The Modern Forgery Hypothesis

[Jorge_Stolfi]

For instance, two samples of the Voynich ink contain titanium...

I suppose you mean samples 17 and 20.  But the titanium signal is weak. 

Titanium is a common contaminant of iron minerals.   Its presence in sample 17 does not imply forgery.  The Vinland Map was exposed as forgery because its ink contained not just titanium, but a titanium white -- a specific synthetic mineral of titanium that only became available in the last 200 years or so.

The (weak) signal of titanium on sample 20 is more intriguing, since that sample is from the "iron-free iron-gall ink" of a Latin letter "a" in the washed part of f1r. But that page has gone though so much that this analysis is not very significant.

By the way, the McCrone report is, how shall I say, unsatisfactory in many ways. 

All the best, --stolfi