One of the pensioners who volunteer there walked us to the shop, talking about the mill and his projects. Turns out that he was the one who made the paper for AGF Klasse 3, a book with recipes for 'class 3' vegetables -- stuff that never gets used because it's blemished. I've seen the description of the project before and it interested me.
He had made the paper himself, experimenting with it until he got the right combinations. Apparently only two of the books were made -- but we got to see and feel all the types of paper he made, because he had them in a binder to show to people.