The scene: a fronded glade by the ocean’s edge. A mustachioed man strums a mandolin for the sultry nude lying beside him on the sand. The green leaves of a tall tree seem to double as the drops of some mysterious green liquid tumbling from on high into a cocktail glass from which she sips. Or rather glugs: face and glass are so awkwardly fused, the woman might be wearing a gas mask.
Chris Ofili’s design for an immense tapestry triptych, woven by Dovecot Studios, is certainly high chrome, opulent, swoony – as you might expect from this celebrated painter. But it is also surprisingly crude. The figures are cursory, sketched in with a sub-Matisse brio; the sea is half-hearted, the landscape almost as clumsy as the botched anatomies.
To the left and right of the central panel, a man and woman apparently hold back some perfunctory curtains on this ill-defined scene – as if it might potentially come to an end. And some people claim to find menace in the atmosphere: paradise (or Trinidad, Ofili’s chosen home) under threat. But atmosphere is exactly what’s missing. The narrative, such as it is, has neither mood nor tone.
The man on the right carries a bird in a cage, and the work is called The Caged Bird’s Song in homage to Maya Angelou. But meaning what, if anything at all? Captions tell us that the curious chaos of punctuation marks in the sky depict the black Italian footballer Mario Balotelli. If I were him, I would ask for my face back.
In the (excellent) accompanying film, Ofili speaks of Balotelli as a nearly mythical figure for him, which may be why the footballer is cast as a quasi-divine cocktail waiter. A bit of football, a bit of The Magic Flute, Arcadia, Ovid, Gauguin, Matisse etc, equals a flavourless mishmash.

Ofili also speaks of “making a tapestry” on commission for the Clothworkers’ Company. But of course he doesn’t make it, so much as supply some whimsical watercolours (shown here to bulk up the show), one of which is then magnified by 887% for the Dovecot weavers to interpret.
And the weaving is spectacular. How could it not be, given that the Dovecot Studios in Edinburgh is among the greatest workshops in the world? The tapestries are meticulous, their surfaces flawlessly smooth and straight, the colours of the wool superbly combined to get at the painter’s palette. In fact the weaving lends graphic coherence to Ofili’s loose sketch. (It is also true, however, that the deliquescent bubbles of the liquid thrive better in watercolour, the white paper sparkling through the wash.)

Tapestry should not be a servant to painting. It can never be just a woollen copy of a painting anyway, given that it’s based on the grid of warp and weft, and always gives unique dimension to flat images. But Dovecot’s weavers have gone to extraordinary lengths over more than two years to simulate Ofili’s quick and casual brushwork, and the discrepancy is all too evident. Like the huge grisaille figures scaled up in gouache by other artists on the surrounding walls – temple dancers with sketchy costumes, hopeless moustaches and hands – every weakness is writ large. This whole enterprise feels like the equivalent of easy listening music performed by a chamber orchestra.

There are birds aplenty in Mat Collishaw’s new show. He paints humble robins and sparrows chained to perches in the manner of Carel Fabritius’s captivating The Goldfinch, except that the wall behind them is not beautifully bare, but covered in virulent graffiti. The little creatures struggle to be seen against all this neon boasting, their plumage obscured by disorienting marks.
That both birds and graffiti artists are on the same evolutionary spectrum – competing entirely in terms of outward appearances – is the theory (proposed by the psychologist Geoffrey Miller) that underpins this show. It has its climax in an extraordinary work that combines a hyperreal sculpture with strobe lighting to create a modern version of the Victorian zoetrope.
Heaped up like a towering wedding cake are alternating tiers of bright flowers and magnificent bowerbirds spreading their wings in courtship, while hummingbirds suck at the pollen. You see them static at first. Then the lights suddenly start to dim. As the sculpture turns, and the light strobes in the darkness, the birds perform their showy courtship dance faster and faster until the ritual becomes a blur. And just as suddenly, the whole stop-motion spectacle begins to slow. With perfect timing, this vision of life switches suddenly back to black. It is a brilliant contemporary vanitas.

But even more affecting, strangely, is the apparition of a silvery tree spreading its vast branches in the darkness. This is the Major Oak of Sherwood Forest, thought to be a thousand years old, appearing as an enormous negative image on a glass plate – or so it seems. Collishaw is again using modern technology to create Victorian illusions. You see the tree on the ground, swaying and shivering, the wind of the past rippling through its wide branches. And you see it standing upright and proud before you. But walk round to examine at the back and the tree simply vanishes – a ghost tree, here and now, as we all are, and then gone.
Star ratings (out of five):
Chris Ofili ★★
Mat Collishaw ★★★★
• Chris Ofili: Weaving Magic is at the National Gallery, London, until 28 August; Mat Collishaw: The Centrifugal Soul is at Blain Southern, London until 27 May