Pinit Conservation-Grade Backings for 20 x 24" Images. .040" thick Alpha Cellulose board. Acid-free, Lignin-free, Buffered. All white. Indefinite Storage. SKU: KAF402024 (0)No Reviews yet Add to Shopping Cart Details Conservation Grade Backing Boards forPrints & Posters 20x 24" .040" thick. All white. Lignin-free. Acid-free. Buffered. Contaminant-free. Meets the ... Details Back DetailsConservation Grade Backing Boards forPrints & Posters 20x 24" .040" thick. All white. Lignin-free. Acid-free. Buffered. Contaminant-free. Meets the Library of Congress archival standards. Indefinite Storage. Reviews 0 Back Ratings & ReviewsNo reviews availableBe the first to Write a Review