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b. 1-4

composition: Op. 28 No. 8, Prelude in F♯ minor

..

In the figurations featuring the interval of an octave, Chopin would often be satisfied with an accidental placed only next to the first note constituting that interval (cf., e.g. the Etude in A Major, Op. 10 No. 10, b. 5-8 or the Ballade in F Major, Op. 38, b. 48). In the Prelude in F Minor, such an extended validity of accidentals is a strictly observed rule – accidentals are absent even in the places where they are necessary to cancel the previous alteration (e.g. on the 2nd demisemiquaver on the 3rd beat of b. 4), while in b. 8 Chopin actually crossed out the necessary accidental next to the 2nd demisemiquaver in the 3rd figure. In the discussed bars, apart from the situation in b. 4 mentioned above, the problem concerns the 8th demisemiquaver in the 3rd group in b. 1-2 and 4, the 8th demisemiquaver in the 1st, 2nd and 4th groups in b. 3 and the 2nd demisemiquaver on the 3rd beat of b. 3. Such a notation is to be found in A (→FC,FEEE1), whereas EE2, GE1 and GE2 added the majority of the necessary accidentals (5, 6 and 7 out of the eight necessary, respectively).
The L.H. quavers falling an octave lower than the first semiquaver of a given figure provided with an accidental are written down in a similar way, without the necessary accidentals – see b. 3-4.  

category imprint: Interpretations within context; Differences between sources

issues: EE revisions , Accidentals in different octaves , GE revisions , Inaccuracies in A , Errors repeated in GE , Errors repeated in FE , Errors repeated in EE

b. 1

composition: Op. 28 No. 8, Prelude in F♯ minor

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EE added a poorly justified cautionary  before a2, probably by analogy with b. 5. In A one can see that Chopin initially wrote that accidental, whereupon he considered it superfluous and crossed it out.

category imprint: Differences between sources; Corrections & alterations; Source & stylistic information

issues: EE revisions , Deletions in A

b. 1-2

composition: Op. 28 No. 8, Prelude in F♯ minor

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FE erroneously gives d instead of c as the last L.H. quaver in each of these bars. The errors, caused probably by this note in bar 1 being written somewhat imprecisely in A (bar 2 is marked as a repetition of bar 1 in the manuscripts), were corrected in FE2 (→EE).

category imprint: Interpretations within context; Differences between sources

issues: Errors in FE , FE revisions

b. 3-4

composition: Op. 28 No. 8, Prelude in F♯ minor

..

As was the case in the R.H. part, in A Chopin omits accidentals next to the quavers ending the four-note L.H. figures if they fall an octave lower than one of the preceding semiquavers. In the discussed bars, such a notation was repeated without changes in FC and FE1. Both necessary naturals – before g in b. 3 and f in b. 4 – were added in EE and GE2, whereas in the remaining editions only one natural was added, in GE1 in b. 3, while in FE2 in b. 4.

category imprint: Interpretations within context; Differences between sources

issues: EE revisions , Accidentals in different octaves , GE revisions , FE revisions , Inaccuracies in A , Errors repeated in GE , Errors repeated in FE

b. 4

composition: Op. 28 No. 8, Prelude in F♯ minor

a1 in A (→FCGE1), literal reading

a1 in FE (→EE) & GE2 (→GE3)

..

When interpreted literally, the version of A (→FCGE1), in which the 4th demisemiquaver on the last beat of the bar is an a1, is most probably a mistake, although the interval structure of the four middle demisemiquavers (from the 3rd to the 6th in the eight-note figure) is strictly analogous to the seven preceding figures. It is indicated by a broader tonal context of this phrase and of the entire Prelude – the second of those four notes is never altered, while the key to which Chopin returns in the 2nd half of that bar is F minor, and not F major. A natural was added – most probably by Fontana – in FE (→EE); an identical addition was also introduced in GE2.

category imprint: Interpretations within context; Differences between sources

issues: Omissions to cancel alteration , GE revisions , Errors of A , FE revisions