Non-objective art is visual art that does not represent a subject external to itself. It isn't a picture of something. It is, rather, colors and forms that compose an image. There will be nothing identifiable as an object within a truly non-objective painting. Neither is a non-objective painting meant to suggest or resemble natural forms. For this reason, the patterns of, for instance, Navajo textiles intended to stand for elements of the landscape do not constitute non-objective art in its strictest sense. The subject of non-objective art may be the process, the color or the pigment itself.
Abstract painting differs from non-objective painting in that the forms of abstract painting are, as the name suggests, abstracted: parts of them are taken away. But because parts of them remain, and can be recognized for what they are, abstract paintings are not truly non-objective. The Italian Futurist Umberto Boccioni's "The City Rises," for example, takes great liberties with architecture, with the landscape and with human figures, organizing them in unexpected ways and distorting their proportions, colors and textures. There is no doubt, however, that figures and buildings are part of this emotional and violent picture. It is an abstract rather than a non-objective painting.
The Russian artist Wassily Kandinsky's elaborate color theories led him to paint what are considered the first non-objective works. He believed that certain colors were more spiritual than others, and all of them possessed a power beyond mere representation. Other non-objective painters of the early 20th century, the Russian Suprematists and the Dutch artists of De Stijl, also expressed the power of color free of the bounds of strict representation. The energetic Abstract Expressionism of the 1940s and 50s built upon the distortions of the Cubists and others, but some of its artists abandoned the subject as their interest in the painting as a record of its own making grew. Non-objective painters of the next wave concerned themselves less with process and more with the barest elements of painting: pigment, line, and a flat canvas.
As painting in the 20th century moved away from the need for representation of the objects of the three-dimensional world and toward an acceptance of the painting as an object itself, it became ever simpler. Minimalist artists stripped away the vestiges of expression in pursuit of the purest kind of painting. Minimalist non-objective art, in its endeavor to rid painting of the personal and accidental, is a precursor of postmodernist ideas that question the meaning of authorship. This drive for a reduction to the minimum, if taken to its logical limit, leads inevitably to the removal of the work of art altogether. The kind of art based on an idea rather than on an object is called conceptual art, and there's not much scope for painters or paintings in it. While artists still produce non-objective art, it exists now as one of many equally valid choices.
While all non-objective art shares the lack of an external subject, it varies in its particulars. The effusive compositions of Kandinsky anticipated the flowing and color-oriented work of the Lyrical Abstraction painters of the late 1960s. Less linear is the work of the Color Field painters, who concentrated largely on the relationships between elements of color and the nature of the surface, its size, shape and texture, as essential to the work. The painters of the contemporaneous Hard-Edged school produced cool, angular work reminiscent of De Stijl and Russian Suprematism, but even cleaner, with less concern about expression.