Today I was re-reading Updike on the subject of Van Dyck and Elsevier fonts he says:
“In these old fonts, too, there were more unusual and tied letters than are now common.”
This is on page 21 of Printing Types Vol 2, in a reprint from 1962, the 3rd edition.
What do you suppose he means by this? What I think of are a) contextual shapes, and b) Type with two glyphs on it like a linotype logotype. But It may be that there are other possibilities.
Because I have started to see what looks like contextual shapes in a Plantin face I am especially wondering if this is what he means and if there might be some metal evidence at the Museum Plantin-Moretus.
Here is a small sample of the Plantin most kindly photographed and sent to me by Wolfgang Mayer (wmayer at typophile.com)

here is some of the cover page:

