Preservation & Storage

Acid-Free Packaging

Core Term Definition

Archival-grade paper envelopes, cores, and spacers manufactured to be completely free of active acid compounds.

Technical Analysis & Context

Standard cardboard and paper contain lignin, which naturally degrades and releases acids that yellow and damage photographic emulsion. Acid-free materials are processed with a calcium carbonate buffer to neutralize any surrounding acidity, ensuring safe physical contact with historic film stocks.