I've always wondered: is there a term for the process that brought those hand drawings into a printable form like that which then enabled it to be mass produced? I understand how it can be done with computers and scanners, but I've struggled finding what tech/process was used back in the day.
Lithography, usually - still widely in use today. Drawings were made or transferred to an etchable surface (initially limestone, then metal) using an etch-resistant substance. Then etching agent (acid, usually) was applied to the surface. Everything was washed and voila, a plate was produced which had a positive image which could be inked and pressed just like letters. By 1938, offset printing might have been employed, which is basically the same thing but with a rubber drum as an intermediary between the plate and the paper.
Lithography is the general term. There are numerous methods depending on the desired result, for instance using an offset can produce full colors pressing one at a time.
https://gallery.lib.umn.edu/exhibits/show/pre-separated-art/...