This .001 thick (16 gm2) acid-free tissue paper has a 3% calcium carbonate buffer added. Buffering agent will help prevent acid migration to the tissue itself and is perfect for storing photographs and clothing sensitive to a higher pH level. Just layer between your photos or digital images to protect them from acid migration and abrasion. Made from acid-free, buffered tissue with a smooth surface for superior protection. 100 sheets per package. 741-1015BF