Acid Free
Acid is used in paper manufacturing to break apart the wood fibers and the lignin which holds them together. If acid remains in the materials used for photo albums, the acid can react chemically with photographs and accelerate their deterioration. Acid-free products have a pH factor of 7.0 or above. It's imperative that all materials (glue, pens, paper, etc.) used in memory albums or scrapbooks be acid-free.

Acid Migration
is the transfer of acidity from one item to another through physical contact or acidic vapors. If a newspaper clipping were put into an album, the area it touched would turn yellow or brown. A de-acidification spray can be used on acidic papers, or they can be color photocopied onto acid-free papers.

Archival Quality
is a term used to indicate materials which have undergone laboratory analysis to determine that their acidic and buffered content is within safe levels.

Buffered Paper
During manufacture a buffering agent such as calcium carbonate or magnesium bicarbonate can be added to paper to neutralize acid contaminants. Such papers have a pH of 8.5.

Lignin
is the bonding material which holds wood fibers together as a tree grows. If lignin remains in the paper product (as with newsprint) it will become yellow and brittle over time. Most paper other than newsprint is lignin-free.

pH factor
refers to the acidity of a paper. The pH scale is the standard for measurement of acidity and alkalinity. It runs from 0 to 14 with each number representing a ten-fold increase; pH neutral is 7. Acid-free products have a pH factor from 7 or above. Special pH tester pens are available to help you determine the acidity or alkalinity of products.

Photo-safe
is a term similar to archival quality but more specific to materials used with photographs. Acid-free is the determining factor for a product to be labeled photo-safe.

Sheet protectors
These are made of plastic to slip over a finished album page. They can be side-loading or top-loading and fit 8 1/2"x11" or 12"x12" pages. It's important that they be acid free and pvc-free. Use those specifically labeled photo-safe or archival quality.