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Permanganate Fans??

pdelrosario

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Seriously - are there any satisfied users of permanganate bleach for BW reversal? Most of the stuff I've read on forums is that they only encounter problems (including myself) when processing using permanganate. Unfortunately, I'm unable to get a hold of dichromate - the favored substance that keeps popping up - so I'd really like to hear of any success stories; particularly for processing Kodak TRI-X 7266 or Foma R100.
 
I can't help you. I have no success stories with anything other than dichromate
 

Look over in the Color Darkroom for a heck of a lot of information on Ferricyanide bleaches. I recently started a thread on it because of my interest in homebrewing as much as I can in color neg processing.

A lot of great information. If you don't find what you want, PM me and I'll try to find the best links.
 
Ferricyanide bleaches are rehalogenating and thus won't work for the standard B&W reversal process as it requires the silver to be removed completely or turned into something that won't redevelop in the second dev.
 
I always had good success with permanganate bleach with ordinary films, but as the OP doesn't mention what problems he is experiencing or the bleach formula he is using, I'm not sure what to offer that might be relevant to his situation.

All I can say is that I followed the Ilford instructions and it worked fine - though with one or two films, I found I got better (less spotty - less emulsion damage?) if I halved the strength of the bleach.

And to remember that permanganate bleaches once mixed for use are "one shot".
 
David Grenet said:
Ferricyanide bleaches are rehalogenating and thus won't work for the standard B&W reversal process as it requires the silver to be removed completely or turned into something that won't redevelop in the second dev.
Click to expand...

Ferricyanide bleaches are only rehalogenating if you add a halide salt. You can use plain Potassium Frricyanide as a reversal bleach.

Ian
 
David Grenet said:
Ferricyanide bleaches are rehalogenating and thus won't work for the standard B&W reversal process as it requires the silver to be removed completely or turned into something that won't redevelop in the second dev.
Click to expand...

I’m wondering if the rehalogenated silver ions are still spectrally sensitized. Perhaps it is possible to fog the positive image with red light without fogging the rehalogenated silver ions.

The permanganate works reliably for me. The trick is to mix acid and permanganate immediately before transferring the film. (when the film is in the stop after development). I just worry about the big amount of permanganate/silver waste.
 
David Grenet said:
Ferricyanide bleaches are rehalogenating and thus won't work for the standard B&W reversal process as it requires the silver to be removed completely or turned into something that won't redevelop in the second dev.
Click to expand...

Shhhhhhhh...............don't tell the E-6 folks!

IIRC, there are extra processing steps to get around that.
 
Reversing E6 and reversing plain black and white are not the same.
In an E6 reversal the bleach is to remove all the developed silver after the second developer
If you do that after the second developer in a black and white reversal ... well, just give it a few moments thought
 

You could Reversal process a B&W film using similar steps to the E6 process and adding Dye couplers to the Colour (2nd) developer then bleach the silver completely and remove it in fixer (or bleach-fix/blix). After all that's the basis of Kodachrome.

Ian
 
But then I suspect that's not quite what was being asked about ...
 
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No problems here with B/W reversal using potassium permanganate bleach as per the Ilford recipe. I don't mix up the full quantities but use a digital (!) balance to mix precisely the weights of chemicals I need with the appropriate volume of water. The process I use is elsewhere on another reversal thread.
Best wishes,
Steve
 
Do not EVER use Ferricyanide bleaches with B&W reversal processes. The reversal B&W bleach functions in a different manner than the color bleach.

PE
 
I give up on permanganate....

I am now in the process of ordering 500 ml of sulfuric acid (10%) and 500 g of potassium dichromate. What would be the recipe to produce 1 liter of bleach for use with Kodak TRI-X 7266 motion film? Any info appreciated.



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Kodak R9 Reversal Bleach

Sodium Dichromate 9.5g
Sulphuric acic (conc) 12ml
Distilled or Deionised Water to 1 litre

Start with 500ml of water add the dichromate and then very slowly add the acid.

As you have 10% Sulphuric acid you need to add 120mm instead.

Ian
 
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Thank you, Ian!


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My advice is that permanganate bleach works if you follow Ilford's formula and directions for the bleach and clearing bath. If you make any alterations then you are asking for trouble.
 
Gerald, do you suggest Ilford's recipe even for the Kodak permanganate (Parts A and B) that I'm using?


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pdelrosario said:
Gerald, do you suggest Ilford's recipe even for the Kodak permanganate (Parts A and B) that I'm using?


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Click to expand...

My advice was mainly to those who like to "tinker" with formulas. Permanganate bleaches are one instance where the manufacturers recipe be followed carefully.

The main problem with permanganate bleaches is the possibility of emulsion softening. Copper bleaches have the same problem.

I don't know which Kodak bleach you are referring to. Kodak uses R-10, a dichromate bleach, for Tri-X reversal.
 
Last edited by a moderator:


This stuff. Permanganate.


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Permanganate


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