Joel Katz Subway Obscura

Based on the principles of the camera obscura, Subway Obscura by Joel Katz uses existing ventilation grates, ambient light, and simple optics to turn the Brooklyn Bridge–City Hall subway station into a giant camera.

A system composed of four mirrors (each 30” x 51”) and a large acrylic lens (27” x 32”) utilizes available daylight to transfer images of the cityscape at the intersection of Chambers and Centre Streets onto a screen above the downtown 4-5-6 subway platform inside the station. The live images are projected onto a two-way screen suspended over the subway platform and are visible when adequate light is available. A metal construction atop a ventilation grate, which houses one of the mirrors, is the only element of Subway Obscura that can be seen aboveground.