Do you have Simulate Overprint enabled in the PDF options?
I did not. Thanks.
One additional question if you don't mind.
I am needing to send a final PDF to the printers. However, I read that simulate overprint should not be used for the final artwork as it can "radically change" the document.
So what do I do? (I guess I am not clear as to what the simulate overprint option is really doing)
Am using Indesign CS5 and Distiller 9
In rereading the post, I may have misinterpreted what you were saying originally (a screen capture is a wonderful way to show us what you are talking about). I thought you were saying the transparent background area was showing as a differnt shade from the rest of the background, but I realize now that probably is not what you meant at all.
First off let's try to get some more details about the file, and about the intended final output. Will this print on a press, or digitally? Are the colors Spot or Process?
What settings are you using to make the PDF? You said "print" to PDF, and if that's the case, you're flattening transparency and what you desbcibe as frame edges showing might be thin white lines at the image bounding boxes. These are called "stitching" and are a flattening artifact that shows on screen and in low resolution prints made from the PDF, but generally not in press output.
Print to PDF is a distillation process and ALWAYS makes PDF with flattened transparency. It's far better to leave transparency live for as long as possible, ideally letting the printer's RIP do the flattening. To keep live transparency you must EXPORT to PDF, not print (and starting in CS5 you for printed output you need to change the default on export from PDF [Interactive] to PDF [Print]) and use Acrobat 5 or higher compatibility. The Press Quality preset is one good choice if you are going to press and you are controlling color management on your end because you know the print conditions (it converts all colors to process and a single output profile). PDF/X-4 will preserve all colors and embedded profiles for the Printer's RIP to do the color management, but not all printers are up to date enough to handle this.
Thanks for your response.
What I am experiencing seems to be the stitching you mentioned. (I've attached a picture just to confirm).
Normally, I am just printing the indesign file to a postscript file and then using Adobe distiller (with the press quality preset) to convert the ps to a pdf.
However, your solution seems to have solved the problem. When I export to PDF (and do the PDF-Print with the press quality preset) the stitching went away.
So I think the problem is solved unless I am missing something.
Thanks very much for that.
Yup, that's stitching, and it makes no difference AT ALL what settings you choose if you distill your PDF. Distilled PDF simply doesn't support live transparency, so if you are using it, exporting is the only way to go.