This is, in fact, precisely how key signature key changes - mid song work.
It is helpful to first neutralize everything and then show the new / next key signature.
In the example below - (indicating a key change to F) it is really visually helpful to see those naturals for the F and C sharps - really helps reset the sight reading brain for the new key.
This is standard and correct practice for writing a key change.
Here’s a quick photo from a book of bass excerpts from common classical repertoire - this is from Cesar Franck’s Symphony in Dminor - the first movement:
This makes sense to me because all the naturals shown here “stick.” There is no subsequent accidental after the natural. Is there an example where something being changed from a sharp to a flat has to be cancelled by a natural first with no note played rather than just indicating the flat?
People may do that as a courtesy or cautionary reminder, just like they may put an accidental on the note the first time it is used after the key signature change but there is no requirement to do that. A new key signature overrides any previous one, you do not have to naturalize any notes unless the current key signature has no flats or sharps ie C or A minor.
I think that adding naturals is just messy and more confusing besides being totally unnecessary.
That’s one crazy key signature change right there - not just from the normal change but popping to a different clef on the same staff. Trying to think if I have seen that before - most of the sheet music I am used to already has parallel staves though so I doubt it.
The only time I’ve seen this ‘cancelling out’ approach to accidentals is in key signatures. In music you can go right from sharp to flat, or vice versa. If a natural shows up, it’s only to get you to play the natural note.
The treble clef bits - and the slightly smaller notes there - indicate a violin (I believe) part that is playing as an audio cue so the bassists can have a little heads up on where to come in and what they are playing in response to.
I suppose there’s no requirement for most of this notation stuff - it’s all best / most common practices. The most common practice that I’ve run into reading music has been to natural-out a key signature, then write the new key signature. I get it if you don’t like it. Must be annoying to have it show up in so much written music.
In bass music nowadays, the bass will be asked to play high stuff in treble clef. In the example above it’s used to indicate the other string part. In lots of old string music, the high bass parts are written in tenor clef… which is a nightmare all on its own, and frustrated the hell out of me trying to play fancy classical parts.
I happened to drop into this topic and here’s my take on various subjects (as a former classical piano player).
The sheet score does indeed mean a change of key from 2sharps (either DMaj or Bmin) to Gflat Maj or Eflat min (most probably Gflat Maj since the first notes and are Dflat Eflat and Bflat e.g. 5th, 6th ad 3rd in Gflat Maj key). In standard music notation is kind of common to “reset” previous key by neutralizing flats or sharps before indicating the new key via its own flats/sharps. Despite what one may think I always used to like this “reset” before change of key. It was (for me) much lesser confusing than it might appear.
Gflat Maj or Cflat Maj keys (such as Fsharp Maj and Csharp Maj keys) aren’t really seen on a “regular basis” by pianists, but there is a fair share of music written in those keys. I just recall Bach’s “Well Tempered Klavier” purposely written in any maj and minor keys. One of Beethovens’ piano sonatas I happened to study is in Fsharp Maj (6 sharps). Chopin’s Etudes Op. 10 n. 5 and 6 both have 6 flats (respectively Gflat Maj and Eflat min keys) Etude op. 25 n. 9 has again 6flats (Gflat Maj).
Change of clef on the same part is quite common for instruments who have wider extension (like piano, organ etc) 'cause if you sticked to the same clef you would need to add too many additional lines and that would be much harder to read (play) than just a change of clef. Mind that players who play those instruments are usually very well used to read and play both treble and bass clef on sight, often together (e.g. pianist usually read treble key for right hand and bass key for left hand. Organists read an additional bass clef line for pedals). If you play a bass part on a piano with both hands the right hand part is written in bass clef, same as if you’re playing a high part with left hand, which will be written in treble key.
I had to take an exam which required to read music in treble, mid-alto, alto, tenor, bariton and bass clef, changing continuely on the same part, which were the way vocal and instrumental parts for some instruments were written in the past and still are for some instruments for the same reason: limiting additional lines on music notation in order to help singers/players read and sing/play their parts accordingly with the extension and range of their voice/instrument. It seems a bit odd but it makes sense especially when parts had to be manually written and copied. It was/is an efficient way of writing music.
The “Play without Bitching about the key” part is my favourite and I’d guess is probably authentic: it probably means that for the instrument who has to play that part that key is notoriously “uneasy” to play and the composer does know it…and maybe has written it on purpose… on the other hand he/she could have written it with 6sharps (F#Maj or D#min) who sound the same pitch on a tempered instrument so…it would be 6 alterations anyway
Typically you wouldn’t see naturals in a key signature. However, I would read this as the key of Gb Major. The F is natural in this key, without having to notate it, but for whatever reason, the composer chose to make sure the performer knew that. I have no idea why he put a natural on the C line though. If he wanted C to be natural, he could have just written it in Db Major.
This is just my opinion of course.
My take is that the “naturalized” C and F are both simply the consequence of the change of key. He/She wanted to “erase” the previous key with 2# and start writing in the new 6flats key. Ofc he/she could have just put the new key without erasing the previous one but he chose to (and i recall that is not that uncommon).
