The PDF file format can’t directly support variable data printing. This should start to change with the introduction of PDF/VT input and APPE 2 output.

Digital print pre-press workflows need to have some provision for handling variable data, even if it’s only for outputting pages in collated order. The weak point of the platesetter workflows discussed on previous pages is that they were built for static images and don’t understand variable data.

This is starting to change as their developers address digital print as a serious part of their potential business, although most of the links so far on the market will simply ‘pass through’ any variable components to the dedicated DPE components and hope that they know what to do with it.

You can create and print documents in variable data friendly formats such as PPML, VIPP or AFP, but these were largely invented for the needs of high volume transactional print and don’t support the aesthetic bells and whistles of modern design programs, notably transparency. PDF and its predecessor, PostScript, which have dominated commercial print pre-press for 20 years, were never designed for variable data. Something better is needed to marry up the creative design and variable requirements more happily. The forthcoming PDF/VT (for Variable Transactional) may well be the answer.

As Adobe migrated its page – print strategy from PostScript to PDF, so the pre-press developers followed, moving from the CPSI PostScript Rips and adopting the Adobe PDF Print Engine (APPE) from 2006 onward. Global Graphics beat it to the punch, moving its Harlequin server to native PDF processing long before APPE appeared.
Native PDF processing allows very late changes to impositions, meaning that jobs can be switched fairly easily between presses at a very late stage if needed. This also allows easier switching between offset and digital output, or mixed jobs that start on digital for fast delivery or market and then move to offset for bulk long runs. However, that lack of variable data support is the Achilles heel, meaning that variable elements are passed through separately to the DPE.

On the creative side, native PDF processing allows direct output of transparency within design created on Adobe’s InDesign layout program. APPE can handle transparency without flattening, which means less potential for errors such as banding, or sharp edges on drop shadows. It also helps with the late changes aspect: if you flatten a file you are rendering it and freezing its resolution. Digital presses and offset platesetter work to different resolutions so flattening for one may not work for the other.

To be continued…

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