Alternatively, at the opposite extreme, theatre is able to do what Sunday in the Park with George does for Seurat's Un dimanche d'ete a l'Ile de la Grande Jatte: palpably recreate the picture in three-dimensional space. In Sondheim's musical, the dissembled constituents of the Seurat, human figures and pointillist cutouts of animals and trees, are shown being regrouped in various provisional arrangements until the painting is finally consummated at the magical close of Act 1 with the freeze-framing of a running figure, who has only made it on in the nick of time.
The first ploy of invisibility comes in handy when the painter and picture are the dramatist's own invention, as is the case with Howard Barker's Scenes from an Execution (1991), set in 16th-century Venice. Though we see her at work on it, the gruesomely realistic, non-celebratory depiction of the Battle of Lepanto which Barker's female artist executes in calculated defiance of the commissioning authorities, remains for the audience a predominantly verbal object.
Far from seeming a dodge, this proves to have distinct dramatic advantages, most sharply noticeable at the end. The tragic irony of the play is that the Venetian establishment contrives to absorb the shock of the painting and neutralise its political threat by turning it into a huge public attraction. We see the queues gawping up at it and we see a horribly mutilated survivor of the battle, now cheerfully taking part in the show, like some circus attraction, but earning a few lire for his loyalist spiel. The fact that the actual images on the canvas are left for the mind's eye, where they can survive in their ideal form, has the effect of heightening the grotesque disparity between the painting's intentions and its consumption.
Such strategies simply aren't available to a playwright who invents a composer, as Alan Ayckbourn's recent Haunting Julia thuddingly proved. That drama's focus was on a trio still coming to terms with the suicide at 19 of a prodigy, nicknamed "Little Miss Mozart". What these people should audibly have been haunted by, of course, was the glorious music she had left behind. But given that snatches from works of alleged musical genius can't be fabricated at the drop of a hat, the play had to remain unnaturally silent on that score.
In Edgar's Pentecost, as in David Hare's The Bay at Nice and Alan Bennett's A Question of Attribution, the authenticity or otherwise of a painting provides the focus for a dazzling debate on moral, as well as aesthetic and monetary, values. However, for reasons that turn out to be intimately related to one another, Edgar's is both the widest ranging of these debates and the only one in which a feeling of the painting's material presence and vulnerability is of crucial importance.
In the Bennett, the slides in which the fourth and fifth men are exposed by X-ray in the "Titian" Triple Portrait find their mischievous parallel in the slides shown to Blunt by his MI5 interrogator who is also out to uncover a fifth man. By implication, both are judged to be arid, never- ending exercises which reduce the enigma of art and of human beings to the state of a riddle which can be solved. In the Hare, the eponymous painting, a possible Matisse that has surfaced in Fifties Leningrad, furnishes the basis for a discussion about what constitutes a true work of art, a valid life and an accurate perception of freedom, but it is not undraped until the final moments and Hare's 1986 production at the National chose to depart from the stage direction in the printed text which called for the background to fade and the stage to be filled with "a pair of open French windows, the sea and the sky".
Instead, in a way that made the work (and the woman contemplating it) immune to scepticism, your only clue about the canvas was the transfigured joy of her reaction.
The painting in Pentecost is also an invented one, but such is the artfulness of the story that it is both possible and necessary to give an audience a strong sense of the work as a physical entity. With a deeply convincing design by Robert Jones, the play is set in an abandoned church in an East European country to whose repeated experience of invasion (Mongol, Turkish, Napoleonic, Nazi) and 40 years of Communist failure the building bears material witness (scratchings on the wall of torture victims; the heroic picture of the revolutionary masses). But what price such memorabilia if the remains were uncovered here of a fresco that could either be an imitation of Giotto or the work of an earlier unknown genius, who had anticipated his use of perspective and capacity to depict individualised emotion by a century?
As a device for highlighting the intricate internal tensions and confusions about values in post-Communist countries, the fresco is brilliantly successful. What interests me here, though, is how cleverly Edgar uses the iconography of the painting to further his themes. For a start, it can be shown to us, since it is essentially Giotto's Lamentation over Christ with certain key details altered. Where Giotto has weeping angels, Edgar's fresco has a star; instead of a hump-shouldered woman, he has a rock. His St John, in contrast to the Giotto, is reaching out to the Virgin.
Aptly, in a play named Pentecost, the riddle of these differences and of the prominence of the painter turns out to be a linguistic one, the painting possibly the work of an itinerant Arab whose St John gestures differently because he was bringing Islamic cultural assumptions to the story.
The opening up of frontiers, the multi-lingual diaspora of the post-Communist world, is tragically exemplified by the group of refugees who take the art experts and then the art work hostage. The fresco is climactically destroyed in the authorities' cackhanded attempt to take control, but we have been allowed a brief glimpse of the inspiring, hopeful message it sent out: that diaspora can create a rich cultural inter-weaving, that there's a non-tragic sense in which "we are the sum of the people who invaded us".
The mood of the ending, sudden elation followed by subdued loss, is so powerful that you find yourself forgetting that both the painting, and the language whose ambiguities initially point the experts in the wrong direction, are both the fabrications of Edgar. Best of all the recent works that have centred on art objects, Pentecost vies with Stoppard's Arcadia for the accolade of being judged the most intellectually stimulating play of the decade.
n 'Pentecost' opens at the Young Vic, London SE1, on Thursday (0171 928 6363)Reuse content