A method for evaluating curing in an ink composition comprises depositing an ink composition on the surface of an object via a direct-to-object inkjet printing system to form a film thereon, the ink composition comprising a photoinitiator capable of initiating a free radical polymerization process in the ink composition upon the absorption of light to cure the deposited film; exposing, in-situ, the deposited film to light generated by a first source of light under conditions which initiate the free radical polymerization process to cure the deposited film; exposing, in-situ, the cured film to light generated by a second source of light under conditions which induce light absorption by unreacted photoinitiator in the cured film; measuring the absorbance of the cured film; and determining a degree of cure in the cured film from the measured absorbance and predetermined calibration data.