In article <4qc7uu$nt7@tofu.alt.net>, tooms@wave.net says...

>I would appreciate any info regarding very high quality dupes.
>It seems like a specific Kodak duping film (forget ####),is
>very heavily used by most labs. but presume other emulsions
>available as well.
>What are some of the finer points of optimal quality duping in
>re: to minimizing contrast increase (unless desired)
>through dupe film choice? minimizing color shifts? preserving
>image sharpness? others?

This will not answer your question, but in my experience,
dupes can be made by many pro labs that are excellent in
every respect but one: sharpness. The problem appears to
be with the available, necessarily low-contrast, duping
films (I have tried my own dupes, with no improvement in
sharpness when using duping films). The only way to
improve sharpness (which is not terrible - just noticeably
less fine that the original) other than using excessively
contrasty standard transparency films (perhaps slightly
fogged to reduce contrast/brilliance) may be to have
enlarged dupes made (6 x 9, or so....).
Hope This Helps