The visual expression of academically untrained artists, including paintings, sculpture, ceramics, metalwork, costume, needlework, implements, and tools. Jean Lipman, editor of "Art in America and folk-art scholar, wrote that folk art "is based upon an essentially non-optical vision. It is a style depending upon what the artist knew rather than upon what he saw, and so the facts of physical reality were largely sifted through the mind and personality of the painter." The degree of excellence "depends upon the clarity, energy, and coherence of the artist's mental picture rather than upon the beauty or interest actually inherent in the subject matter..." (Forward)
According to the Britannica Encyclopedia, there are several categories of Folk Art:
1) decorative that includes the fraktur (document decorating) artists and needle workers;
2) anonymous creations, that is by little-known painters and sculptors who worked for practical purposes such as commercial sign makers and carvers of headstones and decoys; and
3) and painting and sculpture from self-taught folk artists. All share the commonality of being produced outside the mainstream of American art, meaning at the time of creation, the artists have no background of academic art-school training, no involvement with organized advertising of their work, publicity receptions, etc.
Among the best-known American folk artists are John Kane, Edward Hicks, Jacob Maentel, Rufus Porter, Ammi Phillips, Horace Pippin, Grandma Moses, Joseph Pickett, Morris Hirshfield, Clementine Hunter, Bill Traylor and Howard Finster.
Sources: "American Folk Painters of Three Centuries" by Jean Lipman and Tom Armstrong; The "Britannica Encyclopedia of American Art"; AskART database.