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 abstraction was part of a general tendency to move away from the expressive qualities of gestural abstraction. Many painters also sought to avoid the shallow, post-Cubist space of de Kooning's work, and instead adopted the open fields of color seen in the work of Barnett Newman.
• 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 which 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," as he felt that the style marked a classical turn away from the romanticism of Abstract Expressionism.

In the late 1950s, the Californian art critic, poet and psychiatrist Jules Langsner began to observe an emerging trend in abstract art that stemmed from color field painting, yet tended to employ clean lines and contrasting hues. He chose to highlight this by staging an exhibition at the Los Angeles County Museum of Art, in 1959, which included artists Frederick Hammersley, Karl Benjamin, John McLaughlin and Lorser Feitelson. It was titled "Four Abstract Classicists."

Langsner coined the term "hard edge colorforms" to describe the paintings on display and, more generally, the new style of color field painting which was becoming popular in California. He believed it recalled the geometric abstraction of Mondrian, Albers, Reinhardt and others. After LACMA, the show traveled to England and Ireland, at which time British art critic Lawrence Alloway subtitled the show California Hard-edge.

Although the four artists included in Langsner's show were very different, they were united by their use of clean, lucid composition, intense color and lack of surface incident. They were also influenced by the sense of 'wholism', or single, unitary composition, seen in the work of Barnett Newman and other color field painters. Hard-edge abstraction differed greatly from its popular predecessor, action painting, in that the artists applied their paints very carefully and sought to avoid any suggestion of spirituality or soulful expression. Frank Stella is typical of those who might be described as hard-edge painters, and who sought to avoid the high-flown drama of action painting - like him, most felt that, by the mid 1950s, gestural abstraction becoming a manner that was being copied by legions of less talented followers, all of whom were pretending the anguish and existential insight.

Many of the hard-edge painters also differed greatly from more traditional color field painters, because although their work employed color as one of its principle components, they were more preoccupied with design and structure. In fact, even though Kenneth Noland had been a student of Josef Albers, who famously espoused the "interaction of color," he and others like him often tended to employ colors which failed to relate in the way Albers envisaged. Frederick Hammersley's Opposing #15 (1959) is typical of this strategy, since it uses contrasting primaries.

In 1964 Langsner curated another exhibition, this time at the Pavilion Gallery (otherwise known as the Newport Pavilion) in Newport Beach, CA. Combining his original term with the subtitle assigned by Alloway, Langsner called this exhibition California Hard-Edge Painting. Included in the show were the original four from Four Abstract Classicists, along with artists Larry Bell, Helen Lundenberg, John Coplans and several others .

But this should not suggest that the term 'hard-edge' was therefore an established reference point for years to come: it had to compete with several others which attempted to describe similar work in the period, including 'One-Image painting', and 'Systemic painting.' Some curators therefore tried to avoid descriptive labels entirely, and in 1963 an exhibition entitled Second-Generation Abstraction was held at the Jewish Museum in New York. The show consisted of 47 works by nine artists: Al Held, Ellsworth Kelly, Frank Stella, Morris Louis, Kenneth Noland, George Ortman, Paul Brach, Miriam Schapiro and Raymond Parker. It was significant for its introduction of New York-based artists into the hard-edge school of abstract painting. Up to this point, the tendency was only associated with those California artists who were widely considered rebels from the New York School.

Although the term 'hard-edge' is helpful in describing the tendencies of the late 1960s, it had barely been launched before artists were also moving in new directions, and it fell from use as abstract painting explored new problems in the 1970s.