Using A Calibration Target
I first take a photograph of an X-Rite Color checker target and calibrate the monitor in System prefs till they look same. normally do it by eye but can use a Colormunki to be more precise
Then as required I include the target in one of the shots in a set as seen so I can tweak my Raw conversion adjustments to match known standard values i.e. the RGB and other values are known for each patch on the target
page under development more to follow