When oils and water do mix

As a new exhibition - 'Turner and Venice' - is due to open at Tate Britain, Matthew Hoffman explores the unique qualities of the city which have been an enduring inspiration for artists

There is no such thing as an untutored eye; so if beauty is in the eye of the beholder, everything depends on who taught that eye to see. Even Venice, perhaps Venice above all, does not reveal its renowned visual charms in the same manner to all its many visitors. There is, for a start, postcard Venice with its piazzas full of pigeons, its quays crowded with tourists and its canals filled with singing gondoliers. Then there is tour-guide Venice, with stories attached to various locations: here Byron seduced his landlady, there Casanova escaped from prison; in this palazzo Benjamonte Tiepolo planned his rebellion and from that window it was foiled by a falling mortar (which felled the standard-bearer).

But most of all, there is painters' Venice. Has any other cityscape in history been so frequently depicted by so many artists of genius? An excellent way of beginning a visit to really see Venice is to start at the city's principal museum of painting, the Gallerie dell'Accademia. There you will be introduced to two ways of understanding the unique look of the place. Following the famous distinction made by Giorgio Vasari, in his Lives Of The Artists, between disengo (drawing) and colorito (colouring), we can discern two broad ways of catching the look of Venice: the illustrative and the imaginative.

Beginning with the illustrative painters, we might search out Gentile Bellini's grand 1496 canvas depicting a religious procession in Piazza San Marco. The painting has a literalness that is almost photographic in effect, and indeed the picture has been used by art historians to reconstruct some of the architectural history of St Mark's Church. After familiarising yourself with the scenic works of such Venetian painters as Gentile Bellini, Vittore Carpaccio and, of course, the great 18th-century view painter, Canaletto, it is not difficult to see, in your mind's eye, the almost unchanged modern city populated with various antique watercraft, stone-cutters, laundry maids, aristocrats, gondoliers, monks and mountebanks. You will also hardly fail to notice, following your visit to the Accademia, innumerable curious details of chimney stacks, balconies, arches, bridges and the rest of Venice's unique combination of Oriental and Western motifs.

But there is another way of looking at Venice, which is, if anything, even more rewarding. And that is through its unique colorito. From the first room of the Accademia where you encounter the first great Venetian painter, the 14th-century Paolo Veneziano; through the Renaissance masters Giorgione, Giovanni Bellini (the more famous brother of Gentile), Paolo Veronese, and Titian; right up to the 18th-century rococo frescoes of Giambattista Tiepolo, one is immersed in a delightful and seductive rainbow of colour effects. But these are not solely the result of technical innovation and artistic tradition, as you will notice the moment you leave the museum to re-enter the streets, canals and squares of Venice.

For here, you will note, a peculiar deliquescence of colour, softened by the vapours of the lagoon, illuminated by the flickering of the ceaseless wavelets of the watery by-ways and reflected and refracted by mullioned windows, carved stones and peeling, plastered brickwork. Paul Hills, in his fascinating book Venetian Colour, points out that our physiology is so constructed that we orient up and down by assuming the lighter part of our field of vision is up (sky) and the darker down (earth). But in Venice, this normal polarity is often reversed, with the watery canals being brighter than the cloudy skies above. At such times we are subtly disoriented and experience a sensation of floating through the colour fields of La Serenissima.

The greatest painter of this experience is Britain's own William Turner, who painted the glorious coloured light of Venice hundreds of times. Here was a perfect meeting of sensibility, technique and subject matter, as the illuminating (in more than one sense) new exhibition "Turner and Venice" at Tate Britain demonstrates. Turner did not arrive in Venice without preconceptions (his first trip there was in 1819; subsequent visits were in 1833 and 1840, and all three were in late summer when the light is at its most golden - Turner's favourite colour). He had seen paintings and drawings by Canaletto in England, where milords from the Grand Tour had collected them in abundance, and he also knew, and greatly admired, a number of works by Titian, which he had studied for their technical realisation of colour.

But Turner's interest in Venice was not exclusively pictorial. He shared with his British contemporaries a fascination with Shakespeare's The Merchant of Venice, and he knew Byron's poetic depictions of the city's sad decline, from proud independence to inglorious rule by the Austrians. These literary interests determined some of his subject matter, particularly as 19th-century collectors liked their paintings to have a subject.

Turner's early Venetian oil paintings (from the 1830s) combine references to dramatic works, historical resonances and contemporary images in fantastical mélanges, set in recognisable parts of the city; but they are of interest less for their subject matter than their ambience, their skies, their reflections.

