Ironing boards come in fours, but mattresses and washing machines in threes, toeing the sidewalk and teasing the passer-by. TV sets regularly show up dumped in wheelbarrows. Chests of drawers, still wrapped in plastic, are heavily discounted, already obsolete. Shop windows flaunt spectacular compositions of washing-up liquid and Kleenex boxes, while white pumps (once-worn wedding shoes?) are a constant of market displays, like a muted running gag.

And so unfolds the world of Zoe Leonard's Analogue (1998-2009), a collection of over 400 photographs documenting small-scale local commerce and parallel circuits of global exchange. The significance of the project has been recognised since its first presentations at the Wexner Center for the Arts in Columbus, Ohio and at documenta 12 in 2007, yet what the series addresses, beyond the sheer breadth of the investigation, can only be recognised by exploring all of its modes of presentation. Existing concurrently as a book of colour plates, an archive installation of images and a series portfolio of individual prints, Analogue can be understood as a critical reflection on the history of photography and, even more pointedly, on the history of documentary photography.

Leonard has traced the origins of her project to 1998, when she began to record on camera the local shops gradually disappearing from the streets of her New York neighbourhood. From there she moved to a systematic exploration of a visual language of retail that ran parallel to the world of high-street chains and logos. Exhibited together in image sequences of varying number - most often twelve prints and above - the photographs all display a black edge that indicates the negative of the print. This acts as a frame enclosing