Like a procession of Japanese monks with black robes and shaven heads, the 13 late paintings by Ad Reinhardt circle a large white room at David Zwirner Gallery: ascetic, elegant, identical at first glance but subtly different on closer inspection. Each canvas is a five-foot square traversed by a vertical band one-third the width of the canvas, and by a centered horizontal band (of the same width) that crosses over the vertical band. The bands, and the unoccupied corners, are painted in slightly different hues of black: sometimes easily distinguishable, sometimes almost impossible to see.

Reinhardt told Bruce Glaser in 1966 that he was “painting the last painting anyone can paint.” Like Frank Stella’s stripe paintings of the same years, Reinhardt’s pictures reduce composition so radically that the canvas risks becoming, not an image, but an object placed on the wall. Indeed, Donald Judd argued in “Specific Objects” (1966) that there were only so many ways of arranging forms within a rectangle, and that the possibilities for painting had pretty much been exhausted. The logical next step was to abandon painting and make objects instead. Seen in the context of the 1960s, Reinhardt becomes a progenitor of Minimal sculpture.

But Reinhardt’s black paintings look like objects only if you don’t look at them very hard. Give them the time and attention they demand, and they turn back into paintings: they are what Clement Greenberg (discussing Mondrian in 1948) described as a “scene of forms,” even if those forms are often hard to see.

Play the tape backwards, following Reinhardt’s career in reverse. The black paintings of the 1960s and the later 1950s give way to the monochrome canvases of the mid-1950s, with their symmetrical compositions of bars and squares, painted with smoldering reds and transcendental blues. In the early 1950s, Reinhardt’s canvases are populated by shifting arrangements of colored rectangles, floating free in space. By 1950, the rectangles shrink to square brushstrokes woven into shimmering veils of color, so that the paintings look like late Cézanne landscapes minus the mountains and the houses. This is in fact a period style, with variants found in the work of American artists like Philip Guston and Norman Lewis and European artists like Roger Bissière and Marie-Elena Viera da Silva. The artistic goal of all of these artists was to recover something like a pre-cognitive sensation of visual experience: an image of the world as a field of colored patches and films.

This quest to capture pure optical sensation goes back to the Impressionists, who argued that their paintings were more faithful to actual visual experience than were the carefully drawn and shaded compositions of the Salon painters. Little surprise, then, that the emergence of Reinhardt, Guston, and Lewis as important members of the New York School was accompanied in the 1950s by a Monet revival. However, the “scientific” justification of Impressionism, with its appeals to the psychophysiology of Hermann von Helmholtz, has not exactly stood the test of time. Since the pioneering research of David Hubel and Torsten Wiesel in the late 1950s, it has become apparent that the brain is hardwired to detect significant patterns at every stage of visual processing, beginning with the retina, where the cells are organized into groups that differentiate between vertical lines and horizontal ones, and between movement and stasis. We never actually see the world as a field of blurry color patches. Why then have artists persisted in painting it this way?

Different answers are valid at different times and different places. In the 1950s in New York, optical abstraction offered a way to repress the sheer ugliness of the real world. Guston could transform a gritty New York street into a gray field populated by blurs of red and black; Lewis, a Harlem courtyard into a shimmering forest of lines and colors. For Reinhardt, with his Menckenesque hatred of middle-brow culture and art-world can’t, abstraction seems to have offered a way to transform the billboards and advertisements of the urban environment into an abstract simulacrum of the natural world. (The flickering fields of Reinhardt’s European contemporaries can be traced back to the beech forests painted around 1900 by artists like Gustav Klimt and Kazimir Malevich.)

Today, almost 50 years after Reinhardt’s death, we live in a world dominated by virtual images, from the animated billboards atop the railings of subway stations to the YouTube videos that constitute the common currency of conversation around the Keurig coffee maker. In museums, visitors pause in front of paintings just long enough to read the wall label, and snap a photograph with their iPhones. Even for those of us who teach art history, works of art exist primarily as digital images that flash on and off a screen, or tiny icons clustered within a folder in OS X.

The redemptive power of Reinhardt’s black paintings lies in the fact that they can’t be reproduced. (Yes, books and catalogues occasionally include photographs of the black paintings, but by the time the production manager has pumped up the contrast enough that the reader can see the crossing bands, the reproduction no longer looks anything like the actual painting.) If you want to see what one of Reinhardt’s black paintings looks like, you have to stand in front of it for a long time, staring into its depths, waiting patiently for the subtle distinctions between slightly bluish blacks and slightly reddish blacks, for instance, to become perceptible. There is no substitute for the slow, slightly tedious process of actual looking.