Originally posted by preservator:
Sheep aren't dried under great tension. When their
skin has been thinned and stretched and is dried
in that circumstance, it is highly reactive to
having moisture added or subtracted. Parchment
and vellum were largely abandoned, when paper reached Europe, but when they were in use, they
were kept in books with stout covers and strong
clasps that kept the skins under pressure. If you
must mat this material, hinging the entire perimeter may help. Strips of Japanese tissue
and be carefully attatched to the margins or
the skin and pulled out and attached to a robust
back mat. The strips can be invisibly pasted to
each other where they meet. You can also over mat
the edges of the skin and keep it in place with
folded paper edge supports.
Hugh