Chromaticism
Chromaticism is a compositional technique interspersing the primary diatonic pitches and chords with other pitches of the chromatic scale. Chromaticism is in contrast or addition to tonality or diatonicism and modality (the major and minor, or "white key", scales). Chromatic elements are considered, "elaborations of or substitutions for diatonic scale members". Development of chromaticism. The following timeline is abbreviated from its presentation by Benward & Saker: As tonality began to expand during the last half of the nineteenth century, with new combinations of chords, keys and harmonies being tried, the chromatic scale and chromaticism became more widely used, especially in  the works of Richard Wagner, such as the opera "Tristan und Isolde". Increased chromaticism is often cited as one of the main causes or signs of the "breakdown" of tonality, in the form of increased importance or use of: As tonal harmony continued to widen and even break down, the chromatic scale became the basis of modern music written using the twelve-tone technique, a tone row being a specific ordering or series of the chromatic scale, and later serialism. Though these styles/methods continue to (re)incorporate tonality or tonal elements, often the trends that led to these methods were  abandoned, such as modulation. Types of chromaticism. David Cope describes three forms of chromaticism: modulation, borrowed chords from secondary keys, and chromatic chords such as augmented sixth chords. The total chromatic is the collection of all twelve equally tempered pitch classes of the chromatic scale. List of chromatic chords: Other types of chromaticity: Chromatic note. A chromatic note is one which does not belong to the scale of the key prevailing at the time. Similarly, a chromatic chord is one which includes one or more such notes. A chromatic and a diatonic note, or two chromatic notes, create chromatic intervals . A chromatic scale is one which proceeds entirely by semitones, so dividing the octave into twelve equal steps of one semitone each. Linear chromaticism is used in jazz: "All improvised lines ... will include non-harmonic, chromatic notes." Similar to in the bebop scale this may be the result of metric issues, or simply the desire to use a portion of the chromatic scale Chromatic chord. A chromatic chord is a musical chord that includes at least one note not belonging in the diatonic scale associated with the prevailing key, the use of such chords is the use of chromatic harmony . In other words, at least one note of the chord is chromatically altered. Any chord that is not chromatic is a "diatonic chord". For example, in the key of C major, the following chords (all diatonic) are naturally built on each degree of the scale: However, a number of other chords may also be built on the degrees of the scale, and some of these are chromatic. Examples: Chromatic line. In music theory, "passus duriusculus" is a Latin term which refers to chromatic line, often a bassline, whether descending or ascending. From the late 16th century onward, chromaticism has come  to symbolize intense emotional expression in music. Pierre Boulez (1986, p. 254) speaks of a long established "dualism" in Western European harmonic language: "the diatonic on the one hand and the chromatic on the other as in the time of Monteverdi and Gesualdo whose madrigals provide many examples and employ virtually the same symbolism. The chromatic symbolizing darkness doubt and grief and the diatonic light, affirmation and joy—this imagery has hardly changed for three centuries." When an interviewer asked Igor Stravinsky (1959, p. 243) if he really believed in an innate connection between "pathos" and chromaticism, the composer replied  Of course not; the association is entirely due to convention. Nevertheless the convention is a powerful one and the emotional associations evoked by chromaticism have endured and indeed strengthened over the years. To quote Cooke (1959, p. 54) "Ever since about 1850—since doubts have been cast, in intellectual circles, on the possibility, or even the desirability, of basing one's life on the concept of personal happiness—chromaticism has brought more and more painful tensions into our art-music, and finally eroded the major system and with it the whole system of tonality." Examples of descending chromatic melodic lines  that would seem to convey highly charged feeling can be found in: Connotations. Chromaticism is often associated with dissonance. In the 16th century the repeated melodic semitone became associated with weeping, see: passus duriusculus, lament bass, and pianto. Susan McClary (1991) argues that chromaticism in operatic and sonata form narratives can be chosen to be understood through a Marxist narrative as the "Other", racial, sexual, class or otherwise, to diatonicism's "male" self, whether through modulation, as to the secondary key area, or other means. For instance, Catherine Clément calls the chromaticism in Wagner's "Isolde" "feminine stink". However, McClary  also contradicts herself saying that the same techniques used in opera to represent madness in women were historically highly prized in avant-garde instrumental music, "In the nineteenth-century symphony, "Salome"s chromatic daring is what distinguishes truly serious composition of the vanguard from mere cliché-ridden hack work." (p. 101)