Re: gum question
Preshrinking works for some paper and destroys the sizing in others.
It appears that the length of time may be more important than
temperature: less than 1/2 hour may not be long enough for the paper
fibers to get thoroughly wet. I try to use hot water for at least one
hour.
Some papers can' be presoaked at all, hot or cold. An earlier run of
the Cranes Parchment that worked with platinum perfectly with no pre-
treatment would become unusable after a soak in 1% oxalic acid. I
found that out the hard way. It soaked up the emulsion like toilet
paper!
Another variable to contend with.
Sam
On Jun 9, 2008, at 5:04 PM, henk thijs wrote:
Hi Judy,
Preshrinking in 'not-hot-water' reminds of the discussion some time
ago about the large gumprints made by Jean Janssis, belgian gum
printer ( he can be found in musea all over the world); when i asked
him about preshrink , he said he did not sized after two times of
preshrinking in -cold- water , and he did not have any registering
problems he said.
Any luck on the list with this method?; it did not work for me.
Henk
On 9 jun 2008, at 4:24, Judy Seigel wrote:
On Sun, 8 Jun 2008, Diana Bloomfield wrote:
... though I did shrink and size the paper for that particular
zone plate, I had done some others where I hadn't done any pre-
shrinking, and I didn't seem to have trouble re-registering the
negative. I guess that's only because the images were so blurry
and indistinct, anyway, that the edges weren't clearly defined
from the get-go.
It occurs to me to wonder if .... since you're dancing around
minimum pre-shrink, minimum pre-stress, or "virginity," so to
speak, it might make a difference if the pre-shrink wasn't HOT. A
while back I tested a looong preshrink in room temp water vs. the
HOT short preshrink that's the norm.
I found that the long room-temp soak gave the same amount of shrink
that the short hot soak did... I don't remember the times, tho I
could probably find them in Post-Factory, but it occurs to me to
wonder if the room temp soak might "raise the nap" or rough up the
paper less than the hot.
Of course you seem to be doing OK the way you're doing it, & no
need to fix it, if it ain't broke, but I mention the thought,
should a snag arise.
J.
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