Hello, I have seen an issue similar to this for EPS files, or for InDesign, but no answers from Ai CS6. When my students turn in projects, I have them turn in PDFs (for storage constraints), and frequently there are white "stitching" lines that show up in the PDF file (and then in prints that are made). I have tried modifying the PDF options when saving. I have tried expanding objects. I have tried a myriad of loosely related options that have been suggested on the forum.
This issue mostly (but not always) occurs when an object has been Image Traced. Is there an image trace option that I have missed?
Thanks for all of the help! My students work so hard, and I want to show their artwork.