I sometimes try to read the notes from a composer's manuscript instead of from published sheet music, but I run into issues quite frequently. Here are the composers for which I have tried to read the notes from a manuscript:
The only one so far that I have noticed to be problem free is Bach's manuscript. It is so neat, and sure, I might see F# where I don't expect it in the key signature, but very quickly, I realize that key signatures in the Baroque were written differently than they were later on, with every note on the staff that takes a certain accidental, having that accidental(so in the bass clef for example, I would see 2 Bb's or in the treble clef I would see 2 F#'s). It is so neatly written, Bach's manuscript is, that the only reason that I might need an edition is for expression purposes(dynamics, staccato, and so on). In contrast to Bach, Beethoven is like the polar opposite with his manuscript, messy, with lots of crossing out. I find it literally impossible to follow Beethoven's instructions from the manuscript(overlapping notes from other staves, crossing out, tears, etc.), so I always go for the edition, even when Beethoven's manuscript is available, because I can't read from Beethoven's manuscript.
With Haydn and Mozart, issues turn up once again. But unlike with Beethoven, it has nothing to do with how neat or messy the manuscript is. I can easily read from a Mozart manuscript for instance. No, the issues that turn up have to do with an incomplete manuscript(For example, I once looked up the manuscript for K 545 and I got just the first movement of the sonata. As another example, with Eine Kleine Nachtmusik, I get every movement, but only the first one or two pages of it). Also, sometimes, especially in Mozart piano concertos I'm like:
Wait, what dynamic is the piano at? 20 bars later I see a forte dynamic. The orchestra stopped playing while at a loud dynamic. Surely the piano isn't going forte the whole time? Mozart, couldn't you have at least put in a creschendo or something? At least then, I could guess that the piano starts at a piano dynamic. But no, you just have to leave me with absolutely no clue of the starting dynamic.
And it doesn't get much better with editions, this missing dynamic in Concerto issue that I frequently see in Mozart's piano concertos. And there is no way for me to know Mozart's interpretation(It would almost certainly be Mozart playing the piano part of his own Piano Concertos) because:
- It wasn't until Beethoven's time that Mozart's cadenzas were written down(in fact, Beethoven was the first to write down not only his own cadenzas for concertos, but Mozart's cadenzas as well). So, looking at just the Mozart manuscript, it looks like there is an empty bar when the truth is that the empty bar is the cadenza and Mozart just didn't bother to write it down(unlike with Beethoven where an empty bar = a grand pause, the most famous of which is between the 2 ending chords of the first theme of Beethoven's Fifth Symphony)
- Recording technology didn't exist back in Mozart's era
- Mozart left no evidence that would hint at his interpretation
Lastly, Vivaldi. I can easily see what notes are to be played by which instruments(unlike with Beethoven). But sometimes, his sixteenth note beams are so close that I can't tell if they are sixteenths or eighths, even when I zoom in. This is another composer for which I absolutely need the edition to clearly see what the note values are.