I am agreeing with thomaso. This completely threw me and I spent (wasted) a couple of hours wondering what was happening. I came to the conclusion that this was a change brought in by the latest upgrade. To see the document in greyscale on the screen and then see the PDF in colour is really confusing. For the record, I have to produce two versions of my document, one in full colour for a web version, and one with greyscale for hard copy printing, because I can't afford the colour print. Thanks to this forum I found the solution (to tick convert colour image spaces) even though the documentation says the PDF export picks up the colour palette from the document