EXHIBITIONS / Every picture tells half a story: If it has just opened in London, it's probably photography. Tom Lubbock reviews a retrospective of the great Bill Brandt, and rounds up Blumenfeld, Citroen, Modotti and more Brandt

IN THE library of photography, the fiction section turns out to be bigger than one thought. Robert Doisneau's immortal Kiss is now famous for not being the spontaneous clinch it once seemed. Robert Capa's Moment of Death, some have claimed, was a moment rehearsed. And the Barbican's Bill Brandt retrospective seeks to dispel any illusions about the photographer being a documentary realist. The curator, Ian Jeffrey, calls him 'an illustrator, with a taste for melodrama'. We're asked to see his camera not as a witness to the world, but principally as a medium for making pictures.

This is persuasive, and Brandt, who distanced himself from what he called 'action photography', would not have disagreed. In much of his work, indeed, the issue doesn't arise. The post-war interior nudes are organised tableaux. The later pictures of fragmented and elongated body parts are all-too-artistic exercises in abstraction and metamorphosis. And Brandt's portraiture often doesn't function as portraiture at all. It is not about the disclosure of personality. The contre-jour portrait of T S Eliot is a notable exception: the expressiveness of the picture hasn't usurped the expression of the man. More often, the sitters are actors in a drama staged by Brandt.

But the situation is not so different earlier on, when the work is ostensibly reportage. And it might have come as a surprise to the readers of Weekly Illustrated and Picture Post, where many of Brandt's pictures where published in the Thirties and Forties, to learn how far they were staged and manipulated - to learn, for instance, that the girl in the 'I'm no angel' hat on Brighton beach was his sister-in-law, or that 'Pratt, the Perfect Parlourmaid', whose routines Brandt followed for a day-in-the-life sequence, was actually a family employee.

Maybe this doesn't matter much. The papers themselves were quite consciously telling stories. The pictures were arranged in little narratives ('London by Night', 'A Barmaid's Day'), with coaxingly didactic captions which it is now impossible to read without imagining the tones of a British Gaumont News voice- over. Some of his scenes could anyway clearly not have been snapped on the hop. Top Floor, for example - a couple kissing in a bedroom: you see only his back and her arms round his head - was a very careful set-piece.

But whether the scene is made or found, Brandt had his own story, and it generally overrides any job of social observation. In Spring in the Park, the picture denies its breezy title and its potentially charming subject - shaggy sheep grazing by the Serpentine in wartime: the sheep appear as alien creatures colonising human territory. And in the ending of the blackout Brandt finds half-sinister possibilities - the sudden apparitions caught in (newly permitted) car headlights. The vision is grave and spooky, the nation as a haunted house.

In later life Brandt took this approach further, reprinting many pictures in a way that tried to efface their reportage circumstances, establishing them simply as images in absolute blacks and whites. It was an act of artistic self- assertion - 'all my own work', so to say - but a mistake. You're left with just images, stark but disembodied. To remove the traces of actuality is to remove the vision too. These versions are now the best known, and the Barbican does a good service in showing the original prints with their much wider range of half-tones.

In the Sixties and Seventies Brandt also made a series of 'assemblages' of found objects. There are a few in the Barbican and many more at Reed's Wharf Gallery. This is beachcombing work: pictorial collages of feathers, fish-bones, shells, sticks, pebbles and sundry other pickings, stuck onto painted boards. These certainly have curiosity value. They've been exhibited very little, and one wouldn't guess their authorship. Whether they have more than curiosity value is more doubtful. There's a nice, malevolent little homunculus made from a splayed fish with twig limbs, the only figurative piece. The remainder are too much arrangements of interesting bits and pieces, going the bad-tasteful way of most flotsam art. Perhaps colour is part of the problem; at least, they look much less tacky in the photographs Brandt made of them.

There's more Brandt at the Photographers' Gallery, prints from both periods, and you can see the difference clearly. There's work by Tina Modotti too. Modotti is a figure fated to attract the phrase 'in her own right', chiefly because she posed for several portraits and nudes by Edward Weston which have been more celebrated than the photographs she took herself. She did many other things besides (acted on stage and screen, fomented revolution), and her photos date mostly from the Twenties, when she was in Mexico. Modern reprints, very small and almost pink in colour, are on sale.

Her most famous picture, Roses, is certainly a good one, and good for partly resisting Weston's example: the flowers aren't wholly transformed into a pattern of textures. Otherwise, there are some classy but anonymous studies of architectural details and still-lives, and pictures of the Mexican people which, with one or two exceptions, seem to be thwarted by their own decency, missing some needful tension in the composition or subject matter. The contrived emblems of Mexican revolution - still-lives with a bandolier, a guitar and an ear of sweetcorn - don't work at all.

At the same gallery there are pictures from between the wars by Paul Citroen and Erwin Blumenfeld, two boyhood chums with briefly coinciding artistic careers. Blumenfeld ended up as a successful fashion photographer, and Citroen as a painter. This is before that. It's a likeable exhibition: that's to say, the sense of them as creative personalities is stronger than the work itself. The show starts with them playing around with Dadaistic photo-collage, and it's not much good, more or less what anyone might do with a pair of scissors, a pile of magazines and the kind of wit which is, anyway, almost inherent in the medium. Citroen turned to portrait photography, which looks honest and has some flickers of intensity, but would certainly gain a lot from a personal acquaintance with the sitters. Blumenfeld, meanwhile, set his sights on Vogue and Harper's Bazaar, got 'experimental', and indulged in superimposition, solarisation, shooting people through gauze and the various other desperate measures by which fashion photos once sought to add 'art' to beauty. The camera tells lies, that's fine, but it shouldn't tell pointless lies.

'Bill Brandt: Photographs 1928-83', Barbican, EC2 (071-638 4141) to 12 Dec. 'Bill Brandt: Assemblages', Reed's Wharf Gallery, Mill St, SE1 (071-252 1802) to 30 Oct. Modotti, Citroen & Blumenfeld, Photographers' Gallery, Gt Newport St, WC2 (071-831 1772) to 20 Nov.

(Photographs omitted)