Which PDF/X should I use?
Somebody asked me recently what the difference is between PDF/X-1a (first published in 2001) and PDF/X-4 (published in 2010). I thought this might also be interesting to a wider audience.
PDF/X-1a content must all have been transformed into CMYK (optionally plus spots) already, so it puts all of the responsibility for correct separation and transparency handling onto the creation side. When it hits Harlequin, all the RIP can do is to lock in the correct overprint settings and (optionally) pre-flight the intended print output condition, as encapsulated in the output intent.
On the other hand, PDF/X-4 supports quite a few things that PDF/X-1a does not, including:
That moves a lot more of the responsibility downstream into the RIP, because it can carry unseparated colors and transparency.
Back when the earlier PDF/X standards were designed transparency handling was a bit inconsistent between RIPs, and color management was an inaccessible black art to many print service providers, which is why PDF/X-1a was popular with many printers. That’s not been the case for a decade now, so PDF/X-4 will work just fine.
In other words, the choice is more down to where the participants in the exchange want the responsibility to sit than to anything technical any more.
In addition, PDF/X-4 is much more easily transitioned between different presses, and even between completely different print technologies, such as moving a job from offset or flexo to a digital press. And it can also be used much more easily for digital delivery alongside using it for print. For many people that’s enough to push the balance firmly in favour of PDF/X-4.
Global Graphics Software develops innovative core technology that is used by manufacturers and software developers in digital printing solutions. An expert in PDF since the early days of the format, Global Graphics has always taken an active role in industry standards setting bodies and associations and today, our Distinguished Technologist …Read more
Martin Bailey has worked on PDF subset standards since 1994, starting with PDF/X in CGATS and then in ISO. He’s currently the UK’s primary representative to the ISO PDF/X and PDF/VT committees, amongst others. He’s project editor for PDF/VT-3 and chair of the PDF Association’s PDF/VT TWG. In his spare time he’s CTO for Global Graphics Software, and product manager …