A musical notation provided by the composer (or music editor) to make it easier for the performer to read and interpret complex or often confusing music notation. This notation will indicate to the performer that there will be a change in one or more aspects of the composition or that a temporary change that has taken place is no longer in effect. Courtesy Signs can show changes in the clef, the key signature, the time signature, or accidentals. Courtesy Signs are often provided so the performer can keep up with quick changes in the composition or be reminded of the current clef, key or time signatures in new staves or page turns. Their name is appropriate, because they are provided as a courtesy for the performer.
Many courtesy signs will appear at the end of a measure or staff to make the performer aware of changes to the next measure or staff, however, courtesy accidentals are shown at any point in a composition where a note has been changed. Clefs, key signature and time signature changes will be shown in a specific order with a courtesy clef shown before the last barline of the staff, and the courtesy key signature and courtesy time signature are placed after the last barline of the staff. Courtesy accidentals appear in front of notes that are reverting back to their original pitch from an accidental in the previous measure and are often enclosed in parentheses marks.
See also courtesy clef; courtesy key signature; courtesy time signature; courtesy accidental.