I have spent some time creating a double-sided three-fold flyer in Quark 10.5 with blue as the main background colour (box infill, frames etc). Looks superb on screen and on printout from Quark file. However, when I output to PDF, blue translates to black! All pictures show and print correctly. Need to send PDF to commercial printer. I haven't a clue how to rectify this problem as I am not a professional user - merely an enthusiastic amateur. Answers, therefore, in simple, non-technical language please. Hope someone can help.