Unexpected (irregular) vertical spacing

[Simon Albrecht]

Hello,

attached you find one page of a mass setting by Palestrina. The vertical 
spacing is very uneven and seems irrational and I'm a bit at a loss with 
interpretation. I couldn't think of how to make a minimal example 
either, so I attached it with all tweaks &c. Some thoughts on this:
-- The page is slightly overfull (compressed by 6.3 staff-spaces), which 
upon looking doesn't seem to be necessary.
-- Some lyrics lines are followed by large whitespace, while there is 
almost no space inbetween systems.
-- This seems in part, but not consistently (see 2nd system, 2nd staff 
vs. 4th system, 2nd staff) to occur when there are notes reaching below 
the staff: the lyrics then are placed directly below, but the next staff 
seems to be placed so that the lyrics are centered.
-- Tweaking VerticalAxisGroup.nonstaff-unrelatedstaff-spacing doesn't 
seem to help.
(-- Beside the point: the horizontal spacing is brillant, I think, 
especially with \override SpacingSpanner.shortest-duration-space = 1.2 
and even when the movement is forced on six systems. It can almost 
concur with the Breitkopf & Härtel 1881 model 
<http://imslp.org/wiki/Special:ImagefromIndex/301177>)
-- The only potentially related issue I found is issue 1991 
<http://code.google.com/p/lilypond/issues/detail?id=1991>.
It would be nice to improve this. What do you think?

--
Simon Albrecht, Kirchenmusikstudent

Sanctus_vertical spacing
Description: Text document

Sanctus_vertical spacing.pdf
Description: Adobe PDF document