Impressionism
Style movement around 1900 with a focus on tone colour.
What it means
Impressionism designates a direction of music around 1900 that is connected above all with French composers. The term comes from painting and was transferred to music; the composers concerned partly rejected it, because it reduces their work to a slogan. What is meant is a music in which tone colour, surface of sound, and suggestion are more important than thematic development and goal-directed harmony.
Musical use
Characteristic are means that weaken the harmonic pull: whole-tone scale and pentatonic turns, modality, chords led in parallel, sonorities with added notes that act as colour and not as tension. The form is often planar instead of developing; sections stand side by side instead of emerging from one another. Instrumentation gains central importance — muted winds, divided strings, harp, and percussion produce colours that carry the actual content. The influence of non-European music, which European composers encountered at world's fairs, is often named; the concrete effects are to be checked in the individual case.
Performance practice
Work on tone colour and culture of touch; volume is here seldom the means of choice. Keep pedal changes on the piano by ear, because merging harmonies are intended but smearing is not. Shape tempi flexibly but without losing the coherence. Watch for exact observance of the dynamic gradations in the lower range, which are often finely articulated. In the orchestra, balance is the main task: colours arise from mixture, not from assertion.
Bear in mind that the designation was partly rejected by the composers concerned and reduces their work to a slogan: use it with caution and check whether it really holds for a particular work. For the performance the culture of sound is decisive; work on touch, pedal, and balance instead of on volume. Observe the finely graded quiet dynamic levels exactly. Use the pedal according to the sound and not according to the harmony; Debussy seldom notated it and relied on the ear of the players.
With orchestral works, check whether mutes and divided parts are called for, because they substantially determine the colour.