Strange vertical blemish on every frame

[Stanbey]

Update:
Well, I finished the roll that was in the camera and that was perfectly fine. Inspecting the rollers there is no sign of any dirt or coating or anything. Everything looks perfect.
Somebody from Harman got back to me and was incredibly helpful. But after a few back-and-forths we couldn't get any closer to an explanation.

At this point I think I need to just give up and hope it doesn't happen again. Put it down to a UFO: Unexplainable Film Obscurity. :-(

 

[koraks]

Wow, mysterious! So nice that Harman did get back to you; they're quite diligent in this. Too bad the defect didn't ring a bell with them, at least not yet. Let's just hope it stays away!

 

[Tom-Thomas]

I wonder if it is the old Ilford 120 film manufacturing defect. I have a thread posted here about 2 years ago: https://www.photrio.com/forum/threads/these-cant-be-air-bells-or-are-they.193714/

In that thread, I posted the video below and at the 1:17 it shows a very similar blemish like yours.

 

[reddesert]

Stanbey's problem is unlikely to be a manufacturer's coating defect. How would it have occurred as a mark across the film at roughly the same place in each frame? The roll of film doesn't know in advance whether it is going to be loaded into a 6x7, 6x6, 6x4.5, etc camera. The most that one could appeal to is that, say, the emulsion on that roll was unusually soft and it interacted with an unusually sticky roller in the camera, or something like that.

 

[Tom-Thomas]

How would it have occurred as a mark across the film at roughly the same place in each frame?

The OP says that the blemish occurs not just in the frames, but all the way along the film.

• What you cannot see on the attachments -- because I only just noticed it after I made the scans -- is that the blemish _does_ extend into the clear parts of the film outside of the image frame. It's hard to see because everything is clear there anyway, but it is faintly detectable all the way to the edge of the film

IMO, it's not improbable that a defect in manufacturing would result in a pattern like this.

 

[reddesert]

The OP says that the blemish occurs not just in the frames, but all the way along the film.


IMO, it's not improbable that a defect in manufacturing would result in a pattern like this.

Please review the OP's pictures, for example post 8. The OP says that the mark occurs as a specific band roughly the same place in each frame and extends outside of the frame area to the edges of the film. This is consistent with film interacting with something in the camera, like contacting a roller in the film path. It's not a totally satisfactory explanation since the OP has inspected the rollers and they seem clean, but it is not manifesting like backing paper print through, which can be all-over.

 

[Tom-Thomas]

but it is not manifesting like backing paper print through, which can be all-over.

Not necessarily. It would defends on what problem there was during the manufacturing process. It's not so hard to image that a particular problem would affect only a particular portion/part of the backing paper but not all-over the whole sheet. Anyway, I am just guessing (and I said so from the get-go), and, so are you. I don't understand why you are so gung-ho about shooting down my hypothesis. Everyone here is just trying to help, it's not a competition. I don't care for your condescending tone of voice, and so I am out of this thread.