potassium permanganate bleach for bw reversal

[narigas2006]

Folks,

would anyone know if potassium permanganate can be used to bleach foma or adox reversal film (like kodak tri-x)?

thanks!

richardson

 

[jochen]

Hello,
yes it can be used for reversing any BW film and such reversal kits are sold but I have read that sometimes this bleach is not as reliable as the old formulation with potassiumdichromate (K2Cr2O7) and sulfuric acid. Because chromium(VI) compound are toxic and carcinogenic their sale to private customers is forbidden here in Germany.

 

[thefizz]

From the research I have done, dichromate bleach seems to be the preferred bleach for reversal processing.

Moersch-Photochemie sell a dichromate bleach: http://www.moersch-photochemie.de/content/shop/sonstiges/134

 

[Rudeofus]

Foma sells a reversal kit to go with their 100R b&W reversal film, and that kit uses a Permanganate bleach. This flickr page indicates that Adox Silvermax can also be processed with Foma kit.

 

[WayneStevenson]

I use PP bleach. Works great.

 

[jochen]

Hello,
from the info on the website of Moersch-Photochemie I cannot see that the reversal bleach is dichromate-based. I did not found any MSDS and I cannot imagine that chromium(VI) containing products are allowed to be sold to private customers in the EU.

 

[thefizz]

Hello,
from the info on the website of Moersch-Photochemie I cannot see that the reversal bleach is dichromate-based. I did not found any MSDS and I cannot imagine that chromium(VI) containing products are allowed to be sold to private customers in the EU.

I emailed Wolfgang and he confirmed it is a Dichromate bleach.

 

[phildil]

Bit late but this might help you...

I do BW reversal processing at home, and yes, you can use Pot Permanaganate mixed with dilute sulphuric acid (or sodium bisulphate solution - almost the same thing) for the bleach step. The other and better formula is based on Pot Dichromate because the big drawback with pot perm is that it will soften the emulsion on your film so timing of the bleach bath can be critical. Too long, and your emulsion can just wash off ! Pot dichromate does not have this effect however it can be hard to find in some areas and is mildly carcinogenic so should be disposed of properly.

All of these chemicals are easy to get here in the UK.

hth
phil

 

[pdelrosario]

I am 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.