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Film

Tate Modern (until 11 March 2012)

Digital cinema has enormous potential, argues Tacita Dean in the book that accompanies her new installation, but today it is still too "blandly euphoric at all it can achieve...It is vanquishing analogue cinema while still in its infancy and we are being hoodwinked by the industry into believing that it doesn't matter."

As the 12th artist in the Unilever Series asked to create work especially for Tate Modern's Turbine Hall, Dean boldly set out to "understand and preserve" an "independent and irreplaceable medium".

Traditional cinema screens stretch the image to right and left, creating the endless plains we used to see in westerns. Dean has turned horizontal into vertical, landscape into portrait, and set a screen like a tower in front of the far wall. Film plays on a continuous 11-minute loop, with sprocket holes down the sides, flashes between exposures and the screen frequently split into three separate "shots" - constant reminders that we are witnessing something from the pre-digital age.

The visual narrative which unfolds before us is bold, haunting and surreal. As images of the back wall behind the screen keep recurring in a sequence of different colours, we see the space we are standing in colonised by a giant lump of suspended rock, vast eggs and pieces of fruit, cloudy skies and waves breaking against the shore. A garishly red mountain parodies the Paramount logo. An escalator is echoed in a sequence of small waterfalls. A voyeur's eye suddenly appears within a circle.

All this is achieved largely through a range of laborious, low-tech techniques, which are rapidly disappearing as laboratories for printing 16mm film close. The emulsion is literally hand-tinted to build the bright slabs of colour. The aperture masks used for binoculars or speech bubbles in early cinema have been resurrected and incorporated into Dean's camera. Bolts of lightning draw on the long-disused method of matte glass painting.

Undeniably spectacular, the work offers a dramatic celebration of "the language of film"; it remains to be seen whether something so oblique and enigmatic can also act as a call to arms for the defence of a threatened medium.