So I have got the .ai file from our designer and I have to save it to a specific size to then be used on a website.

I have aligned all shapes to pixel raster (not sure if this is required) and I have changed the reference point to left-top (in order to avoid blur).
When saving for web I choose Optimize Art and I save it as a transparent PNG-24.

Now, why is there a mysterious, vague line next to one shape? When I look at it in Illustrator, that same line is visible, but when I zoom in you can see that the shape is perfect without the mysterious line.
In case it might help, the line is there from bottom to 50% of the shape (vertically), everything else is perfectly sharp.

What am I doing wrong?
I hope I used the correct terms, as my Illustrator is in a different language.

  • 3
    In the future, it would help if you posted the image. Or, better yet, post an AI file (it could just be a document with the problem area isolated). Dec 30, 2012 at 6:42
  • Check all your envelopes if exists.
    – user34627
    Dec 9, 2014 at 17:59

7 Answers 7


If you set the "X & Y" coordinates on your artboards to be an integer (a whole number like 10 instead of 10.234) I've noticed this fixes the problem. Also if you turn off the optimizing and anti-aliasing that can fix it too (though usually not recommended since it will give a more pixelated output).

Some of the other suggestions on this thread can work very well, but I've found the X Y solution to work the best for time and the least amount of fixing...just setup your artboards with whole numbers to begin with and you should have no problems, otherwise use one of the other solutions mentioned.

  • Wanna say thanks ! I pulled my hairs for hours with this issue. Your suggestion works great and is full of common sense.
    – TwystO
    Aug 3, 2018 at 9:42

Unfortunately, this is standard for Illustrator. There's quite a few situations where the pixel accuracy of Illustrator's shape rendering, antialiasing and gradient rendering aren't on par with Photoshop, Fireworks and other apps.

I'd recommend using Photoshop or Fireworks. If possible, move the objects over and export from there.

I've written more about the topic here: Illustrator and app design

  • So I thought I had it fixed, but then another line appeared somewhere else. I have already tried importing it as a smart-object to Photoshop, it is the first thing I tried; but it had the same effect. I must be doing something wrong, or is it the system I am working on? Thanks for the link, I will not save images using Illustrator again.
    – Xen
    Jun 16, 2012 at 17:23
  • Smart Objects in Photoshop CS5 have similar antialiasing and dithering issues. Photoshop CS6 has some fixes when dealing with Smart Objects from Illustrator, but they're still not perfect. If you can, you'll be best pasting into Photoshop as a shape layer and colouring in PS. Jun 17, 2012 at 0:51

I've heard lots of complaints about this but my team and I have had very few issues.

I occasionally run into stray anti-aliasing pixels. In those cases, simply dragging the object off the artboard then repositioning solves it.

This approach has worked for me since CS3. Though I haven't personally tried it in CS6 one designer I work with uses 6 primarily and has had no issues I've noticed.

  • Dragging the object off the artboard then repositioning is a terrible work around for ~$1000 software. Have you sent feedback to Adobe? Dec 30, 2012 at 8:57
  • Yeah, I've expressed my concern. I use Adobe's apps just about every day and I'm pretty good with them. But that doesn't prevent me from dreaming of their demise on a regular basis. I'd rather have bugs fixed than fancy new features but they haven't operated that way for a long time. Dec 30, 2012 at 22:20

To avoid this create a new Illustrator file, then copy your vector image to this new file and save.


I have suffered with this issue many times using CS5, especially with 72dpi web graphics.

Usually, I nudge shapes up or down a pixel or two and try Ctrl + shift + alt + S to preview, then keep trying this until the lines are no more. Problem is I know web graphics are pixel sensitive, sometimes you can't afford to move a single part of the illustration while leaving the others, pixel alignment as you know is important, but i have to compromise sometimes because it gets so fking annoying.

I also found that outlining text solve this issue many times.


Click New document...Check "Align new objects to pixel grid"...it worked for me

  • Hi Cope, welcome to GDSE and thanks for your answer. If you have any questions, please see the help center or ping one of us in the Graphic Design Chat once your reputation is sufficient (20). Keep contributing and enjoy the site!
    – Vincent
    Oct 27, 2015 at 15:11

I have been using CS5 for a number of years and don't recall ever running into this problem before. The part of my design that is "streaking" with the small random white lines is a simple silhouette I used live trace on. It was not occurring on any of the other objects in my design. A simple web search brought me here and I tried a few of the suggestions without any success. Then I thought to try layering the silhouette by simply copying it and aligning another identical layer behind it. This has proven successful for my project, thought I would share my experience.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.