Understanding the version of PDF you’re creating

The export menu in programs like InDesign and Quark contains a compatibility version number that relates to a version of Acrobat. This is not about the version of Acrobat being used, but about the features available in the PDF.

If you look in the Export window, the first items to choose are the standard of PDF and the compatibility level. A standard set to “none” allows you to create your own settings. This gives you a choice of different Acrobat versions (4,5,6,7 and so on) and their respective PDF version (1.3, 1.4, 1.5, 1.6, etc). When you select one of the PDF/X standards, you will see that the compatibility changes to Acrobat 4 and PDF 1.3.

PDF 1.3 does not include transparent objects so everything is flattened when saving the PDF. It cannot handle things like monotones and duotones. OpenType font features are not available and neither are version layers. This is the version of PDF available in Acrobat 4. Choosing Acrobat 4 compatibility will give you a PDF that is flattened and has any features listed above removed or converted.

PDF 1.4 and 1.5 allow transparency to be flattened at the end of the process so this transparency remains in your PDF. This allows the best possible flattening for your artwork. Still, some OpenType features are not supported. These versions of PDF will remove or convert these features to make them compatible with Acrobat 5 and 6.

Acrobat 7 brought many changes to the PDF 1.6 level by adding OpenType features, better use of the DeviceN color space and optional content. Beware, not all of the rips out there today can properly produce these features in a PDF 1.6 – Acrobat 7 compatible file.

What does all of this mean when creating InDesign or Quark PDF files?

By understanding the features you are using and the level of PDF that can support them, you will get the best quality file output at the print stage. If you choose to flatten your own files, you run the risk of flattening things, like type, which can rasterize. What is worse, half the type rasterizes and the rest remains as type, making the final product more noticeable.

Another problem with flattening your own files is that they are practically impossible to fix after the fact. Prepress can do more with a transparent file. They are unable to unflatten a PDF and the original layout files will be required for any adjustments.

If you supply your PDF files in the PDF 1.5 format, the files can be flattened at the end of the process – after trapping and after imposing at RIP time. The RIPs do the best job of flattening as they are converting the colour and applying profiles. Be aware of the features that are not supported. If you are using OpenType features such us alternate glyphs you should check your PDF to see if all items have translated properly and be aware of any error messages when you check your file in Acrobat.
Not all RIPs that are running today can handle the special features of PDF 1.6. DeviceN, which is the “placeholder” colour space that InDesign and Quark use to keep items like gradients and colourized images separate from the other spaces before deciding how to flatten, has been increased from eight to 32 items and has caused some problems in non-Adobe RIPs.
Still, there are standards in place for specific workflows that require you to create postscript and distill or provide PDF/X standard files. These standards are in place for a reason. If your print provider allows you to send a PDF 1.5 file, exporting the file from InDesign is what is recommended by Adobe for the best quality file output. Ask your provider how they feel about exporting from Quark first.