Developing Tri-X reversal issue.....What am I doing wrong?

[Philip Kral]

I'm trying to process tri-x as a reversal for the first time.

 

I decided using a permanganate and Sodium Bisulfate mixture for the bleach instead of sulfuric acid because it's easier to find/ handle. When I test the bleach out by itself with a film already developed the silver is bleached out entirely within a minute.

 

However, when I go to use it after developing it I still see an image where it should be clear. I tried 2 different developers and get the same result. It seems that no matter how long I keep it in the bleach (Even a fresh batch) the silver doesn't bleach out.

 

I either get a negative still, or worse a black image or blank one!

 

I'm doing quick snippet tests to just see if it's on the right track of working. Doing so I sometimes skip a clearing bath and go straight to washing. Could that be the culprit? It never did when testing things before (But that was negative).

 

Needless to say, I'm lost in the sauce when it comes to reversal.

[Richard Tuohy]

I'm a bit unsure of what you are reporting. Are you going on to second develop the film and are still getting a negative? Or are you saying that after bleaching you can still see black metailic silver in the negative areas of the film? Of course, after bleaching, you can still see images on the film. This is becuase you still have Silver halide there on the film. So it will look different from the result you got when you dunked already processed (ie already fixed) film in the bleach. But maybe you are already aware of that. So, if you are finding that you still have metalic silver on the film after the bleach bath, then there simply isn't enough strength in the bleach bath to do the job. I have never substituted Sodium bisulphate for Sulphuric acid, but I believe it works. However you do need a lot of the bisulphate if I recall the formula. What rate of Sodium bisulphate are you using?

cheers,

richard

[Philip Kral]

Sorry, for some reason I have a hard time figuring how to describe my problem.

 

I guess it's both- I'm getting a negative as an end result and after bleaching I'm still seeing black metalilic silver. (Although, in trying to figure out what the problem was, I tried different things and at least twice ended up with a blank image!)

 

I remember watching someone else do the reversal process and If I recall: after bleaching, the silver halide was there but the black matalic silver was gone- leaving clear sections where the negative was. Your probably right, perhaps I have to raise the bisulphate. I was using 55grams to a liter of water but maybe I should try 100 grams or more?

Thank you for your help/ response.

Phil

[Richard Tuohy]

It must be that the bleach isn't strong enough i am afraid.

I know a recipie for an alternative R9 bleach that involves 65 grams of Sodium bisulfate, but that is a using Potasiium dichromate, not the pemangenate variant. I read just now a post in an email group I am involved in where someone who wanted to replace dichromate with Permangenate in a bleach that uses Sodium bisulfate as the acidifier, and they calculated they would need 275 grams of the bisulfate per litre in that instance.

I suggest you try using Potasium dichromate 10g with Sodium bisulfate 65g. That does work.

[Philip Kral]

I just finished a test using the formula that someone back in March used on this very forum:

 

http://www.cinematography.com/index.php?showtopic=59181&hl=%2Bsodium+%2Bbisulfate

(Maybe I should have checked that first eh?)

 

...and It worked! Now I just have to tweak/ experiment a bit with times or mixture ratios (Such as the 275 grams you advised).

 

Truth be told, I should be using the mixture your recommending. Using Potassium dichromate would definitely be a smaller and simple solution in theory. The problem is both are equally a pain to get in the United States, with Dichromate seeming to be slightly more toxic both for myself in my home lab and for the environment. Sodium Bisulfate on the other hand I can get literally down the road for cheap.

 

I guess for now I'll stick with this, but I'll keep the dichromate in mind when I run out of the permanganate. Thank you for your help.

[Andres Pardo aka Gral Treegan]

I used to use bleach from minilab and then after the 2nd exposure the second developer i use dektol 1/5 and that was the result: