PURPOSE: An ink composition capable of forming uneven surfaces without causing discoloration and coloration in foaming on the surface of a vinyl chloride resin, comprising a foaming inhibitor, a specific discoloration inhibitor, and a volatile solvent.

CONSTITUTION: A composition comprising (A) 0.5W75wt% of a foaming inhibitor, e.g. maleic acid, (B) 0.5W75wt% of a siscoloration inhibitor consisting of one or more types of (a) a carboxylate, phosphite, alcoholate, phenolate, mercaptide, or alkyl thioglycolate, of an element of the groups Ia, Ib, IVa, and Va, (b) a thiourea, (c) a thionic acid, (d) a thiuram, and (e) an epoxy compound, (C) 20W85wt% of a volatile solvent, e.g. mineral spirit, (D) 0W40wt% of a pigment, and (E) 0W25wt% of a pigment resin carrier.