Dust behaves unpredictably and is difficult to control. Besides that it is not especially popular, being regarded as "dirt" in our culture. As elusive as time seems to us it nevertheless leaves physical traces in the form of dust. The installation "From dust till dawn" made by Markus Decker and Dietmar Offenhuber kicks up a lot of dust and produces noise in the form of acoustic traces. The dust and atmosphere in the empty room form the installation’s interactive medium. Dust is identified by a surface laser and a photographic identification system and becomes a highly unusual means of

interaction. A grid of line lasers installed just above the floor produces a homogeneous carpet of light which is at first invisible. Objects and particles that pierce this carpet, such as dust, cigarette smoke or larger objects, become visible in the laser beams as a silhouette or an outline. The outlines and dust patterns are recorded and their two-dimensional movements converted to sound on an xy raster synthesizer. Every step the visitor makes, indeed his or her mere presence, sets the air moving and causes dust to swirl up. Its deals with a fragile interactive medium which is barely controllable and robs the term tangible media of its intangibility: