The opening of the Theresa Hak Kyung Cha retrospective coincided sadly with the events of September 11. The sense of common tragedy and vulnerability, the spirit of mourning clouded over the celebratory mood of the opening reception. And yet, the memorial character of the exhibition that examines the tragically ended career of this Korean-American artist seemed remarkably appropriate for the occasion. Theresa Cha was murdered in New York in 1982 at the age of 31. The artist's family - her most important collaborators and supporters - as well as those who knew Cha during her student years at UC Berkeley were gratified to be at the museum on that solemn evening. In the days that followed it was hard to ignore the relevance of Cha's work to the images and metaphors brought about by the terrorist attack's aftermath. One of these images - surprising and mournful - was the one of dust at Ground Zero. Colorless, obliterating, homogenizing - dust itself pulverizes objects, reducing them to sameness. A process that should have taken several lifetimes took about an hour. Walls and chairs, desks and clothes, papers and bodies, all became dust, all were coated with dust. The final image of Cha's mesmerizing video piece Exilée (1980) is that of dust. White powder gradually covers up an envelope lying on a surface. At first, the shape of the envelope is distinguishable as a relief, then it is obliterated in the mound of dust. Suddenly, the envelope is lifted, leaving its clear imprint in the thin layer of powder. Dust is both oblivion and memory. Contained in the Exilée image of dust is also a perfect metaphor for a recording medium - a fragile recipient of imprints, a volatile bearer of marks. Surface and mark, substance and imprint, medium and inscription, often in the form of written and spoken language, are central to Cha's oeuvre. These concerns, and her aesthetic approach, are consistent across the many forms her work takes: print, book art, video, film, and performance. Cha's color palette consists of black and white with a rare appearance of red. This palette pervades, from letters typewritten on a strip of paper (Surplus Novel, 1980) to shadows seen through a veil (A Ble Wail, 1975) to images projected on a film screen (Exilée, 1980) to words stamped on a postcard (Mot Caché, 1978). The homogeneity of treatment serves to foreground the fundamental nature of recording. A stenciled piece of cloth is likened to the film screen, which in turn is likened to a sheet of paper. All these surfaces are recipients of marks, of graphic signs that are visual and textural, and of images that remind us of words. Cha allows no traces of her gesture to be visible. Her marks are mechanical, detached, precise, and mediated. The entire oeuvre reflects on the visual culture of the modern world, our culture of recording and (im)printing. And yet the final image, the image of dust, makes us tremble at the thought of the fragility of everything we want to think of as permanent.