White lines appearing on exported PDFs

[AllApp100]

Hello, in the last week I have begun to notice white lines and boxes appearing in my PDFs exported from Adobe Indesign, as well as things like drop shadows, feathers and gradients being replaced with solid white or black boxes. Sometimes these lines and boxes print, other times they dont. This is a new developement just in the last few days, but I can't figure out what, if anything, has changed with the program or the way I'm exporting. Anyone have any ideas?

  

[BobLevine · Accepted solution]

Stop exporting to PDF/X-1a and use PDF/X-4 or any other setting that exports at Acrobat 5 or later.

[Mary Tack050823]

What do you recommend setting the export files on so they are print ready and don't get these lines?

[BobLevine]

The same thing I recommended 2.5 years ago.

[rob day]

Hi @Mary Tack050823 , Is your print provider requesting PDF/X-1a? Many online printers do. Stitching artifacts are caused by low res display anti-aliasing and would not print from a hi-res RIP where there would be no anti -aliasing needed.

In Acrobat you can hide the artifacts by changing the Anti-Aliasing preference—uncheck Smooth line art in the Page Display Preferences.