Diatonic and chromatic

Very often, diatonic refers to musical elements derived from the modes and transpositions of the "white note scale" C–D–E–F–G–A–B.

In ancient Greece there were three standard tunings (known by the Latin word genus, plural genera)[d] of a lyre.

[h][i] The term cromatico (Italian) was occasionally used in the Medieval and Renaissance periods to refer to the coloration (Latin coloratio) of certain notes.

[j] In works of the Ars Nova from the 14th century, this was used to indicate a temporary change in metre from triple to duple, or vice versa.

[9] These uses for the word have no relationship to the modern meaning of chromatic, but the sense survives in the current term coloratura.

For instance Orlando Lasso's Prophetiae Sibyllarum opens with a prologue proclaiming, "these chromatic songs,[11] heard in modulation, are those in which the mysteries of the Sibyls are sung, intrepidly," which here takes its modern meaning referring to the frequent change of key and use of chromatic intervals in the work.

This usage comes from a renewed interest in the Greek genera, especially its chromatic tetrachord, notably by the influential theorist Nicola Vicentino in his treatise on ancient and modern practice, 1555.

The gamut was the series of pitches from which all the Medieval "scales" (or modes, strictly) notionally derive, and it may be thought of as constructed in a certain way from diatonic tetrachords.

In its most strict definition, therefore, a diatonic scale is one that may be derived from the pitches represented in successive white keys of the piano (or a transposition thereof).

[16] In general, diatonic is most often used inclusively with respect to music that restricts itself to standard uses of traditional major and minor scales.

Such a sequence of pitches is produced, for example, by playing all the black and white keys of a piano in order.

Under a generalized meantone tuning, notes such as G♯ and A♭ are not enharmonically equivalent but are instead different by an amount known as a diesis.

This causes intervals that cross the break to be written as augmented or diminished chromatic intervals, with the most notable example being the "wolf fifth" (which is actually a diminished sixth) that occurs when 12-note-per-octave keyboards are tuned to meantone temperaments whose fifths are flatter than those in 12-tone equal temperament.

In a generalized meantone temperament, chromatic semitones (E–E♯) are smaller than or equal to diatonic semitones (E–F) in size,[26] With consonant intervals such as the major third, the nearby interval (a diminished fourth in the case of a major third) is generally less consonant.

If the tritone is assumed diatonic, the classification of written intervals on this definition is not significantly different from the "drawn from the same diatonic scale" definition above as long as the harmonic minor and ascending melodic minor scale variants are not included.

[29] On this understanding, the diminished seventh chord built on the leading note is accepted as diatonic in minor keys.

Instrumental compositions of the late Renaissance and early Baroque periods also began experimenting with the expressive possibilities of contrasting diatonic passages of music with chromatic ones.

58., the long, flowing melody of the first five bars is almost entirely diatonic, consisting of notes within the scale of E minor, the movement's home key.

By contrast, the remaining bars are highly chromatic, using all the notes available to convey a sense of growing intensity as the music builds towards its expressive climax.A further example may be found in this extract from act 3 of Richard Wagner's opera Die Walküre.

The passage is intended to convey the god Wotan putting his daughter Brünnhilde into a deep sleep.

True chromatic progressions (e.g. F–F♯–G) are occasionally allowed in theory (Marchetto, GerbertS [sic], iii, 82–3) and prescribed in manuscript sources.

Increasingly explicit use of accidentals and explicit degree-inflection culminates in the madrigals of Marenzio and Gesualdo, which are remote from medieval traditions of unspecified inflection, and co-exists in the 16th century both with older hexachordal practices and with occasional true melodic chromaticism.