QA can vary from simple procedures to highly developed workflows. Within one of the largest digitization programs in the Netherlands (Metamorfoze) the National Library has the task to ensure the quality of digitized images for preservation. To accomplish that task the National Library has taken several steps and is constantly improving its own process of quality management to ensure high speed, high volume and high standard controls for a huge amount of terabytes of data that will be stored permanently and made available for (online) use. In this paper you can find the questions we had to answer in order to set up the QA workflow, the workflow we did implement, the current status of our workflow and the lessons we learned along the way.