From: Christina Z. Anderson (firstname.lastname@example.org)
Date: 06/28/03-08:55:39 PM Z
It supposedly insolubilizes the gum without exposure, but I just don't
know how I could know that for sure--so I think your guess is as good as
mine on all this.
I'm not sure how much to use either....the 1/9th amount didn't do
terribly much, and it may be that the 1/5 to 1/3 amount is the range...when
I came across it in Demachy, he say to "add a few drops" but he never
mentioned how many exactly and to what amount exactly of gum he was adding
it to. I also thought of maybe using glacial acetic--a drop--that'd really
make it acidic...
I've got 250pp of gum stuff to go thru in the next week so I'll see if
I come across anything further about this. I'm glad someone sees a benefit
One thing I did today, too was to do side by side exposures of am, pot
and sod di to see if there was a speed dif. I swear, am di is really fast!
It gives the clearest, sharpest steps of all three dichromates, is the
speediest, and sod is not much different than pot. I did this test with NO
pigment, just side by side straight dichromate. Then I cleared to see what
remained, and the am di was the only one that printed the numbers and the
words and the steps of the tablet. All were used at saturated solution,
too, am di 30%, pot di 10%, and sod di 100% (give or take a few molecules).
I had found out that Ponton when he first discovered the process was NOT
using pigment and gum in it; he was just coating paper to dichromates and
getting an orange/white image. So I got to thinkin'...
I guess I can't seem to duplicate the supposed low contrast in am di,
as I find just the opposite is true, with no pigment, and with pigment.
----- Original Message -----
From: "Keith Gerling" <email@example.com>
Sent: Saturday, June 28, 2003 5:44 PM
Subject: RE: lemon juice and gum printing
> Thanks for this helpful info. I can think of situations where this might
> very useful, like if one were doing multiple coats using one negative and
> contrast differences were needed.
> Any idea where in the process the lemon juice change is invoked? Meaning,
> does the chemical change effect the contrast during the exposure or during
> the development? For instance, if one were to expose a weak-pigmented
> of "juiced" emulsion, then (without development) progressively expose
> additional layers with more pigment and less juice, I wonder what would
> happen? I guess the juice would creep into the next layer... sorry.
> thinking out loud!
> -----Original Message-----
> From: Christina Z. Anderson [mailto:firstname.lastname@example.org]
> Sent: Saturday, June 28, 2003 3:10 PM
> To: email@example.com
> Subject: lemon juice and gum printing
> 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
> fact be a tool for the gum printer for whatever reason, basically the
> original reason being a hardening of the gum without exposure, thus
> 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
> 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,
> 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
> 1/5, and 1/3; then I did a control group with water in same proportions)
> 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
> 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
> 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
> 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
> 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
> 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
> 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???
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