The transfer of acid from a material containing
acid to one containing less or no acid. This 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.
Also called "acid transfer." See also: BARRIER SHEET .