> The physical mark of the writing implement on the page - ie, a pen leaving
> its furrow. IIRC, these indentations are normally photographed by lighting
> the page very nearly parallel to its plane. :-)
This isn't usually visible on vellum. Consider that the pen would
likely have been a goose or similar quill, or less likely a reed pen.
Vellum presents a very sturdy surface, so usually any indentations
found on vellum are from a scoring knife used to mark up lines
(obviously not used on the VMS), not from the pen.