CHROMATICISM

(from Greek chroma, "colour"), in music, the use of notes foreign to the mode or diatonic scale upon which a composition is based, introduced in order to intensify or colour the melodic line or harmonic texture. In ancient Greek music, the term referred to the tetrachord (q.v.), or four-note series, that contained two half steps. Later, in European music, "chromatic" was applied to optional notes supplementing the diatonic (seven-note) scales and modes, because these notes produced halftone steps that were extraneous to the basic scale or mode. A full set of chromatic tones added to any diatonic scale produces a chromatic scale, an octave of 12 semitones. In European medieval and Renaissance music, chromaticism was associated with the practice of musica ficta (q.v.), which facilitated, and in some instances mandated, halftone steps foreign to the church modes of that time. In the 16th and early 17th centuries, notably in the secular Italian and English madrigal, chromaticism was widely used to heighten expressiveness to the extent that eventually the traditional modes appeared irrelevant. The 16th-century European preoccupation with ancient Greek sources in turn contributed to a growing theoretical interest in the chromatic gender of classical antiquity. The so-called monodic revolution brought all these and related developments to an inevitable head so that, by the middle of the 17th century, functional harmony based on the diatonic major and minor scales was beginning to assert itself as the primary structural device in Western music. In functional harmony, chromaticism permits long-range modulation (changes of key) as well as momentary expressiveness. Its expressive potential was increasingly exploited for dramatic or pictorial purposes by both Classical (e.g., "The Representation of Chaos" at the beginning of Joseph Haydn's oratorio The Creation) and Romantic composers. By the late 19th century, the progressive reliance on chromaticism threatened the very survival of functional harmony, just as it had interfered with modality three centuries earlier. Already in some of Richard Wagner's music, chromaticism was so extensive that it undermined any immediate sense of tonal direction, and, by the time of such post-Wagnerians as Csar Franck and Max Reger, tonal stability had yielded to the tonally ambivalent enchainments of chromatically related chords. In the early 20th century, Arnold Schoenberg and others proceeded to reject the diatonic (seven-note) major and minor scales altogether in favour of a 12-note chromatic scale in which no note is allowed to predominate (see twelve-tone music). Others, including Igor Stravinsky and Sergey Prokofiev, freely intermixed diatonic and chromatic elements.