At some point your grad is to subtle and there aren’t enough colours to spread over the distance of pixels. The only solution is to introduce noise in the composite, like adding fake dither. Be aware that if you compress the delivery format like sending to YouTube you may get the banding back.
Nope you just want to vary the value for the colors to simulate variation over a field (area) of the image. It’s fake interpolation, relying on the eye to blend the colors more smoothly. I guess you may want to target the area that has the banding and not the rest of the image though. Can you pull a mask from the common area to apply the noise in that place?
I understand, thanks. I did exactly that, a vignette is made from a mask anyway, so I just applied the noise to the non masked area.
I’d share the results but unfortunately it’s a private project. It can look, well, noisy, but with a bit of tweaking can probably be perfected. Also depends how large the image is viewed