VViews posted an interesting resource about ink production in the library. I checked it hoping to find a clue to something that can be observed in the VM. The fact that the ink used for drawing and writing has faded considerably, but that certain other parts are still quite black.
Iron gall ink generally has the drawback that it fades over time. So is this unfaded ink from a different recipe? I found the following fragment about this:
"And note, that ink made with wine is good for writing books upon the sciences,
because, when books are written with it, the letters do not fade, and can hardly be scraped out or
discharged from parchment or paper. But if they are written with ink made with water, it is not so, for
they can easily be scraped out, and it may happen that the letters written with it will fade."
From the manuscripts of Jehan Le Bégue, composed in Paris in 1431, which are found in Original treatises, dating from the XIIth to XVIIIth centuries on the arts of painting, in oil, miniature, mosaic, and on glass; of gilding, dyeing, and the preparation of colours and artificial gems; preceded by a general introduction; with translations,prefaces, and notes. By Mrs. Merrifield. v.1, Merrifield, Mary P. (Mary Philadelphia), London, J. Murray, 1849, p. 68.
What I find interesting here is that apparently the "fading" ink was very easy to erase (!). Also, that non-fading ink was apparently of a finer (more expensive?) quality.
Some examples are quite striking, for example in the later Zodiac pages where "dark diadems" have been added. Everything has faded apart from these few black details
and the month name (!)
Does this mean that the person who added or traced the dark lines also wrote the month names? It looks like the same pen to me (line thickness).
Thoughts?