Pigment Blue 15:3 (P.B. 15:3) as the cyan colorant (BASF, Germany), C.I. Pigment Yellow 151 (P.Y. 151) as the yellow colorant (Clari- ant, Switzerland), C.I. Pigment Red 57:1 (P.R. 57:1) and C.I. Pigment Red 122 (P.R. 122) as the magenta colorants (Clariant, Switzerland). Scheme 1 illustrates the pigments structure.