What is PDF/X file?

PDF/X is an ISO 15930 standard published in 2001 with a subset of PDF functionality. The standard was established and published based on specific requirements of the printing and publishing industries. The requirements for this standard were all devised as per the diverse needs of printing and publishing industries. PDF/X requires the conforming files to be complete i.e. self-contained. This requires that elements like fonts used in the page should be part of the document. Contents such as 3D or video cannot be a part of PDF/X document. The information contained in PDF/X document requires it to be accurate.

PDF/X Standards and Revisions

The PDF/X family of standards comprises of several versions, each designed for a specialized result. The development of these standards were aimed to address the many diverse needs of the printing and publishing industries.

  • PDF/X-1a - Also known as the first standard of PDF/X family, PDF/X-1a requires all contents to be part of the PDF document in order to be able to be printed. Document elements such as fonts, forms, password protection, and visible annotations are not allowed. PDF/X-1a has its own specific requirements as well such as those pertaining to transparency and layers are permitted. These also require print elements to use only CMYK, greyscale or spot colours, resulting in no use of RGB or device-independent colour spaces.  is for exchanges in which all files are to be delivered in CMYK (and/or spot colors), with no RGB or colour-managed data. PDF/X-1a is also referred as Complete Exchange due to the completeness of information required by
  • PDF/X-3 - was introduced in 2002 and lifted many restrictions of PDF/X-1a. This enabled graphics in a PDF/X-3 to use CMYK, grescale, RGB, Lab and ICC based colour spaces. It is actually based on PDF standards 1.3 with ICC profile. It is also referred as Color Management due to the flexibility and rules it introduces related to colours included in a PDF document.
  • PDF/X-4 - supports transparencies, so PDF-X/4 contains all data required for output without flattening.
  • PDF/X-5 - is based on PDF/X-4, adding support for external graphics via reference XObjects, as well as external n-colorant profiles for rendering intent. Use it for partial exchange of printing data using PDF version 1.6

References