Disclosed are colorant compounds of the formula wherein R, R1, R2, R3, and R4 each, independently of the others, is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, and wherein R, R1, R2, R3, and R4 each can be joined to a phenyl moiety to form a ring, each R′a, R′b, and R′c, independently of the others, is a halogen atom, an alkyl group, an alkoxy group, a nitrile group, a nitro group, an amide group, or a sulfonamide group, z1, z2, and z3 each, independently of the others, is an integer of 0, 1, 2, 3, or 4, n is an integer representing the number of carbon atoms in each repeat alkylene oxide unit, x is an integer representing the number of repeat alkylene oxide units, D is an anion, and g is the charge on the anion, wherein said colorant has no more than one —OH, —SH, or primary or secondary amino group per molecule.