In August, I purchased a 10-roll "cube" of FP4+ in medium format. Every roll from that batch had exactly the same problem: a strange vertical line going across the entire length of a roll, shown as semi-transparent line on my scans without well-defined edges as shown below:
View attachment 318051
Upon examining the negatives, I quickly found the line on them, so it clearly was not a scanning problem. What was interesting is that it's not an emulsion defect. The line is clearly visible on the back side of the film, i.e. the side which usually is covered by the backing paper.
Closer examination with a high-powered loupe (can't share here because I can't take photos at this magnification) revealed that it's not a scratch, but a strange abnormality in the thickness of the film base. It is only visible at certain angles, I did my best to try to capture it on a cell phone here:
View attachment 318052
So I reached out to Ilford, and yes indeed - they had a manufacturing incident recently. Here's their response:
"I can confirm that the defect was unfortunately as I suspected - its a gel backing line. So huge apologies on behalf of our company - a sI apprecate its disappointing for you to have ruined images/films. Your signed number 4651 - links to carton batch 05CFN1C01-2/01-2"
They are exchanging the defective rolls.
Sharing here. Be aware.
Who at Ilford did you send the email to? Tech Support? Harman Lab? Thanks!