Issues : Last key signature sign

b. 5

composition: Op. 28 No. 14, Prelude in E♭ minor

c-c1 w A, literal reading (→FE,FCGE1)

c-c1 in EE, GE2 (→GE3) & FES

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The missing naturals raising c-c1 to c-c1 are almost certainly Chopin's mistake. It is indicated by the naturals added by Chopin in FES as well as by the cautionary  written in A before c1 in the next bar (eventually crossed out), which suggests that Chopin assumed that it was c that was valid there*.
The naturals were added in EE and GE2 (→GE3).


* A precautionary approach should be taken in the case of a reasoning based on a cautionary accidental – in b. 12 in A we can also observe crossed-out flats before c-c1, although the sound of those notes had already been consolidated at the beginning of b. 10 (Chopin was not always certain which accidentals were included in the key signature).

category imprint: Interpretations within context; Differences between sources; Source & stylistic information

issues: Annotations in teaching copies , EE revisions , GE revisions , Omission of current key accidentals , Deletions in A , Annotations in FES , Last key signature sign

b. 13

composition: Op. 28 No. 14, Prelude in E♭ minor

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In A and the remaining sources there is a cautionary  before c1. In FC (→GE) and EE before c in the L.H. part was also added. In the main text we omit those unjustified accidentals.

category imprint: Differences between sources; Editorial revisions

issues: EE revisions , Cautionary accidentals , Last key signature sign , Fontana's revisions