What convention is used for sharps and flats in chromatic scale notation? [duplicate]

This exercise says to leave the dominant and subdominant notes unaltered (pick up the sharp or flat from the key signature). However, I have also seen convention that says use sharps for ascending chromatic scales and flats for descending. This seems to be contradictory. What is the correct way to write the scales?

• Please add the source of the quoted material. Also, for screen readers, please add the text from the image as a quotation in the post. Jun 5, 2023 at 12:39
• In real life it depends on the harmonic context. In C, for example, a chromatic descent from G to E should use F sharp if the chords are G D7 G7 C. In E flat minor, an ascent from F to A flat should use G flat if the chords are B7 Ebm C#dim7 B7. Jun 5, 2023 at 16:25
• @phoog if we are truly in Eb minor, we would probably call that a Cb7 chord, and use Gb, wouldn't we? Jun 5, 2023 at 16:31
• @nuggethead yes, probably so, but I meant to write Bb7 Ebm C#dim7 Bb7. :-) Jun 5, 2023 at 18:54

Generally one tries to notate chromatic scales so that they as easy as possible to read, which mostly means writing as few accidentals as possible. In C or open key this is most easily achieved by writing sharps on the way up and flats on the way down.

In a flat key you would want to avoid sharps where possible and use naturals instead. The example given in the question is close to best practice (I would have written E-natural instead of F-flat to save an unnecessary accidental on the F). This is also a case where one might make an exception to not mixing sharps and flats: the G-flat could be written as F-sharp.

• In a descending chromatic scale in A minor, though, you would typically use G sharp and F sharp rather than A flat and G flat. Jun 5, 2023 at 16:27
• @phoog I'd be more likely to use flats. A chromatic scale is already outside the tonality. Jun 5, 2023 at 17:12
• @phoog But of course it depends on the context. Jun 5, 2023 at 17:50
• "A chromatic scale is already outside the tonality": There are plenty of tonal pieces that employ chromatic scales without deviating significantly from the tonality. Jun 5, 2023 at 18:56

Rule 1: don't mix flats and sharps without good reason. (A leading-tone would be a good reason, but is not easily encountered with that function in a chromatic passage.)

Rule 2: If in a section with a key signature, the type from the signature is preferred. If you require the natural note while the key signature modifies it, the natural sign is needed.

• "is not easily encountered with that function in a chromatic passage": the seventh degree of the scale (when raised, if the tonal context is minor) is routinely used as such in chromatic passages. Jun 5, 2023 at 15:52

What I have seen is slightly different. Notating a chromatic passage within a given key signature calls for leaving all diatonic notes unmarked; notes that proceed downward scalewise get flats or double flats or naturals and notes that proceed upward scalewise get sharps or double sharps or naturals. There is no mixing of sharps or flats in these passages.

I do not recall seeing notation of chromatic passages that skip around; I'm not sure that these are based on a chromatic scale but are just a bunch of chromatic passing or neighbor tones scattered around. I'd probably try to minimize the total number of accidentals.

• This works as long as you consider both the raised and lowered sixth and seventh scale degrees "diatonic" in minor. The typical common-practice harmonisation of a descending chromatic scale in (e.g.) A minor uses G sharp and F sharp, not A flat and G flat. Jun 5, 2023 at 16:30
• You're right (perhaps the net-ism "your right" could be "your right to be right is my rite"). I forgot to note that one should still have 7 letters (H & B identical in German?) and no letter both sharped and flatted.) I like to think of steps 6 and 7 in a minor as "mutable"; in some sense close to diatonic but with a chromatic tinge. I once counted accidental (non-signature) in a bunch of pieces using the current convention, the Baroque one-less-sharp-or-flat, and a Bartok-like lower sixth step and upper seventh step; all took about the same number of added accidentals. Anecdote, not data.
– ttw
Jun 5, 2023 at 18:54
• "I like to think of steps 6 and 7 in a minor as "mutable"": that is a far more sensible way of approaching it than the knots that people tie themselves into otherwise. Jun 5, 2023 at 18:59
• B seems to have been mutable since pre-history (before 800). It's not a new concept. I have a set of principles somewhere based on reading various suggestions. Mostly pointing out when one uses each. The only real solid recommendation is that one uses the lower 6 for the upper neighbor of 5. Others were: the augmented chord on 3 is rare, and the "3" minor scales are used together in the same passage quite often and in both directions.
– ttw
Jun 5, 2023 at 19:28
• Before 800? I thought Guido introduced that in the 11th century. To what are you referring? Jun 5, 2023 at 19:53

This example baffles me. I was taught that if a chromatic passage or note is ascending, use a natural or sharp to raise the note from within the key; if it is descending, use a natural or flat to lower the a note from within the key. In the key of C then, going up we would have

C C# D D# E F F# G G# A A# B C

And going down we would have

C B Bb A Ab G Gb F E Eb D Db C

Applying this convention to the key of Ab, ascending would be

Ab A Bb B C Dd D Eb E F F# G Ab

I will look for a source to defend what I was taught!

• This rule works for many situations but not for others. The second note in a descending tonic-to-tonic chromatic scale is typically the leading tone, so it should be spelled as such, and in tonal contexts generally pitches in the tonic scale should be spelled as such, giving Ab-G-Gb-F-Fb-Eb in both A flat major and A flat minor. Jun 5, 2023 at 13:54
• I see I misread the answer slightly, but my comment still applies in cases of secondary harmony. For example, in C major or C minor, if the harmony for the half step below G is D major then it should be an F sharp, not G flat. Jun 5, 2023 at 16:33

Several points.

*If the key has sharps, try to keep any accidentals sharp (or natural).

*If a key has flats, try to keep any accidentals flat (or natural).

*If a letter-name note is followed by another, the same letter, but there's an accidental needed, try to use whatever, so the second note doesn't need another accidental to cancel the previous.

*With a scale, it's commonplace to write accidentals as sharps rising, and flats falling (for the above reason).

*Often not used - reflect the accompanying chord name with appropriate notes! I often see, e.g. C7♯9 with an E♭ instead of the 'proper' D♯.

*I don't believe there's one adhered-to convention - writing by all sorts of folk seems to reflect this!

• But the chromatic line descending from A to E in A minor is typically spelled with G sharp (but would be A flat if the chord were Bb7). Similarly, it could use G flat or F sharp depending on the harmony. Jun 5, 2023 at 16:36