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I am using Illustrator CS2 and I am trying to create a sharp circle. Nothing I do works though. My circles are blurred, mostly noticeable on the top, bottom, left and right edges. Example:

enter image description here

I understand that the picture showing above is a PNG, but it looks the same on my screen in Illustrator. Maybe some of my settings are not optimal? Any advice?

  • Your circles "are" not blurred, they are drawn blurred. Your screen resolution is not high enough to draw the circles 'mathematically perfect' - which is impossible on a screen which uses square or rectangular display elements. – usr2564301 Jun 27 '15 at 10:50
  • Thanks for your reply. It doesn't explain why I still can see sharp and unblurred circles on numerous logo's, pictures, etc. though ;) – alstack Jun 27 '15 at 15:04
  • can you post an example of a unblurred logo, Also note that one sided antialiaing edge is easier than the one produced on 2 edges simultaneously.. Mind tough adobe isn't really the king when it comes to doing signal processing. Anyway make sure you use art optimized antialiasing in the save for web dialog. second aim for exact pixel edges. In general antialiasing is a tradeoff between ringing and blurring – joojaa Jun 27 '15 at 15:49
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Here is an attempt to reproduce your picture with Inkscape, which uses a different rendering and PNG-conversion engine, as far as I know:

enter image description here

I would guess that you would consider this to exhibit the same problem as your example pictures. If I am correct, this indicates that your problem is probably not related to you using the wrong options but rather to inevitable shortcomings of pixel displays.

Now, here is a similar picture with all circles being arranged such that they fall exactly into the pixel grid, in particular they are an integer number of pixels wide and some circles are slightly moved such that the relative position of their outer borders to those of the outer circle is an integer number of pixels:

enter image description here

I assume that you consider this image better (though probably not perfect) with regard to your issue. However, if you take a look at the two innermost circles, you probably notice that they are not perfectly concentrical anymore (if you don’t, let me tell you that I notice and find it irritating).

If find the latter issue illustrative of the general trade-off one has to make when rendering graphics such as yours, namely between:

  • Rendering each line as crisp as possible.
  • Keeping the relative positions of lines and sizes of objects as close to the vector data as possible.
  • Keeping the size of the image.

Apparently, Inkscape and Illustrator chose to make this trade-off too much in the direction of the second point for your taste. But for somebody else or another graphics, this choice may be the best one. After all, the rendering engine is only a stupid program and cannot read your thoughts. If you want to tilt the above trade-off, you have to do things manually to some extent or use a software that allows you to instruct it how you prefer things to be rendered (I will come back to this at the end).

Let me give another more drastic example. Here is a 301 pixel-wide rendering of a vector graphics of 56 equidistantly arranged lines.

enter image description here

As 300 is no multiple of 55, the rendering software has to choose between blurring some lines or destroying the equidistancy. The only way to avoid both is to stretch the image to 331 pixels:

enter image description here

Let me finish by saying that there is a type of software that allows you to instruct it how you prefer things to be rendered: fonts or font renderers, respectively. Fonts can store information (so-called hints) about how glyphs should be rendered (e.g., where stems of letters are), which allows font-rendering softwares to produce the good results they do nowadays. But this only works because we humans have clear preferences as to how we want text to be rendered (and there are far fewer issues that can arise with text than with vector graphics in general). For example a good standard m is rendered such that all its stems fall on pixels and the distance between the stems are equally wide – at the expense of making the letter significantly wider or narrower than it would be according to the underlying vector data.

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Have you tried creating this with Illustrator set to align paths to pixels? (Assuming CS2 allows this, of course.)

Rather than rehash it here, this page does a great job of explaining how to do this: http://medialoot.com/blog/3-valuable-pixel-perfect-illustrator-techniques/

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  • Thanks for the reply! I'm afraid CS2 doesn't have all the options described in the blog. Thanks again though! – alstack Jun 27 '15 at 11:11
  • @alstack: Still, it's the correct answer. The old Illy CS2 (and older versions) is a very much a vector drawing application, and as such it does not have the option to align on "pixels" (which I consciently "quoted" because the question would then be "what pixels"). – usr2564301 Jun 27 '15 at 15:35
  • @alstack make grid with 0,5 pixel increment and ypu have something better. – joojaa Jun 27 '15 at 22:01
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This happens because circle or ellipse contains varied angles of paths to complete its shape unlike the square which contains only flat horizontal and vertical paths to complete its shape.

The solution I have come with is to Align the Stroke, go to the Stroke Panel or hit Ctrl+F10 make sure your shapes are selected containing the strokes then go to Align Stroke: you will see the Align Stroke to Center is selected by default change it with either Align Stroke to Inside or Align Stroke to Outside according to your preference.

Here is my PNG image of the almost sharp circle using Align Stroke to Outside




enter image description here



Note: Always draw your shapes using the round and complete values such as 200x200 or 273x273 and avoid values like 200.5x200.5 or 273.5x273.5 this is one of a reason behind why we get shapes with blurry edges instead of the sharp and crisp output.

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  • Thanks for your reply! Unfortunately, it's still blurry.. Straight lines even don't look really sharp. Thanks for the effort though! – alstack Jun 27 '15 at 15:05
  • @alstack No problem I knew that was not completely a sharp output, well the real solution rests in the hands of the Illustrator development team at Adobe. They seriously need to improve their algorithm for rendering paths to output at an optimal level even if it is only 1 pixel – Lightcoder Jun 28 '15 at 1:26
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Under view make sure pixel preview is not checked. Also, i think you can alter how a image renders.

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