Discoloration question (again)

I am camera scanning with a GFX100S, and A VALOI film holder with 6x7 mask for negs from my Mamiya7; using a Kaiser slimite plano light table with most of the light table covered with black paper.

I am getting color banding on some camera scans; seems not to be software related to NegLabPro, as I see the same banding when I do a simple conversation in Lightroom via an inverse curve:

any guidance what is causing this?

Best - Peter

I don’t suppose that you’re getting any ambient light reflections off the top of the film are you? Does this banding always look similar to the one shown, i.e. just a single band in the same approximate position?

IMHO,Kaiser slim light is not really good source of light for scanning negatives regardless of CRI. As far as I tested the CSLite in Cool mode is the best light available on the market. The only thing which is better than CSLite is custom RGB light but that is DIY option not widely available. I will publish my research here on this forum in a few days so you will see what I am talking about.

Vlad: I have no issues with the Kaiser Slim Light - seems fine. But looking forward to seeing the results of your research.
Nitnaros: Banding can be caused by making large luminance or colour adjustments to image files that start life in 8-bit mode; Lightroom processes in something akin to 16-bit but I wonder about the bit depth of the captures themselves.

well, I assume that the data NLP delivers is 16bit - it manipulates the raw DNG and its edits are non-destructive and stay in DNG format, so its gotta be 16-bit. And the discoloration is seen right on the NLP conversion result.
Regarding stray light: I dont think I have that; when I cover the Valoi slide carrier, there is no light showing up in camera (as seen via camera tethering). I will do one more test run to rule out light reflection on the negatives

But you are also using Lightroom curves. Anyhow, re-examining the photo you posted, if by “banding” you mean that orange vertical strip visible in the sky to the right, no it’s not a bit-depth issue. Cancel that. It must be happening at the capture stage if you are getting it from both an NLP and LR conversion. Vlad may be correct that there is a light issue, but I don’t think it’s generic. It could be a defect in your unit, and if it is happening with some camera scans and not others, could perhaps be intermittent misbehviour. If you can test for this using another light source that could be instructive.

It would be helpful to know if there is any correlation between the frames when this occurs, perhaps you could post some other examples?