a print quality control method , comprises the steps of : providing a visual referring target on the printing substrate , setting a specific halftone of black “ k ”; creating a neutral grey tone i . e . ngt ; placing tightly both mgt and ngt next to each other across the printing surface ; and comparing both printed tones result . by adopting the grey balance theory and visual matching technique , the resultant can provide accurate ink balance information for the production personnel to immediate execute the correction on the imbalance inking condition during production .