and bass bassoon encircling us. Plucked harps became sunbeams and cello gut-strings left salty residues in La Mer. But we began with something simple and ravishing. The lyrical pianissimos in the Fauré Pélleas et Mélisande suite usher in little fantasy but a lot of beauty. Rattle balanced the orchestra to perfection. There was a lazy ludic joy to the second movement, a luminescence in the third movement and a rare bit of passion in the death scene.

In the Ravel, Rattle and the OAE were joined by a pianist famed more for his intelligence than his palette, Pierre-Laurent Aimard. However, so flavoursome was his period instrument that Aimard didn't really need to do much to summon up a full spectrum. Each note sounded like a new instrument. Aimard took full advantage of the timbres, deploying the various colours of the piano as a watercolorist might, layering sonic washes through clever pedalling and bleeding melodic statements into these. There was plenty of derring-do in there too in his daring leaps up the keyboard. Rattle and the OAE more than matched the theatre with some glorious brass playing. By contrast, Aimard's encore, "Les sons et les parfums tournent dans l'air du soir" ("The sounds and fragrances swirl through the evening air") was disappointingly limited.

It was a reminder of how difficult Debussy is to play. His works consistently require four-dimensional thinking, the horizontal, vertical, timbral and spatial all demanding the musician's full attention. The OAE dealt with the timbral demands often in a dazzling fashion. And the vertical was always masterfully calibrated by Rattle. But for Debussy to work spatially familiarity is imperative. And sadly familiarity with this repertoire is not something this orchestra has. They were less able to hide this unfamiliarity in the second half. The virtuosity that is required in Prélude à l'après-midi d'un faune (Prelude to the Afternoon of a Faun) and La Mer not only showed up certain sections but also led to a general slackness in tension and messiness in ensemble.

It was quite clear which passages Rattle had had time to work on and which he had been forced to leave

That having been said, the performance of La Mer especially wasn't without isolated excitements: the perspective that was evoked in the brass calls at the start or the sudden entry of piccolo colour amid lurching double bass (who excelled throughout) or the seductive mellifluousness of the horn-playing. It's considered gauche to call Debussy an Impressionist today, but last night his music seemed closer than ever to a painterly style, with so much of the focus on colour and texture. Rattle injected as much of an improvisatory mood into the piece as he dared. But there's only so much he could do. It was quite clear which passages Rattle had had time to work on and which he had been forced to leave. 

Like the music of the Enlightenment, there's a performance practice that accompanies Debussy that takes years to fully grasp. The OAE's exploration of uncharted territory is valiant. But they more than any other ensemble should realise how important an intensive and contextualised immersion in a period style is to getting to the heart of a work. One came away from the concert being reminded that not every orchestra is suited to every period. 

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