Preferably, a trichromatic dye mixture comprising at least one yellow dye, {TAIL ~ at least one red dye} and {HEAD ~ at least one blue dye} is used 
Preferably , a trichromatic dye mixture comprising at least one yellow dye , { TAIL ~ at least one red dye } and { HEAD ~ at least one blue dye } is used
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH