Out with my Pinhole camera today in the slate mining areas of North Wales. It was a bright day so I decided to load the camera with Ilford Pan F 120.

On my return home I thought I would process the images in Rodinal 1:50. It has been a couple of years since I had used Rodinal, and in the past I have always used stand development.

Shock horror when I saw the results:

Air bubbles along the top of the negatives! It’s been a long time since I had those. I assume that air bubbles had been trapped between the film edge and the edge of the reel. I had used my normal agitation method: slow continuous for first minute, then four inversions every minute thereafter, each agitation followed by a vigorous rap of the tank.

So perhaps I was agitating too vigorously, having just come from using PMK-Pyro for 6 months? (PMK requires vigorous agitation). Perhaps Rodinal is quite frothy compared to other developers? I don’t know. I will need to put a test film though Rodinal with more gentle inversions before risking any important film. What a pain!


Postscript 24 April 2019

  1. I ran a test film through Rodinal 1:50. This time I agitated for the first 30 seconds, rather than a minute, and then 3 gentle inversions every minute, rapping the tank hard on the table twice after each agitation cycle. Result?

Air-bells a-plenty. Grrrr!

I need to sort this. Possibilities?

  1. Change from plastic to metal spirals
  2. Stop agitation by moving to stand development
  3. Make agitation more gentle still
  4. Increase developer volume from 600mls to 700 mls (590 mls is recommended volume)

Plenty of people do a good job with plastic reels, so I will keep using them. Stand development produces too extreme acutance effects, so I’m not willing to do this. So I am going to plump for a combination of 3 and 4.

For resolution see my post ‘Film staining‘.

3 thoughts on “Air-bells a-plenty – Grrrr!

  1. Hello! I’ve been having this same issue for some time now and I’ve gone through many rolls of 120 film to figure it out. I’ve been searching all over the internet to find a solution and haven’t even been able to find images that presented the same issue until I stumbled upon the word air bubbles and found this article! I’m going to test this tomorrow as I too have almost always used just distilled water as my bath (except for a few times in which I used actual stop chemistry and from what I remember didn’t have any issues… ugh). So I wanted to thank you for writing this blog! And I also was curious to know if you had these air bells show up in other places other than just the top edge of the film. They have shown up in the same spot as your examples for me as well as in other random areas on different frames. Could this be the same issue? I would GREATLY appreciate any time you can afford to assist me with this. Again, thank you very much!

    1. Hi Luca. Thanks for your comments. I have only had these stains on the upper edge of the film as it is in the developing tank. I don’t think my issues were air-bubbles. It was staining as a result of not using a proper stop bath. I no longer get these stains, so I assume that my diagnosis was correct.However, as you know, so many factors are at play that it’s difficult to be compeletely confident of this. I hope yiou find an answer.

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