EXHIBITIONS: Small, but perfectly formed

From Henry VIII to Victoria, monarchs have loved miniatures. Our queen likes them too, and has put the family album on view

It would be wise to take a magnifying glass to "Masterpieces in Little: Portrait Miniatures from the Collection of Her Majesty Queen Elizabeth II," the exhibition at the Queen's Gallery which has now returned from a popular (and financially successful) tour around America museums. Good miniatures have many virtues, but we can't help admiring them for their artists' microscopic finesse. The techniques of the classical miniaturists were truly remarkable and a little artificial enlargement helps one to understand the fine combination of precision and loving tenderness in these walnut-sized pictures. They do require a special kind of love in the artist who fashions them. Otherwise they are merely small. The best miniatures have a heart, whether or not they were designed for sentimental patrons.

This is not a large exhibition, though it covers the history of miniature portraits from their beginnings in Tudor times to the mid-19th century. The aim has been to show works of significance and very high quality. It's obvious that miniatures can easily become formulaic and repetitious. The catalogue, which has helpful essays by Christopher Lloyd and Vanessa Remington, points out that a skilful miniaturist could complete a work in about seven hours. That's pretty quick, and surely the temptation for any artist/craftsman must have been to produce miniatures in quantity. Hence the abundance of accomplished but routine work in the miniature industry as a whole, with the inevitable problems of dating and attribution. When a miniaturist was working for royalty, however, he was likely to be at the height of his profession, would try to do his best and would not dare to make replicas of his original image. Lloyd, who is the Surveyor of the Queen's Pictures, has therefore been able to pick top examples of this peculiar form of art.

Peculiar because miniaturists are a race apart. They keep to their size and don't paint pictures on a normal scale. Conversely, artists of a more standard type rarely attempt the ultra-small portrait. The exception is Hans Holbein the Younger. He is represented by four pictures of people at the court of Henry VIII. Cool functionary that he was, Holbein realised that miniatures would be an important part of his life as an English court artist. He picked up the craft of miniature painting from another immigrant, Lucas Hornebolte of Ghent, who contributes a nice, relatively unsophisticated portrait of King Henry. Hornebolte had begun life as a manuscript illuminator. Holbein had trained in goldsmithery. This sort of background helped the new expertise in painting miniatures. Their medium was watercolour. They painted on vellum mounted on cut-down playing cards and their brushes were made from the tail hairs of squirrels. All this sounds a bit primitive and improvised but the results are lovely, especially since (as with nearly all miniatures) careful attention was given to framing.

These jewel-like frames are characteristically circular or oval, thus adding further elegance and intimacy to the painting they encompass. The backs of the pictures would often be of silver or gold; or of glass, enclosing perhaps a lock of the sitter's hair. Clasps or pins were used instead of hanging nails, for miniatures could be worn as personal adornment or hidden in some private place. George IV was buried in his nightgown with a locket-miniature of his mistress, Mrs Fitzherbert, and who can say that such a royal tradition may not continue? Lloyd hints that successive monarchs, from the first Elizabeth to the second, have had an intense interest in their collections of miniatures. Queen Victoria was a connoisseur of such things. Queen Mary, we learn, liked miniatures because she collected small objects that had any kind of bearing on her obsession with dynastic history. Lloyd also reveals that the present queen purchases miniatures, such as John Hoskins's portrait of Henrietta Maria, once in the collection of Charles I. She got it at Sotheby's in 1968, when her bidder would have been a previous Surveyor, Anthony Blunt.

I wonder what else the Queen buys at auction. Probably not bigger pictures. It seems that miniatures appeal to people with a strong sense of family, as must be the case with all royals. The paradox is that miniatures are better at romantic sentiment than stately pride. They should be exchanged by sweethearts rather than admired by awed subjects. After the Tudor period no small portrait of a reigning or future monarch really succeeds in emotional tone. Court miniaturists were more at ease with other courtiers, consorts and children. Perhaps they were less overcome by the royal presence if they were foreigners. Christian Kinke's portrait of George II shows us an absurd man in fancy dress. (A neat appreciation of clothes is essential for a miniaturist and I cannot think of a miniature of a nude in any classical culture). Francois Clouet's Mary, Queen of Scots is impressive. Note that her political importance makes him adopt a square format. However, political themes never work in miniature painting.

The miniature is a sub-branch of portraiture. In this show the formal public portrait is approached in Georg Wolffgang's George Frideric Handel, painted on ivory, as miniatures now were. Again, this picture is a rectangle, and it is one of the few paintings in the show that one can imagine on a much larger scale. The picture was probably bought by Prince Albert in 1860. This is only the second occasion that it has been seen in public. Recently - and thanks mainly to Lloyd - the Royal Collection has been more open to the populace. Robert Bowyer's Horatio, lst Viscount Nelson has never before been exhibited, though Nelson is the people's hero and not the sole possession of the crown. Strange how delicate, even effeminate, Bowyer makes him look. The traditions of miniature art have made this old sea dog - minus an eye and an arm when Bowyer painted him - into a sensitive aged Wren.

The catalogue claims that miniature painting was killed by photography. Not so. The Royal Academy has a room of minatures in every summer exhibition and the royal family still commissions portraits in miniature form. It's true that excellence in such art declined with the new democratic spirit of around 1848. Miniatures then had to join the mainstream of popular art. William Charles Rose's Victoria, Princess Royal of 1850 resembles contemporary Pre-Raphaelism. The PRBs learnt a lot from the miniaturist tradition. They too liked the intense colour, loving portraiture and fanatical detail. A number of Pre-Raphaelite paintings, Millais's Ophelia prominent among them, can be interpreted as miniatures on a gigantic scale. Victoria never bought Pre-Raphaelites and the painters of the new middle-class avant-garde movement could never have been artists at the service of the court. And this is how the miniature died.

The Queen's Gallery, Buckingham Palace, SW1 (0171 839 1377), to 5 Oct.