In 1964, Clement Greenberg was invited by the Los Angeles County Museum to organize an exhibition featuring a group of vital, mostly young artists who had issued a challenge to the entrenched norms of gestural Abstract Expressionism. Greenberg collaborated with the L.A. County’s curator James Elliott on a wide ranging selection that included Helen Frankenthaler, Kenneth Noland, Morris Louis, Jules Olitski, Frank Stella, Walter Darby Bannard, Jack Bush, Gene Davis, Friedel Dzubas, Sam Francis, and their colleagues, all of whom were building their paintings with broad areas of unmodulated color, reveling in the expressive possibilities of what Greenberg called “openness and clarity.”

As a nod to the Swiss art historian Heinrich Wölfflin’s celebrated distinctions between the “linear” and the “painterly,” Greenberg titled the show “Post-Painterly Abstraction.” Wölfflin had used the terms to distinguish between the lucidly organized “linear” pictures of Renaissance Florence and the turbulent images of “painterly” Venice, but he had also posited a continuing alternation between these extremes—from the linear Renaissance to the painterly Baroque to linear Neo-Classicism and so on. As the title of the L.A. County show suggests, Greenberg applied Wölfflin’s polarities to more recent art. In 1962, for example, he wrote, “If the label ‘Abstract Expressionism’ means anything, it means painterliness: loose, rapid handling, or the look of it; masses that blotted and fused instead of shapes that stayed distinct; large and conspicuous rhythms; broken color; uneven saturations or densities of paint, exhibited brush, knife, or finger marks—in short, a constellation of qualities