Help with errors processing Scala B&W reversal film?

[stevegoldenberg]

I processed rolls of Scala B&W reversal film recently and they were all screwed up. See the attached frames, there is a pattern in the same place on the first three images with different splotches that look like bright light points. It also looks more like a negative than a positive in those spots.

• Image one: https://photography.stevegoldenberg.com/Private-Portfolio/Film-Examples/n-7qRKrQ/i-8SCdLD6/A
  
• Image two: https://photography.stevegoldenberg.com/Private-Portfolio/Film-Examples/n-7qRKrQ/i-bwZqHGb/A
• Image three, it almost looks like solarized film in spots: https://photography.stevegoldenberg.com/Private-Portfolio/Film-Examples/n-7qRKrQ/i-ZJLvbct/A

I am trying to track down my problem, if it was film handling (I flew on a couple flights with it and it went through check-in-bag X-rays a couple times), expiration (film expired in March 2019) or if I did something wrong with processing. Or all of the above. I used the Foma B&W reversal kit. Any advice would be awesome.

 

[Agulliver]

Did you put the film in check-in bag rather than hand luggage? The x-ray machines used with the checked luggage is far more intense and damaging than the hand bag scanners. However the spots don't look like X-ray damage which I understand is more likely lines across the film or entire frames fogged. Kodak has a page detailing x-ray damage https://www.kodak.com/global/en/service/tib/tib5201.shtml


Slightly expired film shouldn't be a problem.

I haven't tried the Foma reversal kit so can't comment other than I've read good reviews of it.

 

[koraks]

My guess would be to focus on the bleach and the second exposure steps. Something may have gone wrong in either or both of these steps.

Was the bleach mixed fresh before processing or did it sit around in a mixed state for a longer period of time?
How did you do the second exposure?

 

[Anon Ymous]

I had something like this happen to my first ever try. The problem was that the potassium permanganate for the bleach I used hadn't completely dissolved. The solution is too dark anyway and any crystals will go unnoticed. Being somewhat weak because of the undissolved permanganate, it didn't fully bleach the first negative image, which gives this solarised look. Have a look at the bottom of the bleach bottle, you may spot some crystals, although it will be very hard. Next time, try to filter the bleach with a coffee filter.

 

[Rudeofus]

+1 to Anon Ymous. Potassium Permanganate is very difficult to fully dissolve even in 1 g/l amounts. Whatever you do there will be some undissolved grains which create the exact same patterns that OP posted. And you can't store Potassium Permanganate solution either. Been there, done that, got nasty brown spots all over my B&W slides.

Only way to make a decent Potassium Permanganate bleach is to do it well before you start processing the film, by starting with hot water, stirring and shaking as long as bearable and then filtering out the left over grains. It's a lot more time&effort than expected, but it works.

 

[Agulliver]

Ah yes if you're using permanganate bleach this could be an issue, it doesn't store well (for photographic purposes) and while it dissolves quite readily you can't always see if it has dissolved.
I've used potassium dichromate , which I am fortunate enough to still be able to get hold of.

 

[iandvaag]

potassium permanganate for the bleach I used hadn't completely dissolved

Exactly. I've had this experience as well. Rudeofus' comments above are well worth reading.

 

[AgX]

So much about the specks.

What about the (pseudo-)solarisation?

 

[Anon Ymous]

So much about the specks.

What about the (pseudo-)solarisation?

As I said, insufficient bleaching.

 

[AgX]

But how? I mean in the 3rd sample the solarisation is only partially, located at center.
Even if trying to explain this bya rotanional processing, to loo volume level and partially standstill, there sholud be a more sharp devision between affected and unaffected areas. And the image detaios are similar too (no diffence in density that might be effected diffeentially by too weak solution).

 

[Rudeofus]

Especially in the third image the effect is very pronounced in the sky regions, which were presumably a lot brighter than all foreground matter. This would strongly point at underbleaching.

Here is how I would underbleach and get brown/black spots on my film:

1. Read lots of forum postings describing the most awful emulsion damage caused by Permanganate bleaches. Read pages of recommendations telling one to use at most half the amount of Permanganate and to walk like on egg shells.
2. The label on the Potassium Permanganate container looks scary and frightening, so you get only a tiny amount and want to use it sparingly, lest Seal Team 6 is sent after you.
   
3. Decide to mix as recommended by these forum postings. Since Potassium Permanganate solution is said to have short shelf life, prepare the Permanganate in powder form and plan on mixing it during first development to have it available as fresh as possible.
4. Start film development, find out, that agitation every 15 seconds absolutely does not allow for good mixing of 1 g/l Potassium Permanganate in a liter of water. Shake bleach bottle furiously until no Permanganate grains are visible, which is of course pointless, see posting #4. Also, since Sulfuric Acid sounds scary and most published formulas ask for insane (yeah 99%) or undecipherable (what is 7N and how much 15% would you need as substitute?) concentrations of it, use too little of some weaker version (the one they'd sell to you), thereby allow buildup of brown MnO2 stains.
   
5. Now use a bleach which was too weak to begin with, and in which only a small part of the Permanganate was actually dissolved, and use it shorter than recommended to avert this proclaimed emulsion damage.

 

[AgX]

But how? I mean in the 3rd sample the solarisation is only partially, located at center.
Even if trying to explain this bya rotanional processing, to loo volume level and partially standstill, there sholud be a more sharp devision between affected and unaffected areas. And the image detaios are similar too (no diffence in density that might be effected diffeentially by too weak solution).

Especially in the third image the effect is very pronounced in the sky regions, which were presumably a lot brighter than all foreground matter.

I stand corrected.
I looked not well enough at the image and did not realize the artefact only appears at edges to the sky.

 

[koraks]

@Rudeofus your post made me chuckle, but it does have face validity!

 

[Anon Ymous]

I stand corrected.
I looked not well enough at the image and did not realize the artefact only appears at edges to the sky.

Yes, @Rudeofus explained it eloquently, better than I could have said...

Anyway, I've used the permanganate bleach with Rollei Retro 80S, Ilford HP5+ and Kodak Tri-X 400 in the past and it always worked very well, except for the 1st time, where it hadn't completely dissolved. I use half strength (1 g/l) potassium permanganate and 45-50 g/l sodium bisulfate instead of sulfuric acid. I mix these two in different solutions, in half the volume of the bleach I'll use and always use deionised water. I mix permanganate well before I'll need it, stir it very well and let it sit for a fair bit of time to help dissolve even the last bits. I will later pass it through a coffee filter for good measure. I only mix the separate pemanganate and bisulfate solutions when I need the bleach. They have good keeping properties until mixed. 5' of bleaching with basically continuous, but slow agitation (inversion) at 20°C was enough for the aforementioned films. Now, if one has to find out if 5' is enough for film X, then a full processing run is an overkill. I just develop a film clip in whatever first developer I use, for the same time and temperature in a graduate and normal room light obviously. Then this film clip is rinsed and bleached for whatever time seems reasonable. Rinse again, pass it through a clearing bath (sodium metabisulfite) and you should have a clear piece of film. You can check it against a fully fixed piece of the same film.