What is archival board?
Thereof, does acid free mean archival?
Although most places equate the two terms, "Archival" is equal OR better than "Acid-free" basically 'archival' implies pH neutral (or less) and 'acid free', in addition to whatever other characteristics intended for the long term life of the artwork.
Also Know, is foam board archival?
White surface and core (smooth finish) Artcare from Bainbridge is the only foam board that is archival because of the way the foam is made it neutralizes the off gasses from the foam itself. Archival Foamboard with two sided acid free protection, protects artwork from corroding acids found in regular foam core board.
As it applies to materials and supplies, "archival" means something suitable for long-term contact with important objects, safe and stable to museum or library standards. When artists say "archival", usually they really mean "durable to the standards of permanent art".