Health friendly/ier B&W reversal processes?

[Removed Account]

Does anyone know of a B&W reversal process which does not involve the use of potassium dichromate and/or sulfuric acid? I'd like to try this but am leery of chromium salts and battery acid. I was thinking of doing a first developer followed by the potassium ferricyanide bleach I have for sepia toning, then re-exposure, second developer, fix. I'll run some tests tonight just for the heck of it but if you guys can give me a push in the right direction I'd be much obliged.

Just FYI the supplies I have on hand are:

Agfa Rodinal
Ansco 130 (photo formulary blend)
Ilford Multigrade
Ilfotec HC
The ferri bleach from Kodak Sepia II toner
Ilford Rapid Fixer

 

[amuderick]

I've mentioned before that I prefer acute toxicity to chronic/carcinogenic. The sulfuric acid, when created by adding Sodium Bisulfate to water, isn't particularly strong. While watering down battery acid leaves the potential for some nasty burns through carelessness or lack of safety gear, the bisulfate option is pretty trouble-free. And, you can skip the carcinogenic issue with dichromate (not that I'd lose any sleep over it either).

The trick to success is keeping the temperature low during the bleach until you harden the negative. By keeping everything below 64F, I haven't had any problems with the emulsion being so soft as to damage the image. Above 64F, I've noticed things go downhill pretty quickly.

 

[pwitkop]

I think the problem with the ferri bleach is that it's re-halignating (sp?) bleach, meaning it bleaches the developed silver image back to silver halides, so when you re-expose and develop, you expose and develop the silver that formed the original negative as well as the previously unexposed silver making it all black. IIRC what you need for reversal is a bleach that will just remove the metalic silver straight away, not turn it back into halides, i.e. sulfuric acid. That's as I understand it anyway.

Peter

 

[fschifano]

I think the problem with the ferri bleach is that it's re-halignating (sp?) bleach, meaning it bleaches the developed silver image back to silver halides, so when you re-expose and develop, you expose and develop the silver that formed the original negative as well as the previously unexposed silver making it all black. IIRC what you need for reversal is a bleach that will just remove the metalic silver straight away, not turn it back into halides, i.e. sulfuric acid. That's as I understand it anyway.

Peter

That is exactly why pot. ferri. won't work.