Bright Star (PG)

This delicate romance between Keats and Fanny Brawne is much more than a simpering costume drama

Costume drama has an image problem. For many viewers, the very genre is inherently trivial, fixated on surface beauty and reassuring nostalgia. I admit I often incline to this prejudice, suspicious at the faintest whiff of Quality Street. But if any film vindicates this strain of cinema, Jane Campion's Bright Star is it. Portraying the romance between a man of words and a woman of fashion, Bright Star is itself a musing on the costume drama, on the question of style and substance, on the respective powers of language and image to evoke bygone mores and present emotions.

Bright Star is about the poet John Keats and his muse Fanny Brawne. The time is 1818, and Keats (Ben Whishaw) is 23, of small fame and uncertain future, while his young Hampstead neighbour Fanny (Abbie Cornish) is already a woman of accomplishment: she makes her own extraordinary, somewhat showy clothes. The film's opening close-ups of a needle stitching linen don't remotely prepare us for the eccentricity of the raspberry-red confection we soon see.

Fanny's fashions don't always find favour with her literary acquaintances: Keats's friend Charles Brown scoffs at "the well-stitched little Miss Brawne in all her detail". Yet Fanny is no flibbertigibbet, but an artisan who justifiably prides herself on being a pioneer of the "triple-pleated mushroom collar". By contrast, the film is wry about the solemn male work of poetry. "All we do," Keats confesses, "is lie about the room all day begging for inspiration" – which, if we didn't know the fruits of his lounging, might seem to sum the matter up.

Bright Star offers some overt aesthetic debate. When Fanny asks him to explain the art of poetry, Keats derides the idea of discipline: "Poetic craft is a carcass, a sham." But Campion intends to vindicate craft: after all, there are few art forms so mediated, crafted, sewn, as cinema itself.

The film offers its own manifesto when Keats explains that reading a poem is like swimming a lake: you do it not to get to the other side but "to luxuriate in the sensation of water". Bright Star is not out to cross the lake of its love story, but to create a feeling around its characters, all the better for us to luxuriate. For that reason, Campion's film might strike some viewers as prettified, abstract, not sufficiently factual as a literary portrait. But Bright Star is altogether Keatsian in its creation of mood. Greig Fraser's photography, sometimes luminous, sometimes smoky; the verbal rhythms; the dense but spacious sound design: all of it suffuses the film with the proverbial "drowsy numbness". While the world we see is extremely beautiful, it is also concrete and everyday: the interiors look lived in, rather than Georgian show homes. With production and costume designs both the work of Janet Patterson, Bright Star truly is well stitched in all its detail.

Perhaps it takes a non-British director to do this, but the film also reclaims the idyllic romance of the English garden. Set to the turn of seasons, the film uses its floral motifs – drifts of daffodils or bluebells – not as mere decoration but as poetic elements proper. You just have to be prepared to accept a strain of consciously delicate imagery that could have felt coy but that comes out as persuasively fragile – very knowingly so in a haunting episode involving a roomful of butterflies.

As for the distinctive rhythm of the language, it takes a little getting used to. While it sometimes seems consciously mannered, at other times it is entirely casual. After a while, Campion's dialogue feels breathed, relaxed: this is not one of those period pieces in which each line is a petit four offered for our delectation.

The harsher realities behind the idyll are present from the start, not least in the form of Brown, the boorish cynic who possessively seeks to keep his friend imprisoned in the men's smoking room of letters. American actor Paul Schneider gives a strikingly eccentric performance – Brown spends one scene distracting the lovers with an ape impersonation – but a magnificent one, with its idiosyncratic delivery and caustic jokiness.

Keats himself remains something of an enigma, no doubt by design, as much of the film concerns Fanny's attempt to fathom him: she dispatches her little sister to buy a copy of Endymion to see "if he's an idiot or not". Ben Whishaw is a tenderly withdrawn Keats, loitering threadbare at a ball, like a sulky student; his broodiness is likeable and touching, but it also clears a space for Fanny to be the film's true centre.

In her warm but introspective playing, Abbie Cornish establishes Fanny as level headed, sensitive, tenacious. Cornish inhabits the 1800s landscape with absolute naturalness, sometimes appearing to do little but be present: yet it's a superbly unshowy, perfectly judged performance that brings the film to life just as Fanny's costumes breathe colour into her often sombre environment.

Admirers of Campion's The Piano will have wondered how things could have gone so awry in her last films Holy Smoke and In the Cut. But here Campion has rediscovered her fine tuning: there's not a note misplaced. At a key emotional moment, with Fanny in tears, Campion simply fades to black, in silence: melodies unheard and all that.

Bright Star is not the kind of historical romance calculated to wring your tears – it has a subtler, indirect approach to feeling. It's a ravishing film, and more substantial and serious than its unashamedly lyrical beauty might lead you to think. It would belittle the film to call it exquisite; better to use the proper Romantic term and say that, in Bright Star, Campion really achieves the sublime.