Vertical bands along 120 negative: scanning/camera/dev problem?

[mrksgrn]

I shot the following with a hasselblad 503CW with A12 back on Portra 400. Two frames of 12 display this unevenness strongly, a few of the other frames less so. Does anyone have any ideas what is causing the bands? I self-developed this roll of portra in Tetanol; could it be an agitation issue?
Regarding my scanner, I made sure to wipe down my Epson V600 but the bands still appear. Lastly, could it be a camera issue?

Dead Link Removed

 

[Dr Croubie]

Easiest way to tell if it's the scanner, rotate the neg a few degrees and see if the stripes still line up the same way...

 

[mrksgrn]

Thanks!

Looks like it's development; it's on the negative
Dead Link Removed

 

[mrksgrn]

The banding occurs in the sky, but I suppose they aren't overtly obvious unless you're on a big screen

 

[Rudeofus]

Although it looks slightly different from the typical appearance of this issue, the whole situation reminds me of the "yellow streak"-issue many people have when developing 120 roll film in Tetenal's C-41 kit. APUG is full of these reports, and the best solution was the introduction of a stop bath and a wash between color developer and BLIX. Sadly, you can't recover the negs you already processed.

 

[mnemosyne]

All I saw was a slight flare effect probably due to the pickets. I would have not given it another thought, had it been mine.

For me, the banding in the sky is quite pronounced, but its visibility will of course depend on individual display settings (brightness/contrast).

@mrksgrn

Can you see the bands when you look at the negative with a loupe, moving it slowly/tilting it slightly against a light source?

 

[Thomas Bertilsson]

The banding occurs in the sky, but I suppose they aren't overtly obvious unless you're on a big screen

I see it very clearly. It's like a wavy uneven density in the sky, where the density variations are horizontal, and the patterns are vertical.

Usually this happens due to insufficient agitation. I've even had this happen at commercial labs where dip and dunk machines were not used, and it's frustrating.
I've also had it happen with my own processing, and usually with 120 film and where I had too much developer in the tank. When that occurs the developer can't move around in the tank sufficiently when we agitate, which I believe causes these problems.
As soon as I started measuring out exact volume of developer for my various tanks, this problem stopped. Color film (C41) and black & white both.

 

[480sparky]

I hope the OP doesn't mind, but I did a bit of heavy-handed changes to the image to bring the bands out. Hopefully everyone can see the vertical banding in the sky now.

 

[fotch]

I see it now, why, I don't have a clue. Does it always happen or just one roll?

 

[MattKing]

I see it now, why, I don't have a clue. Does it always happen or just one roll?

And equally important, is it only visible on shots with a back-lit snow fence?

 

[fotch]

And equally important, is it only visible on shots with a back-lit snow fence?

Good Question.:confused:

 

[mrksgrn]

As mentioned, the bands are most visible on two frames, both of the snowfield. The other 10 frames on the roll, the bands aren't as visible but pushed in photoshop, the bands are there. So yes, I guess it's exhibited on the entire roll, but only apparently in two frames

 

[480sparky]

So the bands are there in all the frames, just visible in two (most likely due to the large, blue field)?

 

[nbagno]

Although it looks slightly different from the typical appearance of this issue, the whole situation reminds me of the "yellow streak"-issue many people have when developing 120 roll film in Tetenal's C-41 kit. APUG is full of these reports, and the best solution was the introduction of a stop bath and a wash between color developer and BLIX. Sadly, you can't recover the negs you already processed.

I do this, made a huge difference for me.

 

[mrksgrn]

So the bands are there in all the frames, just visible in two (most likely due to the large, blue field)?

Exactly right!