ART / Exhibitions: Just watch this face: Jumping the gun in Edinburgh: quirky portraits and (right) goofy sculptures

THE ARTIST himself has awkward features: a punchy lower jaw, clamped assertively beneath a receding and cleft upper lip and an ineradicable five o'clock shadow. Or so he portrays himself. But it is not a well-known face.

The Edinburgh-born painter Allan Ramsay (1713-84) has fallen into neglect, and the Scottish National Portrait Gallery would like to rescue him. It shouldn't have much difficulty. One can put his claim historically by saying that he was the artist who introduced the French informal manner to British portraiture - or that he was once the leading British portraitist of his age, taking the faces of the Hanoverian court, London and Edinburgh society, and Enlightenment scholars. Some of his subjects, like Rousseau and Flora Macdonald, are well enough remembered. But he is not the kind of portraitist who survives through the lasting fame of his sitters and our continuing need for their likenesses. However forgotten he is, one can still see what his commissioners saw in him. It was something he saw in them.

One of Ramsay's jobs was to take George III's profile for the coinage. And his quietly imposing portrait of David Hume has become the model for all subsequent likenesses of the philosopher. One can imagine his Hume or his forthright Flora Macdonald being used on the banknotes of an independent Scotland - those two pictures have the air of public images. But generally Ramsay's forte is not the kind of categorical likeness which stands for its sitter as the face on a coin stands for the monarch. Perhaps his forte is not even for the distinctive likeness as such. Few of his portraits have the sharp idiosyncrasy he allows himself. What he gets, rather, is a living look.

This is partly why the stately, full- length portraits of king, queen and other nobles are much less engaging than the half-length ones. The faces hang too high up on the wall. What engages in Ramsay is face-to-face eye-contact, often of a wary or tentative nature. The face of General Sir John Sinclair belies the bold brocade of his uniform. The portrait becomes a relationship, an exchange of looks: the record not of an appearance, but an encounter.

His sitters seem to feel that they are being watched; their faces register their portrayed-ness, their poses are held, but temporarily. In Rosamund Sargent, it seems as though she is holding her breath, just giving a few moments of her time. It is artifice of course. The actual sittings would require many more moments. But Ramsay is a master of those devices, some borrowed from French contemporaries, which suggest that the portrait is only a brief interruption in the continuing life of the sitter.

Mary Adam lays down her reading- glasses and book, one finger keeping her place, and turns round with a demeanour of extraordinary mildness. Margaret Ramsay (his second wife) glances up a little anxiously from the flower in her hand - while his male sitters sometimes become studies in not-quite-spontaneous casualness, like Robert Adam pretending to be in the middle of some paperwork.

Ramsay keeps these moments alive with a range of unresolved, transitional expressions. He does it by a version of the Mona Lisa trick. The time- honoured enigma of that elusive smile resides not in what Leonardo does with the mouth, but in the fact that the mouth itself is hardly smiling, while the eyes above it certainly are. Such inconsistencies, and the ambiguous signals they transmit, are not unknown to other portraiture, and Ramsay makes subtle use of them. Typically, he plays between the two sides of the face. In the anonymous Young Lady in a Pink Dress, the muscle round the left eye is slightly tensed, the left corner of the mouth slightly pursed. The right side of the face becomes more open and relaxed, the left more guarded and withdrawn, and you cannot say which way the expression is going. Something like this happens quite often, giving the sitters a mixture of self-presentation and self-consciousness, a hint of puzzlement or wryness - an appropriate attitude to being immortalised.

Scottish National Portrait Gallery, Queen St, Edinburgh (031-556 89210), to 27 Sept. National Portrait Gallery, London (071-306 0055) 16 Oct to 17 Jan.

(Photograph omitted)