Re: Bleach-development with gum

[Loris Medici <mail@loris.medici.name>]

Katharine,

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  
I guess...

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.

Regards,
Loris.

Quoting Katharine Thayer <kthayer@pacifier.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.
>
> http://www.pacifier.com/~kthayer/html/Bleachdev.html
>
>
>
> 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)
> > Marek
> >
> > > Date: Tue, 27 Nov 2007 07:58:31 -0700
> > > From: zphoto@montana.net
> > > Subject: Re: The Fresson/Arvel Process
> > > To: alt-photo-process-l@usask.ca
> > >
> > > 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
> > > heck:
> > >
> > > "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
> > talking, carbon
> > > 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,
> > but back
> > > 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"
> > came into
> > > 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".
> > > Chris
> > >
> > >
> > > ----- Original Message -----
> > > From: "Dave Soemarko" <fotodave@dsoemarko.us>
> > > To: <alt-photo-process-l@usask.ca>
> > > 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
> > relevant
> > > > published information. >>
> > > >
> > > > John and Chris,
> > > >
> > > > Both of you are very nice!
> > > >
> > > >
> > > > Dave
> > > >
> > > >
> > Connect and share in new ways with Windows Live. Connect now!