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‘.