Bill Viola: Five Angels for the Millennium and other new works
Until 21 July
Anthony D'Offay, Dering Street, W1
Mon-Fri 10am-5.30pm, Sat 10am-1pm

Bill Viola's work with the moving image has established him as one of the world's leading video based artists. His current exhibition, at the Anthony D'Offay gallery on Dering Street, W1 until July 21st, employs new plasma screen technology, adapting traditional forms to a contemporary medium and then challenging the way in which these images are processed by their viewer.

The first part of the exhibition takes the portrait as its theme. Screens of different shapes and sizes show close-ups of the faces of actors who have each been briefed to convey a different emotion. These are slowed down to the point where it's almost possible to perceive the distinct electrical impulses that form the different stages of expression through which the message of the image is relayed to the observer. It seems that Viola is attempting to derail the onlooker's normal patterns of perception here, as the visual messages are so changed that the different emotions become extremely difficult to distinguish. It works - human faces become indecipherable and unsettling. It's also interesting that these are actors and that the emotion is therefore synthesised from the start.

Upstairs, in a dark, and physically difficult to navigate room, more plasma screens show pools of water which eject faceless human shapes in clouds of spray. This element of the exhibition shows a progression, as we move from an underwater perspective to an aerial view of a figure emerging from water, and it is perhaps influenced in part by a near-drowning experience which Viola had as a boy. Sound is used here and the representation of churning water, often distorted to become white noise and interspersed with vaguely appropriate sounds like intermittent sonar bleeps, continues the process of disorientation whilst maintaining a subtle connection with the kind of soundscape you'd expect in a clichéd underwater environment. The same process of deconstructing preconceived ideas seems to be at work.

The exhibition is consistently both challenging and great fun to view. Long after I'd left the gallery I found myself scrutinising faces in the street, in an attempt to apply what I'd seen to the regular speed world. Perhaps it could be said that having taken us into his disorientating world, Viola has successfully rehabilitated us, leaving us with a real sense that our interpretations of experiences and emotions are much more open to analysis than we might initially think.

Helen Crump