Acid free. Lignin free. Do you ever wonder what that means? I do.
Maybe I’m just a paper dork. Anyway, I’ve been studying paper in my spare time! We all know we should be using acid free paper in scrapbooks. What does that really mean and where does this acid come from?
Paper can be made from many things. Cotton, linen, grass, straw, wood – lots of things. Currency is very often made from cotton because it’s more durable.
In the 19th century, machines were invented to make wood pulp paper. Mass producing wood pulp paper made paper much cheaper. Previously paper was made by hand. Most paper we use today is wood pulp.
What is lignin, exactly? Lignin is a chemical compound in wood that binds wood fibers together. Lignin can be removed during the paper making process, but mechanical wood pulp production usually leaves lignin in because it is cheaper. High lignin papers turn yellow over time – think about mass market paperback books.
How does acid get into paper? Mass produced wood pulp paper is bleached to make it white. Acid residue is left in paper as a result of this process. Acid residue causes brittleness.
So what is acid/lignin-free paper? It’s not exactly acid or lignin “free.” Acid free papers are made in a way that minimizes acid and lignin presence. Sometimes acid free paper can contain an additive that changes the pH of the paper to minimize the effect of acid in the paper.
What about archival paper? Archival paper is not the same as acid free. Archival papers are made differently, are actually lignin free and contain alkalines that counter balance any acids that may still be present.
So there’s your paper lesson! No, don’t freak out and think that the acid free paper you are using is now not good enough! I’ll have some more thoughts very soon on the longevity of paper that you don’t want to miss!