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 (the major and minor scales). Chromatic elements are considered, "elaborations of or substitutions for diatonic scale members."〔
==Development of chromaticism==
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 "break down" of tonality, in the form of increased importance or use of:
*tonicization of each chromatic step and other secondary key areas
*hierarchical organizations of the chromatic set such as George Perle's
*the use of non-tonal chords as tonic "keys"/"scales"/"areas" such as the Tristan chord.
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 which led to these methods were abandoned, such as modulation.
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