In 1958, after discovering that her welding torch expelled soot when she turned its oxygen levels down, Bontecou set out to "harness the black," as she put it. Here she scraped off areas of soot with a razor blade, creating a labyrinth of narrow rectangles and tunnel-like corridors. She used her fingers to soften edges in some areas and applied tape to create crisp curves in others. The small, soot-filled ovals that punctuate the drawing are precursors to the gaping black cavities that dominate the steel-and-canvas sculptures Bontecou began making roughly a year later in New York.
Gallery label from Lee Bontecou: All Freedom in Every Sense, April 21–August 30, 2010 .