<<Does anyone know of a source for this paper? Has anyone used vellum
as a substrate for pt/pd printing?>>
Tom,
The paper you are referring to is Wyndstone Vellum (also known as
Wyndstone Parchment). I've done some pt/pd printing with this paper
with mixed results. It has a tendency to show some subtle mottling
in areas of broad even tones, especially in the middle and higher
tones. I do alot of photographing in fog and this subtle mottling
has been problematic with those prints. For prints with alot of
texture and detail, this paper works very well. It is also pretty
cheap at about $3.00 for a 25"x38" sheet.
I get my paper from Amsterdam Arts in Berkeley, California. They do
sell by mail order. Their phone number is 800-994-2787. They also
usually carry Arches Platine in stock for anyone looking for a source
of that paper.
Kerik Kouklis