The Modern Forgery Hypothesis

[asteckley]

While titanium was certainly uncommon in medieval and early modern pigments, it's not categorically anachronistic. Here's an early 16th-century manuscript from Germany's Upper Rhine region with a carbon-black pigment that contains detectable titanium, attributed to quartz (and its titanium inclusions) being an ingredient: You are not allowed to view links. Register or Login to view.

Notably, the manuscript above uses both iron-gall ink and a carbon-based blackish pigment containing quartz/titanium. As far as I'm aware, nobody is claiming that this manuscript is a modern forgery. 

So as I see it, the presence of titanium in some (2/10) black ink samples within the VMS is not itself a deal-breaker. What would be a deal-breaker would be anatase of the form, crystallinity, and particle size distribution associated with modern titanium white pigments, You are not allowed to view links. Register or Login to view.. And that hasn't been reported for the VMS.

That's a very helpful find. 
(And agreed-- the presence of anatase would blow up all the proposed theories including the current modern forgery one.)
And Sample 17 does show the elements for quartz. Are they in quantities to support a sufficient amount of quartz to account for the Ti? (I have not checked.)