You can optimize PDF files for different versions of Adobe Acrobat or Acrobat Reader by choosing a compatibility option that matches the type of viewer used by the recipients of the PDF file. In Corel DESIGNER, you can select one of the following compatibility options: Acrobat 4.0, Acrobat 5.0, Acrobat 6.0, Acrobat 8.0, Acrobat 9.0, PDF/X-1a, PDF/X-3, or PDF/A-1b.The available controls differ, depending on which compatibility option you choose. If you are publishing a PDF file for a wide distribution, it is better to choose an earlier compatibility option such as Acrobat 8.0 or 9.0 to ensure that the file can be viewed in earlier versions of Acrobat. However, if security is a concern, you may want to choose a later version because the encryption levels are higher. For more information, see PDF security options.
You can optimize the viewing of a PDF document on the web to speed up the loading time of the PDF.
If you added complex fills to the document, you can choose to convert them to bitmaps, which is also known as rasterizing. This may increase the PDF file size, but it will ensure that the complex fills display correctly.
To preserve layers and layer properties in the published PDF file, you must choose the Acrobat 6.0, Acrobat 8.0, or Acrobat 9.0 option. Note that master layers will not be preserved.
To preserve transparencies in the published PDF file, you must choose the Acrobat 5.0, Acrobat 6.0, Acrobat 8.0, or Acrobat 9.0 option.