acid migration

(also called acid transfer), n. The movement of acid from an acidic material to material of lesser or no acidity, either from direct contact or through exposure to acidic vapors in the surrounding environment.


Roberts and Etherington 1982 [Acid migration] may occur either when the two materials are in contact with each other, or by vapor transfer from one material to nearby materials not actually in contact with it. Boards, endpapers, and protective tissues, as well as the paper covers of books and pamphlets, may contain acid and transfer it to otherwise low-acid or acid-free paper of the text.