A shaft of artistic light amid the gloom of January's dark days

CULTURE SHOCK:LOOKED AT rationally, the tradition of showing the National Gallery's magical collection of 31 JM Turner watercolours only in January is utterly anachronistic.

It made sense in 1900, when Henry Vaughan left his Turners to Dublin and Edinburgh with the stipulation that they be displayed solely during the month when natural light is at its weakest. But the Courtald Gallery in London, for example, has been running an exhibition of Turner watercolours since October.

For a long time now, lighting technology and controlled conditions have made Vaughan’s injunction unnecessary. In their current excellent setting in the National Gallery, they are in a space with no natural light anyway.

Yet this century-old tradition has acquired the dignity, and the wonder, of a great public ritual. The reason for it may now be no more than a caprice, but then the very presence of these works in Dublin is itself marvellously capricious. Part of their pleasure is that they have no special reason to be here. They are an English artist’s responses to landscapes in Britain, Italy, Switzerland and Germany. The bequest by a London-based collector was an expression of a sense of “British” cultural unity that has long since disappeared. Our possession of these treasures is as blissfully accidental as their appearance only in January has become.

Art, however, delights in accident, and the annual, brief unveiling of the Turners has become a sacred drama. It is perhaps a forgivable exaggeration to call it a modern equivalent of the entry of the sun into the passage tomb at Newgrange. A ray of pure beauty enters our lives at the bleakest time, when the days are short, the nights long and the light dim. If the Turners were on show all the time, we would take them for granted. Instead, they mark the turn of the year with a gift of life and light, of energy and sumptuousness.

In other circumstances, the rubric under which the National Gallery is displaying the watercolours, A Light in the Darkness, might be sententious. As it is, it is doubly, and aptly, resonant. It captures this sense of the exhibition as a part of the rhythm of the seasons. It also describes quite precisely the effect of the show. The paintings themselves emerge as swathes of colour in the half-light of the gallery, giving off their own internal glow. And then within the paintings themselves, especially the astonishingly beautiful later works, there is this paranormal emergence of a realm of pure light from the details of place and landscape.

Part of the drama of the exhibition is that Vaughan’s bequest was superbly structured to give a sense of the development of Turner’s vision. The Dublin collection acts like a micro-retrospective, giving the viewer, over the course of a relatively small number of works, an intimate sense of the growth of the artist from brilliant realism to breathtaking transcendence.

TURNER WAS precociously adept and also, in one sense, highly modern in his relationship to the printers of his native Covent Garden. He produced a series of pictures for commercial reproduction, and the earliest works in Dublin are marked by the sheer clarity of their form. They are built to withstand reproduction while retaining their formal precision and the conviction of verisimilitude. But they very quickly acquire a physicality as objects in themselves that goes far beyond such purposes and indeed beyond what we usually think of as watercolours. In the relatively early Great Fall of the Reichenbach, for example, you can see where Turner’s famous “eagle-claw” thumbnail has scratched through the surface of the paper to produce the effect of high-pressure white-water rapids.

You are reminded, in such details, of the contemporary descriptions of the working-class Turner as looking like a farmer or a sailor. There is nothing genteel about these watercolours. They are all speed and work. You can almost see his stocky arms, not just applying the paint, but working it into the desired textures using everything from sponges to dried bread. You can hear the conjurer’s furious command, “Appear!”, and the desired landscape does appear, its elements of rock and water and cloud standing out with a monumentality that makes you completely forget that these are small watercolours and believe that they are vastly epic visions.

But then – and here is the great drama – the conjurer gets bored with appearance and goes in search of disappearance. As the works in the collection move towards the 1840s and Turner moves into his mid-60s, the art is all about making the surface realities dissolve. The flux and blur that he had used for his seas and clouds and sunsets is now applied to the more tangible realities as well.

In A Ship Off Hastings, the pale wash of the paint is used, not to show either the ship or Hastings, but to make them disappear. You can barely make out the ship or the looming cliffs. In Bellinzona, Switzerland with the Fortresses of Uri, Schwyz and Unterwalden three hilltop fortresses seem to suck all the pink, yellow and white light upwards from the town, leaving it in a murk of black, brown and blue shadows in which individual buildings are scarcely discernible. And in the great masterpieces of the collection, Turner’s visions of Venice’s Capriccio and the Doge’s Palace, the physical buildings and landscapes are magically diffused into fractured, uncertain colours, so that they seem to hover between the real and the purely imaginary.

What is left when the real disappears in these works is light itself, not so much captured or frozen as held in place so that it radiates steadily and serenely outwards. There is no better cure for the January blues than to bathe in that light. And, as Swift said in a different context, no nation needs it so much.

A Light in the Darkness: Turner’s Watercolours Silhouettes and Miniatures is at the National Gallery of Ireland, Merrion Square, Dublin until January 31st. Admission is free