Objective Print Quality Measurements Using a Scanner and a Digital Camera

Print quality is still almost exclusively evaluated visually, due to tradition as well as the unavailability of certified measuring devices. This article shows that by use of a low- and a high-resolution measuring device (flatbed scanner, digital camera) many print quality parameters can be measured in an objective, reproducible and fast way. The measurements are carefully designed to atch the average visual impression but are independent of the subjectivity of a visual evaluation and allow objective comparisons of different printing machines. The paper focuses on the parameters that can be measured on flat field prints like process color density, density variations within sheet and its special attributes like streaks, banding, mottle, granularity, background and satellites. These parameters are measured using an analysis system based on a scanner and a digital video camera. Finally the presented analysis system is used for an objective comparison of the flat field printing performance of different digital printing machines