[alt-photo] Re: Alt-photo-process-list Digest, Vol 591, Issue 1

[Stella Schneider]

Thanks, Marek.
I have painted on Yupo and that's why I am so curious.  Luminosity is great
with watercolor, but the paint slides around and off. A rinse in water
brings the original white back, and so I am wondering if you pre-coat with
anything to hold the color, and how development in water works at all.  I am
eager to experiment!
I appreciate the information.
Stella 
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Message: 22
Date: Tue, 21 Feb 2012 03:09:42 +0000
From: Marek Matusz <marekmatusz at hotmail.com>
To: alt photo <alt-photo-process-list at lists.altphotolist.org>
Subject: [alt-photo] Re: Alt-photo-process-list Yosemite Show and Yupo
Message-ID: <COL116-W64757B411CF0C3122C6C53BB670 at phx.gbl>
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FOr some reason gum layers on Yupo look like pigments out of the tube. Yupo
shows what I would call "true" luminosity of pigments. Printed on paper they
always come somewhat dull. Another aspect could be due to the photography
itself. All the gum printers always complain that gum prints on paper do not
photograhs or scan as bright as originals. Yupo seems to bring more
luminosity to the photographs (this could be also how my camera was set at
the time).There are challenges as well. Yupo is slick and gum laeyrs have to
be very thin in order to fomr a good image. I have may pieces that have part
of the image just wash off, just slide.Another  aspect of achieving
luminosity is to have original images that would show that (photshop
adjustments). Luminous and saturated colours are build from the mix of TWO
primary colours. The third colour always dulls the mixtuture. Having any
residual "vail of the third colour" will result in lower chroma. Clearing
the highlights is essential. O
 f course the most transparent pigments are a must.  My primary pigments are
Daniel SMith Quinacridone Rose, PV19. Thalo blue and Nickel Azo yellow
(Py150). The yellow is twice as strong as the other two, so dilute it
accordingly.  For consistency of my tricolour gums I use stock pigment
solutions, they keep indefinitely.As I noticed the gum layer have to be very
thin. Diluting with water works great for Yupo as it does not soak anything
and it is easy to adjust final gum thickness by adiing water. Foam roller
does wonders for smoothing the gum layer. My exposure are short as well.
Under a bank of BL tubes they are typically 30-60 seconds. My paper printing
would be 60-90 seconds for similar paper printing. How is that for a start
Marek   > From: stellaps at cableone.net
> To: alt-photo-process-list at lists.altphotolist.org
> Date: Mon, 20 Feb 2012 16:48:55 -0700
> Subject: [alt-photo] Re: Alt-photo-process-list Yosemite Show and Yupo
> 
> Marek,
> Your photos are marvelous, and I would love to know more about printing
gum
> on Yupo.  Would you tell us more?
> Thanks,
> Stella
>