NOTATIO

Here is a page from Strauss' Don Quixote, by Jos. Aibl Verlag, 1898, from 1904 sold by Universal Edition Wien.
I have never been thinking to reduce note sizes in a crowded page. That is interesting - flexibility and clarity... At the first I believed the notes were graces, but no, all are regular. The most interesting are the clarinets.
(Of course, I assume that the parts are using standard notes.)

I've not been aware of this before, but it certainly seems to be something to to add to one's armoury of possible solutions to problems. To be used with care.

In Finale I don't think there's any way to have one note size for the score and another for the part, so one would have to restore the full note size for the linked parts. Hitherto I have reduced the whole system (which doesn't affect linked parts) when faced with something like this, but what's done here has the potential to be more flexible.

Also interesting, the sizes of dynamics and rests are kept intact for the reduced notes.

Here is another example (flutes, but also accidentals in the clarinets) in Ravel's L'heure espagnole, by Durand & Cie., 1911. Plate D. & F. 7314, 10,605; page 73 Score: http://hz.imslp.info/files/imglnks/usim ... score).pdf

Unless my eyes are fooling me, something similar seems to be going on in Ravel's Ondine for piano solo. Maybe this is a French thing?

Indeed - your eyes are fine!
Maybe not a French thing; Strauss is done by Jos. Aibl Verlag from Munich.

But INTERESTING. I remember I have had numerous difficulties with spacing in some scores and I didn't dare to edit noteheads nor accidentals. This proves it is "perhaps" possible, but definitely shouldn't be misused.

OT, apropos the French thing: I have done some orchestration analysis of Debussy and Ravel published by Fromont and Durand - well, the number of mistakes is overwhelming: missing or wrong clefs, missing notes, missing rests, missing dynamics, barlines across wrong sections, missing pizz or arco, forgotten mutes or to remove it... Just mind-blowing!

Interesting. I haven't been aware of this pragmatic engraving before. It seems that in L'heure espagnole the flutes have smaller notes and accidentals because of more accidentals. In the clarinets there aren't that many accidentals, so the notes are a bit bigger. Or am I mistaken?

I had a look at Beethoven, Op. 110, the first edition according to IMSLP. There was no difference in size between the 'main notes' and the perhaps rather ornamental 32nds at the beginning of the first movement. How does it look in the manuscript, if there is one?

Sorry, OCTO, obviously not just a French thing. And I have also done it in a few extreme cases. Even a slight reduction can sometimes solve difficult spacing problems.

The many mistakes in the first editions of Debussy and Ravel are well-known. The editors and engravers seem to have taken a hands-off approach and just put down what was in the manuscript. But I see the same thing in the first editions of Beethoven's piano sonatas.

Anders, that's an interesting point, but, as far as I know, the small notes in the Classic period indicate only that the notes are not part of the meter, not that they are ornamental or of lesser importance. Chopin may have been the first to use small notes for metered notes that have special expression.

Beethoven's note heads are rather small in general, but he always carefully distinguished the ones that were to be engraved as non-metered small notes. This can be observed in the MS of op. 110:

http://conquest.imslp.info/files/imglnk ... 110_01.pdf

The publishers of Beethoven's may have a far more limited number of font sizes than was apparently available to later publishers, and thus may not have been able to make use reduction to solve spacing issues.