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PDF/X is an umbrella term for several ISO standards that define a subset of the PDF standard. The purpose of PDF/X is to facilitate graphics exchange, and it therefore has a series of printing related requirements, which do not apply to standard PDF files. For example, in PDF/X-1a all fonts need to be embedded and all images need to be CMYK or spot colors. PDF/X-2 and PDF/X-3 accept calibrated RGB and CIELAB colors, while retaining most of the other restrictions of PDF/X-1a.
The printing conditions or output intent need to be specified in the file. This can be specified in the form of standard profiles using codes, like "CGATS TR 001 SWOP".
In a PDF/X file that has color managed data each color managed graphic gets its own color profile, so even though the file as a whole is CMYK, individual graphics may be RGB (with calibration information).
Various boxes must be defined. The MediaBox which defines the size of the entire document, either the ArtBox or the TrimBox, which define the extent of the printable area. If the file is to be printed with bleed, a BleedBox, which must be larger than the TrimBox/ArtBox, but smaller than the MediaBox, must be defined.
Active content is not allowed in a PDF/X file. This means that standard PDF features like forms, signatures, comments and embedded sounds and movies are not allowed in PDF/X. Features that are forbidden in the PDF/X standard can sometimes be used, if they do not affect the rendering of the file. This allows for things like annotations outside of the BleedBox.
List of the PDF/X Standards
PDF/X is formalized in ISO Standard 15929 and 15930:
- ISO 15929 (which was withdrawn in March 2008 and no longer is an official standard) specifies the guidelines and principles for the development of PDF/X standards.
- ISO 15930 defines the specific implementations:
- ISO 15930-1:2001: PDF/X-1a:2001, Blind exchange in CMYK + Spot Colors, based on PDF 1.3
- ISO 15930-2: PDF/X-2, was never published.
- ISO 15930-3:2002: PDF/X-3:2002, Allows CMYK, Spot, Calibrated (managed) RGB, CIELAB, with ICC Profile, based on PDF 1.3.
- ISO 15930-4:2003: PDF/X-1a:2003, revision of PDF/X-1a:2001 based on PDF 1.4
- ISO 15930-5: PDF/X-2, An extension of PDF/X-3 which allows for OPI-like (external linked) data to be included
- ISO 15930-6:2003: PDF/X-3:2003, revision of PDF/X-3:2002 based on PDF 1.4
- ISO 15930-7:2008: PDF/X-4, Colour-managed, CMYK, gray, RGB or spot colour data are supported, as are PDF transparency and optional content. A second conformance level named PDF/X-4p may be used when the ICC Profile in the output intent is externally supplied.
- ISO 15930-8:2008 PDF/X-5,a collection of three conformance levels:
- PDF/X-5g: An extension of PDF/X-4 that enables the use of OPI-like workflows.
- PDF/X-5pg: An extension of PDF/X-4p that enables the use of OPI-like workflows in conjunction with a reference to an external ICC Profile for the output intent.
- PDF/X-5n: An extension of PDF/X-4p that allows the externally supplied ICC Profile for the output intent to use a color space other than Grayscale, RGB and CMYK.
- ISO 15930-1:2001 is adopted
- PDF/X-1 and PDF/X-1a become an international standard
- NPES & ISO members worldwide
August 2, 2001
- 1st PDF/X-1a advertisement (test run - not printed)
- Time Magazine, LTC/Vertis and McCann-Erickson
August 24, 2001
- 1st PDF/X-1a printed advertisement
- Dirt Rag Magazine
- Scott Tully
- LTC Group/Vertis
September 4, 2001
- SWOP PDF/X-1a calibrate kit released
- DDAP, SWOP, Western Laser, Quality House of Graphics, Apago
- 16 pages of editoral and 100% of ads in PDF/X-1a format
- Dragon issue #291
- John Dunn - Wizards of the Coast
January 29, 2002 (release date)
- 1st 100% PDF/X-1a publication
- Dragon issue #292
- John Dunn - Wizards of the Coast
- The PDF/X-4 file format
- For Position Only: The PDF/X Files
- What's going on with the PDF/X standards in 2003?de:PDF/X