Logic Pro X Printing in Windows XP


A friend of mine works at home in Logic and then saves his scores as PDF which he then prints out on the school where he teaches. Until Logic X this has worked fine but now he tells me that there are "shadows" on the PDFs, not only when printed out but also when opening them.
Has anybody else experienced this, I almost never uses score so I don't know.
Please also notice that the computers he prints form are running XP which is not really the latest microsoft effort :)