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RE: curves for gum printing
As I hit the "Send" on that last message, it occurred to me that I should
have mentioned the fact that it DID take me awhile to tweak the composition
of my gum emulsion. In other words, the contrast adjustment that I use is
perhaps more dependent upon chemical/pigment variables than it is on the
Photoshop Curves. I would think that this would be the case for ANY gum
printer, thus making the sharing of Curve functions a futile endeavor. For
the record, I use Daniel Smith pigments, one part saturated Potassium
Dichromate to one part Daniel Smith Gum.
Keith
-----Original Message-----
From: Keith Gerling [mailto:kgerling@ameritech.net]
Sent: Tuesday, July 11, 2000 6:19 PM
To: alt-photo-process-l@sask.usask.ca
Subject: RE: curves for gum printing
Actually, I haven't had much luck using the curves supplied with Dan's book.
In my experience, the curve used to produce a negative for any kind of alt
process is tied directly to the inks and paper/transparency media used.
Gum is the process with which I have the most familiarity. I have had the
most success using an Epson Photo EX printer, MIS inks (black only),
inexpensive Hewlett Packard paper (that I wax) and NO CURVE WHATSOEVER. But
when I use other materials (better paper or transparency material, for
instance) curve adjustments or some other kind of profiling is necessary, as
different amounts of ink are deposited.
Keith
-----Original Message-----
From: jacques verschuren [mailto:fotjver@wxs.nl]
Sent: Tuesday, July 11, 2000 4:49 PM
To: alt. processes list
Subject: curves for gum printing
Reading (again and again) Dan Burkholder's masterpiece on digital
negatives I have not come across or figured out whether any of the
curves, supplied with the book might be used for digital negatives for
gum printing. If there are no "real" gumprinting curves (or near
equivalents" in the book, are there any members of the list who have
(some) experience with this or who are willing to supply me a curve to
start with.
Don't get me wrong; I don't mind trying/applying several of Dan's
curves, but why invent the wheel again when so many photographers may
have gone through this stage with its pitfalls?
Jacques Verschuren
http://home.planet.nl/~fotjver/