JMW Turner's master strokes on display at the Art Gallery of South Australia

TO understand the art of the past - even of the recent past - always demands an effort of the imagination.

Burial at Sea

TO understand the art of the past - even of the recent past - always demands an effort of the imagination, and in many cases it also requires us to dispel fallacies and prejudices arising from more recent artistic practice.

Thus the impressionist insistence on working en plein air has led to a general assumption that landscape painting is a matter of finding an attractive view, setting up one's easel and making a picture.

This simplistic account makes it easy to underestimate the genre as a copying of appearances; a modernist rescue operation has been mounted, meanwhile, to save Monet on the dubious grounds that he is a forerunner of abstract art.

Landscape is in reality a far more complex genre, in which formal, compositional and a priori elements are as important as the observation of nature, in which observation is necessarily selective and the phenomena selected have to be translated into an internally coherent world of forms, tones and colours. Far from being a simple matter of copying a particular view, landscape painting has more affinities with the formal composition of music.

As usual, all this is easier to understand when we approach the subject historically, following its genesis from the past forward rather than reading backwards through the distorting lens of recent prejudice. In modern European art, landscape began as the background to narrative paintings; it was given a new impetus by the development, in Florence, of Renaissance perspective, which made it possible to give a rational pictorial account of the visible world. Venice contributed a moodier sensibility, assimilating the ancient genre of bucolic poetry to imagine nature as a stage for love and music, and suggesting the lonely but evocative experience of wilderness. The Flemish contributed complex and fanciful compositions, and all of these strands came together in Rome, where fragments of ancient landscape frescoes could still be seen, to produce the classical landscape tradition of the 17th century.

It was this tradition, and particularly the work of its greatest exponent, Claude Lorrain, that inspired JMW Turner (1775-1851), who was born almost a century after Claude's death. In fact, Turner left a pair of paintings to the National Gallery in London on condition they be hung beside two by Claude: his own Dido Building Carthage and Sun Rising through Vapour were first displayed with Claude's Landscape with the Marriage of Isaac and Rebecca and Seaport with the Embarkation of the Queen of Sheba in 1852. His relation to Claude was a prominent part of a fascinating exhibition at the Tate Gallery in 2009, Turner and the Masters, and was the exclusive focus of last year's Turner Inspired: In the Light of Claude at the National Gallery in London.

One of the essays in the catalogue that accompanied the National Gallery exhibition reconstructs the circumstances of the will that he first made in 1829, revised in 1831 and enlarged by a codicil in 1848, and which effectively left a huge collection of his paintings and watercolours to the nation. Eventually these were accepted by the Tate Gallery, originally a branch of the National Gallery, and it is from this corpus that a large and diverse exhibition has been sent to the Art Gallery of South Australia.

The exhibition extends from early watercolours, made when the artist was still a teenager, to the luminous seascapes of the last decade of his life. The young Turner's drawings and watercolours are impressive for their precocious talent, but from the beginning and throughout his career it is also his capacity for work that is striking, in countless studies and watercolours made in the course of his travels to the most picturesque parts of Europe, and perhaps above all in the beautiful sketchbooks open in several display cases.

Turner's admiration for Claude as the central reference point of the modern landscape tradition is clear in a number of large compositions in the exhibition, in particular the Dido and Aeneas (c 1805-06), which also echoes one of Claude's favourite literary sources, Virgil's epic poem The Aeneid. Next to it is another large composition in which Turner pays homage to Claude's friend and compatriot in Rome, Nicolas Poussin. Roger de Piles, the most important critic in France at the end of the 17th century, considered Claude and Poussin represented the two main alternative varieties of classical landscape, which he called respectively pastoral and heroic.

The enormous Richmond Hill (1819) also is indebted to Claude, although the overstretched composition with a large awkward terrace perched high above the river view is much less successful. The most curious homage to Claude is in the small version of his Landscape with Psyche, incongruously reproduced among other easel pictures in the foreground of the eccentric Rome, from the Vatican (1820), which anachronistically includes Bernini's colonnade in the background.

But none of these works is really comparable to Claude in quality, and the reason is in part that Turner could not be satisfied with the harmonious equilibrium that Claude maintained between all the parts of his compositions, in particular between the humanistic and hospitable space of his middle grounds and the infinite and sublime perspectives of the backgrounds. Turner simply did not have the same ability to create foregrounds and middle grounds, or the same profound understanding of the trees, in particular, that structure them.

