Naturals are notes without sharps or flats: C, D, E, F, G, A, and B. For example the note D can be called D-natural because it has no sharp or flat.
A
natural sign (♮) placed before a note cancels the sharp (♯) or flat (♭) sign describing a note.
Sharps (♯), flats (♭) and naturals
(♮) not
in the key signature are called ACCIDENTALS.
Accidentals affect every note on the same line or space for
the remainder of the measure/bar.
Bar lines cancel all accidentals from the previous measure
unless a note is tied across the bar line.
RULES FOR ACCIDENTALS
1. An accidental carries through the bar affecting both the note it immediately comes before and any following notes on the same line or space in the measure.
2. Accidentals do not affect the same note of a different octave, unless indicated by a key signature.
3. Accidentals are not repeated on tied notes, unless the tie goes from line to line or page to page.
4. If a sharp or flat pitch is followed directly by its natural form, a natural must be placed before the note.
5. Cautionary accidentals or naturals (in parentheses) may be used to clarify ambiguities, but should be kept to a minimum.