RE: Photogravure question

RE:polymer vs copper

If you use a stochastic screen (or other screen) for a pre-exposure,
the resulting edges within the recessed plate area (pits) are very
similar. The first exposure gives a "texture" very similar to the
asphaltum (ground) and the second exposure to the positive
photographic image similar to the image derived from the tissue. While
there are obvious differences in the processes (the means), the
resulting image (the ends) would be largely indecernible to even a
trained observer without the original plate.(IMHO)

Will historians and the museums of the future make much of a
distinction or be able to tell the differences? Look at the Kallitype
vs platinum debate (I'd say conundrum) exposed at the last APIS.

Wasn't the original question about repeatability? I'd have to say that
results I've seen show a simpler process like photo-polymer would be
more repeatable. That's not the question though.

for a quicky explanation of the process (using Edward Curtis' images)
go to:
http://curtis-collection.com/process.html

-here the author claims the differences is lines not dots

on another site:
http://silverandink.com/DB/process.html

I found this interesting "Contemporary photogravurists sometimes
employ a mezzotint or stochastic screen in place of asphaltum to
produce the pattern of fine mordant-resistant dots… which functions
identically to the hardened dots of asphaltum."

It seems there is a little difference in the image structure, but the
results (again) would be very fifficult to see.

Darryl