Acid free paper is paper with a neutral or basic pH level of PH7.0 to PH9.0 This is achieved during the production process.

Paper made from any type of fiber can be acid free.

When still in pulp stage the material is treated with a small trace amount of calcium carbonate or magnesium bicarbonate. This effectively neutralizes the natural acids in the wood pulp. Thus creating what's called acid free paper. This process extends the life of the paper as well as making it more easily recycled. Acid free papers are considered the best when you want to ensure longevity of the paper without yellowing overtime.

Acid-free paper can often be identified by the 'infinity' symbol.