A radiation curable ink composition includes a first 2,2,6,6-tetramethylpiperidinyl compound. The first 2,2,6,6-tetramethylpiperidinyl compound is present in the radiation curable ink composition at a concentration above 0.5 wt %. A hindered amine group of the first 2,2,6,6-tetramethylpiperidinyl compound is substituted with only carbon or hydrogen and is a solid at 20 degrees centigrade and does not include carbon to carbon double bonds.