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.
In order to overcome these limitations new technologies are required in the preflight tools which allow checking objects in relation to other objects on the page. The order of multiple overlapping objects also plays an important role.
This allows for the first time to solve these tasks:
- Check of overprinting objects in relation to underlying objects
- Check of the contrast of overlapping objects
- Check of the minimal distance of objects (e.g. distance to cutline, bleed)
- Check if objects are masked or (partially) covered by other objects
- Check visible objects only
- Remove invisible objects
- Restrict checking to objects inside a contour (e.g. cutline)
This feature could have been a big help in my PDF/X-4 project for Novartis Pharma since I wanted to exclude administrative information from preflight which are often placed outside the cutline in packaging files. We had to ask the creators to add Trim- and BleedBoxes around the cutline which doesn’t really make sense for folding cartons.
The most frequently used preflight tool is Adobe Acrobat Pro. Since Adobe uses the preflight technology from Callas in Acrobat I hope that Adobe will also include the «Sifter» technology in future Acrobat versions and thus allow (almost) all users to benefit from much better preflight checks!