While trying to save an ai (illustrator) file to pdf, the blur portion of drop shadow lost and it looks blocky. Please look at the screen shot of pdf below: enter image description here

You can see that the blurred portion of drop shadow becomes solid color and even becomes block at SEVEN word. But if I reopen the pdf in illustrator, the blur looks ok.

Why this is happening and how to resolve this issue?

  • I can't replicate the problem with Illustrator CC and viewing with Adobe Acrobat Reader. Which version of Illustrator are you using? Which PDF viewer are you using? Have you tried using Adobe Acrobat Reader? How did you make the drop shadow in Illustrator? Did you use a drop shadow effect or another method? What are your PDF export settings?
    – Billy Kerr
    Nov 7, 2019 at 17:33
  • I am using illustrator cc 2017 and then saving the ai file as pdf. My pdf viewer is Nitro pro 8 or 9. I applied drop shadow from Effect>Stylize>Drop Shadow with a 0.02in blur settings. If I set the blur to 0 (zero), then the Letters are ok. But if I set blur of the drop shadow settings, blurring area changes to solid color after saving as pdf. Hope you have understood. Nov 7, 2019 at 18:31
  • Try using Adobe Acrobat Reader to view it.
    – Billy Kerr
    Nov 7, 2019 at 18:40
  • Try another pdf viewer
    – joojaa
    Nov 8, 2019 at 5:56
  • 1
    That is right! Opening the same pdf by even higher version of Nitro Pro shows the drop shadow and blurs correctly. Thank You all! If you answered my question in a separate comments, I could accept one of your comments. Nov 8, 2019 at 8:59

1 Answer 1


Transparency effects like drop shadows, multiply, <100% opacity, etc., still cause issues with some PDF formats. Try saving to PDF using the PDF/X-4 preset.

  • PDF/X-4 preset does not resolve the issue. Nov 7, 2019 at 18:33
  • Well, a PDF X-4 is not a preset, is a specification where you can potentially define many presets on how to treat your images and elements inside the PDF.
    – Rafael
    Nov 9, 2019 at 13:31
  • When exporting a pdf from Illustrator or Indesign, the various PDF/X specifications are saved as a set of presets that you can select from the "Presets" dropdown list.
    – 13ruce
    Nov 10, 2019 at 21:04

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