Originally Posted by Light Illusion
Please send (e-mail) me the profile used to make the LUT and the actual LUT that shows the banding in the Lumagen.
(I am surprised the Lumagen is the cause of the banding.)
I will do, but I'm certain the Lumagen is at least a contributing factor now.
If you turn off the 3D LUT completely in the Lumagen, reset the Lumagen CMS to default values and just change the blue primary co-ordinate in the 8point CMS from 64,64,940 to something like 64,250,940 the very same banding is visible as with the blue ramp. It looks like the cyclic banding happens as the slow introduction of green happens.
And if you modify the REC709 colourspace to have the same blue co-ordinate as the measured profile then then banding disappears with the LUT.
Originally Posted by RobScreene
I use a JVC X3 in Wide 2 mode, calibrated with a lightspace lut from about a year ago in a Lumagen 2021, no banding noted for blu-ray.
Except on some Netflix eposides for which i also notice some banking on our 4K Sony TV, so I'm pretty sure that is in the source material.
Thanks for the info! Do you have Spears & Munsil V2? A small version of the blue ramp is visible in the "Colourspace Evaluation" chart, but it is easier to see in the large RGB ramps elsewhere in the menus.
Somehow I think S&M designed this ramp to be particularly fragile; lots of things will break it. The "Darbee" enhancement tech in the Lumagen also causes slight issues in these ramps.
I should say that I almost never see banding in "real video" content off high-bitrate sources like BD. I will occasionally see it in computer generated colour gradients on channel ident / movie intros / etc.