How do you know which materials are OK to use in your album? Learn some archival terminology:

• acid-free: Having a pH of 7.0 or higher, indicating the absence of acid. It's important to use acid-free materials since acid breaks down paper and photos.

• acid migration: Transfer of acid from an acidic material (such as newspaper) to a less acidic material (such as a photo) from physical contact.

• archival-quality: A material that's permanent, durable or chemically stable that can safely be used for preservation.

• buffered paper: An originally pH-neutral paper that's been made more alkaline to neutralize acids that may migrate to the paper.

• lignin: Substance present in plants and many types of paper that contributes to deterioration. Lignin is believed to be more harmful to photos than acid.

• mylar (polyester, polypropylene): The highest-quality material used as a protective, clear covering for photos and album pages.

• photo-safe: Term loosely used by companies to indicate that they believe their products are safe to use with photos. No legally enforceable standard prevents companies from using the term on products that aren't actually safe, such as magnetic albums.

• polyvinyl chloride (PVC): Material found in some plastics and adhesives that can break down to form acid.