7=Blue13=Green22=Red28=NIRX[7]/X[13]: the ratio Kblue/Kgreen is well secured at K7/K13=0.74 over the whole depth rangeX[7]/X[22]=0.280 and X[13]/X[22]=0.378 are fairly secure280/378=0.741: this system is consistentit actually is consistent over the whole visible range: this is remarkable