As solutions for quality assurance (QA) like UTT (Universal Test Target) and ‘golden thread’ have been introduced it is now easy to monitor the quality of a digitization system. But several questions remain that have not yet been answered. Among these the following three are the most important ones:1. How do I calibrate the system step by step to meet given specifications like e.g. Metamorfoze?2. Are the existing specifications suitable for my individual application?3. What do I do if one of the image quality aspects is out of the range?This paper tries to answer these questions and to provide guidance for the daily use of the QA solutions.