What's this line

sirch

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#1
Processed a roll of Portra yesterday in Fuji Express and there is a line across most of the negatives. I've punched up the contrast on this to make it stand out more but it is there on most of the roll. It is along the edge of the film but I can't say whether that was at the top or bottom of the spool. As far as I can recall I didn't do anything differently and there was only this one roll of 120 in the drum so it would all have got covered with developer quite quickly.

Portra7.jpg
 
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#2
This is 6x4.5 right, so the crease is running along the top or bottom of the film ?

How do the negs look ? I had a bad batch of Fuji Neopan 400CN (xp2) that had a small crease running along the bottom of the film. Alternatively something in camera or on your drum that's scratching or marking the film ?
 
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sirch

sirch

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#3
This is 6x4.5 right, so the crease is running along the top or bottom of the film ?

How do the negs look ? I had a bad batch of Fuji Neopan 400CN (xp2) that had a small crease running along the bottom of the film. Alternatively something in camera or on your drum that's scratching or marking the film ?
It's 6x6 but I cropped it a bit to reduce the file size, I'll have a look a the neg tonight but I didn't notice anything particular when I was scanning it.

The line is well away from the edge near the spiral and it extends across most frames so some would be inside the spiral and protcted from the drum. Good point about the camera, it hasn't happened before but I'll check that the rollers and pressure plate are clean.
 
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#4
Negatives are always better than prints/positives for analysing problem. Does this extend between frames? It is light in the positive so could be a small linear light leak - shutter if only within the frames, elsewhere if between the frames as well.

What camera is it? Focal-plane shutter versus leaf shutter makes a big difference.
 
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sirch

sirch

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#5
Bronica SQA, leaf shutter, yes its across many frames but is really faint, as I said I pushed up the micro contrast to make it more visible on that image. Here is a crop of a scan of the neg, you can just about make out the line running across the frame border.

Untitled (2).png

I have had a look at the back with a loupe and a bit of paint has flaked off one of the rollers at possibly the right place but it's hard to see how that would create a line given that the rollers are freely rotating.

I've also had a look at the neg with the loupe and it's not a scratch.
 
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StephenM

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#6
Any chance that it's a pressure mark?

Sorry to reply so late - I only think slowly.
 

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#8
I'm not sure that it would necessarily lead to obvious physical damage. I'll see if I can find a reference with photo. They're usually seen as horseshoe shaped marks on 120 film where a thumb or finger nail has exerted pressure during loading.
 
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sirch

sirch

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#9
Could be, there is a "flange", for want of a better word, where the flim enters the spiral in the dev tank, I'll check if that would be in the right place to make this mark.
 

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#10
My online searching has failed. The best I'm going to be able to turn up (eventually) is a reference to a book that can be found on line. There's a brief mention (without illustration) on p407 of Jacobsen's Developing, 18th ed. That's the best I've got so far.
 
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sirch

sirch

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#12
I've had a measure up and the line is 9.5mm in from the edge of the negative and the "sticky-out" bit on the developing spiral is 8.5mm so it's probably not that.
 
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