A new documentairy is on the way, about the Linotype machine. Oldfashioned state of the art typesetting. This machine looks amazing!
And after a little more looking around I found this documenairy from the sixties where the whole process is explained in a super clear and nifty way. It's rather long, but if you're interested it's fantastic. The sheer amount of cogwheels, leavers, buttons and parts is dazzling.