Acid-Free and Archival Paper

In art, archival papers are essential if we want paper-bound works of art to stand the test of time. In business, archival papers might not seem as important (considering the increasing reliance on digital documents), but they still serve a purpose, especially for legal, historical, or other significant documents.

All types of paper can deteriorate over time. There are two ways to slow or eliminate deterioration. First, the production process must remove those things in the paper stock which cause it to change. Secondly, you must observe purposeful and careful storage and handling methods.

Why does paper deteriorate?

While the process is chemically complex, the simple answer is that paper is wood pulp. Wood pulp naturally contains lignin – an acidic substance that makes up the cellular walls in wood pulp. It’s this element that is the main culprit in paper deterioration. That deterioration accelerates through the lignin’s exposure to sunlight, water, or the passage of time.

You’ve probably seen a yellowed, brittle newspaper left outside. Even if it was just new last month, the combination of excessive lignin found in newsprint and the exposure to the elements means the deterioration process was extreme. It has been yellowed, stained, and might even begin to crumble.

Wood pulp can be chemically treated during the paper-making process to remove some, or all, of the lignin, thereby lowering the amount of acid in the paper stock.

It’s worth noting that even high-quality papers with low levels of lignin can suffer when they are not stored correctly for long periods. Semi-archival documents stored in folders made of cheap paper, or even in untreated wooden drawers or cabinets, will deteriorate faster than they usually would just by being in contact with those other, high-lignin content surfaces.

Acid-Free and Archival Papers

The paper’s natural acidity is measured by the alkaline, or pH, levels. The newsprint mentioned above, for example, has a very high pH level. In the 1930s, scientists discovered the connection between the alkaline levels in paper and their archival properties. By the 1950s, printers took steps to remove the acid from paper stock used for archival purposes.

While there are various standards for “acid-free” paper, high-quality papers have either had all the lignin removed through chemical processes or have exceptionally low pH levels that are considered acid-free.

The term “archival” is universal and can be used somewhat freely by paper manufacturers. However, in most cases, “archival” papers are deemed stable because they are usually acid-free, contain no unbleached pulp, and are free from the optical brighteners sometimes used to whiten the paper stock. While those kinds of papers last a long time without any deterioration, a cotton rag is used instead of wood pulp to manufacture truly archival paper. Therefore, it naturally has very little, if any, acidity.

The types of paper available to you for business purposes are wide-ranging. If you are concerned about the durability and stability of the paper, read the packaging. Begin by seeking out acid-free paper stock. Many high-quality papers might also use a combination of cotton rag and wood pulp. The balance between the two will give you a good idea of how you can expect it to age.

Return to the Tech Trends Newsletter