I have been getting lines on my films when scanning them. I first thought it was my scanner, an Epson V600. As it was still under warranty, I got it fixed and they changed the carriage and mainboard.
However, I am still experiencing problems and I feel that it is still the scanner because the lines always appear at the same place, even when turning the film (see the two first pictures). I also tried two different labs to develop the films.
Do you think this line is due to the scanner? The camera I am using is a Mamiya 645.
Here you can see the photos: Scanning problems - Google Drive
Picture 1 and its flipped version, picture 2, shows that it must be the scanner as the line must correlate with a particular position on the scanner, presumably in the direction of travel, longitudinally? Certainly it’s not on the film, so not caused by the camera or processing. It seems extraordinary that it’s been back to Epson for all that work and the line remains. Looks like a sensor problem, or something in the calibration area.
Make sure the calibration area on the scanner is clean and clear before scanning. I’ve had a similar issue when the negative was partly inside the calibration area.
I know that your question is not to me but I think I can explain. Proper holders for your V600 leave a clear strip at the hinge end that is used by the scanner for calibration. Anything in this area, a serious bit of dust or, as waynemel said, anything that might impinge on that area such as an edge of the negative or transparency, will upset the calibration in sometimes unpredictable ways, it can also cause lines on your scans along the length of the scanner.