Different parchment color through Herbal section?

[Jorge_Stolfi]

I would expect the effects of weathering on any singulion collection smaller than on a bound book, since the MS has been bound for the majority of its life and adventures.

Probably.  However, on the other hand, the folios in a book are more protected from dirt, light, oxidation etc than in a stack of loose bifolios. 

Beware also that the "blank" vellum on many pages is darkened by seethrough/bleedthrough from the paints on the other side.  Especially by the obnoxious green "copper resinate" paint.  Is Claude aware of that?

Back to the Herbal section. This graph should be a bit easier to read.

Why are you plotting data per folio rather than per page? I expect that the four pages of a bifolio will show different intensity of darkening/yellowing, because they will get different exposures to the aging agents.  Compare for example You are not allowed to view links. Register or Login to view. and f28v.

When new, vellum should be nearly white -- even because it was usually finished with a chalk paste, sanding, and powdered resin to create a smooth writing surface with the right degree of hydrophobic/hydrophilic character.  If one were to buy a bunch of sheets at the same time from a good dealer, I suppose that the sheets would have been quite uniform in color and finish.

But the VMS vellum is poor quality off-cuts.  So the material that the Scribe received may have been already of varied age, size, and quality, probably from different sources.  Therefore some part of the color variation of the VMS pages may be "primeval", before the sheet were written.  

The Author and/or the Scribe must have trimmed or split several large sheets with horizontal cuts in order to get bifolios of the same height, ~235 mm.  They must have trimmed or split many of them with vertical cuts to get bifolios with the same width; but left some of them uncut, to make the fold-outs.  

I can't imagine them sorting the blank bifolios by color -- which must have been still hard to distinguish, even on the "old" material.  Surely the Scribe just picked each bifolio from the "blank" pile, without any choosing.  Then, over the next 600 years, each page became darker and yellower at a different rate depending on its exposure -- first in the stack of bifolios, then in the bound book.

Thus any ordering of pages, folios, or bifolios that one can obtain by comparing vellum colors will be pretty meaningless.  It will not be correlated with writing order, not even with the original order of the bifolios.

All the best, --stolfi