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Why does my text characters contain white holes or look wrong?


In most cases this is because of embedded fonts in the PDF file which are not following all the font rules resulting in unpredictable rendering and this not only in Esko application but also other 3rd party PDF consuming applications.

  • Fonts need to meet certain specifications concerning winding rules (basically they should look the same whether their outlines are filled using even-odd or non-zero winding rule).
  • Also the outline(s) of each character may not be self-intersecting.

The precise set of rules is more detailed (also different for Type 1 versus TrueType) but basically the previously mentioned two rules are a nice overall summary and also typically the ones which are violated.

If these specifications are not met, the rendering result will be unpredictable. A good example for this is Acrobat (you can use this to demonstrate that even in Acrobat you see unpredictable output for the customer file).

Example 1: When a character outline renders differently depending when it is filled with even-odd winding or non-zero winding: Zooming in or out in Acrobat will toggle between a correct rendering and a rendering where part (or fully) the character gets wrongly filled.

Example 2: When the outline(s) of a character is self intersecting. Then you can typically see white holes (which shouldn't be there) in Acrobat at a certain zoom level and when you change the zoom level (either zooming in, either zooming out) suddenly those white holes disappear:

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Applies to

Esko all software products



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