f82r - label x + St Catherine

[Jorge_Stolfi]

The interesting thing is that the back has the wood grain from his table or the cut marks from a saw blade imprinted on it.

To make vellum, the skin was usually split into two layers.  I don't know how that was done, but presumably it required a series of long cuts with a sharp blade, across the whole skin, each a millimeter deep or less.  I would think that those parallel marks that you point out were the traces of these cuts.

All the best, --jorge