Untitled (São Paolo Series)

Ever since his Rasterbilder of the early 1960s Polke's work has exposed the innate artifice of all imagery and demonstrated the strange new realities and layers of reality that seem to emerge when the skin of our perceptual conventions is pealed back. In the early 1970s Polke translated his simultaneous, multi-layered and interdisciplinary style of painting with its cartoon and photographic imagery, pre-fabricated patterns, mixed-media spillages, chance collisions and hallucinogenic clashes of form and colour into the medium of photography. In a series of photographs made in Paris in 1971, Polke revealed the natural affinity between his art and the fascinating deceptive, fluid and mercurial medium of photography.

Always an alchemist at heart, it is essentially the process of photography - the medium's magical ability to chemically transmute light into imagery - that fascinates Polke and which his photographs both demonstrate and play with. Never one to present one single view or conventional image where many will do, Polke revels in the fluidity and accident of photography in much the same way as he does with the equally fluid and versatile medium of paint.

São Paolo is a series of ten large photographic images which Polke made for the São Paolo Biennale in 1975. Following on, to some extent, from his 1973 series of photographs of the street life of New York's "Bowery bums", his São Paolo series also depicts a series of images of city nightlife in a sequence of intentionally blurred, corrupted and sometimes obscure imagery. The scenes depict a group of men carousing and drinking. To some degree the atmosphere suggested by the stained, scratched and dirty quality of the images evokes a sense of increasing drunkenness progressing towards the dark blackout of the four last images in the sequence of ten. In this respect Polke's São Paolo resembles the drinking sculptures and Gin and Tonic and Dark Shadow series of photographs made by the British artists Gilbert and George in 1973 and 1974. In these, the two 'living sculptures' also catalogued an evening of progressive drunkenness with unorthodox and progressively blurred photography. Polke had himself worked with Gilbert and George only the previous year, photographing them in action as both artists and heavy drinkers for a photographic series of his own.

Unlike Gilbert and George however, Polke is less interested in the figures his work depicts or their lives than in the essentially abstract or multivalent nature of his imagery. Intermingling the burns and corrosions, tears, scratches and chemical smears induced into his images through manipulations of the developing process, Polke generates a mysterious almost spectral atmosphere that informs these seemingly ordinary and bawdy scenes with a sense of the transcendental and the extraordinary.

These effects have been achieved by a whole range of techniques including deliberately over and under exposing the photographs, splashing developing chemicals, scratching the negative and folding the image paper during the process of developing. As a result an integrated feel, unique to photography and its processes, is established between the image and the medium. Images and ghost images emerge or seem to emerge both within and between the photographs which, in the case of the second, third and seventh images for example - which appear to depict the same image - suggest repetition and multiple viewpoints of the same scene. In the dark spectral way in which these works outline a grim and rough-edged image of humanity they, and the Bowery series that precedes it, have also been compared to Goya's searing exposé of human nature Los Caprichos. Certainly there is a similar foreboding atmosphere of the dark and perhaps sinister presence of a spirit world intermingling with the caprice of human behaviour running through both these series of works. Polke's open invocation of the mystic sphere is however, clearly more investigatory, exploratory and perhaps even celebratory than Goya's firmly stated belief that the sleep of reason produces monsters.