For it was really the infinite luminous backgrounds that drew Turner to Claude. Romanticism, rediscovering religious experience after the rationalism of the Enlightenment, was intoxicated with the spectacle of the sublime in nature: of the power and scale of natural phenomena that dwarfed man, inspiring a mixture of terror and exhilaration in the viewer. The clearest expression of this sensibility here is a remarkable early painting of The Fall of an Avalanche in the Grisons (1810), although Turner more characteristically finds the sublime in the sea and the sky.

The old idea of the four elements, once a metaphysical and by extension a medical system, lives on in the poetic imagination as a useful way of thinking of our sensibility to nature. Earth, air, fire and water: all of us are more instinctively drawn to some than others, in life as in artistic expression. Part of what makes the equilibrium of Claude's landscapes is the relation between the elements in them - where fire is represented, of course, by light. In contrast, Dutch landscapes of the same century are all colder and wetter: dominated by earth, air and water rather than fire.

Turner's contemporary John Constable, inspired by the Dutch landscape tradition, is a painter of clouds, earth and water: he loved nothing better than the damp country of East Anglia and the overgrown banks of rivers and canals. Turner could not be more different. He seems instinctively averse to the element of earth: land is often eliminated from his compositions altogether or else reduced to a misty, disembodied vision in the background. Water and air, both animated by fire, are what fascinate him, not only in some of his best-known paintings, such as Rain, Steam and Speed(1844), but in many watercolour and oil pictures included in the present exhibition.

This imbalance in Turner's view of the natural world is one reason that his works do not achieve the wholeness, stillness and harmony of Claude.

Another is the incongruity between his broad and visionary image of nature and the pedestrian, even fussy way he deals with particular motifs that have to be inserted into this world, such as the launch in The Prince of Orange (1832); in fact one is struck by the paradox that as a painter of the sea, Turner is a genius, but as a painter of ships he is merely workmanlike.

Another problem is with the figures. Landscape painters often have difficulty with figures, for the good reason that they have not been properly trained in drawing them. Claude's figures have been much discussed and criticised, yet for all their occasional eccentricity they remain poetically effective and often deeply moving. They also play a crucial and always exactly calibrated role in structuring the composition of the painting. Turner's figures are not only poorly drawn but play no effective role in the composition. Sometimes they drift across the whole foreground, as in Richmond Hill; in many cases they are reduced to an amorphous crowd.

One of the few pictures in which figures are thoroughly integrated into the composition and where, as a result, the quality of their individual delineation is less important, is the dramatically effective A Disaster at Sea (c 1835) which, like Gericault's The Raft of the Medusa (1818-19), on which it is clearly based, deals simultaneously with a contemporary event and with the romantic theme of humanity engulfed in the abyss of the uninhabitable sublime.

Related to the problem with figures is another with the subjects of the pictures, the stories the figures are meant to be enacting. Turner repeats some of Claude's favourite subjects, as we have already seen. But Claude, though his education as a boy was even more rudimentary than Turner's, had an unerring sense of significance in his choice of subjects. Turner occasionally hit on a subject, like those mentioned earlier, that has the power of a haunting dream and has remained one of the great images of the 19th century; but too often, as we see here, he painted subjects that were always obscure or superficially topical and have become all the more obscure today.

He was not alone in this difficulty with subjects: other contemporaries, such as Delacroix or, even worse, Ingres, testify to the collapse of the tradition of stories drawn from the common and perennial sources of scripture and mythology, and to a desperate scouring of medieval and contemporary history for alternatives that mostly appear trivial or gratuitous today.

Turner, then, was not entirely successful in what he aspired to achieve, if it was indeed, as the terms of the will implied, to construct complete and self-sufficient landscapes, as Claude had done. One may, however, question his commitment to this aim, for Claude made fewer and more deeply considered pictures as he grew older, while Turner seems to have painted a lot that were rather poorly thought-out, as the exhibition makes clear.

The effect is aggravated by the inclusion of too many unfinished pictures, especially in the Venice room.

Where Turner was supreme, however, was in his response to real places. In the notebooks and in the many watercolours of sites in Britain, Switzerland or Italy, he is able to see and to reveal to us something that all too often remains invisible before our very eyes: the wholeness and life of nature manifested in the light that dissolves all particular things into unity.

Turner From The Tate: The Making  of a Master
Art Gallery of South Australia, Adelaide, to May 19