From: Richard Sullivan (richsul@earthlink.net)
Date: 08/02/03-09:08:11 AM Z
I had heard that Houston was bad but I've never encountered the dreaded
dark effect in gum printing, but then I've on only printed gum in SoCal and
Santa Fe. I have seen it in carbon however.
Stuart seems to have vanished but maybe you can confirm this as you've
worked with Stu and Kerick on this project: It is my understanding that all
of this staining mumbo jumbo is simply related to paper sizing. At APIS
Stuart said that you could make anything >>not<< work and went on to say
that he and Kerik had made every pigment they had tried work, and by
working he was referring to not having any stain. Stuart came by the lab
numerous times and discussed his progress and I recall that he eventually
found out that staining was all due to poor sizing.
I found his "not work" statement very cogent. I have done lots of research
into alt processes and when I find a reference that says something doesn't
work, I see a red flag. Many times it does work, just not the way the
author tried it.
Then again not getting any stain may also be due to combination of factors
in how Stuart makes his prints. I can see how the roller method may
actually preserve the sizing by not dragging up paper fibers etc that a
brush might do. In this case it is the size and the roller combo that does
the trick. All in all Stuart's method is quite simple. One need not overly
complicate the gum process and get all tangled up in the issue of pigment
staining.
As you have seen yourself he has perfectly clear skies in his prints and so
does Kerik.
I too have my treasured copy of Kosar and have noted the section that talks
about incompatible pigments with chromium. The main one was is ultramarine.
Despite Kosars references I did not see any degradation of ultramarine with
chromium in carbon printing. It is quite transparent compared to thalo and
uses up a ton of pigment, an issue when you are coating 75 sq feet at a time.
Many of the references in Kosar are a bit suspect in my mind. Not unusual
for a compendium work of this nature. Kosar is regurgitating tons of info
and obviously has not tested everything himself. All in all it is an
excellent source book even if the colloid chromium chapters is a bit thin.
--Dick
At 09:53 AM 8/2/2003 -0500, you wrote:
>I know when I was printing gum in my old space here in the murderous
>Houston summer heat and humidity that I had very little window between the
>time the gum coat was dry enough to print and when the dreaded dark effect
>began to kick in. Fogging was common, and I sometimes had to let prints
>develop overnight to clear the gum from the highlights to my
>satisfaction. My old darkroom had a separate paper drying area that was
>not climate controlled - it was in my garage. I pretty much got away from
>doing any gum between June and September because of the difficulties. Now
>that my new darkroom is complete and the whole shebang is climate
>controlled, I can print gum year-round.
>
>Clay
>
>
>>8. Paper will keep, coated, for even 70 days in the ice box, or 3 days at
>>room temp. If paper is dried at room temp high enough to dehydrate coating,
>>dark reaction does not occur and consequently shelf life is very good.
>>(Katharine, with the relative humidity in Montana being so low, this is why
>>I could use sensitized paper for so long without dark reaction ruining it
>>there. Here in MN where it is dripping, this is not the case).
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