Note value
In music notation, a note value indicates the relative duration of a note, using the color or shape of the note head, the presence or absence of a stem, and the presence or absence of flags.
A rest indicates a silence of an equivalent duration.
Table of note values
A note value does not stand for any absolute duration, but can only be understood in relation to other note values. In the table below, each symbol is exactly twice as long in duration as the symbol below it.
| Note | Rest | American name | British name |
|---|---|---|---|
 |
 |
longa | longa |
 |
 |
breve (or double whole note) | breve |
 |
 |
whole note | semibreve |
 |
 |
half note | minim |
 |
 |
quarter note | crochet |
 |
 |
eighth note | quaver |
 |
 |
sixteenth note | semiquaver |
 |
 |
thirty-second note | demisemiquaver |
 |
 |
sixty-fourth note | hemidemisemiquaver |
| File:128th note.gif | File:128th rest.gif | hundred-twenty-eighth note | quasihemidemisemiquaver |
Sometimes the longa is used to indicate a very long note of indefinite duration, as at the end of a piece.
When a stem is present, it can go either up (from the right side of the note head) or down (from the left side, except in the case of the longa). In most cases, the stem goes down if the notehead is on the center line or above, and up otherwise. Any flags always go to the right of the stem.
When two or more notes which would normally have flags (eighth notes or shorter) appear successively, the flags may be replaced by beams, as shown at right. Notes are typically beamed only if they appear in the same beat within the bar.
Modifiers to note values
A note value may be augmented by adding a dot after it. This dot adds the next lower note value, making it 1.5 times its original duration. Two dots add two lower note values, making a total of 1.75 times its original duration. The rare three dots make 1.875 the duration, and so on.
To divide a note value into three equal parts, or some other value than two, tuplets may be used.
History of note values
Gregorian chant
Although note heads of various shapes, and notes with and without stems appear in early Gregorian chant manuscripts, most scholars agree that these symbols do not indicate different durations, although the dot is used for augmentation. See neume.
In the 13th century, chant was sometimes performed according to rhythmic modes, roughly equivalent to meters; however, the note shapes still did not indicate duration in the same way as modern note values.
Mensural notation
Around 1250, Franco of Cologne invented different symbols for different durations, although the relation between different note values could vary; three was the most common ratio. Philippe de Vitry's treatise Ars nova (1320) described a system in which the ratios of different note values could be 2:1 or 3:1, with a system of mensural time signatures to distinguish between them.
This black mensural notation gave way to white mensural notation around 1450, in which all note values were written with white (outline) noteheads. In white notation the use of triplets was indicated by coloration, i.e. filling in the noteheads to make them black (or sometimes red). Both black and white notation periodically made use of ligatures, a holdover from the clivis and porrectus neumes used in chant.
Around 1600 the modern notational system was generally adopted, along with barlines and the practice of writing multipart music in scores rather than only individual parts. In the 17th century, however, old usages came up occasionally. Here's an example from 1692, by Marc-Antoine Charpentier:
Anachronistic use of white mensual notation in Te Deum by Marc-Antoine Charpentier (1643-1704)
