The wraparound cover OP is back with another question. In the help files I found this: "If your artwork contains transparency, ask your prepress service provider if they want to receive flattened or unflattened PDF files. Flattening should be done as late in the workflow as possible, preferably by the service provider. However, if your service provider wants you to flatten transparency, submit a PDF/X‑1a compliant file."
Since the print-on-demand service does request flattened files, I decided to try it. The cover looks very nice with one exception: the title on the back cover has faint lines around it as shown in the screen grab below. None of the other text has them. Can I fix this in the native file so they won't appear? Thanks
My guess is those are "stitching," the transparency flattening artifacts we've mentioned before, but I've never seen them in red before. These artifacts are the primary reason I've been telling you not to flatten if at all possible. They generally don't appear in high resolution prints like those on a press, but usually do show on digital output which is lower resolution. The only way you will know is to see a proof.
The only thing you can do to avoid these is to leave the transparency live (don't flatten).
Thanks, Peter, I'll quit trying to second-guess a problem that may end up not being a problem and order the proof. I appreciate all the patient help offered by you and the other forum experts.