The Hong Kong cinema is by no means just over-the-top action thrillers and escapist comedies. Its serious side is well-represented by the work of such filmmakers as Stanley Kwan and Ann Hui. More than a decade ago Hui's Boat People heralded the social realism movement whose practitioners included filmmakers educated in the West. Since then, however, Hui has zigzagged between costume epics and issueoriented pictures, trying to adjust to Hong Kong moviegoers' taste. Summer Snow, her latest film, is one from the heart, and as its Chinese title, A Woman Over Forty, suggests, it carries autobiographical overtones. In the film May, played by Josephine Siao, oversees a hectic household of three generations while holding down a demanding job. When her family realizes that May's cranky father-in-law (Roy Chiao, the ex-matinee idol in a quiet, dignified performance) has Alzheimer's, she gets stuck caring for him. At first resentful, May not only learns to cope with his childlike behavior but also develops a strong affection for him. May's resilience in dealing with an unfamiliar predicament and encroaching middle age, Hui seems to suggest, is typical of many working-class women, who learn to overcome constant hardship while savoring life's small triumphs. What could easily have been the stuff of pathos is enlivened by gentle humor and a touching humaneness under Hui's assured direction and Siao's spunky, funny performance. The film is being shown as part of the Silver Images Film Festival. Film Center, Art Institute, Columbus Drive at Jackson, Sunday, May 19, 7:45, 443-3737.