How a new exhibition at the Hayward combines the realism of photography with the intimacy of painting

The results are fascinating, says Tom Lubbock

The Painting of Modern Life, at the Hayward Gallery, is the most interesting, intelligent, serious and enlivening display of contemporary art for a long time. It takes its title from an often-borrowed phrase of Baudelaire, a phrase that even after 150 years seems not to have lost its magic - as if the conjunction of "painting" and "modern life" was, and is still, somehow a paradoxical, problematic, yet beguiling idea.

This is a paintings show, exclusively paintings. And the paintings are in some ways of a traditional character - oil, tempera or acrylic, canvas or board, rectangular, hanging on the wall. The works, all made in the last 50 years, are by 22 artists, young, old or dead, from across the world, among them Andy Warhol, David Hockney, Richard Hamilton, Gerhard Richter, Vija Celmins, Luc Tuymans, Martin Kippenberger, Marlene Dumas, Peter Doig, Liu Xiaodong. What they have in common is a procedure.

They all paint, quite closely, after photographs. And I'd just point out how rare it for a contemporary group show to be anthologised on any principle other than subject matter. For works to be gathered on the basis of how they look, how they're made, rather than what they're about, is remarkable in itself.

Still, the concept may not sound very startling. Half the people who turn up at art evening classes want to learn to paint like a photo. And wasn't there a 1960s painting-movement called photorealism? And since the camera was invented in 1839, any number of painters have made use of it. What's so special about this lot?

Well, to borrow the words of another poet, Blake: "Servile copying is the great merit of copying." What marks these recent painters out is a certain deliberate servility. They're interested in what happens to painting when you take or find a photograph and copy it obediently.

They're not using photography as a resource in the creating of new images. In some ways, they're precisely trying to avoid creativity. As Richter has said, working from photos is a way of "not having to invent anything any more". The results are both paradoxical and beguiling.

Now, I should mention that the show does have a subject rubric, too. All the pictures are of - are taken from photos of - modern human life. But in a way the subjects don't matter. Whether the images are as banal as a group of nurses by Richter, say, or as hot as a bullet-riddled car by Celmins, the same thing happens to them. They become haunted, estranged. This is because of how they're made.

Just from looking, you can see what's going on. Though hand-painted, these pictures have photography's unmistakable visual trademarks - its distinctive tonality and visual confusions, its blurs and glares, the way it gives every detail a uniform level of attention, its casual compositions. What's more, the way the paint is put on is visibly slavish. The brush marks aren't in control. They're merely tracing a pattern of light and shade and colour that the photo has already laid down.

These artists depict a preprocessed image of the world, copying in paint the markings on a smooth surface. They're painting things at a remove. In a sense, they're painting them blind.

Seeing the two media jammed together like this makes you very conscious of how sharply they diverge. Photography and painting - modern and ancient! One is quick, the other slow. One is flat and seamless, the other tangible and gritty. One is a direct imprint of the world, an impersonal view, and the other is a conscious translation of the world, by means of the unreliable human body. As George Bernard Shaw remarked, the great thing about photography is that "it evades the clumsy tyranny of the hand, and so eliminates that curious element of monstrosity that we call the painter's style..."

When paint really tries to replicate photo, short-circuits happen. The photo's transparent access to reality is muffled. You're not, as you usually are with a photo, looking straight though it to the world. The painting gets in the way. But conversely the painter's handiwork, not creating its subject, just reiterating the photo's version of it, seems robotic, unhuman.

Typically, the picture becomes distant and numb. The world appears as if through soundproof glass. The artist who delivers this effect in its purest form is probably Celmins. Her images of war and peace, an explosion at sea, a speeding windscreen glimpse of an urban freeway, are like distant but fixated memories, images stuck unalterably in the mind.

But of course there's more than just one way. And by giving you 22 bodies of work, all doing something similar, but differently, the exhibition incites close visual comparisons. Hockney lies at one extreme. Though he uses photos as an aide-memoire, he basically keeps his eyes and hands on his subjects. A bit of photo-look gets into Mr and Mrs Clark and Percy, but the picture is not really transcribing a photograph. In the traditional way, it is translating reality - Mrs Clark's hair, say - into paint. And this handmadeness looks vulnerably "clumsy" and organic, compared to the impersonalised works around it. Warhol is at the other extreme. He isn't even transcribing. He's just painting onto photographic screen prints.

Richter is really the leader of this school. No small sampling can show his range of technique and mood, but he doesn't appear here as strongly as he should do. Dumas looks well, doing a kind of wild comedy - the painting fooling around with its source photo in the very process of transcribing it, adding absurd red and blue faces to a formal school photo (a painted version of the sort of surreptitious arsing about that often gets into school photographs). Tuymans, on the other hand, is the man who can hardly bear to look, hardly bring himself to perform the deeply dubious and compromised act of picturing - just barely touching canvas with brush, transcribing with the weakest hues, the faintest tones.

But the portraits of people and cars by the Californian Robert Bechtle are gripping. What's done to the photo-image seems very subdued, just a slight tuning-up, in which the surfaces of world are cleaned, smoothed, perfected, made even more photographic; a touch of Vermeer. Doig, meanwhile, pursues transcription-as-adornment, decorating the source image with a palette of colours and textures, and transfiguring it in ways it could never have imagined.

You may still say the trick itself is old. What about Vermeer? With his camera lucida he was doing the same thing in the 17th century, painting not the world but a light-projected image of the world. I also suspect that the Hayward exhibition, while displaying the riches of this late-20th-century tendency in painting, coincides with its end, because (a) photo-transcription has now become too much of an art cliche, and (b) due to seamless digital manipulability, the photo is changing.

Paradoxically, through technological advance, the photo is losing its character of mechanical imprint, the thing that once made it seem distinctively modern. Anyone can now mess around with a photo, with hand-held mouse or stylus. In short, photography is itself becoming too much like painting for a photo-painting hybridisation to go on yielding interesting results.

The Painting of Modern Life, Hayward Gallery, London SE1 (0871 663 2500), to 30 December