Ten years later, however, superficialities have been much reduced. In a work such as St Benedeto, Looking Towards Fusina, a favourite of Ruskin's, we are presented with a much purer vision of sky and water. There are still some ghostly figures on the shore and a few gondolas, but the subject is, majestically, the golden sky at sunset and its reflection in the lagoon.

For all the finished splendours of the oils, it is Turner's watercolours that capture Venice's ever-changing subtleties of light and scenography. A night-time study, such as San Marco and the Piazetta, with San Giorgio Maggiore, Night (1840) captures a charming scene: the piazza at night with a crowd watching an illuminated puppet show at the base of the campanile, while also presenting the exquisite purples of the night sky and lagoon.

One could go on, enumerating the pencil sketches, watercolour washes, highlighted details and the rest of the techniques that Turner used to catch the excitement he felt on being presented directly with Venice's splendours. But only a visit to the exhibition can genuinely acquaint the would-be visitor of Venice with the discoveries of Turner's eye and brush.

It is interesting, and informative, however, to note the art history highlight of the show. Through a combination of insight and scholarship, Ian Warrell, the exhibition's curator, has convincingly reassigned the location of two late, unfinished works from Venice to Portsmouth. Both canvasses are painted in Turner's late manner, and depict a central expanse of water with something solid but blurry at the sides. Formally, in composition, they resemble some of Turner's views of the Venetian lagoon, as seen from the Piazetta.

But what struck me on encountering these paintings, after an hour of looking at Turner's images of Venice, is how obvious the misattribution is, for it is instantly apparent that the light is wrong. This is English light, grey and lowering, as it comes off the Solent; not Venetian light limpid between the azure skies and green waters of the lagoon.

Warrell, himself, recently noticed the effect that Turner has on how one sees Venice. One afternoon, a couple of months ago he was in the Cannaregio district of Venice when he found himself struck by the intense red of a brick wall. He took a photograph. On returning home and looking at the printed photo, Warrell realised that Turner had painted that same brick-red in one of the paintings in the exhibition. Unconsciously, Warrell had come to notice a feature of the Venetian cityscape that he would probably have overlooked but for his familiarity with Turner's Venice.

Turner may not have been primarily a painter of topography, but he was certainly one of light, and his unfinished works give one a good opportunity to study his acute colour perception. A painting such as Venice With The Salute (1844), which consists of the preparatory layers of a view across the Grand Canal, shimmers in the summer afternoon sunlight, the familiar dome of Santa Maria della Salute emerging quietly by reflected colours of sky and cloud.

Going to Tate Britain to see the new Turner exhibition is not a substitute for journeying to Venice, nor even a complete preparation. After all, for all his brilliance Turner captures but one aspect of the city. But it is one that he was uniquely equipped to capture and reproduce. More than reproduce, create anew. For although the magnificence of a Venetian sunset seen by boat when returning across the lagoon from one of the outer islands can never be captured by any painting, however accurate, Turner has done something else. He has created a counterpart to that experience; one which, at its best, is just as good.

TRAVELLER'S GUIDE

Getting there: you can fly to Venice's Marco Polo airport from Birmingham, Gatwick or Manchester on British Airways (0870 850 9 850, www.ba.com); from Bristol, East Midlands and Stansted on easyJet (0870 600 0000, www.easyJet.com); from Gatwick on Volare (0800 032 0 992, www.volareweb.com); or from Heathrow on BMI (0870 60 70 555, www.flybmi.com). From the airport, vessels belonging to the Alilaguna fleet depart every hour or so for the voyage to Venice. There are two routes (rosso and blu), serving different parts of the city. The rosso is likely to be the most useful - stopping at Arsenale, St Mark's Square and Zattere - as well as taking the most interesting route. The one-way fare is €10 (£7).

The cheap land option is Actv bus 5 (painted orange), price €3.50 (£2.50), which runs every half-hour from about 5am to 11pm.

Being there: the Galleria dell'Accademia opens 9am-7pm from Tuesday to Friday and 9am-2pm from Saturday to Monday.

The "Turner and Venice" exhibition at Tate Britain begins on 9 October and runs until 11 January next year. The exhibition is open 10am-5pm daily. Tickets, £8.50, are available on the door, or book in advance (subject to a £1 fee) on 020-7887 8888 between 10am and 5pm, Mon-Fri, or at www.tate.org.uk.