HARD-EDGE

Hard-edge painting is a tendency in late 1950s and 1960s art that is closely related to Post-painterly abstraction and color field painting. It describes an abstract style that combines the clear composition of geometric abstraction with the intense color and bold, unitary forms of color field painting. Although it was first identified with Californian artists, today the phrase is used to describe one of the most distinctive tendencies in abstract painting throughout the United States in the 1960s.

Hard-edge painting is known for its economy of form, fullness of color, impersonal execution, and smooth surface planes.
The term "hard-edge abstraction" was devised by Californian art critic Jules Langsner, and was initially intended to title a 1959 exhibition that included four West Coast artists - Karl Benjamin, John McLaughlin, Frederick Hammersley and Lorser Feitelson. Although, later, the style was often referred to as "California hard-edge," and these four artists became synonymous with the movement, Langsner eventually decided to title the show Four Abstract Classicists (1959), as he felt that the style marked a classical turn away from the romanticism of Abstract Expressionism.
Theo van Doesburg- Counter-composition V
June Harwood

*http://www.theartstory.org/movement-hard-edge-painting.htm