Looking for books on Indonesia I found two Guide to Java travel-books. One looked relatively new, the other one not at all. With the second one they actually travelled. The cover was damaged and all the trendy pictures of when it got published looked very retro now. I had to have it.
In it was a yellow, folded piece of paper. It is an instruction page, in Dutch, about how Batik is made in 8 steps. The last owner left it there, the new owner is looking for Batik on Java, perfect!