Being able to tear of pages is an important part of the calendar. So I’ve been investigating the possibilities. At first I hoped the printer, Tiggelman, would just do it for me. Alas their perforation turned out to be too vulnerable. The nice people at St Joost art academy and office supplies Benoist gave me the opportunity to test two different systems for perforation: one with a blade and the other with punch holes: 
The top page has a stamp perforation. The stack is one year. This gives me insight into the size and weight of the calendar. The total weight will be around 5 kilogram. The thickness will be around 32 cm.
I still haven’t decided which perforation to use. I will have to do it by hand whichever one I choose. But the ease in which the papers can be torn off will be decisive.