Re: Bleach-development with gum
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- Subject: Re: Bleach-development with gum
- From: Loris Medici <firstname.lastname@example.org>
- Date: Sat, 01 Dec 2007 19:02:03 +0200
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I got much better results - but there's still plenty of room for
improvement methinks, will share them soon...
But, the bleach I use is 55% sodium hypochlorite, not 5% as yours
(many sodium hypochlorite based bleach brands in Turkey are 55%).
For bleach development, I use 2x the amount of pigment I would
normally use, I cut the dichromate to 1/2x (5%), and exposure is
around 3x (or 4x if I find the coating is on the thick side).
I use 20ml of 55% bleach per liter of water. I first rinse the print
to get rid of the dichromate then put into bleach for 1 minute (face
down), then I put into development water for 10 minutes, then I
evaluate the print and put into bleach for another minute - if it acts
in a lazy manner - and continue to develop in water.
Actually I did a wonderful print yesterday but ruined it later because
I was a little bit impatient and pulled it early in development (I
should give it 5-10 minutes more) and when I left it for drying (flat)
I got serious stain (in form of bleeding).
I get best results on unsized paper. I get flaking with sized paper -
I don't know why!? I never managed to make an acceptable print on
sized paper (both 3% and 6%, hardened with formalin) - kind of a curse
Anyway, even if the results are very good considering they're one-coat
gums, their Dmax is still less than what I get from properly done
3-coats... Will try harder.
Quoting Katharine Thayer <email@example.com>:
This isn't working very well for me; I don't know why. I've posted
a couple examples from an afternoon's efforts.
The main dilemma seems to be that if I leave the print in the bleach
for longer periods of time (10-15 minutes) I get blotching and
mottling of the image, (both with highly pigmented and normally
pigmented mixes of lamp black) but if I soak it in the bleach for
shorter periods of time (1-5 minutes) then development is too slow for
my patience. Perhaps I've overexposed too much at 3x normal, but I
wouldn't have thought so. The bleach I'm using is Western Family
brand; ingredients are listed only as Sodium hypochlorite 6%, "Other
ingredients" 94%. I've used it diluted at 15ml/liter of water. Gum
coating mix is, as always, 1 unit gum/pigment: 1 unit saturated
ammonium dichromate. Arches bright white paper, sized with
gelatin/glyoxal. I've included a normal print, for comparison.
On Nov 27, 2007, at 1:52 PM, Marek Matusz wrote:
Very interesting thread. I was in the Big Bend NP hiking and taking
pictures, happy without a computer or cel phone for a few days. I
only got to read some of the emails now.
Here is my comment from the practical standpoint of a gum printer.
My one coat gum prints have eveloved to a practice that gives
maximum darks and long (relative) tonal range of the final print
(not to be confused with long negative density range). Some of my
prints were included in the travelling portfolio last time around.
Here is a description of my pratice.
Coat the paper with gelatine / harden it.
FOr the gum layer I prefer highly pigmented carbon black.
Use longer exposure (3 to 5 times normal exposures). I really have
not tried to push it even further.
Soak in water to remove dichromate.
Develop in a weak chlorox solution. My dilution is about 20
cc/liter of water. Could be as little as 10cc if I want slow action
or as much as 40 to 50. Once the print starts bleeding the pigment
I place it in water and watch for a few minutes following the
development. If the development is slow, dip back in chlorox for a
few minutes. The reason for moving it back and forth is that the
action of chlorox continues for a few minutes and it is easy to
just wash the gum layer completely.
Actually I use this method a lot for my tricolor gum prints as well.
How close is that to direct carbon? I call it gum, but it has all
the ingredients mentioned in this discussion, geletine, gum,
chlorox (or Javelle water version)
Date: Tue, 27 Nov 2007 07:58:31 -0700
Subject: Re: The Fresson/Arvel Process
Thank you, Dave!
However, the only thing nice and generous about me is my butt after sitting
on it all weekend, 24/7, taking notes out of the 300+ pages I took digipix
of at Geo Eastman House. But it is DONE!!! One further milestone.
Snippet from an 1896 book I told you I'd share about a possible Artigue
formula; they were always trying to guess at it..Since Artigue died with
his secrets and the Fresson family doesn't seem to be willing to share
theirs, it is interesting to look at discoveries before the Artigue paper
that might have been in the air. So this may be worthless but what the
"1863 Mr. Blair of Bridgend took plain paper, coated it with gelatine and
dried; then next coated with albumen mixed with a little syrup, and dried.
Then floated on water and blotted and carbon powdered pigment was brushed
onto the surface in a thin film on top of the albumen. Sensitized by
floating on a solution of pot bi. He did not use gum on top of the gelatin
because it did not take kindly to it and it was more apt to run together
under the operation of the brush and leave small blank spaces, and was also
tackier under moisture, and took up too much pigment." (not a direct quote)
I think that electron microscopy nowadays says that gum IS in Fresson paper
along with gelatin (at least, that is what I read in Chakalis' patent) but
the way this paper is described in the text is even, translucent, and
velvety like the Artigue. It seems that when a lower solution of pot bi
(like 2-5%), warm or hot water development, sawdust, eau de Javelle are
used, gelatin is in the paper. I marvel at their exposing the direct carbon
paper for HOURS in the SUNLIGHT before developing it in Javelle.
BTW, any who may be confused about the differences between carbon printing
and direct carbon (not you Sandy, John, Art) of which we are
printing is the term nowadays used to refer to a transfer process where the
tissue of exposed gelatin is transferred to another piece of paper,
in "the day" the term "carbon printing" referred to the gum process
originally. Then the term was swiped in a drive-by for the carbon transfer
process so towards the end of the century the term "direct carbon"
use for both gum printing and such things as Arvel, Artigue, etc. papers
even if carbon pigment wasn't used. So when researching I always have to
xerox articles that talk about pigment printing, carbon printing, direct
carbon, bi-gum, gum-bichromate (that little hyphen becomes important in
searches), etc. Direct carbon was not transferred to another piece of paper
hence the operative word "direct".
----- Original Message -----
From: "Dave Soemarko" <firstname.lastname@example.org>
Sent: Tuesday, November 27, 2007 6:26 AM
Subject: RE: The Fresson/Arvel Process
> << There are no immediate plans on my agenda to make the process I use
> available on the market. But like yourself I am willing to help others to
> experiment with the Direct Carbon system by pointing them towards
> published information. >>
> John and Chris,
> Both of you are very nice!
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