This 94-minute Imax documentary by Stephen Low (1991) has the same nonaesthetic features of other films in this format--most notably a TV-like lack of precise composition necessitated by the curved screen--but its subject, the risky Canadian-American-Russian expedition to pick over the wreckage of the Titanic, has an inherent fascination and haunted poetry that triumphs over the sometimes hokey, often trumped-up presentation; at times the film becomes a kind of undersea 2001. Oddly, the crew participants are encouraged to relate to the camera like actors and some of the camera angles suggest those of a fiction film (significantly, storyboards are alluded to in the final credits). But a judicious combination of period photographs (some genuine, some composites), a contemporary interview with one of the few living survivors, and views of the ship's remnants two and a half miles below the ocean's surface give this the curious, paradoxical feel of a scientific ghost film. There will be a 15-minute intermission. Museum of Science and Industry, 57th Street at Lake Shore Drive, Friday and Saturday, April 14 and 15, 6:30 and 8:30; Sunday, April 16, 6:30; and Thursday, April 20, 6:30 and 8:30; 684-1414.