Mention Jim Campbell in engineering circles and people will assume you're talking about one of the leading developers of HDTV. Bring up his name in the art world and the cognoscenti will think you're discussing the new media pioneer whose ultra-low-resolution LED screens reduce loops of video to the brink of inscrutability. Of course Campbell the engineer and Campbell the artist are the same man, and his apparently divergent careers meet, like converging rays of light, at the point of human perception. But while his HDTV research concerns how much visual information technology can deliver, and how little might thus be left to the imagination, his LED work explores how little visual information the human mind can tolerate--how much the imagination can invent. Campbell's latest subtle and sublime exhibition, Home Movies (on view at San Francisco's Hosfelt Gallery March 17-April 28) takes his LED investigations to a new extreme. Instead of shooting his own digital video, Campbell begins with found eight- and sixteen-millimeter footage, already more-or-less anonymous, which he digitally degrades to points of light, flickering across an array of LEDs wired ceiling-to-floor in front of a blank wall. Turned away from the viewer, the LEDs cast shadowy scenes on the wall, showing unidentified figures in motion, or surveying an unknown landscape which, reconstituted in the spectator's mind, seems uncannily familiar, like the memory of a distant encounter. Campbell's installation inevitably evokes Plato's cave while provocatively questioning Plato's philosophy. More viscerally experienced than the sharpest HDTV, Campbell's 'Home Movies' suggest that the seat of reality is the imagination. - Jonathon Keats