f17r

[Jorge_Stolfi]

I don't know what this means in practice, but if this is inconsistent with iron gall ink, this would be interesting.

Indeed.  But I would rather understand it better before I discuss it.

Meanwhile, here are the images of the starts of lines 1-7 under 625 nm (red) and 700, 735, 780, 870, and 940 nm (IR), reduced in size 50% and separately normalized  to 0-1 range (thus not in the same color scale):

                       

And here is approximately the same area in the BL 2014 image:
   

So the fading of the text as the wavelength increases is gradual, which seems compatible with "ocher" ink but not iron-gall ink. But it seems also that the glyphs and parts of glyphs that are noticeably darker in the BL 2014 image (which my Superior Pareidolia says are retraced at a later date than the rest) keep their opacity better, up to 940 nm. While that may mean a different "ocher" composition (with more MnO2?), it may also mean that the ink of those strokes contains some iron-gall ink.

All the best, --stolfi