chromaticism

In music, the use of enriched harmonies for added expression, practised by 19th-century composers mainly of French and Russian schools, for example Rimsky-Korsakov, Skriabin, Debussy, Ravel, Messiaen, Honegger, and Dutilleux.

Chromatic harmonies are ambiguous consonances rather than expressionist dissonances, influenced by the sounds of music imported from Indonesia and Japan and heard, for example, at the Paris Exposition of 1889, which influenced Debussy. Chromaticism is associated with the introduction of new timbres to the symphony orchestra including the celesta, glockenspiel, and xylophone.