Ligth vertical streaks on 120 negatives

I have been developing 120 film for a few years now, with the same Paterson tank and spiral and this is the first time I have experienced this kind of streaks on black and white film. I have captured a few samples (negatives on light table captured with my phone's camera) but the whole roll looks like this, please see attached files.


Camera is a Hasselblad with a A12 magazine, which has not given me any trouble so far. Film is FP4+ developed in 500ml of Rodinal 1:50 with 30s initial agitation + 2 inversions every minute, for a total of 15 minutes. I have tried re-fixing and rewashing the film but unfortunately it did not help.

Is there any chance you used less developer than usual?

MattKing said:

Is there any chance you used less developer than usual?

Click to expand...

And the agitation method?

I mentioned my agitation in my post: 30s initial (inversions) + 2 or 3 inversions every minute. I always mix 500ml with about 10ml of Rodinal. Everything was pretty much standard for me.

I've had a result like this when using the Paterson Universal tank PTP115 with only one reel in it. What happened was that the 120 reel slipped up the centre column of the tank during inversion agitation leaving one edge of the film above developer level.

A single streak would suggest agitation/dev level issues.

But multiple streaks like that suggest either a film issue (bad batch) or a roller issue in your camera back.

First thing I would do is shoot a test roll with a different film brand/batch and see if you recreate the streaks.

I agree, low developer or the reel slipped.

I often find myself stumped with some problem: "But I did everything the same..." I tell myself; and then it hits me - obviously I didn't - I did something different and didn't notice it.

@Nicholas Lindan is going to hate me for this
Now if only we could get Darkroom Automation to "do everything the same", and start selling f/stop timers again!

Thank you for your comments.

From your suggestions, I tend to suspect the spiral either not being pushed all the way down to the bottom inside the changing back, or possibly having moved up while developing. I wrongly thought that a 120 spiral would not have had much room to move, but I can see now that there is a non neglibible space between the top of the spiral and the bottom of the light tight lid. I normally put 2 spirals when developing 35mm in the bigger tank, never thought I needed any precaution with 120.

I double checked the bottom of the tank and it suggests to use 500ml for 120 film (I usually load about 500ml water + 10ml developer with rodinal), and I tend to exclude that I may have put less (although everything is possible, of course). It would not be a big deal to add more liquid, but I remember reading somewhere that you should not exceed the recommended volume so that agitation is not hindered by to little room in the tank.

I guess there's always a first time, luckily this was shot 15 minutes from where I live so I can certainly return in one of the rare sunny days here in Southern England at this time of the year.