TELEVISION / Rooted to the spot: Andrew Graham-Dixon reviews Omnibus's 'The Piero Trail' and Gerald Scarfe in Paradise

IT IS never easy to make a documentary about a painter, especially a dead painter, largely because the nature of what you should be attempting to convey on film is essentially unfilmic; silent, still images demanding a form of long and slow contemplation to which the mobile eye of the camera is unsuited. The problem is in a sense straightforward; film moves but paintings stand still. But it is heightened in the case of an artist like Piero della Francesca, the subject of last night's Omnibus (BBC 1).

Piero produced some of the most solemnly frozen art in history. Nothing, absolutely nothing, moves in the National Gallery's Baptism of Christ; the river is a still, reflecting mirror, the dove that hovers so perfectly dead centre in the sky is a curious bird, as incapable of real flight, real motion, as a pinned butterfly; even the water that trickles from the bowl held above Christ's head by John the Baptist seems viscous, peculiarly unfluid. Everything is held in a state of suspension, which is how Piero makes his point. Painting the moment, he turns story into vision - and a vision which makes the sequential telling of a story redundant. He creates an image which does not require other images to justify its meaning. One is enough.

The artist Tom Phillips made the point neatly on last night's programme, remarking that Piero's single images would last long after the thousands of images relayed in this Omnibus profile had been forgotten. It was honest of Anna Benson Gyles to let this implicit criticism of her film into the final cut.

Not that her film itself coped with the problem entirely satisfactorily. Piero's images - the Baptism or the Resurrection, with its baleful, risen Christ - inevitably looked like reproofs to the restlessness of documentary television, its need to tell story through a multitude of images. 'The Piero Trail' was at its worst when it attempted to match Piero's lucid calm - when it tried, for instance, to come up with filmic equivalents to the artist's painting of landscape, framing shots of mist-wreathed Umbrian hills with self- conscious artfulness.

This was peculiarly unsuccessful because where it aimed for a coincidence of effect, it merely achieved a dissonance; Piero's becalmed landscape is invested with tremendous force because it is the stilled arena for a momentous event; the Omnibus camera, by contrast, merely gave you the setting. Art gave way to travelogue.

The film worked better when it was dealing with a subject much closer to its own mobile form - when it was treating not Piero but his interpreters, and conveying the sense of all the busy intellectual activity which has revolved around the still centre of his art. Much of this has been focused on his most enigmatic picture, The Flagellation; John Pope-Hennessey argued that the title was wrong and that it was really a painting of the dream of Saint Jerome; an Italian art historian thought it was a militant, pro-Crusade picture, seeing Piero's image of the flagellated Christ as a metaphor for the plight of persecuted Christian believers in heathen lands. A little later, in a scene of nicely understated comedy, a group of academics gathered around a scale model of the painting's complex architecture and tried to puzzle out its perspective and lighting systems: 'I suppose divine light doesn't quite work in the same way as ordinary light,' remarked Martin Kemp, noticing that a torch shone into the model at the angle of one of Piero's light sources cast shadows that are absent from the picture itself. No one ever managed to explain the nature of Piero's greatness as a painter but maybe that, in the end, was the point of the film; neatly reversing Reithian dogma, it was on a mission to unexplain. Tom Phillips got the last word, remarking that great art is great precisely because it cannot be definitively accounted for.

Gerald Scarfe in Paradise (BBC 2) was another of the cartoonist's dream-sequence films for the BBC whose theme, this time, was the unambitious subject of Life, Death and the Meaning of the Universe. Scarfe imagined that he had been shot dead and proceeded to a sort of multi-denominational limbo filmed in an empty Charles de Gaulle airport where travellers were given the choice between different airlines. All flights on Air Buddha were return trips, whereas the man at the Agnostic Airlines desk didn't really know whether there were any flights available and the Atheist Airlines desk was closed. This was almost funny, but then the film settled into the usual pattern of Scarfe's television programmes, heavy on self-indulgence and self-congratulation, light on interest.

Our hero interviewed sundry nutcases with a belief in the hereafter, ranging from the computer software engineer who intends to have his head deep-frozen so that the technocratic wizards of the future can regenerate him from his brain (but would they want to?), to the member of an obscure group called the Wimbledon Immortals who believe that you can live forever by psychically instructing your cells not to age. In between takes, Scarfe himself raged extravagantly against the dying of the light, smashing mirrors and going berserk with a baseball bat in a car pound: he'd had a vision of hell, an endless dinner party at which he had to sit next to someone a bit boring.

It was at about this point that I fell asleep and had a terrible dream I had died and gone to hell, I had to sit next to Gerald Scarfe at dinner and when I tried to ignore him and turned on the TV they were showing Gerald Scarfe films on all channels. God it was awful.