U of S | Mailing List Archive | alt-photo-process-l | RE: Bleach-development with gum

RE: Bleach-development with gum



Loris,
I like that portrait a lot. It has this hand made feel that I find so attractive about gum, but has a lot of middle gray gradation that bleach development can accomplish.
Marek

> Date: Wed, 5 Dec 2007 01:09:07 +0200
> From: mail@loris.medici.name
> Subject: Re: Bleach-development with gum
> To: alt-photo-process-l@usask.ca
>
> This is my best so far (after six test prints - including this one):
>
> http://www.loris.medici.name/gum/bleach_2.jpg
>
> I was testing with another negative with plenty detail / texture but then I
> decided to change the negative to make a fair comparison (portraits are
> harder since the tones are much more subtle).
>
> Indeed, there's very very slight blotching / mottling when compared to
> normal prints. In my case, I think this is mostly due uneven coating. When
> the coating is not too thin / thick and even, there's no perceptible
> blotching / mottling. In this sample, the coating wasn't perfect. I did
> another before this one which was better, but I ruined it when I tried to
> coat it with polyurethane; eventually it wasn't dry enough and the brush
> awful marks on the print. (I have to learn to be patient!)
>
> It must be noted that this print is not from a negative calibrated for gum
> specifically. It's from a negative (digital) calibrated for Traditional
> Cyanotype on Masa paper. So, probably there's still plenty of room for
> improvement...
>
> I would like to thank Marek for mentioning this method and providing info
> about his tests / procedure. This is a very nice method for those who want
> to make one-coat gums with a high dynamic range - especially for images with
> plenty detail and texture, less so when you need both high dynamic range and
> subtle tonality - but this is not where gum comes into my mind in the first
> place anyway...
>
> Regards,
> Loris.
>
>
> On 12/1/07 7:27 PM, "Katharine Thayer" <kthayer@pacifier.com> wrote:
>
> > Loris, thanks for the report; I look forward to seeing your better
> > results.
> >
> > I am inclined to think that my poor results may be related to the
> > size/hardener, and possibly partly to the amount of dichromate. I
> > agree with Marek that my first mix (that produced the most mottled
> > print) made too thick a layer because it was so heavily pigmented,
> > but that wasn't true of the less pigmented mix, that also eventually
> > mottled after repeated exposure to the bleach. It's interesting to
> > me that such a strong bleach you're using doesn't just take the image
> > right off the paper.
> >
> > I actually really liked something I was getting yesterday, a very low-
> > key print reminiscent of Bill Jacobson's dark portraits. I pulled it
> > out too soon and it dried down too dark, but I may try that again to
> > see if I can get a similar effect to how it looked when wet. In
> > fact, I guess I could just put it back in the bleach and let it
> > develop farther.
> > kt
> >
> >
> >
> > On Dec 1, 2007, at 9:02 AM, Loris Medici wrote:
> >
> >> 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
>
>



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