1) The use of chromatic tones 
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.....
(from Greek chroma, `colour`) in music, the use of notes foreign to the mode or diatonic scale upon which a composition is based.[9 related articles]
Use of the chromatic scale - all twelve notes / semitones
the use of chromatic tones. · a style in which chromatic tones predominate.