Why does old documents turn brown/rusty and brittle? Is there a way to prevent that?
Paper is bleached to turn it white. yellowing is a chemical reaction with air and residual lignin which darkens it - keep paper out of sunlight will help. Embrittlement I beleive is a problem with acid residues in the paper, and is cured by museum curators by neutralising the acid. However I am too lazy at the moment to google it
You can get acid free paper that will not turn brown. It is more expensive than standard paper. I once had a nice engineering drawing that I wanted to frame. I had a copy made onto acid free paper designed for this sort of purpose. The copy has lasted 12 years now with no sign of change.
Paper made from wood pulp is highly acidic and will yellow over time–newspaper is the most acidic and that’s why you can notice such a marked change in the paper with just a few hours exposure to sunlight. Archives store paper at a temp of around 68 degrees and a humidity level of about 50% (if I’m remembering all this correctly.) Never store your books in an attic (too warm, they’ll become very brittle) or a cellar (cool and damp–you’re books will get moldy)
The Northeast Documents Conservation Center has a variety of leaflets on the subject of preservation and they’re all available online. This one on Storage Methods and Handling Practices is available here: http://www.nedcc.org/plam3/tleaf41.htm
Oh, G. Cornelius’ post reminded me of something. If you buy acid free paper, that only means it’s acid free from the time of purchase. If you store it next to acidic paper, the acid can migrate onto the acid free paper. If you’re really concerned about this, you might want to invest in archival paper which is buffered with calcium carbonate and won’t absorb acid from other papers. This site sells archival supplies to libraries–I’ve ordered stuff for myself from here, too.
GEEK ALERT!! GEEK ALERT!!
[sub]damn, and my FIE plot looks like shit now[/sub]
Not too geeky, it was a drawing of the reconstructed Greek Trireme sent to me by Mr Coats (throughly nice chap). It looks rather smart and, as some would say, very unique.
GREEK ALERT!! GREEK ALERT!!
Until the early 19th Century books were such expensive rarities that they were made using expensive paper with very low acidity. Aninteresting consequence of this is that books which are only fifty years old often have dry, yellow, brittle pages while books which are two hundred years old have pages which are still white and creamy smooth.
That also means that we’re in danger of losing some more recent treasures unless they’re transferred to a more stable medium than the acidic paper that they’re on–and, unfortunately, there just doesn’t seem to be enough funding to allow that to happen.
I’ve heard that you can dilute out most of the acid that causes yellowing by laying the paper in a flat pan and letting it soak overnight in seltzer water. Then remove the wet paper and let it dry. Obviously you’d do this one sheet at a time. I’ve never tried this myself so you should probably test this out before trying it one something valuable.
That’s referred to as the “soda pop treatment” there’s also a recipe that uses Milk of Magnesia to supposedly neutralize the acid. These treatments are not recommended. If you do have a document that you want to have conserved you’d be better off taking with someone at a local archive or even contacting the NEDCC http://www.nedcc.org/.