There is provided an aqueous formulation comprising an IR-absorbing
naphthalocyanine dye of formula (II):or a salt form thereof, wherein:M is Ga(A1);A1 is an axial ligand selected from —OH,
halogen, —OR3, —OC(O)R4 or —O(CH2CH2O)eRe wherein e is an integer from 2 to 10 and Re is H, C1-8
alkyl or C(O)C1-8
alkyl;R1 and R2 may be the same or different and are selected from
hydrogen or C1-12 alkoxy;R3 is selected from C1-12
alkyl, C5-12
aryl, C5-12 arylalkyl or Si(Rx)(Ry)(Rz);R4 is selected from C1-12 alkyl, C5-12
aryl or C5-12 arylalkyl; andRx, Ry and Rz may be the same or different and are selected from C1-12 alkyl, C5-12
aryl, C5-12 arylalkyl, C1-12 alkoxy, C5-12 aryloxy or C5-12 arylalkoxy;The formulation has a pH in the range of 3.5 to 7 and is particularly suitable for use as an IR-absorbing inkjet ink, providing compatibility with known CMYK inks together with an optimally red-shifted λmax.