One universally accepted thing to avoid is permanently adhering a poster to its backing. From the 1960s – 1980s it was popular to have posters dry mounted to a board so that they would lie flat in their frames. This process is (almost) irreversible and posters that have been dry mounted are considered by the vast majority of collectors to be both compromised and diminished in value.
Most of the posters I sell here on my website are archival linen backed. Why do I do this?
Linen backing is the best way to preserve and stabilize your poster and provides a canvas for further restorative work.
Linen backing a poster on canvas requires three elements. Linen, acid-free lining paper and a Wheat starch solution containing an alkali buffer which when all combined together produces a stable - but reversible - acid free environment for mounting a poster.