The present invention includes a curable ink composition for digitally printing onto plastic substrates and three dimensional objects comprising an ink composition comprising a pigment, an oligomeric component, a diluent, additives and a mono-functional monomer having a molecular weight of 10 g/mole to 600 g/mole. The curable ink composition adheres to the plastic substrate to thereby allow elongation of 100% to 900% of the printed ink image during thermal processing of the plastic substrate.