Sounds like you have completely misunderstood something and is mixing up two different things.
The photo of a D65 calibrated monitor is used to get custom coefficients for the white balance module. Once that is done, you use color calibration as normal. At no point does delta E enter into it. It’s also explained in the manual.
If you have a color patch target, you can then do lighting/scene specific color calibration, which is when you have to worry about delta E. Note that a simple grey card won’t do for this - you need one of the supported color targets.
No, dont think I have misunderstood. I followed the instructions in Aurilliene Peirre video which entails taking a photo of a D65 colour calibrated display, using it to set the white balance, creating a preset that can be auto applied then using a colour checker to calibrate within the colour calibration module.
And I always get a large delta E, it doesn’t work for me.
Replying to my old thread so I can tie up a loose end. Penny finally dropped after all this time regarding the channel mixer. When I increase input blue in the red channel for example, I am increasing the brightness of the red channel. Red increases more where blue is bright and less where blue is dark, and this is how the channel mixer can be used to shift colours and remove an overall colour cast.
What finally nailed it for me was when I learned to view the red, green and blue channels in isolation and observe where each channel was bright and where each was dark. It just suddenly became clear.