museum board

Museum board is a type of paperboard. Specifically, it is a white, acid free cardboard that bends fairly easily in one direction but is fairly stiff in the other, due to the grain of the paper fibers.{{cite web | title=Bookbinding/Museum board | website=Wikibooks | url=https://en.wikibooks.org/wiki/Bookbinding/Museum_board | access-date=2019-09-01}}