What is PDF/X?

PDF/X is a subset of the Adobe Portable Document Format (PDF) specification that is intended to reflect best practices in graphic arts file exchange. PDF/X-1a restricts the content in a PDF document that does not directly serve the purpose of high-quality print production output, such as annotations, Java Actions, and embedded multimedia.

PDF/X-1a also eliminates the most common errors in file preparation. According to a GATF (Graphic Arts Technology Foundation) survey conducted in January 2002, among the 10 most common errors in client PDF files were the following:

• Fonts not embedded
• Wrong color space
• Images missing
• Overprint/trap issues

Sending your document as a PDF/X-1a file will guarantee that these errors do not occur because for a file to be confirmed as conforming to the PDF/X-1a standard:

• All fonts and images must be embedded
• All elements must be encoded as CMYK or spot
• The file must be identified as trapped or not trapped

In addition:

• MediaBox and TrimBox or ArtBox must be defined; BleedBox is optional
• The output intent* must be specified either by stating a Characterized Printing Condition or identifying an ICC output profile
  * The output intent identifies the press condition the file is prepared for, such as type of press, and inks and paper that will be used.

If you send PDF/X-1a compliant files, you will never again have to worry about being asked to supply missing fonts or images. You will never again have to be concerned about an image being converted from RGB to CMYK without seeing the results. Decisions about whether or not the printer should trap your file will be based on reliable information. And finally, the printer will know if the file was prepared properly for the press it is going to print on.

By adopting a PDF/X-1a workflow, not only will you gain the confidence that your print-ready files will reproduce as you intended, you will save time and money as well. Every document that is returned because it is not prepared properly requires additional time to correct. Additional time costs money, and either you absorb the cost or the client pays for it. Either way it is an unwanted expense that the adoption of PDF/X can greatly reduce and possibly even eliminate. Of even greater concern is the poorly prepared document that does not get returned. The failure to meet the client’s expectations may mean the loss of that client.

An Explanation of the Various PDF/X Standards

PDF/X-1a: 2003
PDF/X-1a: 2003 is a conformance level of the internationally accredited PDF/X standard. Based on PDF 1.4 it has been updated as follows:

• Transparency — partial transparency is prohibited. Although transparency may be used to create content, it must be flattened before converting the file to PDF/X-1a:2003 or PDF/X-3:2003.
• JBIG2 compression — is prohibited.
• Encryption — has always been and continues to be prohibited.

PDF/X-2:2003
PDF/X-2:2003 is a conformance level of the internationally accredited PDF/X standard. Specifically it is a superset of PDF/X-3:2002 because it allows for the use of device independent color spaces like Lab and those based on ICC profiles. However, unlike PDF/X-3, the exchange between sender and recipient is not blind. Communication between the various parties involved in the preparation of the file is required. Although there are a number of situations where PDF/X-2 may be beneficial, it is expected that its most common use will be in an OPI-like workflow. Content creators may gain more control over the file preparation process by creating a master file with referenced elements for their prepress provider, without having to take on the burden of storing and handling high-resolution images.

PDF/X-2:2003 is expected to be published shortly.

PDF/X-3:2003
PDF/X-3:2003 is a conformance level of the internationally accredited PDF/X standard. Like PDF/X-1a: 2003, it is based on PDF 1.4 and has been updated as follows:

• Transparency — partial transparency is prohibited. Although transparency may be used to create content, it must be flattened before converting the file to PDF/X-1a:2003 or PDF/X-3:2003.
• JBIG2 compression — is prohibited.
• Encryption — has always been and continues to be prohibited.

As a superset of PDF/X-1a it has the same requirements, however PDF/X-3 also allows for the use of device independent color spaces such as Lab and those based on ICC profiles, as well as CMYK.

NOTE: Both PDF/X-1a:2003 and PDF/X-3:2003 were approved by the International Standards Organization in May 2003, are published and available from NPES (www.npes.org).

NOTE:The newest versions of these standards (:2003) are only recently approved and published, and DDAP expects to see PDF/X products being upgraded to support these new versions shortly.