In the last ten years of his life, Reinhardt focused solely on square, black paintings. In his unpublished writings, the artist indicates that these pictures relate aesthetically to monotonal Chinese paintings rather than Western painting's concepts of light and dark. These canvases are intentionally enigmatic, painted to resist interpretation and to represent the beginning of a new way of seeing and thinking about art. In 1961, Reinhardt described them thus:
A square (neutral, shapeless) canvas, five feet wide, five feet high, as high as a man, as wide as a man's outstretched arms (not large, not small, sizeless), trisected (no composition), one horizontal form negating one vertical form (formless, no top, no bottom, directionless), three (more or less) dark (lightless) no–contrasting (colorless) colors, brushwork brushed out to remove brushwork, a matte, flat, free–hand, painted surface (glossless, textureless, non–linear, no hard-edge, no soft edge) which does not reflect its surroundings—a pure, abstract, non–objective, timeless, spaceless, changeless, relationless, disinterested painting—an object that is self–conscious (no unconsciousness) ideal, transcendent, aware of no thing but art (absolutely no anti–art).
from Focus: Ad Reinhardt and Mark Rothko, 2008
Abstract Painting contains three distinct shades of black, which become visible only after prolonged looking. Reinhardt was intensely sensitive to such subtle variations. He explained, “There is a black which is old and a black which is fresh. Lustrous black and dull black, black in sunlight and black in shadow.” When Reinhardt’s black paintings were first exhibited at MoMA, in 1963, their reductive imagery and stark palette shocked visitors, prompting at least one Museum membership cancellation in protest.
from Abstract Expressionist New York, October 3, 2010-April 25, 2011
To the hasty viewer, Abstract Painting must present a flat blackness. But the work holds more than one shade of black, and longer viewing reveals an abstract geometrical image. Reinhardt has divided the canvas into a three-by-three grid of squares. The black in each corner square has a reddish tone; the shape between them—a cross, filling the center square of the canvas and the square in the middle of each side—is a bluish black in its vertical bar and a greenish black in its horizontal one.
Works like this were strongly influential for the Minimalist and Conceptual artists of the 1960s, who admired their reductive and systematic rigor. But the poetry of their finely handled surfaces, and their deeply contemplative character, tie them to the Abstract Expressionist generation of which Reinhardt was a member, if a dissident one. Insisting on the separation of art from life, Reinhardt tried to erase from his work any content other than art itself. In the late black canvases that include Abstract Painting (he called them his "ultimate" paintings) he was trying to produce what he described as "a pure, abstract, non-objective, timeless, spaceless, changeless, relationless, disinterested painting—an object that is self-conscious (no unconsciousness), ideal, transcendent, aware of no thing but art."
from The Museum of Modern Art, MoMA Highlights, New York: The Museum of Modern Art, revised 2004, originally published 1999, p. 243