Sustainability of Digital Formats
 Planning for Library of Congress Collections

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PDF/X, PDF for Prepress Graphics File Exchange

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name 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. The aim is for a digital content file that will run through prepress without requiring rework or causing errors and be printed predictably and correctly whether it is a single print job or a magazine ad placed in many publications and printed across the world. For simplicity, the description here currently focuses on the 2003 versions of the PDF/X standard, based on Adobe PDF version 1.4. For most purposes, the discussion applies also to the first versions of the PDF/X standard, based on PDF 1.3. There are plans to bring out updates in 2006 based on PDF version 1.6.

PDF/X restricts the content in a PDF document, prohibiting elements that do not directly serve the purpose of high-quality print production output, such as annotations, Java Actions, and embedded multimedia. PDF/X also eliminates the most common errors in file preparation. Profiles 1a and 3 are intended to support "blind" exchange of graphics files with all elements within a single file. Profile 2 is less constrained but assumes that the two parties share information through other means.

Constraints for blind exchange include:

  • All fonts and images must be embedded
  • Boxes that specify the print and trim areas must be explicitly defined
  • Trapping status must be explicit. [Trapping controls overlap of elements in different layers and applied through separate printing processes; a small degree of overlap is desirable to allow for imprecise registration in the printing process. Trapping can be applied before or after exchange; but should not be applied more than once.]
  • Colorspaces must be specified in a device-independent manner
  • Encryption is disallowed in all PDF/X files compliant with 2003 versions of the standard.
Production phase A middle-state format for exchange during prepress activities. Serves as a final-state digital format to the extent that it is used for online proofing prior to printing.
Relationship to other formats
    Subtype of PDF, PDF, (Portable Document Format)
    Subtype of PDF_1_4, PDF Version 1.4
    Has subtype PDF/X-1a_2003, not yet described.
    Has subtype PDF/X-3_2003, not yet described.
    Has subtype PDF/X-2_2003, not yet described.

Local use Explanation of format description terms

LC experience or existing holdings None.
LC preference The Library of Congress Recommended Format Statement (RFS) includes PDF/X as a preferred format for textual works in digital form, electronic serials, digital musical compositions, and accompanying image/text files for digital audio. The RFS also includes PDF/X as an acceptable format for other graphic images - digital. The RFS does not distinguish between PDF/X profiles but LC will likely prefer those intended for blind exchange.

Sustainability factors Explanation of format description terms

Disclosure Open standard. Prepared by Technical Committee ISO/TC 130, Graphic technology, in collaboration with the United States national body Committee for Graphic Arts Technologies Standards (CGATS) with administrative support from NPES. NPES is a trade association of over 400 companies which manufacture and distribute equipment, systems, software, supplies used in printing, publishing and converting. The standard is maintained by CGATS Subcommittee 6 Task Force 1.

ISO 15929. Graphic technology - Prepress digital data exchange - Guidelines and principles for the development of PDF/X standards.

Specific PDF/X profiles (including the subtypes noted above) are documented in separate parts of ISO 15930.

Adoption Many magazines and journals require that all advertising materials be submitted as PDF/X or TIFF/IT files. As of Spring 2005, it appears that PDF/X is typically preferred over TIFF/IT. According to February 2005 minutes of the Subcommittee maintaining the standard, most use is technically based on the PDF/X versions published in 2001. Acrobat 7 from Adobe will create PDF/X files using the 2003 versions of profiles 1a and 3.
    Licensing and patents See PDF.
Transparency Depends upon compliant software tools to read. Building tools requires sophistication. Encryption is prohibited in the three profiles of PDF/X published in 2003.
Self-documentation Support for embedding any form of metadata for a document is extremely good. XMP metadata packages can be embedded.
External dependencies PDF/X profiles intended for "blind" exchange are constrained to avoid external dependencies. All necessary fonts must be embedded.
Technical protection considerations Encryption is prohibited in the three profiles of PDF/X published in 2003.

Quality and functionality factors Explanation of format description terms

Still Image
Normal rendering Good support.
Clarity (high image resolution) Excellent in professional tools. Third-party PDF viewers may not be able to take advantage of features intended to ensure high-quality print output.
Color maintenance Excellent in professional tools. Third-party PDF viewers may not be able to take advantage of color management features intended to ensure high-quality print output.
Support for vector graphics, including graphic effects and typography Excellent.
Functionality beyond normal rendering Annotations may be embedded. Bookmarks may be provided.
Normal rendering See PDF.
Integrity of document structure See PDF.
Integrity of layout and display See PDF.
Support for mathematics, formulae, etc. See PDF.
Functionality beyond normal rendering See PDF.

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension pdf
Assumed. The standard does not indicate that a different extension should be used to distinguish PDF from PDF/X.
Wikidata Title ID Q1423339

Notes Explanation of format description terms

General The PDF/X standard is aligned to the fullest extent possible with the PDF/A standard.

Format specifications Explanation of format description terms

Useful references


Last Updated: 12/15/2016