Film clearing time for Bergger Pancro 400 sheet film

[mkhajeh]

Hi,
I'm going to find the minimum fixing time for Bergger Pancro 400 sheet film. I cut the film and put a slice in fresh Moersch Alkaline Rapidfixer 1+5. In 35 seconds, I've found the film clear but grey, which was normal to me, because all my previous developments of this film had grey base. To test more, I tried another piece of the film and kept it in the fixer, after 1:30 minutes, the film became magenta and much clearer. However, I never could get this magenta clear base, when I fully develop my photos, even if I keep the film more than 10 minutes in the fixer. Could it be something I am missing in my development?

 

[Anon Ymous]

This magenta colouration could be some dyes that may leach out of the film in the developer, so you may not see it.

That said, there is a stricter, more accurate way of determining clearing time. A drop of fixer is placed on the emulsion side of a piece of film and left there for some time. It's not very critical, 20 seconds is ok. A spot is forming there and the film is the immersed in the fixer solution and a timer started. You keep looking at the film, while agitating as you would normally and note the time it takes for the spot to disappear. This is your clearing time, which should be multiplied by two to give you a fixing time. To be on the safe side, I multiply by 3, it's perfectly safe.

 

[mkhajeh]

Thanks Anon!
I tried your recommendation, and used a complete 4x5 sheet (instead of cutting it). I got almost the same result. After 1:30 min I can not recognise the drop anymore, but at this point the sheet is completely magenta. I also made a test shot on the same type of film and developed it and then fixed it for 4:30 minutes, but the sheet (even the borders) are totally grey.

 

[138S]

Thanks Anon!
I tried your recommendation, and used a complete 4x5 sheet (instead of cutting it). I got almost the same result. After 1:30 min I can not recognise the drop anymore, but at this point the sheet is completely magenta. I also made a test shot on the same type of film and developed it and then fixed it for 4:30 minutes, but the sheet (even the borders) are totally grey.

Let me add that you also can fix with lights open, after stop bath it is safe to open lights and also fix in a tray with lights open, so you know the clearing time depending on film and fixer strength, then you allow a x2 or x3 fixing time. If you have to extend too much fixing to remove the pink stain then you can shorten the fixing time to its optimum (x2 the clearing time) and removing the pink stain with an extended washing time, just leave the sheet in a water tray and change water 2 or three times, you'll wash it perfectly with little water consumption.