It's the way you hang 'em

The ICA has just unveiled Belladonna, its new blockbuster exhibition, crammed full of 29 radically different artists. But, asks Tom Lubbock, will we be able to see the paint for the walls?

The curator's art is exaggerated - or so I used to think. It's exaggerated because it doesn't in the end make that much difference. Clearly a great deal of care and judgement goes into arranging exhibitions and galleries. Clearly shows can be put together more or less beautifully, dramatically, coherently - and one can appreciate these arrangements almost for their own sake. But the main thing is the individual work. So the main part of curating is selecting works, and ensuring their clear visibility, and anything beyond that, in the way of schematic or sensitive presentation, is probably wishful. It reckons without the visitor.

Visitors, after all, are not complete zombies. They come in with their own interests and priorities, they seek things out or stumble on them or have their eyes drawn to the far end of the room. They follow their own paths and make their own connections. That freedom seems both right and inevitable, and, in the face of it, the most carefully laid plot and telling juxtaposition won't count for a lot (except for those voluntarily servile visitors who put on talking headsets). Viewers make their own show and, as for curators, a random miscellany is as rational a procedure as any...

Or so I used to think, until I went to the new Glasgow Gallery of Modern Art last year.

It was a conversion experience: conversion, that is, by recoil. It wasn't the very dodgy quality of the work as such that did the trick. And the gallery's defiant populism - a collection of post-war art specifically culled to appeal to the widest public - was almost attractive in its heresy. No, the problem was in the arrangement, the presentation. I hadn't realised before how ruinously it could be done, and how much I'd just been taking some basic standards for granted. One unforgettable example: a room where some jolly, bouncy paintings by Beryl Cooke were hung in close proximity to the late Jo Spence's photographs of her own body post-mastectomy.

Uh? Did the incongruity of this just not strike anybody? Was there (incredibly) meant to be some "fat women" theme linking the two? Was it deliberate mischief? Or was it an attempt at non-curation, on the visitors-make-their- own-show principle? Hard to say, but it became clear that the principle did have a limit. The conjunction was there, and you couldn't ignore it - and, once noticed, it was utterly destructive of both sets of work.

Reluctant conclusion: individual works can't be left entirely to speak for themselves; the viewer simply is not as free an agent as one might think or hope; the curator's art is, for good and ill, most effectual.

If you know the Glasgow GOMA, you may be reminded of it at the ICA's current show, Belladonna. It's a group exhibition of work by 29 more or less contemporary artists - paintings, objects, videos, working models - organised by two in-house curators, Emma Dexter and Kate Bush. And although, by a quirk of contemporary taste, quite a lot of the work included here might also have got into the Glasgow museum (knowing kitsch and ironic gaucheness coming to look pretty much like the authentic people's choice), it isn't the works that make the comparison pressing. It's Belladonna's quite distrait curatorial strategy.

Belladonna is arranged around a theme, and the theme is fin-de-siecle- ism, late-romantic morbidity and hysteria, taking the familiar line that the 1990s are temperamentally a bit like the 1890s. (The guide-sheet provides this mood-setting list of adjectives: "dreamy, anxious, weird, enigmatic, demented, intoxicated, disturbing, melancholy, playful...") And, in the normal way, it would be easy enough to say that the idea itself is piffling, cultural journalism at its most vapid, and also that with a rubric so loosely suggestive, any bunch of works could be made to fit, so it doesn't much matter anyway. In short, you could shrug the theme off as obligatory but harmless packaging, and get down to looking at the very miscellaneous works on show, one by one.

But you can't take Belladonna like that, either as viewer, or reviewer. It makes its mark, above all, as a curatorial intervention. Theme is here presentation also, and all those adjectives are meant to apply equally to the organisation of the show itself. It offers a spectacle, an experience on its own account. The downstairs galleries have been painted purple, dimly lit and architected into a warren of awkward spaces in which the works are arranged hugger-mugger and higgledy-piggledy, appearing at odd heights, odd angles and odd intervals, reduced almost to props in a mise en scene or the trophies of some eccentric wunderkammer. Nothing can be properly isolated for attention. The curating interposes.

You might wonder why it's not taken further. How much more weird, enigmatic, demented, intoxicated etc the experience would be if, say, the quantity of work was doubled, the architecture was still more complex, if strange sounds and rare perfumes were filtered into the galleries, and the floors were decorated with pentagrams - if indeed the contents weren't confined to certified works of art but included all sorts of other bizarre artefacts and effigies. Of course, this kind of thing has been done elsewhere - for example, in Robert Wilson's massive vault-spectacular HG, or in Peter Greenaway's installation at the Hayward Gallery's Spellbound exhibition last year. But, having crossed the boundary between curating and creating, there's no reason not to go all the way.

The ICA curators try to hold the line. In fact, they clearly want it both ways: to do their own creative, atmospheric bit of stagecraft, but still preserve a vestige of normal responsible exhibition practice. It's a half-way solution from which no one wins. No total-immersion kicks for the viewer - you're always conscious that this is an art show (everything is labelled) - but no clear viewing either. Rather, the works are allowed just enough individuality to set them in a state of helpless mutual "interference".

Mostly this makes for blurral - but, once at least, it rises to a pitch of incongruity worthy of GOMA's worst. In an upstairs room (also purple) there is one of the most finely judged acts of destructive curating you could hope to find. On one wall, there's a 1960s wavey-line op-art painting by Bridget Riley; on the opposite wall, there's a super-ornate pseudo- rococo gilt mirror from Jeff Koons.

Now, what can you make of this conjunction? That both things are curvy? That Koons's cult of swoony decorative excess has something in common with the clean-lined optical pulsations of Riley's surface? That each in its way offers a delirious spectacle? Something like that. And now, though you might want to insist that this link is quite factitious, that Koons's piece is a conscious exercise in the seductions of kitsch and Riley's canvas is nothing remotely of the kind, you can't put it out of mind. The presentation incites a connection and forces the two works into a relationship that jams them both.

The strategy is in its way demented, and of course it's very unfair on the works involved to be treated as raw material for someone else's zany montages. But it must take a certain art, or a serendipity of incompetence, to bring the effect off so perfectly. In fact, one can imagine a great curatorial game that would consist of thinking up just such reciprocally ruinous conjunctions of artworks, clashes so horrible you could hardly bear to look. And perhaps, if curators ever wanted to raise public appreciation for their profession, they might construct a whole exhibition of these malapropisms - just to show us how bad things might ben

`Belladonna' is at the ICA, The Mall, London SW1 (0171-930 3647) to 12 April