Would love any insight to this line across each photo from a roll of 35mm film taken with my new (used) Noblex Pro Sport. The line appears at the same height on each and every photo, but is brighter/lighter depending on the photo settings.
I have three assumptions thus far, but would love more ideas so I know what to avoid/do.
Lab messed up during processing
Wound the film too aggressively at the end, causing the line
A straight, fine line across the frame like this indicates a scratched negative to me. I guess it could be a dodgy scanner too. Examine your negatives closely to see if the scratch is there. You might have a tiny piece of grit somewhere in your camera, or quite possibly around the light seal of the film cassette – but it's too late for verifying that now. I wouldn't be so quick to blame the lab – you have them as suspect number 1. The canned air idea sounds like a good idea to me – worth maybe using a soft brush as well / beforehand.
I don't think this is anything particular to the fact you've used a rotating-lens panoramic camera. By the way, I also have a Noblex – I don't use it as much as I used to, but I get some great images with it. A great camera for wandering city streets with.
The scratch is uneven - the scanner optics is not to blame, it is the negative.
The scratch is colored - it is emulsion-side.
The scratch is thin enough not to happen in the wet part of the lab process (and the lab has no much business with the dry film.
Conclusion: the film was scratched when dry, emulsion-side (in the camera this is lens-side), probably during taking pictures or winding the film back. In all other technological stages the film goes with constant speed and the scratch should be more even.
Cleaning the film path in the camera is a good start.
p.s. Gurus in the film lab where I used to work long ago could recognize if the film was scratched pre- or post-processing, but I think one has to look at the film for this.