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LaminationA process of reinforcing fragile sheet material, usually
using transparent or translucent sheets of plastic or paper. Some forms
of lamination such as those using cellulose acetate are considered unacceptable
as preservation methods because of high heat and pressure during application,
instability of lamination materials or difficulty in removing lamination
from the item, especially a long time after the lamination was performed.
Lamination should never be used on items of long term value. Commercial
laminating films are only suitable for material of short term or ephemeral
value.
LightA very small portion of the electromagnetic spectrum of radiation,
covering the wavelengths from approximately 400 - 700 nanometres (nm)
for visible light, and 300-400 nm for ultraviolet
light. The energy of
light radiation can damage collection materials by causing photochemical
damage. The amount of damage is proportional both to the intensity and
the duration of exposure to light.
LigninA component of the cell walls of plants. Lignin is largely responsible
for the strength and rigidity of plants, but its excessive presence in
paper and board is believed to contribute to chemical degradation. There
can be large amounts of lignin present in pulp made from wood: it is
not removed in the production of mechanical pulp, but it can be removed
almost completely in chemical papermaking processes to produce ‘archival’ quality
paper.
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