Forgive me if you already have seen this, but it is a really interesting look at the PCB manufacturing process back in the 1960s.....at the Tektronix factory.
http://www.vintagetek.org/tektronix-printed-circuit-boards-1969/
wow what a process. what an art!
i love the fir trees in the growing at the factory grounds. Tektronix are still based in Oregon I believe!
Fascinating!