EXHIBITIONS / Farewell grandeur, hello fun: The National Portrait Gallery has a friendlier face now that it also includes portraits of the living. The pomp has gone, but has something been lost with it?

THE NATIONAL Portrait Gallery has completely refurbished its ground floor, thus giving a lot more space to pictures in a pleasantly airy atmosphere. Henceforward these galleries will be used to display portraits from 1945 to the present day, and in the new installation there's an opportunity to see how the NPG has changed in the years since the Second World War. Only recently has it become a liberal and user-friendly museum. The booklet 20th Century Portraits reminds us that the NPG didn't collect portraits of people who were still alive until 1969, and it frankly admits that the gallery was top-heavy with pictures of generals and civil servants. All this has now changed. Here are portraits of athletes, pop stars and television personalities. Even Robert Maxwell has found a place on the NPG walls.

The new hang still has a sequence of prime ministers, from Attlee to Thatcher, and it is proper that they should be there. But a sort of democracy has taken over, and the top politicians now rub shoulders with all sorts of other people. It has an effect on the art. Lord Howe (painted by June Mendoza) and Lord Whitelaw (by Humphrey Ocean) probably wanted conventional and old-fashioned portraits, and these have been provided. On the other hand Glenda Jackson appears in a ceramic sculpture by Glenys Barton, there's Andrew Logan's glass mosaic head of Zandra Rhodes, and Duncan Goodhew is seen via a video portrait in a room that has been set aside for screened displays.

All this suggests that the National Portrait Gallery is alive and well. Can the same be said of the art of portraiture? This is the question posed by the special exhibition The Portrait Now, which occupies the NPG's new temporary exhibition space. It's a significant show because it's international, mixing works by British artists with a range of pictures from Europe and North America. So, in theory, we ought to be able to see if there are significant differences in the practice of portraiture in other countries. And we ought also to be able to judge whether portraiture as such has a leading role in world art.

That's the theory, but in practice the portraits all have more or less the same impact, whoever did them and wherever they come from. This is an extremely mixed exhibition as far as the artists are concerned, and their subjects are mixed too, so it's odd that the pictures seem so even, both in quality and attitude. A lot of the paintings are simply trivial. Here, as elsewhere in the new NPG, one notes the effect of the entertainment industry. We may be glad that the day of the pompous portrait has passed, but something was then lost. Not a single artist in this show truly takes on the problem of grandeur. For good or ill, the idea that painting might accord great respect to an admirable human being has disappeared. Today's portraits are about fun, and they are shot through with irony and knowingness.

Hence the theme of Peter Blake's well-known painting The Meeting or Have a Nice Day, Mr Hockney. It is a triple portrait of the artist and Howard Hodgkin greeting the expatriate painter in a Californian setting. Blake and Hodgkin appear to be offering homage to Hockney, who holds a giant paintbrush in the manner of the artist in Courbet's 1854 Bonjour Monsieur Courbet. The quotation from the French painting underlines that there is a difference in human aspiration between great artists and lesser ones. No one would bother to object to the joke in Blake's picture. At the same time we don't believe that the artist has been genuinely stirred. Courbet's point, though, was that portraiture and the role of the artist was a grand contemporary theme.

Blake has always been a better painter than Hockney, but his real excellence lies in domesticity. Hockney's portrait of the restaurateur Peter Langan (that enemy of domestic life) is embarrassing. He should have been represented by one of his portrait drawings, for these are Hockney's real contribution to art. The Portrait Now has been selected by the NPG's Robin Gibson. He writes interestingly about the subject, but I regret that he has chosen not to include either drawings or photographs. Surely the portrait of our time tends toward intimacy, and drawing is an intimate form of expression. Or modern portraiture takes on the world of publicity and the media, a realm in which the camera is all-important.

Leaving aside the question of drawing and photography, one notices that sculpted portraiture has come to an impasse. The portrait bust cannot rid itself of academicism, especially if the sculptor's fingers have no innate instinct for modelling. So it was with Elizabeth Frink, so it is today for John Davies and Glynn Williams. Eduardo Paolozzi attacks the bust convention with his usual energy, but the convention still overcomes him. The most engaging sculptures in the exhibition are by that undervalued artist Clive Barker, whose bronze head of Jo House laughs at Brancusi, and from Jeff Koons, whose self-portrait bust goes straight for the ultimate in kitsch and avoids aesthetic questions.

Strange that nobody can repeat Koons's act in painting, though plenty of people try. I have a fondness for Alison Watt's Cupid After his Bath. In this picture of a young and quite ordinary-looking man (apparently an ex-boyfriend) there are some good post-modernist tricks, a pose and a technique that are meant to remind us of Ingres, plus some charming amoretti. Magic realism with a high finish is also practised by Sara Rossberg, a German-born artist who lives and works in Britain. Two other young artists, Stephen Conroy and Sarah Raphael, give us the sort of portraits that one used to see in the Royal Academy's summer exhibitions. Conroy's picture of the Duke of Devonshire is gruesome and fawning. Raphael's picture of Sir Garfield Sobers is highly competent but artistically dead.

I suspect that Robin Gibson, like many other people, finds the most distinguished contemporary portraiture in the hands of 'The School of London', artists such as Frank Auerbach and Lucian Freud. Certainly they are more serious painters than most of the contributors to this exhibition. Gibson is also an admirer of the Slade School graduate John Wonnacott, who for many years has been a vocal champion of realist painting. Gibson remarks that his art 'evokes a range of reactions from wild adulation to indifference'. I belong to the latter party, and although I try to feel warmly towards Ian with Renown IV there is a blandness about its manner that depresses me. Obviously the picture lacks painterly inspiration. But something else is wrong. Why does it make one feel so glum?

And are not the School of London painters a depressed group? If you asked them to paint the summer skies they would reach instinctively for their pots of brown. Perhaps it is not right to call them portraitists. They are essentially figure painters with a predilection for interiors. Auerbach needs the stimulus of another person in the room, but it does not follow that he is a portraitist. A painter of portraits should be interested in people's features. Faces should be regarded as marvellous, which they are. Lucian Freud used to regard the face as - how shall we say - the open secret of another person's individuality. But it's curious that so many of his models have come to look like each other, as though he had taken something away from their personalities.

Beside Freud, Kossoff and Auerbach stands their comrade R B Kitaj, and in contrast he looks almost festive. His The Neo-Cubist, yet another portrait of Hockney, was begun as a nude study and was then overlaid with other bits and pieces that suggest Hockney's interest in photomontage. Don't be misled by the title. There is nothing Cubist about it at all. Perhaps Kitaj should be added to the very long list of artists who were wrongly excluded from the Royal Academy's American exhibition. He is a better artist than Julian Schnabel, also better than David Salle. Their portraits are simply not credible, lacking both quality as painting and a sense of human contact.

The international selection doesn't really work, though there are some interesting pictures from Germany. Sighard Gille's double portrait of the aged Salvador Dali and his wife is distantly related to Kokoschka and is a fine meditation on old age. Markus Lupertz's self-portrait shows a real love of paint. Gibson should have cast his international net more widely. It could be that the best portraits nowadays come from countries with underdeveloped media industries. Or so I speculate. You can't draw conclusions from this show, though it does start a number of hares running - in all directions.

NPG, WC2 (071-306 0055), to 6 Feb.

(Photographs omitted)