Ad Reinhardt

Agnes Martin and Ad Reinhardt met in 1952, while Ad was in Taos. They would, later, become close. In an interview, Arne Glimcher has referred to Reinhardt's work as the exhaustion of painting, and to Martin's work, in comparison, as its rebirth.

davidzwirner.com/artists/ad-reinhardt

Ad Reinhardt became very known for his black, or "ultimate" paintings.

Abstract Painting, 1963, at MoMA