The VMS ink is NOT iron-gall

[Jorge_Stolfi]

As far as I'm concerned McCrone's conclusions remain undisputed so far, and would likewise have remained undisputed if they have called it not iron gall in the first place, unless another lab runs their own tests and casts doubts on the conclusions of McCrone's.

Okay, so we have very different opinions about experts in general and McCrone in particular.  I don't know what else I could say to change your mind, so let's leave it at that.

f103r is not a wet qtip but some substance possibly acidic and hot (assuming some stew), which penetrated the page

Tannin is an acid, and when it reacts with green vitriol it releases sulfuric acid.  This is not a problem for writing on vellum, since vellum is relatively resistant to the acid and anyway it is usually impregnated with chalk, that will neutralize the acid.  It is a problem when IGI is used on paper, since the acid speeds up the decay of the paper -- to the point that the writing may fall off, leaving neat letter-shaped holes.  I saw several examples of that in Kircher's Carteggio.

The point is that IGI should not care about the little acid in tomato sauce.  Much less the non-acidic goulash, or whatever that stain is.

(That stain is one of the many missed opportunities in the McCrone examination.  It would be useful to know its composition.  If it is tomato, it would indicate that the clumsy clod who dribbled it was from Italy -- although maybe not North Italy.  If it is goulash, the Austro-Hungarian Empire may be a more likely Origin Theory for that stain.  And if it is a modern synthetic sauce that only became available in the early 1900s, like titanium-based ketchup, it would be strong evidence that the stain was forged by Wilfrid.)

  and which is also very close in color to the actual ink.

That is irrelevant, since the ink was quite clearly erased inside f103v the big stain on f103r -- not just masked by the color of the sauce. 

A very good test happened on f103v, where this substance obviously sipped through to leave a mark on f104r, but didn't visibly disturb the ink.

As I discussed at length You are not allowed to view links. Register or Login to view., the sauce apparently had two components, one water-based ("polar") and one oil-based ("apolar").  It was the watery component that softened the ink on f103r, which presumably was wiped out when the stain was finally cleaned.  

But vellum is treated to be weakly hydrophobic, to prevent the ink from soaking into it and flaring out.  Thus  that watery component mostly stayed put where it was smeared by the closing of the book, leaving a a darker stain with a sharp border.  Very little of it, if any went through the vellum.  

The oily component, on the other hand, soaked into the vellum and spread out, creating a fuzzy light orangish-tan halo around the stains. It also went through the vellum to f103v, creating a fuzzy light orange stain, offsetted onto f104r, and even went through again to f104v.  But, being oily, it did not soften the water-based text ink.

All the best, --stolfi