Chromaticism

Chromaticism is a compositional technique interspersing the primary diatonic pitches and chords with other pitches of the chromatic scale. In simple terms, within each octave, diatonic music uses only seven different notes, rather than the twelve available on a standard piano keyboard. Music is chromatic when it uses more than just these seven notes.

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".