In
musicMusic is an art form whose medium is sound. Common elements of music are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...
, an
accidental is a
noteIn music, the term note has two primary meanings:#a sign used in musical notation to represent the relative duration and pitch of a sound;#a pitched sound itself....
whose
pitchPitch represents the perceived fundamental frequency of a sound. It is one of the three major auditory attributes of sounds along with loudness and timbre. When the actual fundamental frequency can be precisely determined through physical measurement, it may differ from the perceived pitch because...
(or
pitch classIn music, a pitch class is a set of all pitches that are a whole number of octaves apart, e.g., the pitch class C consists of the Cs in all octaves...
) is not a member of a
scaleIn music, a scale is a group of musical notes collected in ascending and descending order, that provides material for or is used to conveniently represent part or all of a musical work including melody and/or harmony...
or
modeMode is a term from Western music theory having three definitions :# the rhythmic relationship between long and short values in the late medieval period;...
indicated by the
most recently appliedIn music, modulation is most commonly the act or process of changing from one key to another. This may or may not be accompanied by a change in key signature. Modulations articulate or create the structure or form of many pieces, as well as add interest...
key signatureIn musical notation, a key signature is a series of sharp or flat symbols placed on the staff, designating notes that are to be consistently played one semitone higher or lower than the equivalent natural notes unless otherwise altered with an accidental...
. In
musical notationMusic notation or musical notation is any system which represents aurally perceived music, through the use of written symbols.-Western history:...
, the symbols used to mark such notes,
sharpsIn music, sharp means higher in pitch. More specifically, in musical notation, sharp means "higher in pitch by a semitone ," and has an associated symbol , which is often confused with the number sign...
, flats , and
naturalsIn musical notation, a natural sign is an accidental sign used to cancel a flat or sharp from either a preceding note or the key signature. If a bar contains a double sharp or double flat accidental and the composer wishes to denote the same note with only a single sharp or flat, a natural sign...
, may also be called accidentals. An accidental sign raises or lowers the following note from its normal pitch, usually by a
semitoneA semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant. The most commonly written form of this interval is the minor second, notated using two adjacent letter names A semitone, also called a...
, although
microtonal musicMicrotonal music is music using microtones — intervals of less than an equally spaced semitone.Microtonal music can also refer to music which uses intervals not found in the Western system of 12 equal intervals to the octave.-Terminology:...
may use "fractional" accidental signs, and one occasionally sees double sharps or flats, which raise or lower the indicated note by a
whole toneA major second , also called a whole step or a whole tone, is a musical interval that occurs between the first and second degrees of a major scale, the tonic and the supertonic. The major second is abbreviated as M2; its inversion is the minor seventh...
(though their most common usage is in keys in which the altered note is already raised or lowered by the key signature, so the altered note is only a half step from its usual pitch in that key). Accidentals apply within the
measureIn musical notation, a bar is a segment of time defined as a given number of beats of a given duration. The word measure is heard more frequently in the U.S., while bar is used in other English-speaking countries, although musicians generally understand both usages...
and
octaveIn music, an octave , is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon which has been referred to as the "basic miracle of music," the use of which is "common in most musical systems." It may be derived from the...
in which they appear, unless canceled by another accidental sign, or
tiedIn music notation, a tie is a curved line connecting the heads of two notes of the same pitch, indicating that they are to be played as a single note with a duration equal to the sum of the individual notes' note values...
into a following measure.
The modern accidental signs derive from the round and square small letter
bB is the second letter in the Latin alphabet. Its name in English is spelled bee, plural bees.-History:The letter B might have started as a pictogram of the floorplan of a house in Egyptian hieroglyphs or the Proto-Sinaitic alphabet...
used in
Gregorian chantGregorian chant is the central tradition of Western plainchant, a form of monophonic liturgical chant in Western Christianity that accompanied the celebration of Mass and other ritual services...
manuscripts to signify the two pitches of B, the only note that could be altered. The round
b became the flat sign, while the square
b diverged into the sharp and natural signs.
Sometimes the black keys on a
musical keyboardA musical keyboard is the set of adjacent depressible levers or keys on a musical instrument, particularly the piano. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the...
are called accidentals or
sharps, and the white keys are called
naturals.
Standard use of accidentals
In most cases, a
sharpIn music, sharp means higher in pitch. More specifically, in musical notation, sharp means "higher in pitch by a semitone ," and has an associated symbol , which is often confused with the number sign...
raises the pitch of a note one
semitoneA semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant. The most commonly written form of this interval is the minor second, notated using two adjacent letter names A semitone, also called a...
while a flat lowers it a
semitoneA semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant. The most commonly written form of this interval is the minor second, notated using two adjacent letter names A semitone, also called a...
. A
naturalIn musical notation, a natural sign is an accidental sign used to cancel a flat or sharp from either a preceding note or the key signature. If a bar contains a double sharp or double flat accidental and the composer wishes to denote the same note with only a single sharp or flat, a natural sign...
is used to cancel the effect of a flat or sharp. This system of accidentals operates in conjunction with the
key signatureIn musical notation, a key signature is a series of sharp or flat symbols placed on the staff, designating notes that are to be consistently played one semitone higher or lower than the equivalent natural notes unless otherwise altered with an accidental...
, whose effect continues throughout an entire piece, unless canceled by another key signature. An accidental can also be used to cancel or reinstate the flats or sharps of the key signature.
Since about 1700, accidentals have been understood to continue for the remainder of the
measureIn musical notation, a bar is a segment of time defined as a given number of beats of a given duration. The word measure is heard more frequently in the U.S., while bar is used in other English-speaking countries, although musicians generally understand both usages...
in which they occur, so that a subsequent note on the same staff position is still affected by that accidental, unless marked as an accidental on its own. Notes on other staff positions, including those an
octaveIn music, an octave , is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon which has been referred to as the "basic miracle of music," the use of which is "common in most musical systems." It may be derived from the...
away, are unaffected. Once a barline is passed, the effect of the accidental ends, except when a note affected by an accidental is
tiedIn music notation, a tie is a curved line connecting the heads of two notes of the same pitch, indicating that they are to be played as a single note with a duration equal to the sum of the individual notes' note values...
to the same note across a barline.
Sight readingSight-reading is the reading and performing of a piece of written music, specifically when the performer has not seen it before. Sight-singing is often used to describe a singer who is sight-reading.-Sight-reading:...
music at speed can be mentally (and physically) taxing, so where an editor or engraver sees a possible opportunity for confusion, a courtesy or cautionary accidental may be placed by a note whose pitch is, strictly speaking, already given.
Though this tradition is still in use particularly in tonal music, it may be cumbersome in music that features frequent accidentals, as is often the case in non-tonal music. As a result, an alternate system of note-for-note accidentals has been adopted with the aim of reducing the number of accidentals required to notate a measure. The system is as follows:
- An accidental carries through the measure affecting both the note it immediately precedes and any following notes on the same line or space in the measure.
- Accidentals do not affect the same note of a different octave, unless indicated by a key signature.
- Accidentals are not repeated on tied notes unless the tie goes from line to line or page to page.
- Accidentals are not repeated for repeated notes unless one or more different pitches [or rests] intervene.
- If a sharp or flat pitch is followed directly by its natural form, a natural is used.
- Cautionary accidentals or naturals (in parentheses) may be used to clarify ambiguities, but should be held to a minimum.
Because seven of the twelve notes of the chromatic equal-tempered scale are naturals, this system can significantly reduce the number of naturals required in a notated passage.
Note that in a few cases the accidental might change the note by more than a
semitoneA semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant. The most commonly written form of this interval is the minor second, notated using two adjacent letter names A semitone, also called a...
: for example, if a G sharp is followed in the same measure by a G flat, the flat sign on the latter note means it will be two semitones lower than if no accidental were present. Thus, the effect of the accidental has to be understood in relation to the "natural" meaning of the note's staff position. For the sake of clarity, some composers put a natural in front of the accidental. Thus, if in this example the composer actually wanted the note a semitone lower than G-natural, he might put first a natural sign to cancel the previous G-sharp, then the flat.
Double accidentals raise or lower the pitch of a note by two semitones, an innovation developed as early as 1615 . An F with a double sharp applied raises it a whole step so it is
enharmonicIn modern music and notation, an enharmonic equivalent is a note , interval , or key signature which is equivalent to some other note, interval, or key signature, but "spelled", or named, differently...
ally equivalent to a G. Usage varies on how to notate the situation in which a note with a double sharp is followed in the same measure by a note with a single sharp: some publications simply use the single accidental for the latter note, whereas others use a combination of a natural and a sharp, with the natural being understood to apply to only the second sharp.
The double accidental with respect to a specific key signature raises or lowers the notes containing a sharp or flat by a half step. For example, when in the key of C sharp minor or E major; F,C,G, and D contain a sharp, adding a double accidental (double sharp) to F for example in this case would only raise the already sharp containing note F, one half step or semitone, creating G natural, respectively.
Conversely, if a double sharp were added to any other note not containing a sharp or flat as indicated by the key signature then the note will be raised two semitones or a whole step with respect to the chromatic scale. For example in the aforementioned key signature any note that is not F, C, G, and D will be raised by a whole step or two semitones instead of one, the note A double sharp is the enharmonic equivalent to B within the key of C sharp minor or E major.
Courtesy accidentals
Although a barline is nowadays understood to cancel the effect of an accidental (except for a tied note), often publishers will use a
courtesy accidental (also referred to as a
cautionary accidental or a
reminder accidental) as a reminder of the correct pitch if the same note occurs in the following measure. This usage varies, although a few situations are construed to require a courtesy accidental, such as
- when the first note in a measure is one which had had an accidental applied in the previous measure
- after a tie carries an accidental across a barline, when the same note appears again in the subsequent measure.
Other uses are inconsistently applied.
Courtesy accidentals are sometimes enclosed in parentheses to emphasize their nature as reminders.
Publishers of
jazzJazz is a musical art form which originated at the beginning of the 20th century in African American communities in the Southern United States from a confluence of African and European music traditions....
music and some
atonalAtonal may refer to:*AtonalityAtonal or Atonaltzin may refer to:*Atonal I*Atonal II...
music sometimes eschew all courtesy accidentals.
Microtonal notation
Composers of
microtonal musicMicrotonal music is music using microtones — intervals of less than an equally spaced semitone.Microtonal music can also refer to music which uses intervals not found in the Western system of 12 equal intervals to the octave.-Terminology:...
have developed a number of notations for indicating the various pitches outside of standard notation. One such system for notating
quarter toneA quarter tone is an interval about half as wide as a semitone, which is half a whole tone.Many composers are known for having written music including quarter tones or the quarter tone scale, first proposed by 19th-century music theorist Mikha'il Mishaqah , including: Pierre Boulez, Julián...
s, used by the Czech
Alois HábaAlois Hába was a Czech composer, musical theorist and teacher. He is primarily known for his microtonal compositions, especially using the quarter tone scale, though he used others such as sixth-tones and twelfth-tones.-Life:Hába came from musical family, his brother Karel Hába was also a...
and other composers, is shown on the right.
In the 19th and beginning 20th century, when Turkish musicians switched from their traditional notation systems — which were not staff-based — to the European staff-based system, they created a refinement to the European accidental system in order to be able to notate Turkish scales which make use of intervals smaller than the tempered semitone. There are several such systems which vary as to the division of the octave they presuppose or merely the graphical shape of the accidentals. The most widely used system (created by
Rauf Yekta BeyRauf Yekta Bey was a Turkish musician, musicologist and writer on music.-Biography:He wrote the first modern account of Turkish classical music available in a Western language .-References:* Turkmusikisi.com -...
) uses a system of 4 sharps (roughly +25
centThe cent is a logarithmic unit of measure used for musical intervals. Typically cents are used to measure extremely small intervals, or to compare the sizes of comparable intervals in different tuning systems, and in fact the interval of one cent is much too small to be heard between successive...
s, +75 cents, +125 cents and +175 cents) and 4 flats (roughly −25 cents, −75 cents, −125 cents and −175 cents), none of which correspond to the tempered sharp and flat. They presuppose a Pythagorean division of the octave taking the
Pythagorean commaIn musical tuning, the Pythagorean comma , named after the ancient mathematician and philosopher Pythagoras, is the microtonal interval defined as the difference between a Pythagorean apotome and a Pythagorean limma, e.g....
(about an 8th of the tempered tone, actually closer to 24 cents, defined as the difference between 7 octaves and 12 just-intonation fifths) as the basic interval. The Turkish systems have also been adopted by some Arab musicians.
Ben Johnston created a system of
notationMusic notation or musical notation is any system which represents aurally perceived music, through the use of written symbols.-Western history:...
for pieces in
just intonationIn music, just intonation is any musical tuning in which the frequencies of notes are related by ratios of whole numbers. Any interval tuned in this way is called a just interval; in other words, the two notes are members of the same harmonic series....
where the unmarked C, F, and G major chords are just major chords (4:5:6) and accidentals are used to create just tuning in other keys.
History of notation of accidentals
The three principal symbols indicating whether a note should be raised or lowered in pitch are derived from variations of the small letter
bB is the second letter in the Latin alphabet. Its name in English is spelled bee, plural bees.-History:The letter B might have started as a pictogram of the floorplan of a house in Egyptian hieroglyphs or the Proto-Sinaitic alphabet...
: the
sharpIn music, sharp means higher in pitch. More specifically, in musical notation, sharp means "higher in pitch by a semitone ," and has an associated symbol , which is often confused with the number sign...
and
naturalIn musical notation, a natural sign is an accidental sign used to cancel a flat or sharp from either a preceding note or the key signature. If a bar contains a double sharp or double flat accidental and the composer wishes to denote the same note with only a single sharp or flat, a natural sign...
signs from the square "b quadratum", and the flat sign from the round "b rotundum".
In the early days of European music notation (4-line staff
Gregorian chantGregorian chant is the central tradition of Western plainchant, a form of monophonic liturgical chant in Western Christianity that accompanied the celebration of Mass and other ritual services...
manuscripts), only the note B could be altered (i.e. have an accidental applied to it): it could be flattened, thus moving from the
hexachordum durum (i.e. the
hard hexachordIn music, a hexachord is a collection of six pitch classes including six-note segments of a scale or tone row. The term was adopted in the Middle Ages and adapted in the twentieth-century in Milton Babbitt's serial theory.-Middle Ages:...
: G-A-B-C-D-E) where it is natural, to the
hexachordum molle (i.e. the
soft hexachord: F-G-A-B-C-D) where it is flat; the note B is not present in the third hexachord
hexachordum naturale (i.e. the
natural hexachord: C-D-E-F-G-A).
This long use of B as the only altered note incidentally helps explain some notational peculiarities:
- the flat sign actually derives from a round b, signifying the B of the soft hexachord, that is, B flat (hence the name of the flat sign in French "bémol" from medieval French "bé mol" — modern French "bé mou" — or "soft b") and originally meant only B;
- both the natural sign and the sharp derive from a square b, signifying the B of the hard hexachord, that is, B natural (hence the name of the natural sign in French "bécarre" from medieval French "bé carre", earlier "bé quarre" — modern French "bé carré" — or "square b") and originally meant only B natural.
In the same way, in German music notation the letter B designates B flat while the letter H, which is actually a deformation of a square B, designates B natural.
As polyphony became more complex, notes other than B needed to be altered in order to avoid undesirable harmonic or melodic intervals (especially the augmented 4th, or
tritoneThe tritone is a musical interval that spans three whole tones. The tritone, sometimes known as the Diabolus in Musica, is the same as an augmented fourth, which in 12-tone equal temperament is enharmonic to a diminished fifth...
, that music theory writers referred to as "
diabolus in musicaDiabolus in Musica can refer to:* Tritone, a certain musical interval.* Diabolus in Musica, a 1998 album by Slayer.* Diabolus in Musica, Accardo interpreta Paganini, an album by Salvatore Accardo....
", i.e. "
the devil in music"). The first sharp in use was F, then came the second flat E, then C, G, etc.; by the 16th century B, E, A, D, G and F, C, G, D and A were all in use to a greater or lesser extent.
However, those accidentals were often not notated in vocal part-books (but the correct pitches were always notated in
tablatureTablature is a form of musical notation indicating instrument fingering rather than musical pitches....
). The notational practice of not marking implied accidentals, leaving them to be supplied by the performer instead, was called
musica fictaMusica ficta was a term used in European music theory from the late twelfth century to about 1600 to describe any pitches, whether notated or to be added by performers in accordance with their training, that lie outside the system of musica recta or musica vera , defined by the hexachord system...
(i.e. "feigned music").
Strictly speaking the medieval signs and indicate that the melody is progressing inside a (fictive)
hexachord of which the signed note is the
mi or the
fa respectively. That means they refer to a group of notes
around the marked note, rather than indicating that the note itself is necessarily an accidental. Occasionally it is possible to see a mi-sign associated with e.g. a D. This
could mean that the D is simply a D, but the note above E is now
fa, i.e. it is one that is actually flattened to E flat (the 'accidental' in modern parlance).