Re: solarized gums?
Ilana, as to the question of whether "flashing" a coated paper pre-
image exposure to give it a little base hardening will help prevent
staining, if you look at the page I gave yesterday showing the (non)-
relationship between stain and exposure, I did a series of tests
where I flashed the paper for various lengths of time; it made no
difference in staining.
http://www.pacifier.com/~kthayer/html/stainexposure.html
Bottom row of test strips.
Hope that's useful,
Katharine
On Feb 14, 2007, at 4:38 AM, ilana swerdlin wrote:
Loris and Katharine,
Thanks! It worked-- gum is becoming incredibly fascinating to me.
Both of
your advice and testing was helpful. Loris, one question when you say
'minimal fog/image'--do you mean to allow the coated paper access
to a small
amount of light before exposing the negative? [or just that the
highlight
should receive a very light, subtle, flat first coat?] And also,
when you
say 'Use a negative density (color) that merely / barely gives you
white on
the print', you mean make my negative overall darker? Or make a
negative--on
the computer--with an ink other than black? Or do you mean print my
highlight with a light pigment?
I think the setup I have wants to have longer exposures. So when I
tried
less pigment/gum after this advice, I needed longer exposure [Also
because I
used an increased amount of dichromate] Anyway, the image was slightly
overexposed but I use the 'water spray' technique to manipulate it,
and I'm
sure with subsequent layers my image will be rich [like I want it to]
Gum is amazing. Thanks for the help.
ilana
-----Original Message-----
From: Loris Medici [mailto:mail@loris.medici.name]
Sent: Tuesday, February 13, 2007 3:22 PM
To: alt-photo-process-l@usask.ca
Subject: Re: solarized gums?
Hi Katharine,
This (as Ilana describes) is no doubt the phenomenon you name "tonal
inversion". I've read the page that you wrote about this issue again
and don't agree with you in:
"...The remedy, of course, the way to eliminate the tonal inversion,
is simply to reduce the pigment/gum ratio..."
Because I've experienced the same effect with a lightly pigmented blue
31-step tablet print before. See:
http://www.loris.medici.name/Gum-Test-01.jpg
The scan doesn't show it well but, to my bare eyes there's definitely
paper white at steps 18, 19 (and maybe 20) + there's definitely tone
(where there shouldn't be) at steps 20+.
I guess we'll agree that the pigment concentration I used on that
print is not excessive since that is easily judged by the scan -> this
is Phtalo Blue; as we all know, this is a dark pigment with immense
covering power...
Regards,
Loris.
--------
Hi Ilana,
My own experience, observations and tests don't support the notion
that failure to clear (aka pigment stain) is a function of
underexposure, so I wouldn't agree with your tentative conclusion that
"parts that should clear are not, because they have not received
enough light." If you're interested, some test strips showing the lack
of relationship I found between stain and exposure are here:
http://www.pacifier.com/~kthayer/html/stainexposure.html
It sounds like what is happening to your highlights, if I understand
the description accurately, is a phenomenon some people call "tonal
inversion." For my take on this phenom, see
http://www.pacifier.com/~kthayer/html/tonalinversion.html
Hope any of that is useful to you,
Katharine
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