Are you a Twiddler when you develop?

The other day I received a comment on one of my videos from Don Bennet where I showed some inversions during development and it was suggested to use the agitation stick rather than normal inversions to prevent the dreadful leaks. Something I have never used before. So I thought I’d give it a go and put it side by side. 

So I made a video shooting HP5 and Developing in Rodinal one where I twiddled and the other where I inverted normality. This was just to see if there would be any difference and mostly to see if the twiddle would work! 

Two tanks, exactly the same temp and same amount of developer and times. And I had both tanks on the go at the same time. 

For the twiddle I rotated the the reel clockwise 5 times each minute. 

I noticed the twiddled tank was slightly lighter and so far so good. I can trust the twiddle! Or can I? 

I then went off the next day and shot a roll of 120 Foma 200 and developed in 510 Pyro for 6 and a half minutes twiddling for the first 10 seconds and then 5 turns each minute. I twiddles one way and then the other. 

Here are two images I scanned from the developed film. I appear to have uneven development which is a shame as I would have liked to have printed a couple from that roll. 

I can only assume that this was caused by insufficient agitation during the development. Which brings me to my initial thought of twiddling. Is there enough fresh developer getting over the film during inversions. Obviously not in this case of medium format. 

I then, as if by magic, received a comment from Gianni in Italy on the video saying that the twiddle method works for 35mm but not so good for medium format! Interesting. 

So I found that interesting. 

For now I think I am going to steer clear of the twiddling but may still experiment with 35mm film but not chance another roll of 120 film. 

What do you guys think ? 

Roger.