The vast majority of Donatello's 80-odd surviving works remain in Italy, most of them in Tuscany. But there are 10 in London museums (one in the Wallace Collection, an amazing nine in the Victoria and Albert Museum), as opposed to five each in Berlin and Paris. The westernmost Donatello in the world, the only one to be found across the Atlantic, is the Madonna of the Clouds in Boston. After that, the two westernmost and anyway the northernmost genuine 100 per cent top quality drop-dead Donatellos are currently to be found (on loan from the V & A) at the admirable Henry Moore Institute in Leeds.

They are well chosen for contrast. The small bronze relief of the Lamentation Over the Dead Christ shows the sculptor's ability to convey anguish in an extreme form. The centrepiece of the exhibition, which is called "Depth of Field: The Place of Relief in the time of Donatello", is the long rectangular marble relief of The Ascension with Christ Giving the Keys to St Peter. The composition has the same grandeur as Masaccio's frescoes for the Brancacci Chapel in Florence (where it is sometimes said the work was originally shown), while the execution is in the very finest style of shallow relief, the style known as schiacciato or "squashed".

This is the style said to have been invented by Donatello, which hardly digs at all into the stone, but which seems to draw on it with the chisel, so that in certain passages what you are looking at is little more than a scratched line in marble. There are exceedingly few of these examples of Donatello's work. The Madonna in Boston, already mentioned, is one. Another, accessible from London by Eurostar, is the Presentation of John the Baptist's Head to Herod in the Musée des Beaux-Arts, Lille. This is one of the great, and surprisingly little visited, Donatellos. A third is in Naples.

However often you have seen the Donatello Ascension relief in London, it is worth visiting it also in Leeds. Lighting is crucial to it. When it has been removed from display (where it is, for reasons tedious to explain, not well lit) and examined under laboratory conditions, it responds surprisingly to light from different sources. The marble itself is only five centimetres thick, so the carving can hardly go much deeper than a centimetre, over most of the surface. The angle at which the light falls, and the intensity of illumination, are the key variables.

From the point of view of the V & A, where there are active plans for a new display of the renaissance sculpture collection, there is an interest in seeing important items from their collection presented in different ways. The Leeds show offers 45 objects set out in three rooms, the last of which is occupied by the Ascension relief alone. The second of the rooms, which is a converted courtyard and consequently has some height, is filled with the kind of Madonna reliefs one would have found on the walls of palaces and private homes, and in street shrines. These were often designed to be shown above head height, although that is not always the way one sees them in museums.

In the first of the rooms, there is a clever selection of reliefs and objects associated therewith. Most recherché are the wafering irons (waffle irons, if you prefer) used to make a circular wafer to be eaten at a wedding feast, a large pair of tongs by means of which the two sides of the mould were pressed together, while the cooking batter took the shape of the reliefs. It was by means of a device like this that mints, before the age of machines, were able to turn out coins on which the "heads" side always turned out at the same angle in relation to the "tails", whereas on earlier coins the relation between the two sides was entirely haphazard. The classical art of relief, which the renaissance artists were so keen to copy, had best survived on the surfaces of coins, gems and seals.

Here also we see a case made of cuir bouilli or "boiled leather", the process by which wet leather could be moulded, stamped or incised to produce a design in relief, which was then set by application of moderate heat. And here is a parade shield, wooden, decorated in gesso relief then gilded to catch the light. Here are tombstones of the kind that you often find have been simply worn smooth by countless feet. Here is a marriage chest, an ivory comb, a casket decorated with sections of carved bone.

Among the other artists represented, the star is Bartolommeo Bellano, whose Lamentation Over the Dead Christ is what remains of a Paduan altarpiece. This is the one exhibit to which the show does less than justice, placing it in a corner and rather low. For the rest, the chaste display works admirably.

You could make a Donatello study trip, starting in Leeds and proceeding through London and Lille to Paris. Padua would be a logical next stop. By the time you reached Florence you would have some expertise, having with luck seen (numerically) about a quarter of his works. Florence and Siena alone would add another half.