As an additional point of data, many older inks especially black were carbon in a carrier of something like linseed oil which would eventually "dry". Some actually dried and hardened, others only dried a bit.
This pic shows two card proofs of stamps printed sometime in the 1890's (There were 5 printings over several years and they're really hard to tell apart) I bought them on Ebay maybe 4 years ago from a seller in the UK. Neither had a transfer. They were both put in the same small envelope inside the package and the transfer happened while they were in the mail.
While it's intaglio ink rather than lithographic ink, the formulations for black were usually similar. And the ink hasn't actually totally dried in over a century.
Steve B
