Impressionism was a term at first used mockingly
to describe the work of the French painter Monet and his circle, who later
made use of the word themselves. It was similarly used to describe an element
of vagueness and imprecision coupled with a perceived excess of attention
to color in the early music of Debussy,
who did not accept the criticism or the label, although his harmonic innovations
and approach to composition have points in common with the ideals of Monet.
It was a style whose artistic language included
suggestive colors, lines, words, melodies, and harmonies. The listener,
viewer, and reader were called upon to supply the details and complete
the images. Led by Debussy, composers denied both the objectivity
of programmatic composers and the pathos of the Romantic idealists.
Impressionistic music was a music of coloristic effects, of vague harmonies,
and loosely knit forms.
The word impromptu was first used as a title for
a musical composition in 1822 by the Bohemian composer Vorisek for six
piano pieces, to be imitated by Schubert’s publisher in naming a set of
four piano Impromptus, to be followed by four more, perhaps so named by
the composer. Chopin used the title for four compositions in this seemingly
improvised form, and there are further impromptus by other composers from
that period onwards, generally, but not always, for a single instrument.
Improvisation was once a normal part of a performer’s
stock-in-trade. Many of the greatest composer-performers, from Bach to
Mozart and Beethoven, were masters of improvisation, but in the 19th century
this became a less common part of public performance, although it remained
and remains a necessary skill for a church organist, traditionally required
to provide a musical accompaniment of varying length to liturgical ritual.
In baroque music the realisation of a figured bass, the improvisation of
a keyboard part from a given series of chords, was a necessary musical
accomplishment, while the improvisatory element in the addition of ornaments
to a melodic part remained normal in opera and other kinds of solo performance.
Instrumentation is generally used to mean orchestration,
the art of writing music for instruments, or, alternatively, the actual
scoring of a particular composition.
In the theatre an interlude performs the same function
as an entr’acte, music between acts or scenes, designed to bridge a gap.
It may also be used to indicate music played or sung between two other
works or two sections of a work.
Earlier signifying a comic interlude inserted between
the acts of an opera seria, the 19th century intermezzo was often either
a musical interlude in a larger composition or a piece of music in itself,
often for solo piano. In this second sense it is used by Schumann and later
by Brahms in their piano music, while both Mendelssohn and Brahms use the
word as a movement title in chamber music.
In music an interval is the distance in pitch between
two notes, counted from the lower note upwards, with the lower note as
the first of the interval. The violin, for example, is tuned in intervals
of a fifth, G to D, D to A and A to E, the double bass in fourths, from
E to A, A to D and D to G. Harmonic intervals occur simultaneously, as
when a violinist tunes the instrument, listening carefully to the sound
of two adjacent strings played together. Melodic intervals occur between
two notes played one after the other.
Interval class (ic)
The distance, measured in semitones, between two
classes. Interval classes group the eleven perfect and imperfect consonances
(excluding octaves and unisons) into six discrete classes by including
an interval and its inversion in the same class. Hence:
ic1 = m2 / M7
ic2 = M2 / m7
ic3 = m3 / M6
ic4 = M3 / m6
ic5 = P4 / P5
ic6 = tritone
Intonation is the exactness of pitch or lack of it
in playing or singing. Collective intonation is that of a group of instruments,
where slight individual variations in pitch can be lost in a generally
more favourable effect.
The two-part Inventions of Johann Sebastian Bach
are contrapuntal two-voice keyboard compositions, and the word is often
understood in this sense, although it had a less precise meaning in earlier
L’istesso tempo, the same speed, is found as an instruction
to the player to return to the previous speed of the music.