Though each of these five silent films by Ernie Gehr focuses on a specific subject--cars on a highway, an apartment still life--his real theme is the paradoxes of the film-viewing process. In the black-and-white Field (1970, 10 min.) diagonal lines continually rush by, the result of the camera rapidly panning across a field. While the continuing streaks become meditative, the fineness of the lines recalls the granular structure of celluloid, almost as if the viewer is being relocated to the film's surface. Untitled: Part One (1986, 30 min.) is a study of figures on Brooklyn streets, seen mostly in tight close-up: a hand grips a walker, a winter coat fills the frame. Rapidly edited, the compositions bump up against each other in perceptual frissons, rendering the crowded city as a series of collisions. The program totals 71 minutes. Univ. of Chicago Film Studies Center, 5811 S. Ellis, Saturday, May 3, 6:00, 773-702-8596.