PAPER RESTORATION

PAPER RESTORATION is half art, half chemistry, and there are very few paper conservators (compared to oil painting conservators) because paper is so delicate.
The most common damage to paper is brown spots (foxing) and browned paper that has become brittle. All of this damage is caused either because the art/document was written/printed on acidic paper or because the mat boards, backing boards, etc. that came in contact with the paper contained acid. The value of any print or document is reduced by such damage.
There are two parts of paper restoration: one is removing or neutralizing the acid in the paper; the other is lightening the paper and perhaps foxing, which are purely cosmetic. Both involve using special chemicals, sometimes completely submerging the paper. (Again, this is why there are so few paper conservators.)
Although we can lighten the discoloration with a special bleaching process, this lightens the paper evenly, all over. It may lighten the inks on the paper, too; so usually we do not bleach a piece.
During our recent restoration of a document signed by Abraham Lincoln, we first had to relax the paper, which had been very tightly rolled for many years. This took two weeks of very delicate work, but eventually the paper flattened. We deacidified the document, leaving it a neutral PH.
Folds are actually tears in the paper fibers. We spent a great deal of time mending the tears (some are no longer visible, all are much less obvious), as well as reinforcing the torn and brittle edges all around the paper. The procedure is virtually identical for original art on paper (etchings, lithographs, engravings, serigraphs, woodcuts), except we're much more likely not to bleach the print, as many inks and paints are unstable.
Please don't hesitate to e-mail us with any questions you might have!