From: Christina Z. Anderson (zphoto@montana.net)
Date: 06/28/03-02:09:39 PM Z
Hi All,
I've been working with the lemon juice thing and step tablets. My
reasons for testing this in the first place is to see if added acid could in
fact be a tool for the gum printer for whatever reason, basically the
original reason being a hardening of the gum without exposure, thus lending
stability to the midtones.
My results, which I tested again to see if I could repeat them, and
they did, were the following:
Short form: lemon juice slows the speed of exposure, lessens contrast,
and contributes to pigment stain but lessens temporary dichromate stain.
Long form:
1) The dichromate stain mostly clears out of the lemon juice strips
during development, not so with the water control group--no biggie, though,
since it'll come out anyway with the pot metabi soak.
2) The more lemon juice I added (I added, to 1/2 tsp or 40 drops of
combined am di/gum pigment, first 5 drops, then 10, then 20; a ratio of 1/9,
1/5, and 1/3; then I did a control group with water in same proportions) the
more staining occurred in the highlights. This was NOT true of the water
control group. The added water, in these limited amounts anyway, did not
contribute to stain as far as I can tell. Lemon juice did.
3) The added liquid on both did, justifiably, slow down exposure.
4) The water exposed more steps, more definable, sharp steps and this
means that the water control group was faster exposing and more contrasty.
Even the numbers on the test strips were nice and sharp on all water samples
and soft on all lemon juice samples (about 32 total samples). Thus lemon
juice slows down the speed of the dichromate and softens contrast.
BTW, I kept EVERYTHING exactly the same, even exposing the test strips
all at the exact time and in the same frame, same paper, same dichromate,
and because the results were repeated several days later, I think they are
as reliable as one can get with this very inexact scientific process (e.g.
Minnesota well water, the given humidity, yada yada yada). I did also expose
2 real prints, one with lemon, one without, and the lemon juiced print was
too low contrast for my liking. OH, and I did do those two prints after
letting the paper sit for 3 or 4 days, and they exposed/worked just fine,
even in humid conditions.
I even was able, with the added acids, on the first test anyway, to get
the proverbial darker highlights to lighter midtones that Judy reported a
while back (in other words, staining in the highest highlights so they
became darker); this followed greater steps of staining with greater lemon
juice added. I have not run this particular test again and verified it so
it could be a fluke, but it is worth a test, if anyone has a leftover lemon
lying around from their gin and tonics.
So I guess I am puzzled at Demachy's thinking this would use this to
"add more stability to the midtones" when, in fact, I myself can't really
distinguish my results from lowered contrast and stain--both not good
things. Am I missing something? Or perhaps I just need to see it work
wonders on that bullet proof high contrast neg.
Thanks to Jack, Keith, and Katharine, I didn't even have to do this all
in a dark room under buglight!
OH, I also went and researched at the rare book library again; got
about 250pp of material, and do you know that from 1926 (!) they were
advocating use of the hair drier to dry layers for exposure???
Chris
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