museum collotype

well, its a rather old technique that gets revived in fine arts every so often. It doesnt use dots and halftone screens like offset or other mchanical lithos.
Its a tedious process ans you usually dont score a lot of prints in a set.
In all cases much of what efines the value (besides the recognition of the artist an their subject. The artist's signature "Not in the stone" will giv the max value (Assuming the print isnt all hogged up or foxy and faded. Collotypes can fase over the yers but so do most all prints other than silk screen or cuts.

Alfred Stieglitz used to run his multi print photos as collographic prints.

You said its a "poster" Why did you call it a poster??

Itd be nice if you post the work so we can see it