Simple photo book stand

My wife takes photos of the family and while traveling and then creates large format photo books and calendars from this material.

We (and also the people she gives them to ;-) like to present the photo books on a shelf, table or even on a desk in the office - the problem was to find/create a stand suitable for such a presentation.

The format of the books is typically DIN A4 (210x297mm, large book closed or small book opened) or A3 (297x420mm, large book opened) and, because it's a ring bi