Incorrect LUT Scaling will cause calibration issues when the LUT is uploaded in a display or LUT box.
Therefore it is important to understand when to apply LUT Video Scale and how to spot the need.
LUT Scale
The most obvious LUT Scale issue is when the 3D LUT within the display or LUT box uses a full-range cube, but the signal path is TV Legal, meaning that the LUT data needs to be scaled to match the TV Legal range within a data range LUT, using the ColourSpace Video Scale function.
If the LUT is not scaled correct, the gamut will be larger than target, assuming the display's native gamut is also larger than the target gamut, and the grey scale will show unexpected errors.
With the LUT correctly scaled, the gamut and grey scale match the correct targets, and also match a ColourSpace Active LUT verification.
