In a podcast (27:42) at Podcasts from the Printerverse David Zwang, Chairman of the Ghent Workgroup (GWG), shares some trends he is seeing in the industry, and how the Ghent Workgroup is developing new possibilities with PDF 2.0 to help printers and designers optimize their production files in conjunction with evolving digital print technology.
I wrote an article entitled How PDF changed prepress production dramatically in the last 25 years for the recently launched blog from Callas Software.
The latest updates of the most important preflight tools (Enfocus PitStop and Callas pdfToolbox) feature new technologies which allow to substantially leverage the quality of preflight checks. We had to wait long time for such possibilities!
Until now preflight tools could only check for properties of single isolated PDF objects. The classical example is black text which is not overprinting. A corresponding check has also issued an error message if the black text was not placed on top of a color background but over the paper white. In this case it’s irrelevant if the text is overprinting or not! This created a lot of unjustified error message (false positives) which was irritating for the user. This has often led to ignore serious error messages. This is a big problem with the preflight profiles of the Ghent Workgroup and PDFX-ready since they feature many overprint checks.
In the past preflight also checked invisible objects which were masked or covered by other objects.
A restriction of the objects to check was only possible with the page geometry boxes (e.g. BleedBox, TrimBox). A restriction of the preflight to an arbitrary contour (e.g. cutline) was not possible.
David Zwang, Chairman of the Ghent Workgroup (GWG), talks at WhatTheyThink about the role of PDF in packaging as it moves digital. The organization has developed the PDF Processing Steps specification which is on its way to becoming an ISO standard that includes not only the file components but a standardized way to communicate embellishments and other aspects of packaging production to enable increased automation.
In the last survey I have asked for your preferred PDF format. The result is interesting. Almost forty percent prefer PDF/X-4. That’s very encouraging!
Alarming is the fact that 22% have voted for PDF/X-3. This format was orginally ment for media neutral PDF/X files using ICC source profiles. But this does not work any more with InDesign as soon as a page contains transparency. Since transparency is not allowed in PDF/X-3, InDesign must flatten transparency before exporting the PDF file. For this all objects on the page (regardless if they are involved in the transparency or not) are first color converted into the transparency blend space (document CMYK). During this operation the media neutral colors get lost (e.g. for ICCbased RGB images).
For layouts with transparency (which is very common these days) PDF/X-3 cannot be used. These was one of the reasons that we have published the ISO standard PDF/X-4 in 2008.