Thanks; to be honest, I never do this and just mix a small batch at a time. I use permanganate for clearing the DAS stain from carbon transfer prints. The 'official' documentation (Charles Berger, Sandy King et al.) suggest to use what is essentially a working stock permanganate bleach and dilute that for this particular purpose. I find this is (1) unnecessary and (2) counterproductive and simply dissolve a small amount of permanganate in plain tap water. I mix about 200ml at a time and this keeps fine for a couple of months (in the dark). I understand Calgon/hexametaphosphate can help even more; I don't have any handy and fortunately, even without this, the permanganate solution as such seems to be sufficiently stable for my needs (I've used it on occasion as a silver halide bleach as well, coincidentally!)
to avoid the formation of the purple/red patina in the emulsion (due to the permanganate reduction)
YesInteresting, and as you said, convenient.
Does a bisulfite afterbath help with this? That's what we use in carbon transfer. Permanganate to reduce the DAS sensitizer which leaves a stain, and the bisulfite to clear the stain and remaining discoloration due to the permanganate.
With a thiourea developer I think you'd quite effectively convert all silver halide into silver sulfide. The slides will come out in shades of brown and yellow, of course. This can be beautiful if that's what you're looking for.
Ive also read that sulfur based toners can be used in the same way as a thiourea developer
there are som more neutral then the thiourea developer
| Working solution: | grams | ||
| 100ml | . | NaOH | Thiourea |
| A | Yellow | 5 | 10 |
| B | . | 7 | 7 |
| C | . | 8 | 5 |
| D | . | 9 | 3 |
| E | Purple-brown | 10 | 1 |
If its too strong it might be a bit much. But if Im honest, the last couple of years Ive been looking for the most convenient way to do BW reversal (which is why I use dichromat and Iron Out). Ive also read that sulfur based toners can be used in the same way as a thiourea developer, and maybe there are som more neutral then the thiourea developer - but can any sulfur based toner be used?
A potent redeveloper is an hydrazine derivative, quite toxic.
Another is tin(II) chloride, the same fogging agent as in E6 line. A recipe of which you can find in the Fomapan 100 R pdf instruction (on the Foma website).
Ive been using tin(II) chloride, but Iron Out is more convenient. And as good with clear based films. Whats this hydrazine derivative stuff? Is it possible to get in solutions that keeps?
Please don't use thiocyanate in the first developer if the subsequent bleach is permanganate.
I would not use hydrazine.
I have - so far - never seen a source for any form of Hydrazine
Last time I was close to any was at a nuclear power plant.
I didn't ask them to give me any; I guess it must have slipped my mind.
Thanks @Alessandro Serrao . The recipe seems to call for fixing, so I see noe reason to use that instead of Iron Out. Some sort of Thiourea redeveloper might be a more convenient option then. Something off the shelf would be good
The PDF document link provided by @Alessandro Serrao marks Hydrazine Sulfate with an (*), and the footnote says, that it is a strong irritant and needs immediate attention. Sodium Hydroxide, Sulfuric Acid, Potassium Dichromate and Glacial Acetic Acid listed in the same batch of formulas bear no such (*) mark. This tells me, that Hydrazine Sulfate is not something you want anywhere near you.
I'd suggest part B of the Foma sepia kit, is based on thiourea.
It works very well, tested.
Thanks. How did you dilute it? And, do you know what its keeping properties are like?
Exactly.
Also the Bellini reversal kit has a redeveloper in it that is based upon boranes, another kind of fogging specimen.
Bellini had problems with their previous redeveloper formulation, that was based on Sn(II)Cl which expired so fast that the redeveloper was useless. They switched to boranes.
The redeveloper working solution is very alkaline, which is not exactly becoming if you want to keep Stannous ions in solution. Not even ATMP will help you at pH 12.
If SnCl is in separate solution, will it have good stability?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?