Hepworth in Colour — The Joseph Hage Aaronson & Bremen Exhibition, Courtauld Gallery

We are gathered, the seventeen of us, beneath a title so long it requires its own catalogue. The Joseph Hage Aaronson & Bremen Exhibition: Hepworth in Colour. By the time you have read the sponsorship to its end you have aged, slightly, and missed the first three sculptures.

A wall text greets us at the threshold. This is to be a focused exhibition. A research-driven exhibition. The Courtauld would like us to know, before we have surrendered a single penny, that this is emphatically not a blockbuster, so we should lower our expectations to the correct, curatorially approved height. Eighteen sculptures. Twenty-six drawings. We are not here to be dazzled. We are here to learn.

And the thing we are here to learn is that Barbara Hepworth liked colour. Not in the way you or I like colour, you understand — vulgarly, on a sofa — but in a highly original and unexpected way. She put it inside the holes. She painted the hollows pale blue. She strung them, like a harp nobody is allowed to play, and we nod, because we too have always felt that an oval of carved wood was crying out for a bit of duck-egg in the cavity.

“In a way my colour has been accepted but never understood,” Hepworth told her son-in-law, who was an art historian and therefore obliged to write it down. The Courtauld has built an entire show around being the ones who finally Understand. You sense the relief. After ninety years, somebody has read the brief.

We process. Truth to materials, says the wall. Direct carving, says the wall. The wall is having a wonderful time. The sculptures, to be fair, are magnificent — luminous, serene, smug in the way only a perfect ovoid can be — and you find yourself moved despite the literature, which is the highest compliment a research-driven exhibition can receive.

Then bronze. Then painted marble. Then, mercifully, the 1950s, where she takes up actual painting and it turns out she could do that too, which feels almost rude.

Upstairs, as a consolation prize for those expecting more, are the Hampstead studio photographs — Hepworth and Ben Nicholson, 1933, looking impossibly handsome and certain among the plaster dust, back when the rent was payable and the marriage was not yet a footnote. These are the best thing in the building. Nobody has written a wall text long enough to ruin them yet.

You exit, as one must, through the catalogue, edited by Dr Alexandra Gerstein and weighing slightly more than a small Hepworth. The Times gave it five stars. The Guardian, four — because somewhere a critic also resented the title.

★★★★ — Ravishing. Understood at last. Now please understand the gift shop.