What printing process is this?

Back in the 1970s my father self-published a newsletter, and I’m trying to figure out what the printing process was that he used.

He laid everything out by hand (of course) and then there was a step that looks like a photographic negative and another step (not sure which came first) on a metallic sheet with maroon-colored text.

What process was he using?

Answer

You’re describing offset lithography. The maroon (and silver) metal plate was the actual printing plate made by a photomechanical process in a process camera then in a contact printing frame 1:1.

In the printing press, the plate is wet with a “fountain” solution. The silver part (zinc-coated aluminum foil) remains wet. The pink parts are water-resistant so the water won’t stick but the ink does. (Oil and water don’t mix.) Then, the inked plate is pushed against a soft rubber (blanket) roller. The ink is transferred to the rubber which is in turn pushed against the paper.

The ink image (which is fragile) is “offset” onto the “impression” roller (blanket) which contacts the paper. This is done to avoid the abrasive effects of rubbing rough paper surface (thousands of times) against a thin foil ink-carrying printing plate.

Attribution
Source : Link , Question Author : Betty Crokker , Answer Author : Rafael

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