Reinhardt’s works in black take a long time to see, challenging most viewers’ patience. These works appear to be solid fields of black, but are in fact subtle compositions incorporating intensely dark shades of red, blue, and green. Reinhardt continued refining his black artworks until his untimely death in 1967, considering them the resolution to his quest for the freest artistic freedom. These works mark the end of years of experimentation. Thomas Merton, a Trappist monk and friend of Reinhardt’s, said: "One must turn away from everything else and concentrate on the picture as though peering through a window into the night."