1. A method for evaluating printing defects, in printing technology, the method comprising: receiving a captured image of a printed sheet; generating a profile, of the printed sheet, representative of tonal variations in the printed sheet; analyzing the profile in a plurality of different scales; assessing the significance of one or more features of a printing defect throughout the plurality of different scales; and evaluating from the assessed significance of the one or more features, in each of the plurality of different scales, the severity of the printing defect.