Why
Colorimetric tests are fairly accurate, but require calibration to work. There is always an investment in time, effort and material with each point that needs to be calibrated. A minimal calibration is the least number of points you need to calibrate for to have a working device of reasonable accuracy. Typically these are three points per parameter. A full calibration will give you accurate results, but need a larger number of points.
Calibration settings
Go to Settings
Choose Colorimetric Test
Choose Minimal or Full Calibration as required.