is a technique developed by the Library of Congress for the
long-term preservation of rare and valuable sheet documents.
is done in two steps.
the item is chemically stablized and deacidified, and then
it is sealed in an acid-free polyester enclosure.
polyester (Mylar) capsule is a tough, clear and attractive
material that can withstand routine handling and moving for
seal keeps the item dry and free of contaminants, while the
transparent polyester allows the paper to be viewed from both
polyester capsule itself is not attached to the paper in any
way, and thus the poster can always be safely removed. The
only loss in the event of removal would be breakage of the
seal, but the unsealed capsule could still be reused as a
like sticking your poster in a clear envelope and it can still