Centered Spectra vs. Loading Spectra

I´m preparing a presentation for a training about Chemometrics and PCAs,  so I´m going to use R Graphics, because are really fantastic to introduce NIR users to R.

 Following with the centered spectra, this time I overplot the centered spectra with the first 4 loadings. Every centered spectrum can be rebuild using a linear combination with their scores and the loading vectors (eigenvectors), remaining a residual noisy spectra (e).