Twenty years of PDF/X
From PostScript to PDF/X – the development of PDF standards and their influence on the printing industry
What does PDF have to do with graphic arts and the printing industry?
The 20th anniversary of the first ISO PDF/X standard at the beginning of 2021 can be used as an opportunity to take a closer look at the development of PDF/X. What did the path to today’s PDF/X standard look like and what has also influenced the development of other PDF-based standards accordingly?
Start of Adobe PostScript 1984 – From PostScript to PDF/X
The development of PDF/X began with the announcement of Adobe PostScript in 1984, which was of course closely linked to the development of printers and the changes in the printing industry that were taking place at the time. The innovative and unique thing about PostScript at that time was that in its purest form it was neither vendor nor device specific and brought with it a full range of integrated, sophisticated graphics operators. Files for graphics and printed pages were created in PostScript format to make it possible for them to be printed reliably and without loss on the various output devices, i.e. printers.
Although PostScript is considered a page description language, it is also a stack-based, fully interpretive programming language with built-in mathematical functions. As a kind of general-purpose programming language, accounting applications and games, for example, can be written in PostScript.
So, above all, PostScript offered a great deal of flexibility, but it was not without its problems. PostScript was not page-independent, for example, and there were difficulties if you wanted to reprint individual pages or the like. In addition, PostScript was often bound to certain devices in practice.
The 90s: Elaboration and improvement of PostScript
John Warnock is considered the founder of Adobe, along with Charles Geschke, who died in April 2021. He recognised the strengths of PostScript for publishing and worked on his vision of Interchange PostScript (IPS), removing the high overhead and lack of deterministic behaviour of a general-purpose programming language and adding full page independence. Further developments in this area finally led to the birth of the Portable Document Format (PDF) and the first version of Acrobat in 1993.
The search at that time was for a viable alternative to PostScript to be considered not only for screen display of graphics but also for print output. The first PDF version (PDF version 1.2 (Acrobat 3.0, end 1996) developed out of this need. In contrast to PostScript, PDF had a number of advantages. These included page independence, device independence including external print job control. It is also suitable for long-term archiving of content as well as for corrections and edits.
PDF/X advantages in terms of functionality, reliability and performance
As a result, the printing industry also became aware of PDF and the PDF/X standard was developed, as the PDF format posed a challenge for print publishing, especially when the PDF specification increased in size and complexity.
All parties involved were looking for a way to “blindly exchange” PDF files for print output. It should be guaranteed at all times that all files could be printed without errors and post-processing at the recipient. So the first PDF/X-1 standard was developed and published in 1999. X here stands for “blind exchange”. PDF/X was then further developed as a multi-part ISO standard 15930.
The aim of the various parts of ISO 15930 was to maintain the required degree of flexibility while minimising uncertainty. Of the two conformance levels of ISO 15930-1:2001, PDF/X-1a has been particularly successful and popular due to its relative simplicity and ease of use. And this was the case with print publishers as well as publishers and print service providers, as PDF/X-1a was particularly reliable as a carefully crafted PDF subset and could significantly improve the complete publishing workflow.
The PDF/X standards continued to evolve after PDF/X-1a gained strong acceptance and the changes that were also occurring in the world of print needed to be addressed. The need for newer, more advanced PDF/X standards was there.
Further developments after PDF/X-1a
Adobe PDF 1.4 finally introduced solid support for live object transparency, which was an important demand from the creative industry. Adobe PDF 1.5 added JPEG 2000 image compression and optional content groups (with layer support and other advanced features) as well as object streams and their compression. With the ISO PDF 2.0 specification, official support for black point compensation was then added. You can read more about this in the highly recommended four-part series of articles by the PDF Association, which describes the 20-year development of PDF/X in detail:
The future of printing technology
Digitalisation may have given the impression that the printing industry will no longer play a major role in the future. But this is a fallacy. Certainly, the nature of printing and the things that are printed have changed massively. The modern way of printing compared to printing 20 years ago is technically much more sophisticated and serves different purposes. Nevertheless, printing technology is still needed and the printing industry continues to evolve.
In the third part of the series of articles about PDF/X on pdfa.org, author Dov Isaacs brings several concrete examples of what today’s print jobs look like and what this means for PDF/X:
20 years of PDF/X – Important lessons learned – What can be improved in the implementation of standardisation?
Victory and defeat are sometimes close together. There have been some important successes within the 20-year history of PDF/X. At the same time, there have been problems in the industry and in the standards development process.
On the one hand, the reliability of the end-to-end publishing process has improved significantly with the use of PDF/X standards, especially when using the most appropriate version of PDF/X for the content and production requirements. For content with colour and/or transparency effects, for example, using a PDF/X-4-based workflow generally produces more reliable and consistent results than a PDF/X-1a-based workflow. It turns out that careful definition and use of well-defined subsets of the PDF specification can greatly optimise many workflows. An example of this is PDF/A for archiving. On the other hand, PDF/X standards have unfortunately been slow to be adopted, ultimately causing the printing industry to suffer.
Many factors can play a role in the slow acceptance of PDF/X-4 or PDF/X-6:
It has happened that the use cases presented by the developers of the standards had little to do with real customer needs in reality. In addition, as in many other industries, outdated processes are often retained or there is a lack of good documentation and training. It is also clear that print service providers and print associations should play an active role in ensuring that new standards are more widely adopted.
It is important to bring the two perspectives and experience together. Both technology experts from the industry who develop the standards and the manufacturers or the product managers of the manufacturers should sit at the same table. After all, the most important thing is that the standards are ultimately implemented in products. In addition: the suppliers and printing associations should also be trained in the technical background.
You can find out more about the PDF/X sub-formats in Part 2:
More on the developments around PDF/X: