Editing Accidental (music) (section)

==Standard use==
In most cases, a [[Sharp (music)|sharp]] raises the pitch of a note one [[semitone]] while a [[flat (music)|flat]] lowers it one semitone. A [[natural sign|natural]] is used to cancel the effect of a flat or sharp. This system of accidentals operates in conjunction with the [[key signature]], whose effect continues throughout an entire piece, or until another key signature is indicated. An accidental can also be used to cancel a previous accidental or reinstate the flats or sharps of the key signature.

Accidentals apply to subsequent notes on the same [[staff position]] for the remainder of the measure where they occur, unless explicitly changed by another accidental. Once a [[Bar (music)|barline]] is passed, the effect of the accidental ends, except when a note affected by an accidental is tied to the same note across a barline. An accidental that carries past the barline through a tied note does not apply to subsequent notes.

:<div style="background-color: white;"><score> {
    \relative c'' {
        \time 3/4
        g4 gis gis | g? ges ges~ | ges gis g
    }
}
</score></div>

Under this system, the notes in the example above are:

* '''{{Abbr|m.|measure}} 1''': G{{music|natural}}, G{{music|sharp}}, G{{music|sharp}} (the sharp carries over)
* '''m. 2''': G{{music|natural}} (with [[courtesy accidental]]), G{{music|flat}}, G{{music|flat}} (the flat carries over)
* '''m. 3''': G{{music|flat}} (which is tied from the previous note), G{{music|sharp}}, G{{music|natural}} (the natural sign cancels the sharp sign)

Though this convention is still in use particularly in [[Tonality|tonal music]], it may be cumbersome in music that features frequent accidentals, as is often the case in [[Atonality|atonal music]]. As a result, an alternative system of note-for-note accidentals has been adopted, with the aim of reducing the number of accidentals required to notate a [[bar (music)|bar]]. According to Kurt Stone, the system is as follows:<ref>Stone, Kurt. ''Music Notation in the Twentieth Century: A Practical Guidebook'', p. 56. New York: W. W. Norton & Co., 1980.</ref>

# Accidentals affect only those notes which they immediately precede.
# 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.
# Courtesy accidentals or naturals (in parentheses) may be used to clarify ambiguities but are kept to a minimum

Because seven of the twelve notes of the chromatic equal-tempered scale are naturals (the "white notes", A; B; C; D; E; F; and G on a piano keyboard) this system can significantly reduce the number of naturals required in a notated passage.

Occasionally, an accidental may change the note by more than a semitone: for example, if a G{{Music|sharp}} is followed in the same measure by a G{{Music|flat}}, the flat sign on the latter note means it is two semitones lower than if no accidental were present. Thus, the effect of the accidental must be understood in relation to the "natural" meaning of the note's [[staff position]].

In some atonal scores (particularly by composers of the [[Second Viennese School]]), an accidental is notated on every note, including natural notes and repeated pitches. This system was adopted for "the specific intellectual reason that a note with an accidental was not simply an [[Inflection (music)|inflected]] version of a natural note but a pitch of equal status."<ref>{{Cite book|title=[[Behind Bars: The Definitive Guide to Music Notation]]|last=Gould|first=Elaine|year=2011|isbn=978-0571514564|location=London|pages=86|oclc=701032248}}</ref>