Editing Accidental (music) (section)

==Courtesy accidentals==
{{Image frame|content=<score> {
\override Score.TimeSignature
#'stencil = ##f
    \relative c'' {
        \time 4/4
        aes1 a?
    }  }
</score>|width=180|caption=An A{{music|flat}} followed by an A{{music|natural}} in the next measure. The A{{music|natural}} is given a courtesy accidental to remind the player that the flat sign does not apply to it.}}
In modern scores, a barline cancels an accidental, with the exception of tied notes. ''Courtesy accidentals'', also called ''cautionary accidentals'' or ''reminder accidentals'' are used to remind the musician of the correct pitch if the same note occurs in the following measure. The rules for applying courtesy accidentals (sometimes enclosed in parentheses) vary among publishers, though in a few situations they are customary:

* When the first note of a measure had an accidental in the previous measure
* After a tie carries an accidental across a barline, and the same note appears in the next measure
* When a chord contains a diminished or augmented octave
* When there is a [[false relation|cross relation]] with another part

Publishers of [[free jazz]] music and some [[atonal]] music sometimes eschew all courtesy accidentals.<ref>Marshall, Wolf (2008). ''Stuff! Good Guitar Players Should Know: An A-Z Guide to Getting Better'', p.59. {{ISBN|9781423430087}}.</ref>