I'm using InDesign CS6.
I'v finished now a layout for a folder, and I put a photoshop-image with transparency over a InDesign-rectangle which I have filled with a cmyk-color in yellow.
When I export a PDF with the Settings "PDF X-3:2002" (with PDF-Standard 1.3) the Photoshop-image shows uggley jagged edges at the border to the InDesign-colored background. However, the Photoshop-images which are over another bitmap-image (as background), this images don't show this annoying edges.
When I export to PDF-Standard 1.4 the problem doesn't occor, however my printing-service requests PDF 1.3.
I know, the workaround for this problem is, to replace the yellow background-color with an bitmap-file with the same color, but is there any other option to get a correct result without this more time-consuming image trick?
I think it has to do with the transparency reduction which is necessary if using PDF 1.3. When I examine the PDF-File in Illustrator, this edges occurs mostly at the borders from the tiles in which the image is cut during the transparency reduction process. Although, if I open the rendered PDF in Photoshop this jagged edeges are visible, so it is definitly a render error.
I would be glad if someone of you has a solution for this problem, in the attachment is an image which illustrate the problem.