I know from experience how many of the large publicity posters are normally printed . To promote an exhibition there are approximately 30 spots in a city that are used for promotional purposes.Each spot is serviced with 3 large posters set up in a triangle to maximize exposure. These print runs are expensive so only the necessary posters are printed. This is the reason why I am always focussed on these large publicity posters since the ones that remain after the exhibitions are extremely scarce. This way I acquired posters by Sol LeWitt, Carl Andre, Serra and now I can offer 2 by Marlene Dumas. One from Bern and the other from the Museum Overholland which does not exist anymore. Both are available at www.ftn-books.com and I believe these are not offered anywhere else at the moment.