After applying the above-mentioned selection steps to the period between 1781 and 1800, approx. 12,000 of the roughly 17,000 titles in STCN remain. It was necessary to limit the selection even further in order to arrive at 1.3 million pages. Various parties involved were consulted and based on the responses to the survey form sent to academics, it was determined that there was also a need for content-based selection criteria. A random selection is considered not to be very useful, because it would mean that only part of the collections would be digitized and therefore, it would not serve the purpose of research very well. At the same time, given the size of the project, it is not possible to select the thousands of titles manually based on research topics. That is why we used the STCN subject key words. Each title in this database has been given one or more key words. By selecting books based on these words, clearly specified subjects can be digitized.
Subject key words were submitted to an Academic advisory board. Departing from the assumption that a book consists of, on average, 250 pages, they were asked to select key words up to a total of 7500 works. To simplify the choice, the key words were divided up into thematic clusters. On this occasion, the advisory board selected the following clusters: History & Politics, Economy & Trade, Science & Ideas, Religion & Society, Daily Life & Education. These clusters together produced 4,687 titles, including various journals and other periodicals.
The selection was then extended when, during the preparation of the material, it became apparent that the average book contained not 250 but 130 pages. The entire Visual Arts cluster was added, as well as the key words Drama, Dramaturgy and Musicology, Dialogues and the Parodies Genre from the cluster Literature & Drama. This brings the total to 1.3 million pages. Left over money made it possible to extend the selection even further with an extra 800.000 pages. This means that the number of digitized pages is over 2 million.