Select: 
Category
All
Graphic ambiguousness
Interpretations within context
Differences between sources
Editorial revisions
Corrections & alterations
Source & stylistic information
Pitch
All
Pitch
Rhythm
Slurs
Articulation, Accents, Hairpins
Verbal indications
Pedalling
Fingering
Ornaments
Shorthand & other
Importance
All
Important
Main


Pitch

b. 68

composition: Op. 10 No 12, Etude in C minor

..

The cautionary natural before was added in a proofreading of FE (→GE,EE), most probably by Chopin.
A (→FEEE,GE1GE2) includes a repeated  before the 12th note in the L.H. The unnecessary in this context accidental was removed in GE3 (→GE4).

category imprint: Differences between sources; Editorial revisions

issues: Cautionary accidentals , Authentic corrections of FE

b. 75

composition: Op. 10 No 12, Etude in C minor

No accidentals in A

 f &  f in FE (→GE,EE

..

The text of A is generally correct. Lack of the  before the 2nd note is however most probably a result of Chopin's distraction (haste). It is revealed by the place before the note, most probably left for the accidental to be inserted and, above all, by a later proofreading of FE (→GE,EE), in which both the  and the cancelling it  before the 8th semiquaver were added. It is not the only omission of an accidental introducing alteration of this kind in Chopin's works, although it rarely occurs (e.g., in the Etude in F minor, Op. 25 No. 2, bar 56).

category imprint: Differences between sources

issues: Omissions to cancel alteration , Errors of A , Authentic corrections of FE

b. 75

composition: Op. 10 No 12, Etude in C minor

b (without ) in A (→FEGE1,EE3)

in GE2 (→GE3GE4) & EE4

b with , our suggestion

..

The fact that the  added in GE2 (→GE3GE4) does not correspond to Chopin's intention is revealed by the melodic analogy in bars 18 and 58, which in the authentic sources are also devoid of , and, additionally, by Chopin's fingering.

category imprint: Differences between sources

issues: GE revisions

b. 77

composition: Op. 10 No 12, Etude in C minor

..

We add a cautionary  before b. The addition was already performed in GE3 (→GE4), in which a  before B in the 4th group of semiquavers was added. 

category imprint: Differences between sources; Editorial revisions

issues: GE revisions

b. 77

composition: Op. 10 No 12, Etude in C minor

..

In A (→FEEE) there is no  lowering to d. This patent inaccuracy was corrected in GE. In the identical situation in bar 79  is included in all sources.  

category imprint: Interpretations within context; Differences between sources

issues: Accidentals in different octaves