If your bookshelf is overflowing, and it’s time to get another one, read this first. Did you know that your bookcase could be emitting acidic gases that damage your books? This post is likely a little intense for the average person who just wants to put their books somewhere off the floor. But if you have some precious old books, or if you want to take your love for books to the next level, you might find this information helpful.
Fresh wood and wood-like substances (plywood, particle board, some laminates) that contain formaldehyde should be avoided due to the acids they emit. Formaldehyde emits formic acid, which can lead to fading pigments and weakened paper. Paper that is stored near something that contains formaldehyde can then absorb the acid it emits, and we all know what happens with acidic paper: it becomes weak and brittle (see picture below).
The paper in the images shown here has acid in it. The yellow colour and brittleness was not caused purely from being on a wood shelf. But the acids from unsealed storage can exacerbate problems in paper that is already acidic, and it can accelerate deterioration. If you have an old wooden bookcase, then the off-gassing has already occurred and it is okay for your books to be stored there. Just remember to keep the collection well ventilated. If your wooden bookcase is not old, however, you can seal the wood so it will not emit any gases. DO NOT use oil-based anything, as the oil will emit corrosive gases. But latex paint, or air-drying enamels are okay.
More information on the subject can be found in the Northeast Document Conservation Center’s pamphlet on Storage and Handling.