U of S | Mailing List Archive | alt-photo-process-l | RE: another 3 layer gum attempt

RE: another 3 layer gum attempt



Paul, see this comparison for RGB versus CMY(K) negatives (no curve applied
to both sets):

http://www.loris.medici.name/gum/RGB_vs_CMY/

To me (with my methods) the CMY negatives are unprintable if you need shadow
detail... (The separations were made with 0% black, so there's not a missing
channel there!)

Probably others have adjusted their workflow to able to print those negs,
mine is definitely not adequate... Any hint would be highly appreciated.

Regards,
Loris.

________________________________

From: Paul Viapiano [mailto:viapiano@pacbell.net] 
Sent: Friday, July 17, 2009 7:52 AM
To: alt-photo-process-l@usask.ca
Subject: Re: another 3 layer gum attempt


As I continue on my journey, I decided to look at some CMY separations
(printed pos, not negative) on the web tonight and in some books I have
(Benson - The Printed Picture). I wanted to see what they looked like in
terms of relative density, etc. It was interesting to note that the Y
separations, looked much denser than the C and M. In fact, large parts of
the shadows look almost blocked on the Y.
 
I was curious because today I printed a first layer Y, using more pigment in
the mixture (1 gram / 9ml gum) rather than my previous (.6 gram / 9ml gum).
The neg remained the same and I cleared for 20 minutes, and it looks much
darker than any other Y layer I've printed thus far, but holding detail
quite well.
 
Tomorrow I'll try to finish it and see what I come up with. I think this is
a move in the right direction.
 
Thanks for letting me collect my thoughts here...
 
Paul