The Pioneering Prints of Dox Thrash

'Artist Dox Thrash (1893–1965), who attended night classes at the Art Institute of Chicago while working as an elevator operator, revolutionized printmaking in the 1930s by pioneering a completely new process called carborundum mezzotint – scraping away dark layers to reveal lighter grays and whites underneath. Faith Salie looks at the unique work of the African American artist.' -- CBS Sunday Morning