BUCHI NIRCal User Manual
Page 197
Chemometrics
NIRCal 5.5 Manual, Version A
197
There is a clear separation of the 4 different properties spectra according to the PC 1 and 2.
There is no separation with the scores of PC 4, this PC is necessary for the acetone spectra.
Here PC 1, 2 and 3 are secondary PCs, the PC 4 is not a secondary PC.
The separation with 3 selected calibration PCs is visible in a 3 D graphics.