Impressionism began in France during the late nineteenth century as a painting style depicting visual impressions of the moment, especially shifting light and color. The shimmering textures and misty forms of these paintings appear shapeless viewed close but reveal their understated form from across the room.
Impression, soleil levant | Claude Monet, 1840-1926 | This painting introduced Impressionism to France in 1874. | Metropolitan Museum of Art
Music was late to the Impressionistic movement, trailing visual artists and poets by a generation. As Impressionism gained monument, it was organized across disciples with musicians, poets and artists uniting with common goals and values.
Musical Style
Musical Impressionism was anti-realism and anti-romantic, avoiding the extreme emotions of Romantic music. It eschewed detailed programs and musical conventions common to Romanticism. Instead, Impressionism focused on suggestion and atmosphere, conveying fleeting moods and emotions with a kaleidoscope of shifting harmonies and timbres.
France | France (red) is located in Europe (green) | Wikimedia Commons
Musical Impressionists further differentiated themselves by breaking the Classical and Romantic rules of melody, harmony, orchestration and meter. For example, Romantic composers used an extreme range of dynamics whereas Impressionists preferred understatement, light textures and delicately graded dynamics.
Timbre
The most significant Impressionistic technique is the expressive use of timbre. Impressionistic composers often used instruments in a soloistic manner, striving to highlight individual timbres rather than blend them. New timbres were created by using extreme ranges of instruments or by placing mutes on string instruments and brass to create a soft and distant sound.
Extended harp arpeggios were often employed to create sound "mist" around delicate solos. Listen to the harp arpeggios with French horn solo from Debussy's Prelude to the Afternoon of a Faun:
Harp Arpeggios and French Horn Solo
String tremolos were also used to create "mist" around understated solos. Here's an oboe solo with muted string tremolos in Prelude to the Afternoon of a Faun:
String Tremolo and Oboe Solo
Musical Texture
Taking clues from gamelan textures, unusual instrumental combinations and chord voicings—e.g., high pitched violin harmonics with low brass—were often used. Orchestral textures were lighter and more transparent compared to the dense all-hands-on-deck sound of Romantic symphonies. Thus, softer instruments such as the harp and flute were often used as soloists within the orchestra.
Harmony
Other elements of Impressionism involve, again, breaking the rules of Romantic and Classical harmony: choosing chords for color rather than function, adding dissonant notes to chords and using chords in parallel motion (chord streams) without resolving. For example, the final chord of Ravel's Menuet from Le tombeau de Couperin is a G major nine (Gmaj9) with five chord tones (G B D F-sharp A). A typical Classical or Romantic piece uses a simple G Major chord with three chord tones (G B D). The extra chord tones in Ravel's final chord were considered dissonant tones in prior eras but are used for color here.
G major chord followed by G major 9
End of Ravel's Menuet with G major 9
Scales
Ambiguous tonality was further enhanced by avoiding major and minor scales in melodies. Instead, melodies were often based on pentatonic scales, modes and whole tone scales, further distancing Impressionism from German Romanticism while embracing influences from Asian traditions such as gamelan.
Pentatonic scales have five tones (major and minor scales have seven):
Pentatonic melody in Maurice Ravel's Empress of the Pagodas:
A whole tone scale is made of six tones separated by whole steps (two half-steps). This scale is unique insomuch as it confuses or suspends traditional tonality.
Whole tone scale passage from Debussy's Prelude to the Afternoon of a Faun:
Claude Debussy (1862-1918) and Maurice Ravel (1875-1937) were the main proponents of musical Impressionism. Debussy's works were a seminal force in the music of the late nineteenth and early twentieth century, extending far beyond the borders of his native France.
Born in St. Germain de Fleurville, France in 1862, Debussy studied music at the Paris Conservatory. Like Berlioz before him, Debussy won the Prix de Rome. His influences include Russian and Asian music, and the ideas of French writers and poets such as Verlaine, Mallarmè and Baudelaire.
Debussy developed an original system of harmony and formal structure that expressed musically the ideals of Impressionist painters and Symbolist writers. His major works include Clair de lune (1890–1905), Pelléas et Mélisande (1902), La Mer (1905, The Sea) and Prélude à l’après-midi d’un faune (1894, Prelude to the Afternoon of a Faun). His final set of chamber works were left unfinished: a German bombing raid on Paris killed Debussy on March 25, 1918.
Debussy's Prelude to the Afternoon of a Faun (Prélude à l'après-midi d'un faune), written in 1894, is among the best known examples of musical Impressionism. He avoids the dense sound of Romantic orchestral textures; instead, his textures are transparent, sonorous and sensuous—often sprinkled with solos. Woodwinds are prominent and used in extreme registers for coloristic effect. Brass are often muted for color and control of volume, yielding a faraway sound. String tremolos and harp arpeggios are often used to create a floating, shimmering effect.
Debussy has this to say about the work:
The music of this prelude is a very free illustration of Mallarmé's beautiful poem. By no means does it claim to be a synthesis of it. Rather there is a succession of scenes through which pass the desires and dreams of the faun in the heat of the afternoon. Then, tired of pursuing the timorous flight of nymphs and naiads, he succumbs to intoxicating sleep, in which he can finally realize his dreams of possession in universal Nature.
A Seated Faun | Jean Restout II, 1692-1768 | The faun is a hybrid of human and goat. He's an accomplished flautist and Don Juan. | Museum of Fine Arts
Prelude to the Afternoon of a Faun is a one-movement orchestral piece and, although Debussy didn't refer to it as programmatic, it suggests the sights and sounds of an amorous woodland creature, the faun, and his dreamy escapades with flute, wine and nymphs.
Form
Prelude is organized in three sections: A B A', ternary form. The Faun's flute solo is the main theme and is heard immediately. Due to the lack of a strong metric pulse, rhythms flow lazily from the flute, while chromatic tones obscure tonality:
As the piece gains momentum, a playful theme is introduced by an oboe:
In the B section, woodwinds present a lyrical theme while building a crescendo:
Prelude to the Afternoon of a Faun (1894) | Claude Debussy (11:45)
Vocabulary
Impressionism, pentatonic scale, whole tone scale, faun
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Musical Style
France
Timbre
String Tremolo and Oboe Solo 
Musical Texture
Harmony
Prelude to the Afternoon of a Faun
