I’m trying out NLP and on a lot of my images the ‘white balance’ appears to change from the centre to the edge of the frame. It is always warmer in the centre and colder at the edges. The image below demonstrates this. It is particularly bad in this image as colour should be uniform throughout. It is definitely related to my capture set up as it happens across all negatives and I can see blue tinting on the black film mask on the RAW file before crop and conversion.
My set up is a Canon 650D with a Sigma 50mm F2.8 Macro, at F8, ISO100, 1/5 shutter. I use a small light table as a source, and have tried varying the distance between the film and light table but no luck. I’ve tried with and without the lens correction profile in Lightroom.
Any advice on how to fix this would be greatly appreciated.