The BP Portrait Award's new open-door policy may have helped boost entries by 70 per cent but while a quarter of those selected for this year's exhibition are older than 40 (the previous cut-off point), it's the younger artists who provide much of the interest.

Among the under-forties, Jeremy Andrews has brought tattoos and piercings into the gallery with his image of performance artist Franko B, while John Ball has based his painting on pictures of a commuter taken on his mobile. Some have even upgraded their portraits to high definition.

In Edward Sutcliffe's painting of a stranger, for example, the face comes out of the canvas with wrinkles and broken capillaries like a landscape made of crÍpe paper. It's a popular style: three of the four portraits shortlisted for the prize (which is announced tomorrow) veer towards the photorealist.

Twentysomethings Johan Andersson and Hynek Martinec both opted for billboard-like portraits: while Andersson's looks like it could have been airbrushed, all in soft focus, Martinec's has the slickness of a Mario Testino photo.

But maturity may have the last laugh - the strongest piece in the show is the shortlisted Michael Simpson (pictured) by 60-year-old Paul Emsley. Another detailed, large image with skin as thin as a layer of milk on a cup of tea, Simpson has an expression that changes at every glance, creating a rare magnetic quality that raises it above the gilded youth.

Fiona Macdonald

Until Sep 16, National Portrait Gallery, St Martin's Place WC2, daily 10am to 6pm (Thu and Fri to 9pm), free. Tel: 020 7306

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