Know the Difference Between Acidic and Acid-Free Paper!
People ask me all the time about acidic materials vs. acid free materials. Lots of materials used in bookbinding, art, archives, paper conservation and photography should be acid free to help ensure longevity; these include papers, adhesives, and photo sleeves. Acidity matters in paper because it contributes to yellowing, brittleness and overall deterioration of the paper over time. We’ve all had the experience of seeing old newspaper or book pages that simply fall apart in our hands; that weakness and lack of flexibility is due to the effects of acidity on the internal structure of the paper fibers. Acidity is measured on the pH scale (1-14).
While most art papers and fine writing papers have long been acid free, now even plain old printer paper from chain stores can be acid free. If you want to check on the relative acidity of your paper, you can use one of my favorite gadgets- the pH pen. They are available at good arts stores and online, they look like a regular felt tip pen and they’re super easy to use: just draw a tiny line on your paper and check the resulting color. If the line is lavender or purple the paper is acid free; if the line is yellow or colorless the paper is acidic. Easy!
