Talent doesn't always run in the family

A new show celebrates paintings by three generations of the Wyeth clan. Their creative legacy is both inspired and ludicrous, writes Tom Lubbock

There isn't a lot to see. But then, we hardly ever see it at all. I'd guess there isn't a single Andrew Wyeth in any British collection or gallery, and there hasn't been a retrospective here since it was shown at the RA, 30 years ago.

But, of course, he remains a famous artist. We know his art. People may have a poster of Christina's World, or perhaps Sea Boots. And some people love these works, and some people absolutely despise them. This smallish show at Dulwich Picture Gallery is a reminder. The artist died last year, at 91.

Actually, there's more than one artist. This exhibition is called The Wyeth Family: Three Generations of American Art, and includes his father, and his son, and also his aunt and uncle. This is not exactly curating. All the works are on loan from the collection from a US bank. So an Andrew Wyeth exhibition turns out to be even smaller than you might have imagined. It's bulked out with the handiwork of his relatives, who are frankly...

OK. The dad is genuinely ludicrous. N C Wyeth, in his day, was a hearty illustrator, doing book plates and magazine covers. Comic melodrama was his style, in extraordinarily coarse oil-painting. At his very best, he can look like Winslow Homer at his worst. His subjects are olde England, imperial Russia, magicians, goblins, and George Washington being historical ("Why, this map is invaluable. What is your name, my boy?").

The son, meanwhile, flourishes and hasn't got a clue. It's clear what the deal was, but the gallery must have felt a little embarrassed to realise that Jamie Wyeth is the most incompetent artist they have ever hung by a long shot. There is a supposedly heroic image of 9/11. There is a supposedly menacing image of a bull. And there are rather a lot of his paintings. As for aunt and uncle – let them go.

Andrew Wyeth is the only Wyeth worth looking at. But in his own way, he is a problem too. Critics can get very cross about his reputation. Of course, it seems an overreaction. So people love Wyeth's work – why should we critics mind? Have other, better artists had their fame stolen or diminished? Is it a horrible spectacle, to see the general public deceiving themselves? At any rate, if the case really does matter, at least let's try to get the case right.

And for a start, let's put the rude word illustration to one side. We get bogged down in this insult. There are great illustrators. (Daumier, for example.) Ditto popular ones. (Don't forget Van Gogh.) And as for art that is enjoyed in reproduction, who can pretend that we don't spend quite a lot of our attention on books, posters, postcards – and on the other hand, Wyeth too can gain something in the original, as this exhibition makes it clear.

There is none of his legendary paintings. But they are all characteristic. They don't change much over the years. His turning point was his father's death in a car crash in 1945 – the artist took up tempera paint, with dry surfaces and muted colours and rugged subjects: land, sea, faces, wind. There are three or four set-piece paintings here, such as Undermined – an abandoned white-board house perilously on the edge of a shore – where he wants a bit of atmosphere, and then a little bit more.

He is often accused of being a storyteller. That's true, but only slightly. It's a nudge, an extra. And that's the trouble. Undermined would have been enough, just being a landscape, without the implied hint that mining is going to bring the house down. But Wyeth doesn't have confidence in a pure scene – nor in a real drama. He likes an add-on, a clue to pick up. Likewise in On the Edge, the woman stands on a rock, by a stormy sea, with her head turned away. It says: what's going on? Who knows? The picture will neither speak out nor shut up.

But his main agenda, and what he's most admired for, is his exact realism. That's the word. People like his very precise and dense observation – a kind of photorealism that takes detail, and heightens and intensifies it. We notice the minutiae and the textures of the world. There is a uniform deep focus. Whether it's the wood of clapperboard planks, the speckles of sand, rough grass, wild waves, a spruce tree, a pair of boots, near or far we scan every bit, and everything is under the artist's control. There is a technique that offers us a sense of certainty and safety.

Now a British viewer may feel glutted by this kind of art. When Wyeth arrived, we'd had the Pre-Raphaelites for a century already, and they're still very popular, and all through they're pursuing detail: "The inexhaustible perfection of nature's details", as John Ruskin put it; "absolute uncompromising truth, obtained by working everything, down to the most minute detail, from nature, and from nature only."

To be sure, there are obvious differences. They have evident moral contrasts. The Pre-Raphs were often explicitly literary, and medieval, and Catholic. Their nature is glorious and grows richly in the hedgerow. Wyeth is about rocks and farms and puritan values. His nature is spare and dry and hard to cultivate.

More to the point, there is a very deep difference. The Pre-Raphs are extremists. They're determined to number every hair, the blade of grass, the daisy's petal, the vein of leaf and rock. Their point-blank refusal to see the wood for the trees, and the trees for the grain of the bark, is unequalled in European painting.

Whereas Wyeth is never extreme. His apparently precise observation is a very limited thing. His eye doesn't surrender itself to the world. He wants to produce a look of infinite minutiae, but he pursues this to a certain level of detail, and no further. His technique is impressive but always contented with itself. He isn't interested in the unpredictable, in variety, in the chaos of nature. He creates areas of uniform texture. His realism is a matter of recipes.

And beyond that, he does compositions. It's odd that critics have noticed his stories, and haven't noticed his much more conspicuous arrangements. Wyeth sets out formal elements in very simple combinations – one shape against another shape, one tone against another. The Antler Crown shows some kind of large Christmas decoration, hanging in a window. The curling caribou antlers are bright against a dark blind; the prickly spruce is dark against the bright snowscape outside. His fans may not use this language of abstraction, but his patterns are blindingly decorative.

So it's strange that Wyeth is sometimes classed as no artist. On the contrary, he's all too arty. His father and his son are both catastrophically vulgar, but the man himself is a paragon of tastefulness. His textures, his arrangements, his moods, his discrete suggestions, everything is neat. It's interesting to see his surfaces. I can't see how anyone could hate this work. But he is an operator, and rigidly humourless.

Never mind about the old Pre-Raphs. Just turn to our own 20th-century people's favourite, L S Lowry – there is sadness and comedy and gregariousness. I wouldn't want to spend a lot of time in the company of either art, but I know what I'd choose if I had to.

The Wyeth Family: Three Generations of American Art, Dulwich Picture Gallery, London SE21 (020-8693 5254; www.dulwichpicturegallery.org.uk), 9 June to 22 August