Hard Edge Painting Term coined in 1959 to describe abstract (but not geometric) painting, using large, flat areas of colour with precise edges. (visual-arts-cork.com)
His tendency in the late 1960s to use a large central area of colour led to paintings in the 1970s with soft, uneven washes of color and narrow, irregular color borders. (artmiami.com)
His style was highly original; his landscape painting employs clearly defined areas of colour structured by abstract patterns and shapes. (visual-arts-cork.com)