New images: Marci letter wax

[ReneZ]

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.

This is a good example of what Tavie pointed out: hashed and rehashed.
For an earlier discussion see (among others) here: You are not allowed to view links. Register or Login to view.
especially posts in the 20's+ range.

Let's stick to the watermark here.
(Had the watermark been from 2 centuries later - or earlier - we would have to have the other discussion).