His paintings, drawings and prints are characterized by a stark palette and simple, decisive forms, often featuring black forms against flat fields of color. (lamodern.com)
When the series mostly ends four years later, it has become clean black bars centered on fields of color. (haberarts.com)
Created in 1965 - 66, they mark a radical shift from his earlier striped paintings in their use of large fields of color. (museumpublicity.com)