Sublime, lyrical and serene

For Bridget Riley, the unique grande dame of European painting since her appearance at the Venice Biennale in 1968, the critic is compelled to plunder his thesaurus of superlatives. I can do no better than employ those of the propagandists of Tate Britain, where her latest exhibition is on view. They offer '40 years of uncompromising and remarkable innovation... of undeniable and surprising beauty... lyrical, powerful and serene...' and throw in 'dazzling', 'celebrated', 'singular', 'respected' and 'of truly international reputation' to lend weight.

The history of her many solo exhibitions between 1962, when she was 31, and 2003, when she is 72, lends weight enough. The roll of her honours - trusteeship of the National Gallery, doctorates of Oxford and Cambridge Universities - lends more weight still. Widespread regard for her as an academic, a writer, a theorist and as an expert on old masters in Trafalgar Square, on Seurat and Cezanne - all this, too, lends weight, perhaps more than her narrow range as a painter should be made to bear.

It is a measure of the sameness of her lifetime's work that the Tate is mounting a retrospective with only 56 of her paintings - but then one experiment with optical delusion is much the same as another and it hardly matters that one employs rectangles to deceive in one and in others spots or triangles. What governs them all is an eye utterly calculating, dispassionate and controlled.

Miss Riley's art could well be that of the computer. She has never shown the slightest interest in the features that lend a modicum of sensuality to hard-edged abstract art - the mark of the brushstroke, the occasionally impastose touch of paint - and has striven mightily to reduce all evidence of the human hand. And whose human hand might that be? Not hers, for from the moment of her first success she has employed assistants to do the deadly chore of painting her pictures. She sees herself as the composer, her assistants as the orchestra - she dictates the colours and their tone; she dictates the dimensions of her stripes and zigs. But what we see, and the success of it, depends entirely on the skill and abject humility of those who are her slaves and skivvies.

Who is she? In Who's Who's words she is Bridget Louise Riley, born 24 April 1931, educated at Cheltenham Ladies' College (there's one in the eye for Tracey Emin and Sarah Lucas), Goldsmiths' School Of Art (1949-52) and the Royal College (1952-55). She was a very late starter as an independent and identifiable artist and it was only in 1961, after six years of drift and depression, that at the age of 30 she lit upon an optical formula for black and white puzzle pictures. Her early past suppressed, she concentrated on the trickery of making the eye struggle to discern whether the underlying form of the black spots, triangles and rectangles recedes into the canvas or protrudes from it, and with these paradoxical explorations of the physiology of perception she became an Op Art painter, neither the first nor best. She was, like Hockney, a phenomenon of the intellectually generous Sixties, and those few years were enough to establish for her an unassailable reputation as a pillar of the art establishment.

She has always had the gift of jabberwocky and could joust in art jargon with the most obscurative theorist. Of her Op Art she said this: 'In each of my paintings a particular situation is stated. Certain elements remain constant. Others precipitate the destruction of themselves, by themselves. Recurrently, as a result of the cycle of repose, disturbance and repose, the original statement is re-stated.' To me, this, stripped of pomposity and mystification, boils down to the old conjurer's dictum: 'Now you see it, now you don't.'

These black and white abstractions were replaced in the later mid-Sixties with coloured stripes. By the early Eighties these had settled down to being decorated planes with not a pulsating optical trick to be seen, apart from the jarring unneighbourliness of colour, and were swiftly accepted by idiot critics as reflections of landscape, the flickering of light on water, the scud of clouds across the sky. Suddenly Miss Riley was no longer the bright and brittle Swinging Sixties nymphet - she had become heiress to the English Romantic landscape tradition.

She does not, however, sit - as her heroes Seurat and Cèzanne sat - on a river bank or under a tree, contemplating a distant bridge or craggy hill. Her stripes and zigs and the large overlapping leaf forms with which she entered the new century are entirely devoid of such direct stimuli, though some claim is made for the influence of landscape colour. It is now argued that she does not represent, for example, light, but communicates 'an experience of illumination'. Nothing suggests a real experience of landscape as the root cause of any of Miss Riley's paintings - the connection is made only after their completion, in the whimsical application of the title.

Her current contribution to the history of art is the ancestral business of painting on walls, but of exhibition galleries rather than caves, her subject not the stick man and his bison, but intersecting circles of identical diameter. Critics and curators who insist on applying meaning to the meaningless will again have a high old time with superlatives and jabberwocky - but then, looking back on Miss Riley's career, it is evident that she has always been their creature and their construct, the ideal vehicle for their vanity.