Photo purchased from … www.depositphotos.com
Back in the 1990s when I was an art director, I actually sent our
print books to press as pasted-up “mechanicals.” From these, the printers would make negatives and from these blueline proofs. Finally they would “burn” plates from the same negatives used for the bluelines. Late in the ‘90s I had switched to submitting artwork as digital files rather than as mechanicals, and the printers had begun to expose and process custom printing plates without the interim step of creating negatives.