BW reversal: mix of negatives and positives on same roll
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I don't know what you mean by Iron Out, but if it's a purer form of Sodium dithionite, it's quite unstable at lower pH. Commercial kits use a lot of filler, usually sulfites, but it's not clear what variations there are. Despite the additives, if the pH still drops below a certain limit, the dithionite, while still active, may have started to decompose...
Iron Out: https://summitbrands.com/wp-content/uploads/2018/03/Iron-OUT-Powder-English-GHS-Rev-02-12-2018.pdf
Ive used it many times.
Ive used it many times.
This might be. I refill the battery water bottles with cold water (if that is what its called in english, its distilled water for car batteries), and then mark these bottles so I know its not battery water. If I forgot to mark these bottles there is a chance I took the wrong water. I did mix right before use though.
yes, but maybe it did fail on the original film and succeeded in the second test.
if the bleach worked as intended, there would be no negative image left anywhere since it would have been, uh, bleached out.
exactly.
if the fogging and second developer worked as intended, the area outside of the frames would be fully black.
so as said, it seems to be a combination of at least bleach and fogging/2nd developer.
since at least one of the frames seem to be half positive and half negative, it could also mean that there wasn't enough working solution in the tank.
as said before, I'd toss all solutions, mix new ones, and use re-exposure rather than fogging agents.
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I do not understand how the exact same bleach can fail first, then work.
I have used Iron Out many times without any problems.
Recently I face a similar issue where darker areas of the image, like frame intervals and foliage, show some brightness reversal. Comparing with samples from the same roll that had longer reversal exposure times and didn't have this problem, I think the issue may be within the reversal exposure and second development.
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me neither, but if you get a negative image I can only think of two explanations:
- your 1st developer AND your fogging agent failed (meaning the 2nd dev acts as 1st dev).
- your bleach AND your fogging agent or 2nd developer failed
well, this time there obviously were problems, so what ever worked until now didn't work this time.
the only explanation I can think of for a transparent sprocket area is either the fogging agent or the 2nd dev failed (the blotchiness makes me suspect the fogging agent).
so combine this with the deduction above, you seem to have a combination of problems in at least two solutions. which brings me to the same recommendations that I already gave twice
The idea posted by @Raghu Kuvempunagar about chloride contamination would also make sense. If you still have that batch of bleach you could test for that on a section of film that was fully exposed and developed.
What do I look for in that test to confirm chloride contamination? I dont really understand how contamination could have occurred either as the same batch has worked fine before. I did test a developed film ledger and the film cleared.
Did you try to redevelop it?
No.
You could try that with this bleach. If you get redevelopment, it's rehalogenating.
However, I don't think you'll find that redevelopment does anything. For the chloride hypothesis to work, it would have gone something like this: the bleach got contaminated with chloride for instance because it was poured into a vessel that held significant traces of a solution with chloride ions or some grains of salt. This added just enough chloride to allow partial rehalogenation to take place during the bleaching of your affected film. Since that was partial, the chloride apparently ran out halfway, so virtually none was left in the bleach solution. Hence, you wouldn't easily find it with the redevelopment test - although you might.
In all honesty though, I'm not sure how likely this scenario is.
However, I don't think you'll find that redevelopment does anything. For the chloride hypothesis to work, it would have gone something like this: the bleach got contaminated with chloride for instance because it was poured into a vessel that held significant traces of a solution with chloride ions or some grains of salt. This added just enough chloride to allow partial rehalogenation to take place during the bleaching of your affected film. Since that was partial, the chloride apparently ran out halfway, so virtually none was left in the bleach solution. Hence, you wouldn't easily find it with the redevelopment test - although you might.
In all honesty though, I'm not sure how likely this scenario is.
Honestly the simplest thing would be to just do a test in the same batches of everything and see what happens.
We can only speculate the cause and hope that our musings help OP in some way to fix the problem. Coming to the source of Chloride impurity in the bleach, it could be Bisulphate used commonly to acidify dichromate bleach. If OP has used Sulphuric Acid then obviously this is a moot point.
Fellas,
So, I did two more runs. One more time with Adox MCC 1+2 (I mix it like that as it is mixed 1+4 for paper, and PQ Universal is mixed 1+5 for bw reversal instead of 1+9 as it is for paper - I just assumed then that MCC would be the same strength as PQ). Same weird failed results. Then I tried a run with some old Dektol mixed 1+1 (instead of 1+3 - same mixing logic as with MCC) and got very nice results indeed.
So, it means then that it is the Adox MCC there is something wrong with (for this purpose). I recently printed paper just fine with it, and I tested a filmstrip in it today diluted 1+2 and as far as I can tell it is as active as it should be.
I dont understand why it isn't working - does anyone have some sort of explanation?
Cheers
Peter
So, I did two more runs. One more time with Adox MCC 1+2 (I mix it like that as it is mixed 1+4 for paper, and PQ Universal is mixed 1+5 for bw reversal instead of 1+9 as it is for paper - I just assumed then that MCC would be the same strength as PQ). Same weird failed results. Then I tried a run with some old Dektol mixed 1+1 (instead of 1+3 - same mixing logic as with MCC) and got very nice results indeed.
So, it means then that it is the Adox MCC there is something wrong with (for this purpose). I recently printed paper just fine with it, and I tested a filmstrip in it today diluted 1+2 and as far as I can tell it is as active as it should be.
I dont understand why it isn't working - does anyone have some sort of explanation?
Cheers
Peter
You should check with Adox about the compatibility of this developer with thiocyanate based reversal first development.
The effect you see is a re-revesal caused by permanganate bleach.
Please have a look at this page https://unblinkingeye.com/Articles/PBR/pbr.html
Developers have nothing to do with it.
He's using dichromate bleach.
He specifically tested two developers, one gave problems, the other doesn't. The effect appears to be reproducible.
Then it's the same. A bleach problem. The developers don't have nothing to do with it.
Adox MCC doesn't have anything that could interfere with the bleach action.
Adox MCC doesn't have anything that could interfere with the bleach action.
So why does the bleach work with Dektol then? Ive kept all parameters the same - except the developer.
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