Abstract: In a combined system or method for extending the life expectancy of an article of cellulosic material such as a book or other paper, the book or other paper is put in preservation storage at subnormal temperature and subnormal humidity. The resulting loss of flexibility of the paper is remedied upon withdrawal of the book or other paper from storage through its accelerated simultaneous exposure to a partial vacuum of about 5 to 50 torr and to water vapor; a partial vacuum of about 12 to about 30 torr is preferred. This procedure restores both the temperature and moisture content of the paper to normal values.

Abstract: Books and other documents that are produced wholly or partly on paper of wood pulp origin are preserved by storing in an enclosed space containing a controlled atmosphere including about 0.05 to 10 ppm ammonia gas. This invention and all United States patent rights thereunder are assigned to the Government of the United States as represented by the Librarian of Congress. The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon.