Beautiful Dresden

Perhaps both tales are true - the uncle, notoriously fond of money, had once had to reimburse a patron to whom he had sold four views of Venice as by himself rather than the true painter, his teenage nephew, and the nephew had quite certainly taken to calling himself by his uncle's name; what better way to rid himself of a rival than for Canaletto to dispatch Bellotto to Dresden, half a continent away in eastern Saxony?

Whatever the reason, Bellotto went to Dresden, there to be appointed Court Painter within a year, and was content to stay - with one long break in Vienna and Munich - for almost two decades, very generously paid.

He developed the manners of a courtier and never again worked for a bourgeois patron, serving Augustus well and his first minister even better, for Count Br¸hl, though he wore a new suit every day and kept a dozen tailors in constant employment, commissioned many paintings and never paid for one.

Bellotto's output in these years was by no means large - three dozen paintings, most of them townscapes of Dresden and landscapes nearby for Augustus, replicas for Br¸hl, smaller copies for other court patrons, and some fine etchings - but the pictures are so purged of the mannerisms of his Venetian style, so different from the bright clarity of products from Canaletto's workshop, that they astonish us.

Dresden made Bellotto. With his appointment there, the history of landscape, and particularly townscape painting, took a great leap. That his temperament was very different from Canaletto's is evident even in the very early paintings, but it was trapped in the uncle's formula.

In Dresden it was released to create paintings that have legitimate claim to be among the greatest landscapes of the 18th century. There is nothing tentative or hesitant about them: they are large, more than four feet tall and slightly less than eight feet long; they are exquisitely organised so that each view is framed and controlled by what is in it and, in turn, each discreetly controls the way that the spectator's eyes explore it.

Bellotto's business is, it seems, scrupulous accuracy; in the hierarchy of subjects suitable for the ambitious academic painter, landscape and townscape are on the lowest levels, but Bellotto gives both the stature of great scale, commanding the spectator to stand still and give them more than the attention that he might a complicated allegory or some obscure tale of Alexander.

He provides such a feast of detail that the eye moves slowly from point to point, identifying the buildings on the Elbe's further bank that lend each panorama a lively particularity of place, toying with reflections in the water; led leisurely to a far horizon, the eye at last rests on a tranquil sky.

In his foregrounds he offers half-adozen little narratives: a stout grandee talking to a Turk, a lively mongrel licking a peasant woman's face, the artist himself, perhaps, sketching, but interrupted by a pair of would-be connoisseurs. Bellotto sketching? Yes, of course - hundreds of sketches must have contributed to the immaculate perfection of these views, pieced together with uncommon accuracy to control the pace at which plane and block and interval march across the canvas and off into the distance along a shared line that conforms approximately to the golden section, that "mystical" proportion of 13:8; is it this simple classical device that makes the Dresden panoramas seem so perfect?

I dare say David Hockney attributes perfection to Bellotto's employment of the camera obscura - but on the one certain occasion on which he painted himself at work in the open air, there is no sign of that contraption. and stare. Consider, too, the long shadows, the sense that day is done, that the warmth of afternoon is fading to chill night, that almost everyone is going home or on the point of it.

In some of the later Dresden pictures, not included in this exhibition, there is a sense of impending threat in the shadows and the dramatic contrasts have something of the surreal Giorgio de Chirico effect. In the later landscapes the drama is most often caused by lines of sight that plunge diagonally from top to bottom and swerve away into the distance, and in these the shadows lie cool and grey, seeming more the creatures of moonlight than the sun.

Art historians may write at length about the influence of 17th century Dutch painting on Bellotto, but I am sceptical; in photographs that make all paintings seem the same size it may seem obvious, but when an eight foot stretch of Bellotto's rich paint hangs cheek by jowl with meticulous little things by minor Dutchmen, his genius seems entirely of his own making.

It is often said that he had no significant influence, but this is an opinion based on ignorance of the school of landscape painting that developed in Saxony and Thuringia after Bellotto's departure for Poland - a school of which the best stem wholly from his work.

Augustus and Br¸hl died in 1763. After three wretched years without the support of their patronage and only the support of an unimportant post as a teacher of perspective at the Academy of Fine Arts - where the director spoke in exasperation of his "dreary art" - Bellotto left for Russia. He got no further than Warsaw, where, until his death in 1780, he performed much the same service for that city as he had for Dresden - the perfect topographical record from which it could be reconstructed after the Second World War - but with a veil of percipient melancholy.

Masterpieces from Dresden, the Royal Academy, Piccadilly, W1. Daily 10am-6pm. Admission £7.50. Until 8 June.

For further information on Bellotto, the most accessible book is Bernardo Bellotto and the Capitals of Europe, edited by Edgar Peter Bowron (Yale University Press, 2001, £45). Max Hastings's book, Bomber Command (Pan Grand Strategy Series, £7.99), deals with the Allied bombing of Dresden.